SemaStmt.cpp revision de344bdcfd849680f534721f8029e6afc58f869c
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 CallExpr *CE = dyn_cast<CallExpr>(E)) { 97 // If the callee has attribute pure, const, or warn_unused_result, warn with 98 // a more specific message to make it clear what is happening. 99 if (const Decl *FD = CE->getCalleeDecl()) { 100 if (FD->getAttr<WarnUnusedResultAttr>()) { 101 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result"; 102 return; 103 } 104 if (FD->getAttr<PureAttr>()) { 105 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure"; 106 return; 107 } 108 if (FD->getAttr<ConstAttr>()) { 109 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const"; 110 return; 111 } 112 } 113 } 114 115 Diag(Loc, DiagID) << R1 << R2; 116} 117 118Action::OwningStmtResult 119Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R, 120 MultiStmtArg elts, bool isStmtExpr) { 121 unsigned NumElts = elts.size(); 122 Stmt **Elts = reinterpret_cast<Stmt**>(elts.release()); 123 // If we're in C89 mode, check that we don't have any decls after stmts. If 124 // so, emit an extension diagnostic. 125 if (!getLangOptions().C99 && !getLangOptions().CPlusPlus) { 126 // Note that __extension__ can be around a decl. 127 unsigned i = 0; 128 // Skip over all declarations. 129 for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i) 130 /*empty*/; 131 132 // We found the end of the list or a statement. Scan for another declstmt. 133 for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i) 134 /*empty*/; 135 136 if (i != NumElts) { 137 Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin(); 138 Diag(D->getLocation(), diag::ext_mixed_decls_code); 139 } 140 } 141 // Warn about unused expressions in statements. 142 for (unsigned i = 0; i != NumElts; ++i) { 143 // Ignore statements that are last in a statement expression. 144 if (isStmtExpr && i == NumElts - 1) 145 continue; 146 147 DiagnoseUnusedExprResult(Elts[i]); 148 } 149 150 return Owned(new (Context) CompoundStmt(Context, Elts, NumElts, L, R)); 151} 152 153Action::OwningStmtResult 154Sema::ActOnCaseStmt(SourceLocation CaseLoc, ExprArg lhsval, 155 SourceLocation DotDotDotLoc, ExprArg rhsval, 156 SourceLocation ColonLoc) { 157 assert((lhsval.get() != 0) && "missing expression in case statement"); 158 159 // C99 6.8.4.2p3: The expression shall be an integer constant. 160 // However, GCC allows any evaluatable integer expression. 161 Expr *LHSVal = static_cast<Expr*>(lhsval.get()); 162 if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent() && 163 VerifyIntegerConstantExpression(LHSVal)) 164 return StmtError(); 165 166 // GCC extension: The expression shall be an integer constant. 167 168 Expr *RHSVal = static_cast<Expr*>(rhsval.get()); 169 if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent() && 170 VerifyIntegerConstantExpression(RHSVal)) { 171 RHSVal = 0; // Recover by just forgetting about it. 172 rhsval = 0; 173 } 174 175 if (getSwitchStack().empty()) { 176 Diag(CaseLoc, diag::err_case_not_in_switch); 177 return StmtError(); 178 } 179 180 // Only now release the smart pointers. 181 lhsval.release(); 182 rhsval.release(); 183 CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc, 184 ColonLoc); 185 getSwitchStack().back()->addSwitchCase(CS); 186 return Owned(CS); 187} 188 189/// ActOnCaseStmtBody - This installs a statement as the body of a case. 190void Sema::ActOnCaseStmtBody(StmtTy *caseStmt, StmtArg subStmt) { 191 CaseStmt *CS = static_cast<CaseStmt*>(caseStmt); 192 Stmt *SubStmt = subStmt.takeAs<Stmt>(); 193 CS->setSubStmt(SubStmt); 194} 195 196Action::OwningStmtResult 197Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc, 198 StmtArg subStmt, Scope *CurScope) { 199 Stmt *SubStmt = subStmt.takeAs<Stmt>(); 200 201 if (getSwitchStack().empty()) { 202 Diag(DefaultLoc, diag::err_default_not_in_switch); 203 return Owned(SubStmt); 204 } 205 206 DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt); 207 getSwitchStack().back()->addSwitchCase(DS); 208 return Owned(DS); 209} 210 211Action::OwningStmtResult 212Sema::ActOnLabelStmt(SourceLocation IdentLoc, IdentifierInfo *II, 213 SourceLocation ColonLoc, StmtArg subStmt) { 214 Stmt *SubStmt = subStmt.takeAs<Stmt>(); 215 // Look up the record for this label identifier. 216 LabelStmt *&LabelDecl = getLabelMap()[II]; 217 218 // If not forward referenced or defined already, just create a new LabelStmt. 219 if (LabelDecl == 0) 220 return Owned(LabelDecl = new (Context) LabelStmt(IdentLoc, II, SubStmt)); 221 222 assert(LabelDecl->getID() == II && "Label mismatch!"); 223 224 // Otherwise, this label was either forward reference or multiply defined. If 225 // multiply defined, reject it now. 226 if (LabelDecl->getSubStmt()) { 227 Diag(IdentLoc, diag::err_redefinition_of_label) << LabelDecl->getID(); 228 Diag(LabelDecl->getIdentLoc(), diag::note_previous_definition); 229 return Owned(SubStmt); 230 } 231 232 // Otherwise, this label was forward declared, and we just found its real 233 // definition. Fill in the forward definition and return it. 234 LabelDecl->setIdentLoc(IdentLoc); 235 LabelDecl->setSubStmt(SubStmt); 236 return Owned(LabelDecl); 237} 238 239Action::OwningStmtResult 240Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, DeclPtrTy CondVar, 241 StmtArg ThenVal, SourceLocation ElseLoc, 242 StmtArg ElseVal) { 243 OwningExprResult CondResult(CondVal.release()); 244 245 VarDecl *ConditionVar = 0; 246 if (CondVar.get()) { 247 ConditionVar = CondVar.getAs<VarDecl>(); 248 CondResult = CheckConditionVariable(ConditionVar); 249 if (CondResult.isInvalid()) 250 return StmtError(); 251 } 252 Expr *ConditionExpr = CondResult.takeAs<Expr>(); 253 if (!ConditionExpr) 254 return StmtError(); 255 256 if (CheckBooleanCondition(ConditionExpr, IfLoc)) { 257 CondResult = ConditionExpr; 258 return StmtError(); 259 } 260 261 Stmt *thenStmt = ThenVal.takeAs<Stmt>(); 262 DiagnoseUnusedExprResult(thenStmt); 263 264 // Warn if the if block has a null body without an else value. 265 // this helps prevent bugs due to typos, such as 266 // if (condition); 267 // do_stuff(); 268 if (!ElseVal.get()) { 269 if (NullStmt* stmt = dyn_cast<NullStmt>(thenStmt)) 270 Diag(stmt->getSemiLoc(), diag::warn_empty_if_body); 271 } 272 273 Stmt *elseStmt = ElseVal.takeAs<Stmt>(); 274 DiagnoseUnusedExprResult(elseStmt); 275 276 CondResult.release(); 277 return Owned(new (Context) IfStmt(IfLoc, ConditionVar, ConditionExpr, 278 thenStmt, ElseLoc, elseStmt)); 279} 280 281Action::OwningStmtResult 282Sema::ActOnStartOfSwitchStmt(FullExprArg cond, DeclPtrTy CondVar) { 283 OwningExprResult CondResult(cond.release()); 284 285 VarDecl *ConditionVar = 0; 286 if (CondVar.get()) { 287 ConditionVar = CondVar.getAs<VarDecl>(); 288 CondResult = CheckConditionVariable(ConditionVar); 289 if (CondResult.isInvalid()) 290 return StmtError(); 291 } 292 SwitchStmt *SS = new (Context) SwitchStmt(ConditionVar, 293 CondResult.takeAs<Expr>()); 294 getSwitchStack().push_back(SS); 295 return Owned(SS); 296} 297 298/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have 299/// the specified width and sign. If an overflow occurs, detect it and emit 300/// the specified diagnostic. 