SemaStmt.cpp revision cc15f010672a13b38104a32e3cefc7adc07ffbf7
1//===--- SemaStmt.cpp - Semantic Analysis for Statements ------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements semantic analysis for statements. 11// 12//===----------------------------------------------------------------------===// 13 14#include "clang/Sema/SemaInternal.h" 15#include "clang/Sema/Scope.h" 16#include "clang/Sema/ScopeInfo.h" 17#include "clang/Sema/Initialization.h" 18#include "clang/AST/APValue.h" 19#include "clang/AST/ASTContext.h" 20#include "clang/AST/DeclObjC.h" 21#include "clang/AST/ExprCXX.h" 22#include "clang/AST/ExprObjC.h" 23#include "clang/AST/StmtObjC.h" 24#include "clang/AST/StmtCXX.h" 25#include "clang/AST/TypeLoc.h" 26#include "clang/Lex/Preprocessor.h" 27#include "clang/Basic/TargetInfo.h" 28#include "llvm/ADT/STLExtras.h" 29#include "llvm/ADT/SmallVector.h" 30using namespace clang; 31using namespace sema; 32 33StmtResult Sema::ActOnExprStmt(FullExprArg expr) { 34 Expr *E = expr.get(); 35 if (!E) // FIXME: FullExprArg has no error state? 36 return StmtError(); 37 38 // C99 6.8.3p2: The expression in an expression statement is evaluated as a 39 // void expression for its side effects. Conversion to void allows any 40 // operand, even incomplete types. 41 42 // Same thing in for stmt first clause (when expr) and third clause. 43 return Owned(static_cast<Stmt*>(E)); 44} 45 46 47StmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc, bool LeadingEmptyMacro) { 48 return Owned(new (Context) NullStmt(SemiLoc, LeadingEmptyMacro)); 49} 50 51StmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, 52 SourceLocation StartLoc, 53 SourceLocation EndLoc) { 54 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 55 56 // If we have an invalid decl, just return an error. 57 if (DG.isNull()) return StmtError(); 58 59 return Owned(new (Context) DeclStmt(DG, StartLoc, EndLoc)); 60} 61 62void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) { 63 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 64 65 // If we have an invalid decl, just return. 66 if (DG.isNull() || !DG.isSingleDecl()) return; 67 // suppress any potential 'unused variable' warning. 68 DG.getSingleDecl()->setUsed(); 69} 70 71void Sema::DiagnoseUnusedExprResult(const Stmt *S) { 72 if (const LabelStmt *Label = dyn_cast_or_null<LabelStmt>(S)) 73 return DiagnoseUnusedExprResult(Label->getSubStmt()); 74 75 const Expr *E = dyn_cast_or_null<Expr>(S); 76 if (!E) 77 return; 78 79 if (E->isBoundMemberFunction(Context)) { 80 Diag(E->getLocStart(), diag::err_invalid_use_of_bound_member_func) 81 << E->getSourceRange(); 82 return; 83 } 84 85 SourceLocation Loc; 86 SourceRange R1, R2; 87 if (!E->isUnusedResultAWarning(Loc, R1, R2, Context)) 88 return; 89 90 // Okay, we have an unused result. Depending on what the base expression is, 91 // we might want to make a more specific diagnostic. Check for one of these 92 // cases now. 93 unsigned DiagID = diag::warn_unused_expr; 94 if (const ExprWithCleanups *Temps = dyn_cast<ExprWithCleanups>(E)) 95 E = Temps->getSubExpr(); 96 97 E = E->IgnoreParenImpCasts(); 98 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 99 if (E->getType()->isVoidType()) 100 return; 101 102 // If the callee has attribute pure, const, or warn_unused_result, warn with 103 // a more specific message to make it clear what is happening. 104 if (const Decl *FD = CE->getCalleeDecl()) { 105 if (FD->getAttr<WarnUnusedResultAttr>()) { 106 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result"; 107 return; 108 } 109 if (FD->getAttr<PureAttr>()) { 110 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure"; 111 return; 112 } 113 if (FD->getAttr<ConstAttr>()) { 114 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const"; 115 return; 116 } 117 } 118 } else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E)) { 119 const ObjCMethodDecl *MD = ME->getMethodDecl(); 120 if (MD && MD->getAttr<WarnUnusedResultAttr>()) { 121 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result"; 122 return; 123 } 124 } else if (isa<ObjCPropertyRefExpr>(E)) { 125 DiagID = diag::warn_unused_property_expr; 126 } else if (const CXXFunctionalCastExpr *FC 127 = dyn_cast<CXXFunctionalCastExpr>(E)) { 128 if (isa<CXXConstructExpr>(FC->getSubExpr()) || 129 isa<CXXTemporaryObjectExpr>(FC->getSubExpr())) 130 return; 131 } 132 // Diagnose "(void*) blah" as a typo for "(void) blah". 133 else if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(E)) { 134 TypeSourceInfo *TI = CE->getTypeInfoAsWritten(); 135 QualType T = TI->getType(); 136 137 // We really do want to use the non-canonical type here. 138 if (T == Context.VoidPtrTy) { 139 PointerTypeLoc TL = cast<PointerTypeLoc>(TI->getTypeLoc()); 140 141 Diag(Loc, diag::warn_unused_voidptr) 142 << FixItHint::CreateRemoval(TL.getStarLoc()); 143 return; 144 } 145 } 146 147 DiagRuntimeBehavior(Loc, PDiag(DiagID) << R1 << R2); 148} 149 150StmtResult 151Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R, 152 MultiStmtArg elts, bool isStmtExpr) { 153 unsigned NumElts = elts.size(); 154 Stmt **Elts = reinterpret_cast<Stmt**>(elts.release()); 155 // If we're in C89 mode, check that we don't have any decls after stmts. If 156 // so, emit an extension diagnostic. 157 if (!getLangOptions().C99 && !getLangOptions().CPlusPlus) { 158 // Note that __extension__ can be around a decl. 159 unsigned i = 0; 160 // Skip over all declarations. 161 for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i) 162 /*empty*/; 163 164 // We found the end of the list or a statement. Scan for another declstmt. 165 for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i) 166 /*empty*/; 167 168 if (i != NumElts) { 169 Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin(); 170 Diag(D->getLocation(), diag::ext_mixed_decls_code); 171 } 172 } 173 // Warn about unused expressions in statements. 174 for (unsigned i = 0; i != NumElts; ++i) { 175 // Ignore statements that are last in a statement expression. 176 if (isStmtExpr && i == NumElts - 1) 177 continue; 178 179 DiagnoseUnusedExprResult(Elts[i]); 180 } 181 182 return Owned(new (Context) CompoundStmt(Context, Elts, NumElts, L, R)); 183} 184 185StmtResult 186Sema::ActOnCaseStmt(SourceLocation CaseLoc, Expr *LHSVal, 187 SourceLocation DotDotDotLoc, Expr *RHSVal, 188 SourceLocation ColonLoc) { 189 assert((LHSVal != 0) && "missing expression in case statement"); 190 191 // C99 6.8.4.2p3: The expression shall be an integer constant. 192 // However, GCC allows any evaluatable integer expression. 193 if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent() && 194 VerifyIntegerConstantExpression(LHSVal)) 195 return StmtError(); 196 197 // GCC extension: The expression shall be an integer constant. 198 199 if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent() && 200 VerifyIntegerConstantExpression(RHSVal)) { 201 RHSVal = 0; // Recover by just forgetting about it. 202 } 203 204 if (getCurFunction()->SwitchStack.empty()) { 205 Diag(CaseLoc, diag::err_case_not_in_switch); 206 return StmtError(); 207 } 208 209 CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc, 210 ColonLoc); 211 getCurFunction()->SwitchStack.back()->addSwitchCase(CS); 212 return Owned(CS); 213} 214 215/// ActOnCaseStmtBody - This installs a statement as the body of a case. 216void Sema::ActOnCaseStmtBody(Stmt *caseStmt, Stmt *SubStmt) { 217 CaseStmt *CS = static_cast<CaseStmt*>(caseStmt); 218 CS->setSubStmt(SubStmt); 219} 220 221StmtResult 222Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc, 223 Stmt *SubStmt, Scope *CurScope) { 224 if (getCurFunction()->SwitchStack.empty()) { 225 Diag(DefaultLoc, diag::err_default_not_in_switch); 226 return Owned(SubStmt); 227 } 228 229 DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt); 230 getCurFunction()->SwitchStack.back()->addSwitchCase(DS); 231 return Owned(DS); 232} 233 234StmtResult 235Sema::ActOnLabelStmt(SourceLocation IdentLoc, IdentifierInfo *II, 236 SourceLocation ColonLoc, Stmt *SubStmt, 237 const AttributeList *Attr) { 238 // According to GCC docs, "the only attribute that makes sense after a label 239 // is 'unused'". 240 bool HasUnusedAttr = false; 241 for ( ; Attr; Attr = Attr->getNext()) { 242 if (Attr->getKind() == AttributeList::AT_unused) { 243 HasUnusedAttr = true; 244 } else { 245 Diag(Attr->getLoc(), diag::warn_label_attribute_not_unused); 246 Attr->setInvalid(true); 247 } 248 } 249 250 return ActOnLabelStmt(IdentLoc, II, ColonLoc, SubStmt, HasUnusedAttr); 251} 252 253StmtResult 254Sema::ActOnLabelStmt(SourceLocation IdentLoc, IdentifierInfo *II, 255 SourceLocation ColonLoc, Stmt *SubStmt, 256 bool HasUnusedAttr) { 257 // Look up the record for this label identifier. 258 LabelStmt *&LabelDecl = getCurFunction()->LabelMap[II]; 259 260 // If not forward referenced or defined already, just create a new LabelStmt. 261 if (LabelDecl == 0) 262 return Owned(LabelDecl = new (Context) LabelStmt(IdentLoc, II, SubStmt, 263 HasUnusedAttr)); 264 265 assert(LabelDecl->getID() == II && "Label mismatch!"); 266 267 // Otherwise, this label was either forward reference or multiply defined. If 268 // multiply defined, reject it now. 269 if (LabelDecl->getSubStmt()) { 270 Diag(IdentLoc, diag::err_redefinition_of_label) << LabelDecl->getID(); 271 Diag(LabelDecl->getIdentLoc(), diag::note_previous_definition); 272 return Owned(SubStmt); 273 } 274 275 // Otherwise, this label was forward declared, and we just found its real 276 // definition. Fill in the forward definition and return it. 277 LabelDecl->setIdentLoc(IdentLoc); 278 LabelDecl->setSubStmt(SubStmt); 279 LabelDecl->setUnusedAttribute(HasUnusedAttr); 280 return Owned(LabelDecl); 281} 282 283StmtResult 284Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, Decl *CondVar, 285 Stmt *thenStmt, SourceLocation ElseLoc, 286 Stmt *elseStmt) { 287 ExprResult CondResult(CondVal.release()); 288 289 VarDecl *ConditionVar = 0; 290 if (CondVar) { 291 ConditionVar = cast<VarDecl>(CondVar); 292 CondResult = CheckConditionVariable(ConditionVar, IfLoc, true); 293 if (CondResult.isInvalid()) 294 return StmtError(); 295 } 296 Expr *ConditionExpr = CondResult.takeAs<Expr>(); 297 if (!ConditionExpr) 298 return StmtError(); 299 300 DiagnoseUnusedExprResult(thenStmt); 301 302 // Warn if the if block has a null body without an else value. 303 // this helps prevent bugs due to typos, such as 304 // if (condition); 305 // do_stuff(); 306 // 307 if (!elseStmt) { 308 if (NullStmt* stmt = dyn_cast<NullStmt>(thenStmt)) 309 // But do not warn if the body is a macro that expands to nothing, e.g: 310 // 311 // #define CALL(x) 312 // if (condition) 313 // CALL(0); 314 // 315 if (!stmt->hasLeadingEmptyMacro()) 316 Diag(stmt->getSemiLoc(), diag::warn_empty_if_body); 317 } 318 319 DiagnoseUnusedExprResult(elseStmt); 320 321 return Owned(new (Context) IfStmt(Context, IfLoc, ConditionVar, ConditionExpr, 322 thenStmt, ElseLoc, elseStmt)); 323} 324 325/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have 326/// the specified width and sign. If an overflow occurs, detect it and emit 327/// the specified diagnostic. 328void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val, 329 unsigned NewWidth, bool NewSign, 330 SourceLocation Loc, 331 unsigned DiagID) { 332 // Perform a conversion to the promoted condition type if needed. 333 if (NewWidth > Val.getBitWidth()) { 334 // If this is an extension, just do it. 335 Val = Val.extend(NewWidth); 336 Val.setIsSigned(NewSign); 337 338 // If the input was signed and negative and the output is 339 // unsigned, don't bother to warn: this is implementation-defined 340 // behavior. 341 // FIXME: Introduce a second, default-ignored warning for this case? 342 } else if (NewWidth < Val.getBitWidth()) { 343 // If this is a truncation, check for overflow. 344 llvm::APSInt ConvVal(Val); 345 ConvVal = ConvVal.trunc(NewWidth); 346 ConvVal.setIsSigned(NewSign); 347 ConvVal = ConvVal.extend(Val.getBitWidth()); 348 ConvVal.setIsSigned(Val.isSigned()); 349 if (ConvVal != Val) 350 Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10); 351 352 // Regardless of whether a diagnostic was emitted, really do the 353 // truncation. 354 Val = Val.trunc(NewWidth); 355 Val.setIsSigned(NewSign); 356 } else if (NewSign != Val.isSigned()) { 357 // Convert the sign to match the sign of the condition. This can cause 358 // overflow as well: unsigned(INTMIN) 359 // We don't diagnose this overflow, because it is implementation-defined 360 // behavior. 361 // FIXME: Introduce a second, default-ignored warning for this case? 362 llvm::APSInt OldVal(Val); 363 Val.setIsSigned(NewSign); 364 } 365} 366 367namespace { 368 struct CaseCompareFunctor { 369 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 370 const llvm::APSInt &RHS) { 371 return LHS.first < RHS; 372 } 373 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 374 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 375 return LHS.first < RHS.first; 376 } 377 bool operator()(const llvm::APSInt &LHS, 378 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 379 return LHS < RHS.first; 380 } 381 }; 382} 383 384/// CmpCaseVals - Comparison predicate for sorting case values. 385/// 386static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs, 387 const std::pair<llvm::APSInt, CaseStmt*>& rhs) { 388 if (lhs.first < rhs.first) 389 return true; 390 391 if (lhs.first == rhs.first && 392 lhs.second->getCaseLoc().getRawEncoding() 393 < rhs.second->getCaseLoc().getRawEncoding()) 394 return true; 395 return false; 396} 397 398/// CmpEnumVals - Comparison predicate for sorting enumeration values. 399/// 400static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 401 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 402{ 403 return lhs.first < rhs.first; 404} 405 406/// EqEnumVals - Comparison preficate for uniqing enumeration values. 407/// 408static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 409 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 410{ 411 return lhs.first == rhs.first; 412} 413 414/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of 415/// potentially integral-promoted expression @p expr. 416static QualType GetTypeBeforeIntegralPromotion(const Expr* expr) { 417 if (const CastExpr *ImplicitCast = dyn_cast<ImplicitCastExpr>(expr)) { 418 const Expr *ExprBeforePromotion = ImplicitCast->getSubExpr(); 419 QualType TypeBeforePromotion = ExprBeforePromotion->getType(); 420 if (TypeBeforePromotion->isIntegralOrEnumerationType()) { 421 return TypeBeforePromotion; 422 } 423 } 424 return expr->getType(); 425} 426 427StmtResult 428Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond, 429 Decl *CondVar) { 430 ExprResult CondResult; 431 432 VarDecl *ConditionVar = 0; 433 if (CondVar) { 434 ConditionVar = cast<VarDecl>(CondVar); 435 CondResult = CheckConditionVariable(ConditionVar, SourceLocation(), false); 436 if (CondResult.isInvalid()) 437 return StmtError(); 438 439 Cond = CondResult.release(); 440 } 441 442 if (!Cond) 443 return StmtError(); 444 445 CondResult 446 = ConvertToIntegralOrEnumerationType(SwitchLoc, Cond, 447 PDiag(diag::err_typecheck_statement_requires_integer), 448 PDiag(diag::err_switch_incomplete_class_type) 449 << Cond->getSourceRange(), 450 PDiag(diag::err_switch_explicit_conversion), 451 PDiag(diag::note_switch_conversion), 452 PDiag(diag::err_switch_multiple_conversions), 453 PDiag(diag::note_switch_conversion), 454 PDiag(0)); 455 if (CondResult.isInvalid()) return StmtError(); 456 Cond = CondResult.take(); 457 458 if (!CondVar) { 459 CheckImplicitConversions(Cond, SwitchLoc); 460 CondResult = MaybeCreateExprWithCleanups(Cond); 461 if (CondResult.isInvalid()) 462 return StmtError(); 463 Cond = CondResult.take(); 464 } 465 466 getCurFunction()->setHasBranchIntoScope(); 467 468 SwitchStmt *SS = new (Context) SwitchStmt(Context, ConditionVar, Cond); 469 getCurFunction()->SwitchStack.push_back(SS); 470 return Owned(SS); 471} 472 473static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) { 474 if (Val.getBitWidth() < BitWidth) 475 Val = Val.extend(BitWidth); 476 else if (Val.getBitWidth() > BitWidth) 477 Val = Val.trunc(BitWidth); 478 Val.setIsSigned(IsSigned); 479} 480 481StmtResult 482Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch, 483 Stmt *BodyStmt) { 484 SwitchStmt *SS = cast<SwitchStmt>(Switch); 485 assert(SS == getCurFunction()->SwitchStack.back() && 486 "switch stack missing push/pop!"); 487 488 SS->setBody(BodyStmt, SwitchLoc); 489 getCurFunction()->SwitchStack.pop_back(); 490 491 if (SS->getCond() == 0) 492 return StmtError(); 493 494 Expr *CondExpr = SS->getCond(); 495 Expr *CondExprBeforePromotion = CondExpr; 496 QualType CondTypeBeforePromotion = 497 GetTypeBeforeIntegralPromotion(CondExpr); 498 499 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr. 500 UsualUnaryConversions(CondExpr); 501 QualType CondType = CondExpr->getType(); 502 SS->setCond(CondExpr); 503 504 // C++ 6.4.2.p2: 505 // Integral promotions are performed (on the switch condition). 