301void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val, 302 unsigned NewWidth, bool NewSign, 303 SourceLocation Loc, 304 unsigned DiagID) { 305 // Perform a conversion to the promoted condition type if needed. 306 if (NewWidth > Val.getBitWidth()) { 307 // If this is an extension, just do it. 308 llvm::APSInt OldVal(Val); 309 Val.extend(NewWidth); 310 311 // If the input was signed and negative and the output is unsigned, 312 // warn. 313 if (!NewSign && OldVal.isSigned() && OldVal.isNegative()) 314 Diag(Loc, DiagID) << OldVal.toString(10) << Val.toString(10); 315 316 Val.setIsSigned(NewSign); 317 } else if (NewWidth < Val.getBitWidth()) { 318 // If this is a truncation, check for overflow. 319 llvm::APSInt ConvVal(Val); 320 ConvVal.trunc(NewWidth); 321 ConvVal.setIsSigned(NewSign); 322 ConvVal.extend(Val.getBitWidth()); 323 ConvVal.setIsSigned(Val.isSigned()); 324 if (ConvVal != Val) 325 Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10); 326 327 // Regardless of whether a diagnostic was emitted, really do the 328 // truncation. 329 Val.trunc(NewWidth); 330 Val.setIsSigned(NewSign); 331 } else if (NewSign != Val.isSigned()) { 332 // Convert the sign to match the sign of the condition. This can cause 333 // overflow as well: unsigned(INTMIN) 334 llvm::APSInt OldVal(Val); 335 Val.setIsSigned(NewSign); 336 337 if (Val.isNegative()) // Sign bit changes meaning. 338 Diag(Loc, DiagID) << OldVal.toString(10) << Val.toString(10); 339 } 340} 341 342namespace { 343 struct CaseCompareFunctor { 344 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 345 const llvm::APSInt &RHS) { 346 return LHS.first < RHS; 347 } 348 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 349 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 350 return LHS.first < RHS.first; 351 } 352 bool operator()(const llvm::APSInt &LHS, 353 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 354 return LHS < RHS.first; 355 } 356 }; 357} 358 359/// CmpCaseVals - Comparison predicate for sorting case values. 360/// 361static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs, 362 const std::pair<llvm::APSInt, CaseStmt*>& rhs) { 363 if (lhs.first < rhs.first) 364 return true; 365 366 if (lhs.first == rhs.first && 367 lhs.second->getCaseLoc().getRawEncoding() 368 < rhs.second->getCaseLoc().getRawEncoding()) 369 return true; 370 return false; 371} 372 373/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of 374/// potentially integral-promoted expression @p expr. 375static QualType GetTypeBeforeIntegralPromotion(const Expr* expr) { 376 const ImplicitCastExpr *ImplicitCast = 377 dyn_cast_or_null<ImplicitCastExpr>(expr); 378 if (ImplicitCast != NULL) { 379 const Expr *ExprBeforePromotion = ImplicitCast->getSubExpr(); 380 QualType TypeBeforePromotion = ExprBeforePromotion->getType(); 381 if (TypeBeforePromotion->isIntegralType()) { 382 return TypeBeforePromotion; 383 } 384 } 385 return expr->getType(); 386} 387 388/// \brief Check (and possibly convert) the condition in a switch 389/// statement in C++. 390static bool CheckCXXSwitchCondition(Sema &S, SourceLocation SwitchLoc, 391 Expr *&CondExpr) { 392 if (CondExpr->isTypeDependent()) 393 return false; 394 395 QualType CondType = CondExpr->getType(); 396 397 // C++ 6.4.2.p2: 398 // The condition shall be of integral type, enumeration type, or of a class 399 // type for which a single conversion function to integral or enumeration 400 // type exists (12.3). If the condition is of class type, the condition is 401 // converted by calling that conversion function, and the result of the 402 // conversion is used in place of the original condition for the remainder 403 // of this section. Integral promotions are performed. 404 405 // Make sure that the condition expression has a complete type, 406 // otherwise we'll never find any conversions. 407 if (S.RequireCompleteType(SwitchLoc, CondType, 408 PDiag(diag::err_switch_incomplete_class_type) 409 << CondExpr->getSourceRange())) 410 return true; 411 412 llvm::SmallVector<CXXConversionDecl *, 4> ViableConversions; 413 llvm::SmallVector<CXXConversionDecl *, 4> ExplicitConversions; 414 if (const RecordType *RecordTy = CondType->getAs<RecordType>()) { 415 const UnresolvedSetImpl *Conversions 416 = cast<CXXRecordDecl>(RecordTy->getDecl()) 417 ->getVisibleConversionFunctions(); 418 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 419 E = Conversions->end(); I != E; ++I) { 420 if (CXXConversionDecl *Conversion = dyn_cast<CXXConversionDecl>(*I)) 421 if (Conversion->getConversionType().getNonReferenceType() 422 ->isIntegralType()) { 423 if (Conversion->isExplicit()) 424 ExplicitConversions.push_back(Conversion); 425 else 426 ViableConversions.push_back(Conversion); 427 } 428 } 429 430 switch (ViableConversions.size()) { 431 case 0: 432 if (ExplicitConversions.size() == 1) { 433 // The user probably meant to invoke the given explicit 434 // conversion; use it. 435 QualType ConvTy 436 = ExplicitConversions[0]->getConversionType() 437 .getNonReferenceType(); 438 std::string TypeStr; 439 ConvTy.getAsStringInternal(TypeStr, S.Context.PrintingPolicy); 440 441 S.Diag(SwitchLoc, diag::err_switch_explicit_conversion) 442 << CondType << ConvTy << CondExpr->getSourceRange() 443 << CodeModificationHint::CreateInsertion(CondExpr->getLocStart(), 444 "static_cast<" + TypeStr + ">(") 445 << CodeModificationHint::CreateInsertion( 446 S.PP.getLocForEndOfToken(CondExpr->getLocEnd()), 447 ")"); 448 S.Diag(ExplicitConversions[0]->getLocation(), 449 diag::note_switch_conversion) 450 << ConvTy->isEnumeralType() << ConvTy; 451 452 // If we aren't in a SFINAE context, build a call to the 453 // explicit conversion function. 454 if (S.isSFINAEContext()) 455 return true; 456 457 CondExpr = S.BuildCXXMemberCallExpr(CondExpr, ExplicitConversions[0]); 458 } 459 460 // We'll complain below about a non-integral condition type. 461 break; 462 463 case 1: 464 // Apply this conversion. 465 CondExpr = S.BuildCXXMemberCallExpr(CondExpr, ViableConversions[0]); 466 break; 467 468 default: 469 S.Diag(SwitchLoc, diag::err_switch_multiple_conversions) 470 << CondType << CondExpr->getSourceRange(); 471 for (unsigned I = 0, N = ViableConversions.size(); I != N; ++I) { 472 QualType ConvTy 473 = ViableConversions[I]->getConversionType().getNonReferenceType(); 474 S.Diag(ViableConversions[I]->getLocation(), 475 diag::note_switch_conversion) 476 << ConvTy->isEnumeralType() << ConvTy; 477 } 478 return true; 479 } 480 } 481 482 return false; 483} 484 485/// ActOnSwitchBodyError - This is called if there is an error parsing the 486/// body of the switch stmt instead of ActOnFinishSwitchStmt. 487void Sema::ActOnSwitchBodyError(SourceLocation SwitchLoc, StmtArg Switch, 488 StmtArg Body) { 489 // Keep the switch stack balanced. 490 assert(getSwitchStack().back() == (SwitchStmt*)Switch.get() && 491 "switch stack missing push/pop!"); 492 getSwitchStack().pop_back(); 493} 494 495Action::OwningStmtResult 496Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, StmtArg Switch, 497 StmtArg Body) { 498 Stmt *BodyStmt = Body.takeAs<Stmt>(); 499 500 SwitchStmt *SS = getSwitchStack().back(); 501 assert(SS == (SwitchStmt*)Switch.get() && "switch stack missing push/pop!"); 502 503 SS->setBody(BodyStmt, SwitchLoc); 504 getSwitchStack().pop_back(); 505 506 if (SS->getCond() == 0) { 507 SS->Destroy(Context); 508 return StmtError(); 509 } 510 511 Expr *CondExpr = SS->getCond(); 512 QualType CondTypeBeforePromotion = 513 GetTypeBeforeIntegralPromotion(CondExpr); 514 515 if (getLangOptions().CPlusPlus && 516 CheckCXXSwitchCondition(*this, SwitchLoc, CondExpr)) 517 return StmtError(); 518 519 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr. 520 UsualUnaryConversions(CondExpr); 521 QualType CondType = CondExpr->getType(); 522 SS->setCond(CondExpr); 523 524 // C++ 6.4.2.p2: 525 // Integral promotions are performed (on the switch condition). 526 // 527 // A case value unrepresentable by the original switch condition 528 // type (before the promotion) doesn't make sense, even when it can 529 // be represented by the promoted type. Therefore we need to find 530 // the pre-promotion type of the switch condition. 531 if (!CondExpr->isTypeDependent()) { 532 if (!CondType->isIntegerType()) { // C99 6.8.4.2p1 533 Diag(SwitchLoc, diag::err_typecheck_statement_requires_integer) 534 << CondType << CondExpr->getSourceRange(); 535 return StmtError(); 536 } 537 538 if (CondTypeBeforePromotion->isBooleanType()) { 539 // switch(bool_expr) {...} is often a programmer error, e.g. 540 // switch(n && mask) { ... } // Doh - should be "n & mask". 541 // One can always use an if statement instead of switch(bool_expr). 542 Diag(SwitchLoc, diag::warn_bool_switch_condition) 543 << CondExpr->getSourceRange(); 544 } 545 } 546 547 // Get the bitwidth of the switched-on value before promotions. We must 548 // convert the integer case values to this width before comparison. 549 bool HasDependentValue 550 = CondExpr->isTypeDependent() || CondExpr->isValueDependent(); 551 unsigned CondWidth 552 = HasDependentValue? 0 553 : static_cast<unsigned>(Context.getTypeSize(CondTypeBeforePromotion)); 554 bool CondIsSigned = CondTypeBeforePromotion->isSignedIntegerType(); 555 556 // Accumulate all of the case values in a vector so that we can sort them 557 // and detect duplicates. This vector contains the APInt for the case after 558 // it has been converted to the condition type. 559 typedef llvm::SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy; 560 CaseValsTy CaseVals; 561 562 // Keep track of any GNU case ranges we see. The APSInt is the low value. 563 std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRanges; 564 565 DefaultStmt *TheDefaultStmt = 0; 566 567 bool CaseListIsErroneous = false; 568 569 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue; 570 SC = SC->getNextSwitchCase()) { 571 572 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) { 573 if (TheDefaultStmt) { 574 Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined); 575 Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev); 576 577 // FIXME: Remove the default statement from the switch block so that 578 // we'll return a valid AST. This requires recursing down the AST and 579 // finding it, not something we are set up to do right now. For now, 580 // just lop the entire switch stmt out of the AST. 581 CaseListIsErroneous = true; 582 } 583 TheDefaultStmt = DS; 584 585 } else { 586 CaseStmt *CS = cast<CaseStmt>(SC); 587 588 // We already verified that the expression has a i-c-e value (C99 589 // 6.8.4.2p3) - get that value now. 590 Expr *Lo = CS->getLHS(); 591 592 if (Lo->isTypeDependent() || Lo->isValueDependent()) { 593 HasDependentValue = true; 594 break; 595 } 596 597 llvm::APSInt LoVal = Lo->EvaluateAsInt(Context); 598 599 // Convert the value to the same width/sign as the condition. 600 ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned, 601 CS->getLHS()->getLocStart(), 602 diag::warn_case_value_overflow); 603 604 // If the LHS is not the same type as the condition, insert an implicit 605 // cast. 606 ImpCastExprToType(Lo, CondType, CastExpr::CK_IntegralCast); 607 CS->setLHS(Lo); 608 609 // If this is a case range, remember it in CaseRanges, otherwise CaseVals. 610 if (CS->getRHS()) { 611 if (CS->getRHS()->isTypeDependent() || 612 CS->getRHS()->isValueDependent()) { 613 HasDependentValue = true; 614 break; 615 } 616 CaseRanges.push_back(std::make_pair(LoVal, CS)); 617 } else 618 CaseVals.push_back(std::make_pair(LoVal, CS)); 619 } 620 } 621 622 if (!HasDependentValue) { 623 // Sort all the scalar case values so we can easily detect duplicates. 624 std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals); 625 626 if (!CaseVals.empty()) { 627 for (unsigned i = 0, e = CaseVals.size()-1; i != e; ++i) { 628 if (CaseVals[i].first == CaseVals[i+1].first) { 629 // If we have a duplicate, report it. 630 Diag(CaseVals[i+1].second->getLHS()->getLocStart(), 631 diag::err_duplicate_case) << CaseVals[i].first.toString(10); 632 Diag(CaseVals[i].second->getLHS()->getLocStart(), 633 diag::note_duplicate_case_prev); 634 // FIXME: We really want to remove the bogus case stmt from the 635 // substmt, but we have no way to do this right now. 636 CaseListIsErroneous = true; 637 } 638 } 639 } 640 641 // Detect duplicate case ranges, which usually don't exist at all in 642 // the first place. 643 if (!CaseRanges.empty()) { 644 // Sort all the case ranges by their low value so we can easily detect 645 // overlaps between ranges. 646 std::stable_sort(CaseRanges.begin(), CaseRanges.end()); 647 648 // Scan the ranges, computing the high values and removing empty ranges. 