506 // 507 // A case value unrepresentable by the original switch condition 508 // type (before the promotion) doesn't make sense, even when it can 509 // be represented by the promoted type. Therefore we need to find 510 // the pre-promotion type of the switch condition. 511 if (!CondExpr->isTypeDependent()) { 512 // We have already converted the expression to an integral or enumeration 513 // type, when we started the switch statement. If we don't have an 514 // appropriate type now, just return an error. 515 if (!CondType->isIntegralOrEnumerationType()) 516 return StmtError(); 517 518 if (CondExpr->isKnownToHaveBooleanValue()) { 519 // switch(bool_expr) {...} is often a programmer error, e.g. 520 // switch(n && mask) { ... } // Doh - should be "n & mask". 521 // One can always use an if statement instead of switch(bool_expr). 522 Diag(SwitchLoc, diag::warn_bool_switch_condition) 523 << CondExpr->getSourceRange(); 524 } 525 } 526 527 // Get the bitwidth of the switched-on value before promotions. We must 528 // convert the integer case values to this width before comparison. 529 bool HasDependentValue 530 = CondExpr->isTypeDependent() || CondExpr->isValueDependent(); 531 unsigned CondWidth 532 = HasDependentValue? 0 533 : static_cast<unsigned>(Context.getTypeSize(CondTypeBeforePromotion)); 534 bool CondIsSigned = CondTypeBeforePromotion->isSignedIntegerType(); 535 536 // Accumulate all of the case values in a vector so that we can sort them 537 // and detect duplicates. This vector contains the APInt for the case after 538 // it has been converted to the condition type. 539 typedef llvm::SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy; 540 CaseValsTy CaseVals; 541 542 // Keep track of any GNU case ranges we see. The APSInt is the low value. 543 typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy; 544 CaseRangesTy CaseRanges; 545 546 DefaultStmt *TheDefaultStmt = 0; 547 548 bool CaseListIsErroneous = false; 549 550 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue; 551 SC = SC->getNextSwitchCase()) { 552 553 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) { 554 if (TheDefaultStmt) { 555 Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined); 556 Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev); 557 558 // FIXME: Remove the default statement from the switch block so that 559 // we'll return a valid AST. This requires recursing down the AST and 560 // finding it, not something we are set up to do right now. For now, 561 // just lop the entire switch stmt out of the AST. 562 CaseListIsErroneous = true; 563 } 564 TheDefaultStmt = DS; 565 566 } else { 567 CaseStmt *CS = cast<CaseStmt>(SC); 568 569 // We already verified that the expression has a i-c-e value (C99 570 // 6.8.4.2p3) - get that value now. 571 Expr *Lo = CS->getLHS(); 572 573 if (Lo->isTypeDependent() || Lo->isValueDependent()) { 574 HasDependentValue = true; 575 break; 576 } 577 578 llvm::APSInt LoVal = Lo->EvaluateAsInt(Context); 579 580 // Convert the value to the same width/sign as the condition. 581 ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned, 582 Lo->getLocStart(), 583 diag::warn_case_value_overflow); 584 585 // If the LHS is not the same type as the condition, insert an implicit 586 // cast. 587 ImpCastExprToType(Lo, CondType, CK_IntegralCast); 588 CS->setLHS(Lo); 589 590 // If this is a case range, remember it in CaseRanges, otherwise CaseVals. 591 if (CS->getRHS()) { 592 if (CS->getRHS()->isTypeDependent() || 593 CS->getRHS()->isValueDependent()) { 594 HasDependentValue = true; 595 break; 596 } 597 CaseRanges.push_back(std::make_pair(LoVal, CS)); 598 } else 599 CaseVals.push_back(std::make_pair(LoVal, CS)); 600 } 601 } 602 603 if (!HasDependentValue) { 604 // If we don't have a default statement, check whether the 605 // condition is constant. 606 llvm::APSInt ConstantCondValue; 607 bool HasConstantCond = false; 608 bool ShouldCheckConstantCond = false; 609 if (!HasDependentValue && !TheDefaultStmt) { 610 Expr::EvalResult Result; 611 HasConstantCond = CondExprBeforePromotion->Evaluate(Result, Context); 612 if (HasConstantCond) { 613 assert(Result.Val.isInt() && "switch condition evaluated to non-int"); 614 ConstantCondValue = Result.Val.getInt(); 615 ShouldCheckConstantCond = true; 616 617 assert(ConstantCondValue.getBitWidth() == CondWidth && 618 ConstantCondValue.isSigned() == CondIsSigned); 619 } 620 } 621 622 // Sort all the scalar case values so we can easily detect duplicates. 623 std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals); 624 625 if (!CaseVals.empty()) { 626 for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) { 627 if (ShouldCheckConstantCond && 628 CaseVals[i].first == ConstantCondValue) 629 ShouldCheckConstantCond = false; 630 631 if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) { 632 // If we have a duplicate, report it. 633 Diag(CaseVals[i].second->getLHS()->getLocStart(), 634 diag::err_duplicate_case) << CaseVals[i].first.toString(10); 635 Diag(CaseVals[i-1].second->getLHS()->getLocStart(), 636 diag::note_duplicate_case_prev); 637 // FIXME: We really want to remove the bogus case stmt from the 638 // substmt, but we have no way to do this right now. 639 CaseListIsErroneous = true; 640 } 641 } 642 } 643 644 // Detect duplicate case ranges, which usually don't exist at all in 645 // the first place. 646 if (!CaseRanges.empty()) { 647 // Sort all the case ranges by their low value so we can easily detect 648 // overlaps between ranges. 649 std::stable_sort(CaseRanges.begin(), CaseRanges.end()); 650 651 // Scan the ranges, computing the high values and removing empty ranges. 652 std::vector<llvm::APSInt> HiVals; 653 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 654 llvm::APSInt &LoVal = CaseRanges[i].first; 655 CaseStmt *CR = CaseRanges[i].second; 656 Expr *Hi = CR->getRHS(); 657 llvm::APSInt HiVal = Hi->EvaluateAsInt(Context); 658 659 // Convert the value to the same width/sign as the condition. 660 ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned, 661 Hi->getLocStart(), 662 diag::warn_case_value_overflow); 663 664 // If the LHS is not the same type as the condition, insert an implicit 665 // cast. 666 ImpCastExprToType(Hi, CondType, CK_IntegralCast); 667 CR->setRHS(Hi); 668 669 // If the low value is bigger than the high value, the case is empty. 670 if (LoVal > HiVal) { 671 Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range) 672 << SourceRange(CR->getLHS()->getLocStart(), 673 Hi->getLocEnd()); 674 CaseRanges.erase(CaseRanges.begin()+i); 675 --i, --e; 676 continue; 677 } 678 679 if (ShouldCheckConstantCond && 680 LoVal <= ConstantCondValue && 681 ConstantCondValue <= HiVal) 682 ShouldCheckConstantCond = false; 683 684 HiVals.push_back(HiVal); 685 } 686 687 // Rescan the ranges, looking for overlap with singleton values and other 688 // ranges. Since the range list is sorted, we only need to compare case 689 // ranges with their neighbors. 690 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 691 llvm::APSInt &CRLo = CaseRanges[i].first; 692 llvm::APSInt &CRHi = HiVals[i]; 693 CaseStmt *CR = CaseRanges[i].second; 694 695 // Check to see whether the case range overlaps with any 696 // singleton cases. 697 CaseStmt *OverlapStmt = 0; 698 llvm::APSInt OverlapVal(32); 699 700 // Find the smallest value >= the lower bound. If I is in the 701 // case range, then we have overlap. 702 CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(), 703 CaseVals.end(), CRLo, 704 CaseCompareFunctor()); 705 if (I != CaseVals.end() && I->first < CRHi) { 706 OverlapVal = I->first; // Found overlap with scalar. 