649 std::vector<llvm::APSInt> HiVals; 650 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 651 CaseStmt *CR = CaseRanges[i].second; 652 Expr *Hi = CR->getRHS(); 653 llvm::APSInt HiVal = Hi->EvaluateAsInt(Context); 654 655 // Convert the value to the same width/sign as the condition. 656 ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned, 657 CR->getRHS()->getLocStart(), 658 diag::warn_case_value_overflow); 659 660 // If the LHS is not the same type as the condition, insert an implicit 661 // cast. 662 ImpCastExprToType(Hi, CondType, CastExpr::CK_IntegralCast); 663 CR->setRHS(Hi); 664 665 // If the low value is bigger than the high value, the case is empty. 666 if (CaseRanges[i].first > HiVal) { 667 Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range) 668 << SourceRange(CR->getLHS()->getLocStart(), 669 CR->getRHS()->getLocEnd()); 670 CaseRanges.erase(CaseRanges.begin()+i); 671 --i, --e; 672 continue; 673 } 674 HiVals.push_back(HiVal); 675 } 676 677 // Rescan the ranges, looking for overlap with singleton values and other 678 // ranges. Since the range list is sorted, we only need to compare case 679 // ranges with their neighbors. 680 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 681 llvm::APSInt &CRLo = CaseRanges[i].first; 682 llvm::APSInt &CRHi = HiVals[i]; 683 CaseStmt *CR = CaseRanges[i].second; 684 685 // Check to see whether the case range overlaps with any 686 // singleton cases. 687 CaseStmt *OverlapStmt = 0; 688 llvm::APSInt OverlapVal(32); 689 690 // Find the smallest value >= the lower bound. If I is in the 691 // case range, then we have overlap. 692 CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(), 693 CaseVals.end(), CRLo, 694 CaseCompareFunctor()); 695 if (I != CaseVals.end() && I->first < CRHi) { 696 OverlapVal = I->first; // Found overlap with scalar. 697 OverlapStmt = I->second; 698 } 699 700 // Find the smallest value bigger than the upper bound. 701 I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor()); 702 if (I != CaseVals.begin() && (I-1)->first >= CRLo) { 703 OverlapVal = (I-1)->first; // Found overlap with scalar. 704 OverlapStmt = (I-1)->second; 705 } 706 707 // Check to see if this case stmt overlaps with the subsequent 708 // case range. 709 if (i && CRLo <= HiVals[i-1]) { 710 OverlapVal = HiVals[i-1]; // Found overlap with range. 711 OverlapStmt = CaseRanges[i-1].second; 712 } 713 714 if (OverlapStmt) { 715 // If we have a duplicate, report it. 716 Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case) 717 << OverlapVal.toString(10); 718 Diag(OverlapStmt->getLHS()->getLocStart(), 719 diag::note_duplicate_case_prev); 720 // FIXME: We really want to remove the bogus case stmt from the 721 // substmt, but we have no way to do this right now. 722 CaseListIsErroneous = true; 723 } 724 } 725 } 726 } 727 728 // FIXME: If the case list was broken is some way, we don't have a good system 729 // to patch it up. Instead, just return the whole substmt as broken. 730 if (CaseListIsErroneous) 731 return StmtError(); 732 733 Switch.release(); 734 return Owned(SS); 735} 736 737Action::OwningStmtResult 738Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond, 739 DeclPtrTy CondVar, StmtArg Body) { 740 OwningExprResult CondResult(Cond.release()); 741 742 VarDecl *ConditionVar = 0; 743 if (CondVar.get()) { 744 ConditionVar = CondVar.getAs<VarDecl>(); 745 CondResult = CheckConditionVariable(ConditionVar); 746 if (CondResult.isInvalid()) 747 return StmtError(); 748 } 749 Expr *ConditionExpr = CondResult.takeAs<Expr>(); 750 if (!ConditionExpr) 751 return StmtError(); 752 753 if (CheckBooleanCondition(ConditionExpr, WhileLoc)) { 754 CondResult = ConditionExpr; 755 return StmtError(); 756 } 757 758 Stmt *bodyStmt = Body.takeAs<Stmt>(); 759 DiagnoseUnusedExprResult(bodyStmt); 760 761 CondResult.release(); 762 return Owned(new (Context) WhileStmt(ConditionVar, ConditionExpr, bodyStmt, 763 WhileLoc)); 764} 765 766Action::OwningStmtResult 767Sema::ActOnDoStmt(SourceLocation DoLoc, StmtArg Body, 768 SourceLocation WhileLoc, SourceLocation CondLParen, 769 ExprArg Cond, SourceLocation CondRParen) { 770 Expr *condExpr = Cond.takeAs<Expr>(); 771 assert(condExpr && "ActOnDoStmt(): missing expression"); 772 773 if (CheckBooleanCondition(condExpr, DoLoc)) { 774 Cond = condExpr; 775 return StmtError(); 776 } 777 778 Stmt *bodyStmt = Body.takeAs<Stmt>(); 779 DiagnoseUnusedExprResult(bodyStmt); 780 781 Cond.release(); 782 return Owned(new (Context) DoStmt(bodyStmt, condExpr, DoLoc, 783 WhileLoc, CondRParen)); 784} 785 786Action::OwningStmtResult 787Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 788 StmtArg first, FullExprArg second, DeclPtrTy secondVar, 789 FullExprArg third, 790 SourceLocation RParenLoc, StmtArg body) { 791 Stmt *First = static_cast<Stmt*>(first.get()); 792 793 if (!getLangOptions().CPlusPlus) { 794 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) { 795 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 796 // declare identifiers for objects having storage class 'auto' or 797 // 'register'. 798 for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end(); 799 DI!=DE; ++DI) { 800 VarDecl *VD = dyn_cast<VarDecl>(*DI); 801 if (VD && VD->isBlockVarDecl() && !VD->hasLocalStorage()) 802 VD = 0; 803 if (VD == 0) 804 Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for); 805 // FIXME: mark decl erroneous! 806 } 807 } 808 } 809 810 OwningExprResult SecondResult(second.release()); 811 VarDecl *ConditionVar = 0; 812 if (secondVar.get()) { 813 ConditionVar = secondVar.getAs<VarDecl>(); 814 SecondResult = CheckConditionVariable(ConditionVar); 815 if (SecondResult.isInvalid()) 816 return StmtError(); 817 } 818 819 Expr *Second = SecondResult.takeAs<Expr>(); 820 if (Second && CheckBooleanCondition(Second, ForLoc)) { 821 SecondResult = Second; 822 return StmtError(); 823 } 824 825 Expr *Third = third.release().takeAs<Expr>(); 826 Stmt *Body = static_cast<Stmt*>(body.get()); 827 828 DiagnoseUnusedExprResult(First); 829 DiagnoseUnusedExprResult(Third); 830 DiagnoseUnusedExprResult(Body); 831 832 first.release(); 833 body.release(); 834 return Owned(new (Context) ForStmt(First, Second, ConditionVar, Third, Body, 835 ForLoc, LParenLoc, RParenLoc)); 836} 837 838Action::OwningStmtResult 839Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc, 840 SourceLocation LParenLoc, 841 StmtArg first, ExprArg second, 842 SourceLocation RParenLoc, StmtArg body) { 843 Stmt *First = static_cast<Stmt*>(first.get()); 844 Expr *Second = static_cast<Expr*>(second.get()); 845 Stmt *Body = static_cast<Stmt*>(body.get()); 846 if (First) { 847 QualType FirstType; 848 if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) { 849 if (!DS->isSingleDecl()) 850 return StmtError(Diag((*DS->decl_begin())->getLocation(), 851 diag::err_toomany_element_decls)); 852 853 Decl *D = DS->getSingleDecl(); 854 FirstType = cast<ValueDecl>(D)->getType(); 855 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 856 // declare identifiers for objects having storage class 'auto' or 857 // 'register'. 858 VarDecl *VD = cast<VarDecl>(D); 859 if (VD->isBlockVarDecl() && !VD->hasLocalStorage()) 860 return StmtError(Diag(VD->getLocation(), 861 diag::err_non_variable_decl_in_for)); 862 } else { 863 if (cast<Expr>(First)->isLvalue(Context) != Expr::LV_Valid) 864 return StmtError(Diag(First->getLocStart(), 865 diag::err_selector_element_not_lvalue) 866 << First->getSourceRange()); 867 868 FirstType = static_cast<Expr*>(First)->getType(); 869 } 870 if (!FirstType->isObjCObjectPointerType() && 871 !FirstType->isBlockPointerType()) 872 Diag(ForLoc, diag::err_selector_element_type) 873 << FirstType << First->getSourceRange(); 874 } 875 if (Second) { 876 DefaultFunctionArrayConversion(Second); 877 QualType SecondType = Second->getType(); 878 if (!SecondType->isObjCObjectPointerType()) 879 Diag(ForLoc, diag::err_collection_expr_type) 880 << SecondType << Second->getSourceRange(); 881 } 882 first.release(); 883 second.release(); 884 body.release(); 885 return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body, 886 ForLoc, RParenLoc)); 887} 888 889Action::OwningStmtResult 890Sema::ActOnGotoStmt(SourceLocation GotoLoc, SourceLocation LabelLoc, 891 IdentifierInfo *LabelII) { 892 // Look up the record for this label identifier. 893 LabelStmt *&LabelDecl = getLabelMap()[LabelII]; 894 895 // If we haven't seen this label yet, create a forward reference. 896 if (LabelDecl == 0) 897 LabelDecl = new (Context) LabelStmt(LabelLoc, LabelII, 0); 898 899 return Owned(new (Context) GotoStmt(LabelDecl, GotoLoc, LabelLoc)); 900} 901 902Action::OwningStmtResult 903Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc, 904 ExprArg DestExp) { 905 // Convert operand to void* 906 Expr* E = DestExp.takeAs<Expr>(); 907 if (!E->isTypeDependent()) { 908 QualType ETy = E->getType(); 909 AssignConvertType ConvTy = 910 CheckSingleAssignmentConstraints(Context.VoidPtrTy, E); 911 if (DiagnoseAssignmentResult(ConvTy, StarLoc, Context.VoidPtrTy, ETy, 912 E, AA_Passing)) 913 return StmtError(); 914 } 915 return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E)); 916} 917 918Action::OwningStmtResult 919Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) { 920 Scope *S = CurScope->getContinueParent(); 921 if (!S) { 922 // C99 6.8.6.2p1: A break shall appear only in or as a loop body. 923 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop)); 924 } 925 926 return Owned(new (Context) ContinueStmt(ContinueLoc)); 927} 928 929Action::OwningStmtResult 930Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) { 931 Scope *S = CurScope->getBreakParent(); 932 if (!S) { 933 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body. 934 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch)); 935 } 936 937 return Owned(new (Context) BreakStmt(BreakLoc)); 938} 939 940/// ActOnBlockReturnStmt - Utility routine to figure out block's return type. 941/// 942Action::OwningStmtResult 943Sema::ActOnBlockReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 944 // If this is the first return we've seen in the block, infer the type of 945 // the block from it. 946 if (CurBlock->ReturnType.isNull()) { 947 if (RetValExp) { 948 // Don't call UsualUnaryConversions(), since we don't want to do 949 // integer promotions here. 950 DefaultFunctionArrayConversion(RetValExp); 951 CurBlock->ReturnType = RetValExp->getType(); 952 if (BlockDeclRefExpr *CDRE = dyn_cast<BlockDeclRefExpr>(RetValExp)) { 953 // We have to remove a 'const' added to copied-in variable which was 954 // part of the implementation spec. and not the actual qualifier for 955 // the variable. 956 if (CDRE->isConstQualAdded()) 957 CurBlock->ReturnType.removeConst(); 958 } 959 } else 960 CurBlock->ReturnType = Context.VoidTy; 961 } 962 QualType FnRetType = CurBlock->ReturnType; 963 964 if (CurBlock->TheDecl->hasAttr<NoReturnAttr>()) { 965 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr) 966 << getCurFunctionOrMethodDecl()->getDeclName(); 967 return StmtError(); 968 } 969 970 // Otherwise, verify that this result type matches the previous one. We are 971 // pickier with blocks than for normal functions because we don't have GCC 972 // compatibility to worry about here. 973 if (CurBlock->ReturnType->isVoidType()) { 974 if (RetValExp) { 975 Diag(ReturnLoc, diag::err_return_block_has_expr); 976 RetValExp->Destroy(Context); 977 RetValExp = 0; 978 } 979 return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp)); 980 } 981 982 if (!RetValExp) 983 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr)); 984 985 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 986 // we have a non-void block with an expression, continue checking 987 988 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 989 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 990 // function return. 991 992 // In C++ the return statement is handled via a copy initialization. 993 // the C version of which boils down to CheckSingleAssignmentConstraints. 994 // FIXME: Leaks RetValExp. 995 if (PerformCopyInitialization(RetValExp, FnRetType, AA_Returning)) 996 return StmtError(); 997 998 if (RetValExp) CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 999 } 1000 1001 return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp)); 1002} 1003 1004/// IsReturnCopyElidable - Whether returning @p RetExpr from a function that 1005/// returns a @p RetType fulfills the criteria for copy elision (C++0x 12.8p15). 1006static bool IsReturnCopyElidable(ASTContext &Ctx, QualType RetType, 1007 Expr *RetExpr) { 1008 QualType ExprType = RetExpr->getType(); 1009 // - in a return statement in a function with ... 1010 // ... a class return type ... 1011 if (!RetType->isRecordType()) 1012 return false; 1013 // ... the same cv-unqualified type as the function return type ... 1014 if (!Ctx.hasSameUnqualifiedType(RetType, ExprType)) 1015 return false; 1016 // ... the expression is the name of a non-volatile automatic object ... 1017 // We ignore parentheses here. 1018 // FIXME: Is this compliant? 