707 OverlapStmt = I->second; 708 } 709 710 // Find the smallest value bigger than the upper bound. 711 I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor()); 712 if (I != CaseVals.begin() && (I-1)->first >= CRLo) { 713 OverlapVal = (I-1)->first; // Found overlap with scalar. 714 OverlapStmt = (I-1)->second; 715 } 716 717 // Check to see if this case stmt overlaps with the subsequent 718 // case range. 719 if (i && CRLo <= HiVals[i-1]) { 720 OverlapVal = HiVals[i-1]; // Found overlap with range. 721 OverlapStmt = CaseRanges[i-1].second; 722 } 723 724 if (OverlapStmt) { 725 // If we have a duplicate, report it. 726 Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case) 727 << OverlapVal.toString(10); 728 Diag(OverlapStmt->getLHS()->getLocStart(), 729 diag::note_duplicate_case_prev); 730 // FIXME: We really want to remove the bogus case stmt from the 731 // substmt, but we have no way to do this right now. 732 CaseListIsErroneous = true; 733 } 734 } 735 } 736 737 // Complain if we have a constant condition and we didn't find a match. 738 if (!CaseListIsErroneous && ShouldCheckConstantCond) { 739 // TODO: it would be nice if we printed enums as enums, chars as 740 // chars, etc. 741 Diag(CondExpr->getExprLoc(), diag::warn_missing_case_for_condition) 742 << ConstantCondValue.toString(10) 743 << CondExpr->getSourceRange(); 744 } 745 746 // Check to see if switch is over an Enum and handles all of its 747 // values. We only issue a warning if there is not 'default:', but 748 // we still do the analysis to preserve this information in the AST 749 // (which can be used by flow-based analyes). 750 // 751 const EnumType *ET = CondTypeBeforePromotion->getAs<EnumType>(); 752 753 // If switch has default case, then ignore it. 754 if (!CaseListIsErroneous && !HasConstantCond && ET) { 755 const EnumDecl *ED = ET->getDecl(); 756 typedef llvm::SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> EnumValsTy; 757 EnumValsTy EnumVals; 758 759 // Gather all enum values, set their type and sort them, 760 // allowing easier comparison with CaseVals. 761 for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin(); 762 EDI != ED->enumerator_end(); ++EDI) { 763 llvm::APSInt Val = EDI->getInitVal(); 764 AdjustAPSInt(Val, CondWidth, CondIsSigned); 765 EnumVals.push_back(std::make_pair(Val, *EDI)); 766 } 767 std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals); 768 EnumValsTy::iterator EIend = 769 std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals); 770 771 // See which case values aren't in enum. 772 // TODO: we might want to check whether case values are out of the 773 // enum even if we don't want to check whether all cases are handled. 774 if (!TheDefaultStmt) { 775 EnumValsTy::const_iterator EI = EnumVals.begin(); 776 for (CaseValsTy::const_iterator CI = CaseVals.begin(); 777 CI != CaseVals.end(); CI++) { 778 while (EI != EIend && EI->first < CI->first) 779 EI++; 780 if (EI == EIend || EI->first > CI->first) 781 Diag(CI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 782 << ED->getDeclName(); 783 } 784 // See which of case ranges aren't in enum 785 EI = EnumVals.begin(); 786 for (CaseRangesTy::const_iterator RI = CaseRanges.begin(); 787 RI != CaseRanges.end() && EI != EIend; RI++) { 788 while (EI != EIend && EI->first < RI->first) 789 EI++; 790 791 if (EI == EIend || EI->first != RI->first) { 792 Diag(RI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 793 << ED->getDeclName(); 794 } 795 796 llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context); 797 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 798 while (EI != EIend && EI->first < Hi) 799 EI++; 800 if (EI == EIend || EI->first != Hi) 801 Diag(RI->second->getRHS()->getExprLoc(), diag::warn_not_in_enum) 802 << ED->getDeclName(); 803 } 804 } 805 806 // Check which enum vals aren't in switch 807 CaseValsTy::const_iterator CI = CaseVals.begin(); 808 CaseRangesTy::const_iterator RI = CaseRanges.begin(); 809 bool hasCasesNotInSwitch = false; 810 811 llvm::SmallVector<DeclarationName,8> UnhandledNames; 812 813 for (EnumValsTy::const_iterator EI = EnumVals.begin(); EI != EIend; EI++){ 814 // Drop unneeded case values 815 llvm::APSInt CIVal; 816 while (CI != CaseVals.end() && CI->first < EI->first) 817 CI++; 818 819 if (CI != CaseVals.end() && CI->first == EI->first) 820 continue; 821 822 // Drop unneeded case ranges 823 for (; RI != CaseRanges.end(); RI++) { 824 llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context); 825 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 826 if (EI->first <= Hi) 827 break; 828 } 829 830 if (RI == CaseRanges.end() || EI->first < RI->first) { 831 hasCasesNotInSwitch = true; 832 if (!TheDefaultStmt) 833 UnhandledNames.push_back(EI->second->getDeclName()); 834 } 835 } 836 837 // Produce a nice diagnostic if multiple values aren't handled. 838 switch (UnhandledNames.size()) { 839 case 0: break; 840 case 1: 841 Diag(CondExpr->getExprLoc(), diag::warn_missing_case1) 842 << UnhandledNames[0]; 843 break; 844 case 2: 845 Diag(CondExpr->getExprLoc(), diag::warn_missing_case2) 846 << UnhandledNames[0] << UnhandledNames[1]; 847 break; 848 case 3: 849 Diag(CondExpr->getExprLoc(), diag::warn_missing_case3) 850 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 851 break; 852 default: 853 Diag(CondExpr->getExprLoc(), diag::warn_missing_cases) 854 << (unsigned)UnhandledNames.size() 855 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 856 break; 857 } 858 859 if (!hasCasesNotInSwitch) 860 SS->setAllEnumCasesCovered(); 861 } 862 } 863 864 // FIXME: If the case list was broken is some way, we don't have a good system 865 // to patch it up. Instead, just return the whole substmt as broken. 866 if (CaseListIsErroneous) 867 return StmtError(); 868 869 return Owned(SS); 870} 871 872StmtResult 873Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond, 874 Decl *CondVar, Stmt *Body) { 875 ExprResult CondResult(Cond.release()); 876 877 VarDecl *ConditionVar = 0; 878 if (CondVar) { 879 ConditionVar = cast<VarDecl>(CondVar); 880 CondResult = CheckConditionVariable(ConditionVar, WhileLoc, true); 881 if (CondResult.isInvalid()) 882 return StmtError(); 883 } 884 Expr *ConditionExpr = CondResult.take(); 885 if (!ConditionExpr) 886 return StmtError(); 887 888 DiagnoseUnusedExprResult(Body); 889 890 return Owned(new (Context) WhileStmt(Context, ConditionVar, ConditionExpr, 891 Body, WhileLoc)); 892} 893 894StmtResult 895Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body, 896 SourceLocation WhileLoc, SourceLocation CondLParen, 897 Expr *Cond, SourceLocation CondRParen) { 898 assert(Cond && "ActOnDoStmt(): missing expression"); 899 900 if (CheckBooleanCondition(Cond, DoLoc)) 901 return StmtError(); 902 903 CheckImplicitConversions(Cond, DoLoc); 904 ExprResult CondResult = MaybeCreateExprWithCleanups(Cond); 905 if (CondResult.isInvalid()) 906 return StmtError(); 907 Cond = CondResult.take(); 908 909 DiagnoseUnusedExprResult(Body); 910 911 return Owned(new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen)); 912} 913 914StmtResult 915Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 916 Stmt *First, FullExprArg second, Decl *secondVar, 917 FullExprArg third, 918 SourceLocation RParenLoc, Stmt *Body) { 919 if (!getLangOptions().CPlusPlus) { 920 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) { 921 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 922 // declare identifiers for objects having storage class 'auto' or 923 // 'register'. 924 for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end(); 925 DI!=DE; ++DI) { 926 VarDecl *VD = dyn_cast<VarDecl>(*DI); 927 if (VD && VD->isLocalVarDecl() && !VD->hasLocalStorage()) 928 VD = 0; 929 if (VD == 0) 930 Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for); 931 // FIXME: mark decl erroneous! 