1019 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(RetExpr->IgnoreParens()); 1020 if (!DR) 1021 return false; 1022 const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()); 1023 if (!VD) 1024 return false; 1025 return VD->hasLocalStorage() && !VD->getType()->isReferenceType() 1026 && !VD->getType().isVolatileQualified(); 1027} 1028 1029Action::OwningStmtResult 1030Sema::ActOnReturnStmt(SourceLocation ReturnLoc, ExprArg rex) { 1031 Expr *RetValExp = rex.takeAs<Expr>(); 1032 if (CurBlock) 1033 return ActOnBlockReturnStmt(ReturnLoc, RetValExp); 1034 1035 QualType FnRetType; 1036 if (const FunctionDecl *FD = getCurFunctionDecl()) { 1037 FnRetType = FD->getResultType(); 1038 if (FD->hasAttr<NoReturnAttr>()) 1039 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) 1040 << getCurFunctionOrMethodDecl()->getDeclName(); 1041 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) 1042 FnRetType = MD->getResultType(); 1043 else // If we don't have a function/method context, bail. 1044 return StmtError(); 1045 1046 if (FnRetType->isVoidType()) { 1047 if (RetValExp && !RetValExp->isTypeDependent()) { 1048 // C99 6.8.6.4p1 (ext_ since GCC warns) 1049 unsigned D = diag::ext_return_has_expr; 1050 if (RetValExp->getType()->isVoidType()) 1051 D = diag::ext_return_has_void_expr; 1052 1053 // return (some void expression); is legal in C++. 1054 if (D != diag::ext_return_has_void_expr || 1055 !getLangOptions().CPlusPlus) { 1056 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 1057 Diag(ReturnLoc, D) 1058 << CurDecl->getDeclName() << isa<ObjCMethodDecl>(CurDecl) 1059 << RetValExp->getSourceRange(); 1060 } 1061 1062 RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp); 1063 } 1064 return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp)); 1065 } 1066 1067 if (!RetValExp && !FnRetType->isDependentType()) { 1068 unsigned DiagID = diag::warn_return_missing_expr; // C90 6.6.6.4p4 1069 // C99 6.8.6.4p1 (ext_ since GCC warns) 1070 if (getLangOptions().C99) DiagID = diag::ext_return_missing_expr; 1071 1072 if (FunctionDecl *FD = getCurFunctionDecl()) 1073 Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/; 1074 else 1075 Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/; 1076 return Owned(new (Context) ReturnStmt(ReturnLoc, (Expr*)0)); 1077 } 1078 1079 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1080 // we have a non-void function with an expression, continue checking 1081 1082 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1083 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1084 // function return. 1085 1086 // C++0x 12.8p15: When certain criteria are met, an implementation is 1087 // allowed to omit the copy construction of a class object, [...] 1088 // - in a return statement in a function with a class return type, when 1089 // the expression is the name of a non-volatile automatic object with 1090 // the same cv-unqualified type as the function return type, the copy 1091 // operation can be omitted [...] 1092 // C++0x 12.8p16: When the criteria for elision of a copy operation are met 1093 // and the object to be copied is designated by an lvalue, overload 1094 // resolution to select the constructor for the copy is first performed 1095 // as if the object were designated by an rvalue. 1096 // Note that we only compute Elidable if we're in C++0x, since we don't 1097 // care otherwise. 1098 bool Elidable = getLangOptions().CPlusPlus0x ? 1099 IsReturnCopyElidable(Context, FnRetType, RetValExp) : 1100 false; 1101 // FIXME: Elidable 1102 (void)Elidable; 1103 1104 // In C++ the return statement is handled via a copy initialization. 1105 // the C version of which boils down to CheckSingleAssignmentConstraints. 1106 OwningExprResult Res = PerformCopyInitialization( 1107 InitializedEntity::InitializeResult(ReturnLoc, 1108 FnRetType), 1109 SourceLocation(), 1110 Owned(RetValExp)); 1111 if (Res.isInvalid()) { 1112 // FIXME: Cleanup temporaries here, anyway? 1113 return StmtError(); 1114 } 1115 1116 RetValExp = Res.takeAs<Expr>(); 1117 if (RetValExp) 1118 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1119 } 1120 1121 if (RetValExp) 1122 RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp); 1123 return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp)); 1124} 1125 1126/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently 1127/// ignore "noop" casts in places where an lvalue is required by an inline asm. 1128/// We emulate this behavior when -fheinous-gnu-extensions is specified, but 1129/// provide a strong guidance to not use it. 1130/// 1131/// This method checks to see if the argument is an acceptable l-value and 1132/// returns false if it is a case we can handle. 1133static bool CheckAsmLValue(const Expr *E, Sema &S) { 1134 // Type dependent expressions will be checked during instantiation. 1135 if (E->isTypeDependent()) 1136 return false; 1137 1138 if (E->isLvalue(S.Context) == Expr::LV_Valid) 1139 return false; // Cool, this is an lvalue. 1140 1141 // Okay, this is not an lvalue, but perhaps it is the result of a cast that we 1142 // are supposed to allow. 1143 const Expr *E2 = E->IgnoreParenNoopCasts(S.Context); 1144 if (E != E2 && E2->isLvalue(S.Context) == Expr::LV_Valid) { 1145 if (!S.getLangOptions().HeinousExtensions) 1146 S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue) 1147 << E->getSourceRange(); 1148 else 1149 S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue) 1150 << E->getSourceRange(); 1151 // Accept, even if we emitted an error diagnostic. 1152 return false; 1153 } 1154 1155 // None of the above, just randomly invalid non-lvalue. 1156 return true; 1157} 1158 1159 1160Sema::OwningStmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, 1161 bool IsSimple, 1162 bool IsVolatile, 1163 unsigned NumOutputs, 1164 unsigned NumInputs, 1165 const std::string *Names, 1166 MultiExprArg constraints, 1167 MultiExprArg exprs, 1168 ExprArg asmString, 1169 MultiExprArg clobbers, 1170 SourceLocation RParenLoc, 1171 bool MSAsm) { 1172 unsigned NumClobbers = clobbers.size(); 1173 StringLiteral **Constraints = 1174 reinterpret_cast<StringLiteral**>(constraints.get()); 1175 Expr **Exprs = reinterpret_cast<Expr **>(exprs.get()); 1176 StringLiteral *AsmString = cast<StringLiteral>((Expr *)asmString.get()); 1177 StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get()); 1178 1179 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; 1180 1181 // The parser verifies that there is a string literal here. 1182 if (AsmString->isWide()) 1183 return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character) 1184 << AsmString->getSourceRange()); 1185 1186 for (unsigned i = 0; i != NumOutputs; i++) { 1187 StringLiteral *Literal = Constraints[i]; 1188 if (Literal->isWide()) 1189 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1190 << Literal->getSourceRange()); 1191 1192 TargetInfo::ConstraintInfo Info(Literal->getStrData(), 1193 Literal->getByteLength(), 1194 Names[i]); 1195 if (!Context.Target.validateOutputConstraint(Info)) 1196 return StmtError(Diag(Literal->getLocStart(), 1197 diag::err_asm_invalid_output_constraint) 1198 << Info.getConstraintStr()); 1199 1200 // Check that the output exprs are valid lvalues. 