932 } 933 } 934 } 935 936 ExprResult SecondResult(second.release()); 937 VarDecl *ConditionVar = 0; 938 if (secondVar) { 939 ConditionVar = cast<VarDecl>(secondVar); 940 SecondResult = CheckConditionVariable(ConditionVar, ForLoc, true); 941 if (SecondResult.isInvalid()) 942 return StmtError(); 943 } 944 945 Expr *Third = third.release().takeAs<Expr>(); 946 947 DiagnoseUnusedExprResult(First); 948 DiagnoseUnusedExprResult(Third); 949 DiagnoseUnusedExprResult(Body); 950 951 return Owned(new (Context) ForStmt(Context, First, 952 SecondResult.take(), ConditionVar, 953 Third, Body, ForLoc, LParenLoc, 954 RParenLoc)); 955} 956 957/// In an Objective C collection iteration statement: 958/// for (x in y) 959/// x can be an arbitrary l-value expression. Bind it up as a 960/// full-expression. 961StmtResult Sema::ActOnForEachLValueExpr(Expr *E) { 962 CheckImplicitConversions(E); 963 ExprResult Result = MaybeCreateExprWithCleanups(E); 964 if (Result.isInvalid()) return StmtError(); 965 return Owned(static_cast<Stmt*>(Result.get())); 966} 967 968StmtResult 969Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc, 970 SourceLocation LParenLoc, 971 Stmt *First, Expr *Second, 972 SourceLocation RParenLoc, Stmt *Body) { 973 if (First) { 974 QualType FirstType; 975 if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) { 976 if (!DS->isSingleDecl()) 977 return StmtError(Diag((*DS->decl_begin())->getLocation(), 978 diag::err_toomany_element_decls)); 979 980 Decl *D = DS->getSingleDecl(); 981 FirstType = cast<ValueDecl>(D)->getType(); 982 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 983 // declare identifiers for objects having storage class 'auto' or 984 // 'register'. 985 VarDecl *VD = cast<VarDecl>(D); 986 if (VD->isLocalVarDecl() && !VD->hasLocalStorage()) 987 return StmtError(Diag(VD->getLocation(), 988 diag::err_non_variable_decl_in_for)); 989 } else { 990 Expr *FirstE = cast<Expr>(First); 991 if (!FirstE->isTypeDependent() && !FirstE->isLValue()) 992 return StmtError(Diag(First->getLocStart(), 993 diag::err_selector_element_not_lvalue) 994 << First->getSourceRange()); 995 996 FirstType = static_cast<Expr*>(First)->getType(); 997 } 998 if (!FirstType->isDependentType() && 999 !FirstType->isObjCObjectPointerType() && 1000 !FirstType->isBlockPointerType()) 1001 Diag(ForLoc, diag::err_selector_element_type) 1002 << FirstType << First->getSourceRange(); 1003 } 1004 if (Second && !Second->isTypeDependent()) { 1005 DefaultFunctionArrayLvalueConversion(Second); 1006 QualType SecondType = Second->getType(); 1007 if (!SecondType->isObjCObjectPointerType()) 1008 Diag(ForLoc, diag::err_collection_expr_type) 1009 << SecondType << Second->getSourceRange(); 1010 else if (const ObjCObjectPointerType *OPT = 1011 SecondType->getAsObjCInterfacePointerType()) { 1012 llvm::SmallVector<IdentifierInfo *, 4> KeyIdents; 1013 IdentifierInfo* selIdent = 1014 &Context.Idents.get("countByEnumeratingWithState"); 1015 KeyIdents.push_back(selIdent); 1016 selIdent = &Context.Idents.get("objects"); 1017 KeyIdents.push_back(selIdent); 1018 selIdent = &Context.Idents.get("count"); 1019 KeyIdents.push_back(selIdent); 1020 Selector CSelector = Context.Selectors.getSelector(3, &KeyIdents[0]); 1021 if (ObjCInterfaceDecl *IDecl = OPT->getInterfaceDecl()) { 1022 if (!IDecl->isForwardDecl() && 1023 !IDecl->lookupInstanceMethod(CSelector)) { 1024 // Must further look into private implementation methods. 1025 if (!LookupPrivateInstanceMethod(CSelector, IDecl)) 1026 Diag(ForLoc, diag::warn_collection_expr_type) 1027 << SecondType << CSelector << Second->getSourceRange(); 1028 } 1029 } 1030 } 1031 } 1032 return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body, 1033 ForLoc, RParenLoc)); 1034} 1035 1036StmtResult 1037Sema::ActOnGotoStmt(SourceLocation GotoLoc, SourceLocation LabelLoc, 1038 IdentifierInfo *LabelII) { 1039 // Look up the record for this label identifier. 1040 LabelStmt *&LabelDecl = getCurFunction()->LabelMap[LabelII]; 1041 1042 getCurFunction()->setHasBranchIntoScope(); 1043 1044 // If we haven't seen this label yet, create a forward reference. 1045 if (LabelDecl == 0) 1046 LabelDecl = new (Context) LabelStmt(LabelLoc, LabelII, 0); 1047 1048 LabelDecl->setUsed(); 1049 return Owned(new (Context) GotoStmt(LabelDecl, GotoLoc, LabelLoc)); 1050} 1051 1052StmtResult 1053Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc, 1054 Expr *E) { 1055 // Convert operand to void* 1056 if (!E->isTypeDependent()) { 1057 QualType ETy = E->getType(); 1058 QualType DestTy = Context.getPointerType(Context.VoidTy.withConst()); 1059 AssignConvertType ConvTy = 1060 CheckSingleAssignmentConstraints(DestTy, E); 1061 if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing)) 1062 return StmtError(); 1063 } 1064 1065 getCurFunction()->setHasIndirectGoto(); 1066 1067 return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E)); 1068} 1069 1070StmtResult 1071Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) { 1072 Scope *S = CurScope->getContinueParent(); 1073 if (!S) { 1074 // C99 6.8.6.2p1: A break shall appear only in or as a loop body. 1075 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop)); 1076 } 1077 1078 return Owned(new (Context) ContinueStmt(ContinueLoc)); 1079} 1080 1081StmtResult 1082Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) { 1083 Scope *S = CurScope->getBreakParent(); 1084 if (!S) { 1085 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body. 1086 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch)); 1087 } 1088 1089 return Owned(new (Context) BreakStmt(BreakLoc)); 1090} 1091 1092/// \brief Determine whether the given expression is a candidate for 1093/// copy elision in either a return statement or a throw expression. 1094/// 1095/// \param ReturnType If we're determining the copy elision candidate for 1096/// a return statement, this is the return type of the function. If we're 1097/// determining the copy elision candidate for a throw expression, this will 1098/// be a NULL type. 1099/// 1100/// \param E The expression being returned from the function or block, or 1101/// being thrown. 1102/// 1103/// \param AllowFunctionParameter 1104/// 1105/// \returns The NRVO candidate variable, if the return statement may use the 1106/// NRVO, or NULL if there is no such candidate. 1107const VarDecl *Sema::getCopyElisionCandidate(QualType ReturnType, 1108 Expr *E, 1109 bool AllowFunctionParameter) { 1110 QualType ExprType = E->getType(); 1111 // - in a return statement in a function with ... 1112 // ... a class return type ... 1113 if (!ReturnType.isNull()) { 1114 if (!ReturnType->isRecordType()) 1115 return 0; 1116 // ... the same cv-unqualified type as the function return type ... 1117 if (!Context.hasSameUnqualifiedType(ReturnType, ExprType)) 1118 return 0; 1119 } 1120 1121 // ... the expression is the name of a non-volatile automatic object 1122 // (other than a function or catch-clause parameter)) ... 1123 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(E->IgnoreParens()); 1124 if (!DR) 1125 return 0; 1126 const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()); 1127 if (!VD) 1128 return 0; 1129 1130 if (VD->hasLocalStorage() && !VD->isExceptionVariable() && 1131 !VD->getType()->isReferenceType() && !VD->hasAttr<BlocksAttr>() && 1132 !VD->getType().isVolatileQualified() && 1133 ((VD->getKind() == Decl::Var) || 1134 (AllowFunctionParameter && VD->getKind() == Decl::ParmVar))) 1135 return VD; 1136 1137 return 0; 1138} 1139 1140/// \brief Perform the initialization of a return value. 1141/// 1142/// This routine implements C++0x [class.copy]p33, which attempts to treat 1143/// returned lvalues as rvalues in certain cases (to prefer move construction), 1144/// then falls back to treating them as lvalues if that failed. 1145static ExprResult initializeReturnValue(Sema &S, 1146 const VarDecl *NRVOCandidate, 1147 SourceLocation ReturnLoc, 1148 QualType ResultType, 1149 Expr *RetValExp) { 1150 // C++0x [class.copy]p33: 1151 // When the criteria for elision of a copy operation are met or would 1152 // be met save for the fact that the source object is a function 1153 // parameter, and the object to be copied is designated by an lvalue, 1154 // overload resolution to select the constructor for the copy is first 1155 // performed as if the object were designated by an rvalue. 