1201 Expr *OutputExpr = Exprs[i]; 1202 if (CheckAsmLValue(OutputExpr, *this)) { 1203 return StmtError(Diag(OutputExpr->getLocStart(), 1204 diag::err_asm_invalid_lvalue_in_output) 1205 << OutputExpr->getSourceRange()); 1206 } 1207 1208 OutputConstraintInfos.push_back(Info); 1209 } 1210 1211 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; 1212 1213 for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { 1214 StringLiteral *Literal = Constraints[i]; 1215 if (Literal->isWide()) 1216 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1217 << Literal->getSourceRange()); 1218 1219 TargetInfo::ConstraintInfo Info(Literal->getStrData(), 1220 Literal->getByteLength(), 1221 Names[i]); 1222 if (!Context.Target.validateInputConstraint(OutputConstraintInfos.data(), 1223 NumOutputs, Info)) { 1224 return StmtError(Diag(Literal->getLocStart(), 1225 diag::err_asm_invalid_input_constraint) 1226 << Info.getConstraintStr()); 1227 } 1228 1229 Expr *InputExpr = Exprs[i]; 1230 1231 // Only allow void types for memory constraints. 1232 if (Info.allowsMemory() && !Info.allowsRegister()) { 1233 if (CheckAsmLValue(InputExpr, *this)) 1234 return StmtError(Diag(InputExpr->getLocStart(), 1235 diag::err_asm_invalid_lvalue_in_input) 1236 << Info.getConstraintStr() 1237 << InputExpr->getSourceRange()); 1238 } 1239 1240 if (Info.allowsRegister()) { 1241 if (InputExpr->getType()->isVoidType()) { 1242 return StmtError(Diag(InputExpr->getLocStart(), 1243 diag::err_asm_invalid_type_in_input) 1244 << InputExpr->getType() << Info.getConstraintStr() 1245 << InputExpr->getSourceRange()); 1246 } 1247 } 1248 1249 DefaultFunctionArrayConversion(Exprs[i]); 1250 1251 InputConstraintInfos.push_back(Info); 1252 } 1253 1254 // Check that the clobbers are valid. 1255 for (unsigned i = 0; i != NumClobbers; i++) { 1256 StringLiteral *Literal = Clobbers[i]; 1257 if (Literal->isWide()) 1258 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1259 << Literal->getSourceRange()); 1260 1261 std::string Clobber(Literal->getStrData(), 1262 Literal->getStrData() + 1263 Literal->getByteLength()); 1264 1265 if (!Context.Target.isValidGCCRegisterName(Clobber.c_str())) 1266 return StmtError(Diag(Literal->getLocStart(), 1267 diag::err_asm_unknown_register_name) << Clobber); 1268 } 1269 1270 constraints.release(); 1271 exprs.release(); 1272 asmString.release(); 1273 clobbers.release(); 1274 AsmStmt *NS = 1275 new (Context) AsmStmt(AsmLoc, IsSimple, IsVolatile, MSAsm, NumOutputs, 1276 NumInputs, Names, Constraints, Exprs, AsmString, 1277 NumClobbers, Clobbers, RParenLoc); 1278 // Validate the asm string, ensuring it makes sense given the operands we 1279 // have. 1280 llvm::SmallVector<AsmStmt::AsmStringPiece, 8> Pieces; 1281 unsigned DiagOffs; 1282 if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) { 1283 Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID) 1284 << AsmString->getSourceRange(); 1285 DeleteStmt(NS); 1286 return StmtError(); 1287 } 1288 1289 // Validate tied input operands for type mismatches. 1290 for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) { 1291 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; 1292 1293 // If this is a tied constraint, verify that the output and input have 1294 // either exactly the same type, or that they are int/ptr operands with the 1295 // same size (int/long, int*/long, are ok etc). 1296 if (!Info.hasTiedOperand()) continue; 1297 1298 unsigned TiedTo = Info.getTiedOperand(); 1299 Expr *OutputExpr = Exprs[TiedTo]; 1300 Expr *InputExpr = Exprs[i+NumOutputs]; 1301 QualType InTy = InputExpr->getType(); 1302 QualType OutTy = OutputExpr->getType(); 1303 if (Context.hasSameType(InTy, OutTy)) 1304 continue; // All types can be tied to themselves. 1305 1306 // Int/ptr operands have some special cases that we allow. 1307 if ((OutTy->isIntegerType() || OutTy->isPointerType()) && 1308 (InTy->isIntegerType() || InTy->isPointerType())) { 1309 1310 // They are ok if they are the same size. Tying void* to int is ok if 1311 // they are the same size, for example. This also allows tying void* to 1312 // int*. 1313 uint64_t OutSize = Context.getTypeSize(OutTy); 1314 uint64_t InSize = Context.getTypeSize(InTy); 1315 if (OutSize == InSize) 1316 continue; 1317 1318 // If the smaller input/output operand is not mentioned in the asm string, 1319 // then we can promote it and the asm string won't notice. Check this 1320 // case now. 1321 bool SmallerValueMentioned = false; 1322 for (unsigned p = 0, e = Pieces.size(); p != e; ++p) { 1323 AsmStmt::AsmStringPiece &Piece = Pieces[p]; 1324 if (!Piece.isOperand()) continue; 1325 1326 // If this is a reference to the input and if the input was the smaller 1327 // one, then we have to reject this asm. 1328 if (Piece.getOperandNo() == i+NumOutputs) { 1329 if (InSize < OutSize) { 1330 SmallerValueMentioned = true; 1331 break; 1332 } 1333 } 1334 1335 // If this is a reference to the input and if the input was the smaller 1336 // one, then we have to reject this asm. 1337 if (Piece.getOperandNo() == TiedTo) { 1338 if (InSize > OutSize) { 1339 SmallerValueMentioned = true; 1340 break; 1341 } 1342 } 1343 } 1344 1345 // If the smaller value wasn't mentioned in the asm string, and if the 1346 // output was a register, just extend the shorter one to the size of the 1347 // larger one. 1348 if (!SmallerValueMentioned && 1349 OutputConstraintInfos[TiedTo].allowsRegister()) 1350 continue; 1351 } 1352 1353 Diag(InputExpr->getLocStart(), 1354 diag::err_asm_tying_incompatible_types) 1355 << InTy << OutTy << OutputExpr->getSourceRange() 1356 << InputExpr->getSourceRange(); 1357 DeleteStmt(NS); 1358 return StmtError(); 1359 } 1360 1361 return Owned(NS); 1362} 1363 1364Action::OwningStmtResult 1365Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc, 1366 SourceLocation RParen, DeclPtrTy Parm, 1367 StmtArg Body, StmtArg catchList) { 1368 Stmt *CatchList = catchList.takeAs<Stmt>(); 1369 ParmVarDecl *PVD = cast_or_null<ParmVarDecl>(Parm.getAs<Decl>()); 1370 1371 // PVD == 0 implies @catch(...). 