1156 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 1157 ResultType, 1158 NRVOCandidate != 0); 1159 1160 ExprResult Res = ExprError(); 1161 if (NRVOCandidate || S.getCopyElisionCandidate(ResultType, RetValExp, true)) { 1162 ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack, 1163 RetValExp->getType(), CK_LValueToRValue, 1164 RetValExp, VK_XValue); 1165 1166 Expr *InitExpr = &AsRvalue; 1167 InitializationKind Kind 1168 = InitializationKind::CreateCopy(RetValExp->getLocStart(), 1169 RetValExp->getLocStart()); 1170 InitializationSequence Seq(S, Entity, Kind, &InitExpr, 1); 1171 1172 // [...] If overload resolution fails, or if the type of the first 1173 // parameter of the selected constructor is not an rvalue reference 1174 // to the object’s type (possibly cv-qualified), overload resolution 1175 // is performed again, considering the object as an lvalue. 1176 if (Seq.getKind() != InitializationSequence::FailedSequence) { 1177 for (InitializationSequence::step_iterator Step = Seq.step_begin(), 1178 StepEnd = Seq.step_end(); 1179 Step != StepEnd; ++Step) { 1180 if (Step->Kind 1181 != InitializationSequence::SK_ConstructorInitialization) 1182 continue; 1183 1184 CXXConstructorDecl *Constructor 1185 = cast<CXXConstructorDecl>(Step->Function.Function); 1186 1187 const RValueReferenceType *RRefType 1188 = Constructor->getParamDecl(0)->getType() 1189 ->getAs<RValueReferenceType>(); 1190 1191 // If we don't meet the criteria, break out now. 1192 if (!RRefType || 1193 !S.Context.hasSameUnqualifiedType(RRefType->getPointeeType(), 1194 ResultType)) 1195 break; 1196 1197 // Promote "AsRvalue" to the heap, since we now need this 1198 // expression node to persist. 1199 RetValExp = ImplicitCastExpr::Create(S.Context, 1200 RetValExp->getType(), 1201 CK_LValueToRValue, 1202 RetValExp, 0, VK_XValue); 1203 1204 // Complete type-checking the initialization of the return type 1205 // using the constructor we found. 1206 Res = Seq.Perform(S, Entity, Kind, MultiExprArg(&RetValExp, 1)); 1207 } 1208 } 1209 } 1210 1211 // Either we didn't meet the criteria for treating an lvalue as an rvalue, 1212 // above, or overload resolution failed. Either way, we need to try 1213 // (again) now with the return value expression as written. 1214 if (Res.isInvalid()) 1215 Res = S.PerformCopyInitialization(Entity, SourceLocation(), RetValExp); 1216 1217 return Res; 1218} 1219 1220/// ActOnBlockReturnStmt - Utility routine to figure out block's return type. 1221/// 1222StmtResult 1223Sema::ActOnBlockReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1224 // If this is the first return we've seen in the block, infer the type of 1225 // the block from it. 1226 BlockScopeInfo *CurBlock = getCurBlock(); 1227 if (CurBlock->ReturnType.isNull()) { 1228 if (RetValExp) { 1229 // Don't call UsualUnaryConversions(), since we don't want to do 1230 // integer promotions here. 1231 DefaultFunctionArrayLvalueConversion(RetValExp); 1232 CurBlock->ReturnType = RetValExp->getType(); 1233 if (BlockDeclRefExpr *CDRE = dyn_cast<BlockDeclRefExpr>(RetValExp)) { 1234 // We have to remove a 'const' added to copied-in variable which was 1235 // part of the implementation spec. and not the actual qualifier for 1236 // the variable. 1237 if (CDRE->isConstQualAdded()) 1238 CurBlock->ReturnType.removeLocalConst(); // FIXME: local??? 1239 } 1240 } else 1241 CurBlock->ReturnType = Context.VoidTy; 1242 } 1243 QualType FnRetType = CurBlock->ReturnType; 1244 1245 if (CurBlock->FunctionType->getAs<FunctionType>()->getNoReturnAttr()) { 1246 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr) 1247 << getCurFunctionOrMethodDecl()->getDeclName(); 1248 return StmtError(); 1249 } 1250 1251 // Otherwise, verify that this result type matches the previous one. We are 1252 // pickier with blocks than for normal functions because we don't have GCC 1253 // compatibility to worry about here. 1254 ReturnStmt *Result = 0; 1255 if (CurBlock->ReturnType->isVoidType()) { 1256 if (RetValExp) { 1257 Diag(ReturnLoc, diag::err_return_block_has_expr); 1258 RetValExp = 0; 1259 } 1260 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 1261 } else if (!RetValExp) { 1262 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr)); 1263 } else { 1264 const VarDecl *NRVOCandidate = 0; 1265 1266 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1267 // we have a non-void block with an expression, continue checking 1268 1269 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1270 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1271 // function return. 1272 1273 // In C++ the return statement is handled via a copy initialization. 1274 // the C version of which boils down to CheckSingleAssignmentConstraints. 1275 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 1276 ExprResult Res = initializeReturnValue(*this, NRVOCandidate, ReturnLoc, 1277 FnRetType, RetValExp); 1278 if (Res.isInvalid()) { 1279 // FIXME: Cleanup temporaries here, anyway? 1280 return StmtError(); 1281 } 1282 1283 if (RetValExp) { 1284 CheckImplicitConversions(RetValExp, ReturnLoc); 1285 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1286 } 1287 1288 RetValExp = Res.takeAs<Expr>(); 1289 if (RetValExp) 1290 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1291 } 1292 1293 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 1294 } 1295 1296 // If we need to check for the named return value optimization, save the 1297 // return statement in our scope for later processing. 1298 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 1299 !CurContext->isDependentContext()) 1300 FunctionScopes.back()->Returns.push_back(Result); 1301 1302 return Owned(Result); 1303} 1304 1305StmtResult 1306Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1307 if (getCurBlock()) 1308 return ActOnBlockReturnStmt(ReturnLoc, RetValExp); 1309 1310 QualType FnRetType; 1311 if (const FunctionDecl *FD = getCurFunctionDecl()) { 1312 FnRetType = FD->getResultType(); 1313 if (FD->hasAttr<NoReturnAttr>() || 1314 FD->getType()->getAs<FunctionType>()->getNoReturnAttr()) 1315 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) 1316 << getCurFunctionOrMethodDecl()->getDeclName(); 1317 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) 1318 FnRetType = MD->getResultType(); 1319 else // If we don't have a function/method context, bail. 1320 return StmtError(); 1321 1322 ReturnStmt *Result = 0; 1323 if (FnRetType->isVoidType()) { 1324 if (RetValExp && !RetValExp->isTypeDependent()) { 1325 // C99 6.8.6.4p1 (ext_ since GCC warns) 1326 unsigned D = diag::ext_return_has_expr; 1327 if (RetValExp->getType()->isVoidType()) 1328 D = diag::ext_return_has_void_expr; 1329 else { 1330 IgnoredValueConversions(RetValExp); 1331 ImpCastExprToType(RetValExp, Context.VoidTy, CK_ToVoid); 1332 } 1333 1334 // return (some void expression); is legal in C++. 1335 if (D != diag::ext_return_has_void_expr || 1336 !getLangOptions().CPlusPlus) { 1337 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 1338 Diag(ReturnLoc, D) 1339 << CurDecl->getDeclName() << isa<ObjCMethodDecl>(CurDecl) 1340 << RetValExp->getSourceRange(); 1341 } 1342 1343 CheckImplicitConversions(RetValExp, ReturnLoc); 1344 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1345 } 1346 1347 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 1348 } else if (!RetValExp && !FnRetType->isDependentType()) { 1349 unsigned DiagID = diag::warn_return_missing_expr; // C90 6.6.6.4p4 1350 // C99 6.8.6.4p1 (ext_ since GCC warns) 1351 if (getLangOptions().C99) DiagID = diag::ext_return_missing_expr; 1352 1353 if (FunctionDecl *FD = getCurFunctionDecl()) 1354 Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/; 1355 else 1356 Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/; 1357 Result = new (Context) ReturnStmt(ReturnLoc); 1358 } else { 1359 const VarDecl *NRVOCandidate = 0; 1360 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1361 // we have a non-void function with an expression, continue checking 1362 1363 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1364 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1365 // function return. 1366 1367 // In C++ the return statement is handled via a copy initialization. 1368 // the C version of which boils down to CheckSingleAssignmentConstraints. 1369 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 1370 ExprResult Res = initializeReturnValue(*this, NRVOCandidate, ReturnLoc, 1371 FnRetType, RetValExp); 1372 if (Res.isInvalid()) { 1373 // FIXME: Cleanup temporaries here, anyway? 1374 return StmtError(); 1375 } 1376 1377 RetValExp = Res.takeAs<Expr>(); 1378 if (RetValExp) 1379 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1380 } 1381 1382 if (RetValExp) { 1383 CheckImplicitConversions(RetValExp, ReturnLoc); 1384 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1385 } 1386 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 1387 } 1388 1389 // If we need to check for the named return value optimization, save the 1390 // return statement in our scope for later processing. 1391 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 1392 !CurContext->isDependentContext()) 1393 FunctionScopes.back()->Returns.push_back(Result); 1394 1395 return Owned(Result); 1396} 1397 1398/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently 1399/// ignore "noop" casts in places where an lvalue is required by an inline asm. 1400/// We emulate this behavior when -fheinous-gnu-extensions is specified, but 1401/// provide a strong guidance to not use it. 1402/// 1403/// This method checks to see if the argument is an acceptable l-value and 1404/// returns false if it is a case we can handle. 1405static bool CheckAsmLValue(const Expr *E, Sema &S) { 1406 // Type dependent expressions will be checked during instantiation. 1407 if (E->isTypeDependent()) 1408 return false; 1409 1410 if (E->isLValue()) 1411 return false; // Cool, this is an lvalue. 1412 1413 // Okay, this is not an lvalue, but perhaps it is the result of a cast that we 1414 // are supposed to allow. 1415 const Expr *E2 = E->IgnoreParenNoopCasts(S.Context); 1416 if (E != E2 && E2->isLValue()) { 1417 if (!S.getLangOptions().HeinousExtensions) 1418 S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue) 1419 << E->getSourceRange(); 1420 else 1421 S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue) 1422 << E->getSourceRange(); 1423 // Accept, even if we emitted an error diagnostic. 1424 return false; 1425 } 1426 1427 // None of the above, just randomly invalid non-lvalue. 1428 return true; 1429} 1430 1431 1432StmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, 1433 bool IsSimple, 1434 bool IsVolatile, 1435 unsigned NumOutputs, 1436 unsigned NumInputs, 1437 IdentifierInfo **Names, 1438 MultiExprArg constraints, 1439 MultiExprArg exprs, 1440 Expr *asmString, 1441 MultiExprArg clobbers, 1442 SourceLocation RParenLoc, 1443 bool MSAsm) { 1444 unsigned NumClobbers = clobbers.size(); 1445 StringLiteral **Constraints = 1446 reinterpret_cast<StringLiteral**>(constraints.get()); 1447 Expr **Exprs = exprs.get(); 1448 StringLiteral *AsmString = cast<StringLiteral>(asmString); 1449 StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get()); 1450 1451 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; 1452 1453 // The parser verifies that there is a string literal here. 1454 if (AsmString->isWide()) 1455 return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character) 1456 << AsmString->getSourceRange()); 1457 1458 for (unsigned i = 0; i != NumOutputs; i++) { 1459 StringLiteral *Literal = Constraints[i]; 1460 if (Literal->isWide()) 1461 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1462 << Literal->getSourceRange()); 1463 1464 llvm::StringRef OutputName; 1465 if (Names[i]) 1466 OutputName = Names[i]->getName(); 1467 1468 TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName); 1469 if (!Context.Target.validateOutputConstraint(Info)) 1470 return StmtError(Diag(Literal->getLocStart(), 1471 diag::err_asm_invalid_output_constraint) 1472 << Info.getConstraintStr()); 1473 1474 // Check that the output exprs are valid lvalues. 1475 Expr *OutputExpr = Exprs[i]; 1476 if (CheckAsmLValue(OutputExpr, *this)) { 1477 return StmtError(Diag(OutputExpr->getLocStart(), 1478 diag::err_asm_invalid_lvalue_in_output) 1479 << OutputExpr->getSourceRange()); 1480 } 1481 1482 OutputConstraintInfos.push_back(Info); 1483 } 1484 1485 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; 1486 1487 for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { 1488 StringLiteral *Literal = Constraints[i]; 1489 if (Literal->isWide()) 1490 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1491 << Literal->getSourceRange()); 1492 1493 llvm::StringRef InputName; 1494 if (Names[i]) 1495 InputName = Names[i]->getName(); 1496 1497 TargetInfo::ConstraintInfo Info(Literal->getString(), InputName); 1498 if (!Context.Target.validateInputConstraint(OutputConstraintInfos.data(), 1499 NumOutputs, Info)) { 1500 return StmtError(Diag(Literal->getLocStart(), 1501 diag::err_asm_invalid_input_constraint) 1502 << Info.getConstraintStr()); 1503 } 1504 1505 Expr *InputExpr = Exprs[i]; 1506 1507 // Only allow void types for memory constraints. 1508 if (Info.allowsMemory() && !Info.allowsRegister()) { 1509 if (CheckAsmLValue(InputExpr, *this)) 1510 return StmtError(Diag(InputExpr->getLocStart(), 1511 diag::err_asm_invalid_lvalue_in_input) 1512 << Info.getConstraintStr() 1513 << InputExpr->getSourceRange()); 1514 } 1515 1516 if (Info.allowsRegister()) { 1517 if (InputExpr->getType()->isVoidType()) { 1518 return StmtError(Diag(InputExpr->getLocStart(), 1519 diag::err_asm_invalid_type_in_input) 1520 << InputExpr->getType() << Info.getConstraintStr() 1521 << InputExpr->getSourceRange()); 1522 } 1523 } 1524 1525 DefaultFunctionArrayLvalueConversion(Exprs[i]); 1526 1527 InputConstraintInfos.push_back(Info); 1528 } 1529 1530 // Check that the clobbers are valid. 1531 for (unsigned i = 0; i != NumClobbers; i++) { 1532 StringLiteral *Literal = Clobbers[i]; 1533 if (Literal->isWide()) 1534 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1535 << Literal->getSourceRange()); 1536 1537 llvm::StringRef Clobber = Literal->getString(); 1538 1539 if (!Context.Target.isValidGCCRegisterName(Clobber)) 1540 return StmtError(Diag(Literal->getLocStart(), 1541 diag::err_asm_unknown_register_name) << Clobber); 1542 } 1543 1544 AsmStmt *NS = 1545 new (Context) AsmStmt(Context, AsmLoc, IsSimple, IsVolatile, MSAsm, 1546 NumOutputs, NumInputs, Names, Constraints, Exprs, 1547 AsmString, NumClobbers, Clobbers, RParenLoc); 1548 // Validate the asm string, ensuring it makes sense given the operands we 1549 // have. 1550 llvm::SmallVector<AsmStmt::AsmStringPiece, 8> Pieces; 1551 unsigned DiagOffs; 1552 if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) { 1553 Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID) 1554 << AsmString->getSourceRange(); 1555 return StmtError(); 1556 } 1557 1558 // Validate tied input operands for type mismatches. 1559 for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) { 1560 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; 1561 1562 // If this is a tied constraint, verify that the output and input have 1563 // either exactly the same type, or that they are int/ptr operands with the 1564 // same size (int/long, int*/long, are ok etc). 1565 if (!Info.hasTiedOperand()) continue; 1566 1567 unsigned TiedTo = Info.getTiedOperand(); 1568 Expr *OutputExpr = Exprs[TiedTo]; 1569 Expr *InputExpr = Exprs[i+NumOutputs]; 1570 QualType InTy = InputExpr->getType(); 1571 QualType OutTy = OutputExpr->getType(); 1572 if (Context.hasSameType(InTy, OutTy)) 1573 continue; // All types can be tied to themselves. 1574 1575 // Decide if the input and output are in the same domain (integer/ptr or 1576 // floating point. 