1372 if (PVD) { 1373 // If we already know the decl is invalid, reject it. 1374 if (PVD->isInvalidDecl()) 1375 return StmtError(); 1376 1377 if (!PVD->getType()->isObjCObjectPointerType()) 1378 return StmtError(Diag(PVD->getLocation(), 1379 diag::err_catch_param_not_objc_type)); 1380 if (PVD->getType()->isObjCQualifiedIdType()) 1381 return StmtError(Diag(PVD->getLocation(), 1382 diag::err_illegal_qualifiers_on_catch_parm)); 1383 } 1384 1385 ObjCAtCatchStmt *CS = new (Context) ObjCAtCatchStmt(AtLoc, RParen, 1386 PVD, Body.takeAs<Stmt>(), CatchList); 1387 return Owned(CatchList ? CatchList : CS); 1388} 1389 1390Action::OwningStmtResult 1391Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, StmtArg Body) { 1392 return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, 1393 static_cast<Stmt*>(Body.release()))); 1394} 1395 1396Action::OwningStmtResult 1397Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, 1398 StmtArg Try, StmtArg Catch, StmtArg Finally) { 1399 CurFunctionNeedsScopeChecking = true; 1400 return Owned(new (Context) ObjCAtTryStmt(AtLoc, Try.takeAs<Stmt>(), 1401 Catch.takeAs<Stmt>(), 1402 Finally.takeAs<Stmt>())); 1403} 1404 1405Action::OwningStmtResult 1406Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, ExprArg expr,Scope *CurScope) { 1407 Expr *ThrowExpr = expr.takeAs<Expr>(); 1408 if (!ThrowExpr) { 1409 // @throw without an expression designates a rethrow (which much occur 1410 // in the context of an @catch clause). 1411 Scope *AtCatchParent = CurScope; 1412 while (AtCatchParent && !AtCatchParent->isAtCatchScope()) 1413 AtCatchParent = AtCatchParent->getParent(); 1414 if (!AtCatchParent) 1415 return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch)); 1416 } else { 1417 QualType ThrowType = ThrowExpr->getType(); 1418 // Make sure the expression type is an ObjC pointer or "void *". 1419 if (!ThrowType->isObjCObjectPointerType()) { 1420 const PointerType *PT = ThrowType->getAs<PointerType>(); 1421 if (!PT || !PT->getPointeeType()->isVoidType()) 1422 return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object) 1423 << ThrowExpr->getType() << ThrowExpr->getSourceRange()); 1424 } 1425 } 1426 return Owned(new (Context) ObjCAtThrowStmt(AtLoc, ThrowExpr)); 1427} 1428 1429Action::OwningStmtResult 1430Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, ExprArg SynchExpr, 1431 StmtArg SynchBody) { 1432 CurFunctionNeedsScopeChecking = true; 1433 1434 // Make sure the expression type is an ObjC pointer or "void *". 1435 Expr *SyncExpr = static_cast<Expr*>(SynchExpr.get()); 1436 if (!SyncExpr->getType()->isObjCObjectPointerType()) { 1437 const PointerType *PT = SyncExpr->getType()->getAs<PointerType>(); 1438 if (!PT || !PT->getPointeeType()->isVoidType()) 1439 return StmtError(Diag(AtLoc, diag::error_objc_synchronized_expects_object) 1440 << SyncExpr->getType() << SyncExpr->getSourceRange()); 1441 } 1442 1443 return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, 1444 SynchExpr.takeAs<Stmt>(), 1445 SynchBody.takeAs<Stmt>())); 1446} 1447 1448/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block 1449/// and creates a proper catch handler from them. 1450Action::OwningStmtResult 1451Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, DeclPtrTy ExDecl, 1452 StmtArg HandlerBlock) { 1453 // There's nothing to test that ActOnExceptionDecl didn't already test. 1454 return Owned(new (Context) CXXCatchStmt(CatchLoc, 1455 cast_or_null<VarDecl>(ExDecl.getAs<Decl>()), 1456 HandlerBlock.takeAs<Stmt>())); 1457} 1458 1459class TypeWithHandler { 1460 QualType t; 1461 CXXCatchStmt *stmt; 1462public: 1463 TypeWithHandler(const QualType &type, CXXCatchStmt *statement) 1464 : t(type), stmt(statement) {} 1465 1466 // An arbitrary order is fine as long as it places identical 1467 // types next to each other. 1468 bool operator<(const TypeWithHandler &y) const { 1469 if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr()) 1470 return true; 1471 if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr()) 1472 return false; 1473 else 1474 return getTypeSpecStartLoc() < y.getTypeSpecStartLoc(); 1475 } 1476 1477 bool operator==(const TypeWithHandler& other) const { 1478 return t == other.t; 1479 } 1480 1481 QualType getQualType() const { return t; } 1482 CXXCatchStmt *getCatchStmt() const { return stmt; } 1483 SourceLocation getTypeSpecStartLoc() const { 1484 return stmt->getExceptionDecl()->getTypeSpecStartLoc(); 1485 } 1486}; 1487 1488/// ActOnCXXTryBlock - Takes a try compound-statement and a number of 1489/// handlers and creates a try statement from them. 1490Action::OwningStmtResult 1491Sema::ActOnCXXTryBlock(SourceLocation TryLoc, StmtArg TryBlock, 1492 MultiStmtArg RawHandlers) { 1493 unsigned NumHandlers = RawHandlers.size(); 1494 assert(NumHandlers > 0 && 1495 "The parser shouldn't call this if there are no handlers."); 1496 Stmt **Handlers = reinterpret_cast<Stmt**>(RawHandlers.get()); 1497 1498 llvm::SmallVector<TypeWithHandler, 8> TypesWithHandlers; 1499 1500 for (unsigned i = 0; i < NumHandlers; ++i) { 1501 CXXCatchStmt *Handler = llvm::cast<CXXCatchStmt>(Handlers[i]); 1502 if (!Handler->getExceptionDecl()) { 1503 if (i < NumHandlers - 1) 1504 return StmtError(Diag(Handler->getLocStart(), 1505 diag::err_early_catch_all)); 1506 1507 continue; 1508 } 1509 1510 const QualType CaughtType = Handler->getCaughtType(); 1511 const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType); 1512 TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler)); 1513 } 1514 1515 // Detect handlers for the same type as an earlier one. 1516 if (NumHandlers > 1) { 1517 llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end()); 1518 1519 TypeWithHandler prev = TypesWithHandlers[0]; 1520 for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) { 1521 TypeWithHandler curr = TypesWithHandlers[i]; 1522 1523 if (curr == prev) { 1524 Diag(curr.getTypeSpecStartLoc(), 1525 diag::warn_exception_caught_by_earlier_handler) 1526 << curr.getCatchStmt()->getCaughtType().getAsString(); 1527 Diag(prev.getTypeSpecStartLoc(), 1528 diag::note_previous_exception_handler) 1529 << prev.getCatchStmt()->getCaughtType().getAsString(); 1530 } 1531 1532 prev = curr; 1533 } 1534 } 1535 1536 // FIXME: We should detect handlers that cannot catch anything because an 1537 // earlier handler catches a superclass. Need to find a method that is not 1538 // quadratic for this. 1539 // Neither of these are explicitly forbidden, but every compiler detects them 1540 // and warns. 1541 1542 CurFunctionNeedsScopeChecking = true; 1543 RawHandlers.release(); 1544 return Owned(new (Context) CXXTryStmt(TryLoc, 1545 static_cast<Stmt*>(TryBlock.release()), 1546 Handlers, NumHandlers)); 1547} 1548