1577 enum AsmDomain { 1578 AD_Int, AD_FP, AD_Other 1579 } InputDomain, OutputDomain; 1580 1581 if (InTy->isIntegerType() || InTy->isPointerType()) 1582 InputDomain = AD_Int; 1583 else if (InTy->isRealFloatingType()) 1584 InputDomain = AD_FP; 1585 else 1586 InputDomain = AD_Other; 1587 1588 if (OutTy->isIntegerType() || OutTy->isPointerType()) 1589 OutputDomain = AD_Int; 1590 else if (OutTy->isRealFloatingType()) 1591 OutputDomain = AD_FP; 1592 else 1593 OutputDomain = AD_Other; 1594 1595 // They are ok if they are the same size and in the same domain. This 1596 // allows tying things like: 1597 // void* to int* 1598 // void* to int if they are the same size. 1599 // double to long double if they are the same size. 1600 // 1601 uint64_t OutSize = Context.getTypeSize(OutTy); 1602 uint64_t InSize = Context.getTypeSize(InTy); 1603 if (OutSize == InSize && InputDomain == OutputDomain && 1604 InputDomain != AD_Other) 1605 continue; 1606 1607 // If the smaller input/output operand is not mentioned in the asm string, 1608 // then we can promote it and the asm string won't notice. Check this 1609 // case now. 1610 bool SmallerValueMentioned = false; 1611 for (unsigned p = 0, e = Pieces.size(); p != e; ++p) { 1612 AsmStmt::AsmStringPiece &Piece = Pieces[p]; 1613 if (!Piece.isOperand()) continue; 1614 1615 // If this is a reference to the input and if the input was the smaller 1616 // one, then we have to reject this asm. 1617 if (Piece.getOperandNo() == i+NumOutputs) { 1618 if (InSize < OutSize) { 1619 SmallerValueMentioned = true; 1620 break; 1621 } 1622 } 1623 1624 // If this is a reference to the input and if the input was the smaller 1625 // one, then we have to reject this asm. 1626 if (Piece.getOperandNo() == TiedTo) { 1627 if (InSize > OutSize) { 1628 SmallerValueMentioned = true; 1629 break; 1630 } 1631 } 1632 } 1633 1634 // If the smaller value wasn't mentioned in the asm string, and if the 1635 // output was a register, just extend the shorter one to the size of the 1636 // larger one. 1637 if (!SmallerValueMentioned && InputDomain != AD_Other && 1638 OutputConstraintInfos[TiedTo].allowsRegister()) 1639 continue; 1640 1641 Diag(InputExpr->getLocStart(), 1642 diag::err_asm_tying_incompatible_types) 1643 << InTy << OutTy << OutputExpr->getSourceRange() 1644 << InputExpr->getSourceRange(); 1645 return StmtError(); 1646 } 1647 1648 return Owned(NS); 1649} 1650 1651StmtResult 1652Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc, 1653 SourceLocation RParen, Decl *Parm, 1654 Stmt *Body) { 1655 VarDecl *Var = cast_or_null<VarDecl>(Parm); 1656 if (Var && Var->isInvalidDecl()) 1657 return StmtError(); 1658 1659 return Owned(new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, Body)); 1660} 1661 1662StmtResult 1663Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body) { 1664 return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, Body)); 1665} 1666 1667StmtResult 1668Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try, 1669 MultiStmtArg CatchStmts, Stmt *Finally) { 1670 getCurFunction()->setHasBranchProtectedScope(); 1671 unsigned NumCatchStmts = CatchStmts.size(); 1672 return Owned(ObjCAtTryStmt::Create(Context, AtLoc, Try, 1673 CatchStmts.release(), 1674 NumCatchStmts, 1675 Finally)); 1676} 1677 1678StmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc, 1679 Expr *Throw) { 1680 if (Throw) { 1681 DefaultLvalueConversion(Throw); 1682 1683 QualType ThrowType = Throw->getType(); 1684 // Make sure the expression type is an ObjC pointer or "void *". 1685 if (!ThrowType->isDependentType() && 1686 !ThrowType->isObjCObjectPointerType()) { 1687 const PointerType *PT = ThrowType->getAs<PointerType>(); 1688 if (!PT || !PT->getPointeeType()->isVoidType()) 1689 return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object) 1690 << Throw->getType() << Throw->getSourceRange()); 1691 } 1692 } 1693 1694 return Owned(new (Context) ObjCAtThrowStmt(AtLoc, Throw)); 1695} 1696 1697StmtResult 1698Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw, 1699 Scope *CurScope) { 1700 if (!Throw) { 1701 // @throw without an expression designates a rethrow (which much occur 1702 // in the context of an @catch clause). 1703 Scope *AtCatchParent = CurScope; 1704 while (AtCatchParent && !AtCatchParent->isAtCatchScope()) 1705 AtCatchParent = AtCatchParent->getParent(); 1706 if (!AtCatchParent) 1707 return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch)); 1708 } 1709 1710 return BuildObjCAtThrowStmt(AtLoc, Throw); 1711} 1712 1713StmtResult 1714Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, Expr *SyncExpr, 1715 Stmt *SyncBody) { 1716 getCurFunction()->setHasBranchProtectedScope(); 1717 1718 DefaultLvalueConversion(SyncExpr); 1719 1720 // Make sure the expression type is an ObjC pointer or "void *". 1721 if (!SyncExpr->getType()->isDependentType() && 1722 !SyncExpr->getType()->isObjCObjectPointerType()) { 1723 const PointerType *PT = SyncExpr->getType()->getAs<PointerType>(); 1724 if (!PT || !PT->getPointeeType()->isVoidType()) 1725 return StmtError(Diag(AtLoc, diag::error_objc_synchronized_expects_object) 1726 << SyncExpr->getType() << SyncExpr->getSourceRange()); 1727 } 1728 1729 return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, SyncExpr, SyncBody)); 1730} 1731 1732/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block 1733/// and creates a proper catch handler from them. 1734StmtResult 1735Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl, 1736 Stmt *HandlerBlock) { 1737 // There's nothing to test that ActOnExceptionDecl didn't already test. 1738 return Owned(new (Context) CXXCatchStmt(CatchLoc, 1739 cast_or_null<VarDecl>(ExDecl), 1740 HandlerBlock)); 1741} 1742 1743namespace { 1744 1745class TypeWithHandler { 1746 QualType t; 1747 CXXCatchStmt *stmt; 1748public: 1749 TypeWithHandler(const QualType &type, CXXCatchStmt *statement) 1750 : t(type), stmt(statement) {} 1751 1752 // An arbitrary order is fine as long as it places identical 1753 // types next to each other. 1754 bool operator<(const TypeWithHandler &y) const { 1755 if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr()) 1756 return true; 1757 if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr()) 1758 return false; 1759 else 1760 return getTypeSpecStartLoc() < y.getTypeSpecStartLoc(); 1761 } 1762 1763 bool operator==(const TypeWithHandler& other) const { 1764 return t == other.t; 1765 } 1766 1767 CXXCatchStmt *getCatchStmt() const { return stmt; } 1768 SourceLocation getTypeSpecStartLoc() const { 1769 return stmt->getExceptionDecl()->getTypeSpecStartLoc(); 1770 } 1771}; 1772 1773} 1774 1775/// ActOnCXXTryBlock - Takes a try compound-statement and a number of 1776/// handlers and creates a try statement from them. 1777StmtResult 1778Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock, 1779 MultiStmtArg RawHandlers) { 1780 unsigned NumHandlers = RawHandlers.size(); 1781 assert(NumHandlers > 0 && 1782 "The parser shouldn't call this if there are no handlers."); 1783 Stmt **Handlers = RawHandlers.get(); 1784 1785 llvm::SmallVector<TypeWithHandler, 8> TypesWithHandlers; 1786 1787 for (unsigned i = 0; i < NumHandlers; ++i) { 1788 CXXCatchStmt *Handler = llvm::cast<CXXCatchStmt>(Handlers[i]); 1789 if (!Handler->getExceptionDecl()) { 1790 if (i < NumHandlers - 1) 1791 return StmtError(Diag(Handler->getLocStart(), 1792 diag::err_early_catch_all)); 1793 1794 continue; 1795 } 1796 1797 const QualType CaughtType = Handler->getCaughtType(); 1798 const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType); 1799 TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler)); 1800 } 1801 1802 // Detect handlers for the same type as an earlier one. 1803 if (NumHandlers > 1) { 1804 llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end()); 1805 1806 TypeWithHandler prev = TypesWithHandlers[0]; 1807 for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) { 1808 TypeWithHandler curr = TypesWithHandlers[i]; 1809 1810 if (curr == prev) { 1811 Diag(curr.getTypeSpecStartLoc(), 1812 diag::warn_exception_caught_by_earlier_handler) 1813 << curr.getCatchStmt()->getCaughtType().getAsString(); 1814 Diag(prev.getTypeSpecStartLoc(), 1815 diag::note_previous_exception_handler) 1816 << prev.getCatchStmt()->getCaughtType().getAsString(); 1817 } 1818 1819 prev = curr; 1820 } 1821 } 1822 1823 getCurFunction()->setHasBranchProtectedScope(); 1824 1825 // FIXME: We should detect handlers that cannot catch anything because an 1826 // earlier handler catches a superclass. Need to find a method that is not 1827 // quadratic for this. 1828 // Neither of these are explicitly forbidden, but every compiler detects them 1829 // and warns. 1830 1831 return Owned(CXXTryStmt::Create(Context, TryLoc, TryBlock, 1832 Handlers, NumHandlers)); 1833} 1834