SemaStmt.cpp revision 559fb554602bedb57dbbf3cc14ac8a38264b4547
1//===--- SemaStmt.cpp - Semantic Analysis for Statements ------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements semantic analysis for statements. 11// 12//===----------------------------------------------------------------------===// 13 14#include "clang/Sema/SemaInternal.h" 15#include "clang/Sema/Scope.h" 16#include "clang/Sema/ScopeInfo.h" 17#include "clang/Sema/Initialization.h" 18#include "clang/AST/APValue.h" 19#include "clang/AST/ASTContext.h" 20#include "clang/AST/DeclObjC.h" 21#include "clang/AST/ExprCXX.h" 22#include "clang/AST/ExprObjC.h" 23#include "clang/AST/StmtObjC.h" 24#include "clang/AST/StmtCXX.h" 25#include "clang/AST/TypeLoc.h" 26#include "clang/Lex/Preprocessor.h" 27#include "clang/Basic/TargetInfo.h" 28#include "llvm/ADT/STLExtras.h" 29#include "llvm/ADT/SmallVector.h" 30using namespace clang; 31using namespace sema; 32 33StmtResult Sema::ActOnExprStmt(FullExprArg expr) { 34 Expr *E = expr.get(); 35 assert(E && "ActOnExprStmt(): missing expression"); 36 // C99 6.8.3p2: The expression in an expression statement is evaluated as a 37 // void expression for its side effects. Conversion to void allows any 38 // operand, even incomplete types. 39 40 // Same thing in for stmt first clause (when expr) and third clause. 41 return Owned(static_cast<Stmt*>(E)); 42} 43 44 45StmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc) { 46 return Owned(new (Context) NullStmt(SemiLoc)); 47} 48 49StmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, 50 SourceLocation StartLoc, 51 SourceLocation EndLoc) { 52 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 53 54 // If we have an invalid decl, just return an error. 55 if (DG.isNull()) return StmtError(); 56 57 return Owned(new (Context) DeclStmt(DG, StartLoc, EndLoc)); 58} 59 60void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) { 61 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 62 63 // If we have an invalid decl, just return. 64 if (DG.isNull() || !DG.isSingleDecl()) return; 65 // suppress any potential 'unused variable' warning. 66 DG.getSingleDecl()->setUsed(); 67} 68 69void Sema::DiagnoseUnusedExprResult(const Stmt *S) { 70 const Expr *E = dyn_cast_or_null<Expr>(S); 71 if (!E) 72 return; 73 74 SourceLocation Loc; 75 SourceRange R1, R2; 76 if (!E->isUnusedResultAWarning(Loc, R1, R2, Context)) 77 return; 78 79 // Okay, we have an unused result. Depending on what the base expression is, 80 // we might want to make a more specific diagnostic. Check for one of these 81 // cases now. 82 unsigned DiagID = diag::warn_unused_expr; 83 E = E->IgnoreParens(); 84 if (isa<ObjCImplicitSetterGetterRefExpr>(E)) 85 DiagID = diag::warn_unused_property_expr; 86 87 if (const CXXExprWithTemporaries *Temps = dyn_cast<CXXExprWithTemporaries>(E)) 88 E = Temps->getSubExpr(); 89 90 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 91 if (E->getType()->isVoidType()) 92 return; 93 94 // If the callee has attribute pure, const, or warn_unused_result, warn with 95 // a more specific message to make it clear what is happening. 96 if (const Decl *FD = CE->getCalleeDecl()) { 97 if (FD->getAttr<WarnUnusedResultAttr>()) { 98 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result"; 99 return; 100 } 101 if (FD->getAttr<PureAttr>()) { 102 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure"; 103 return; 104 } 105 if (FD->getAttr<ConstAttr>()) { 106 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const"; 107 return; 108 } 109 } 110 } 111 else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E)) { 112 const ObjCMethodDecl *MD = ME->getMethodDecl(); 113 if (MD && MD->getAttr<WarnUnusedResultAttr>()) { 114 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result"; 115 return; 116 } 117 } else if (const CXXFunctionalCastExpr *FC 118 = dyn_cast<CXXFunctionalCastExpr>(E)) { 119 if (isa<CXXConstructExpr>(FC->getSubExpr()) || 120 isa<CXXTemporaryObjectExpr>(FC->getSubExpr())) 121 return; 122 } 123 // Diagnose "(void*) blah" as a typo for "(void) blah". 124 else if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(E)) { 125 TypeSourceInfo *TI = CE->getTypeInfoAsWritten(); 126 QualType T = TI->getType(); 127 128 // We really do want to use the non-canonical type here. 129 if (T == Context.VoidPtrTy) { 130 PointerTypeLoc TL = cast<PointerTypeLoc>(TI->getTypeLoc()); 131 132 Diag(Loc, diag::warn_unused_voidptr) 133 << FixItHint::CreateRemoval(TL.getStarLoc()); 134 return; 135 } 136 } 137 138 DiagRuntimeBehavior(Loc, PDiag(DiagID) << R1 << R2); 139} 140 141StmtResult 142Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R, 143 MultiStmtArg elts, bool isStmtExpr) { 144 unsigned NumElts = elts.size(); 145 Stmt **Elts = reinterpret_cast<Stmt**>(elts.release()); 146 // If we're in C89 mode, check that we don't have any decls after stmts. If 147 // so, emit an extension diagnostic. 148 if (!getLangOptions().C99 && !getLangOptions().CPlusPlus) { 149 // Note that __extension__ can be around a decl. 150 unsigned i = 0; 151 // Skip over all declarations. 152 for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i) 153 /*empty*/; 154 155 // We found the end of the list or a statement. Scan for another declstmt. 156 for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i) 157 /*empty*/; 158 159 if (i != NumElts) { 160 Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin(); 161 Diag(D->getLocation(), diag::ext_mixed_decls_code); 162 } 163 } 164 // Warn about unused expressions in statements. 165 for (unsigned i = 0; i != NumElts; ++i) { 166 // Ignore statements that are last in a statement expression. 167 if (isStmtExpr && i == NumElts - 1) 168 continue; 169 170 DiagnoseUnusedExprResult(Elts[i]); 171 } 172 173 return Owned(new (Context) CompoundStmt(Context, Elts, NumElts, L, R)); 174} 175 176StmtResult 177Sema::ActOnCaseStmt(SourceLocation CaseLoc, Expr *LHSVal, 178 SourceLocation DotDotDotLoc, Expr *RHSVal, 179 SourceLocation ColonLoc) { 180 assert((LHSVal != 0) && "missing expression in case statement"); 181 182 // C99 6.8.4.2p3: The expression shall be an integer constant. 183 // However, GCC allows any evaluatable integer expression. 184 if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent() && 185 VerifyIntegerConstantExpression(LHSVal)) 186 return StmtError(); 187 188 // GCC extension: The expression shall be an integer constant. 189 190 if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent() && 191 VerifyIntegerConstantExpression(RHSVal)) { 192 RHSVal = 0; // Recover by just forgetting about it. 193 } 194 195 if (getCurFunction()->SwitchStack.empty()) { 196 Diag(CaseLoc, diag::err_case_not_in_switch); 197 return StmtError(); 198 } 199 200 CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc, 201 ColonLoc); 202 getCurFunction()->SwitchStack.back()->addSwitchCase(CS); 203 return Owned(CS); 204} 205 206/// ActOnCaseStmtBody - This installs a statement as the body of a case. 207void Sema::ActOnCaseStmtBody(Stmt *caseStmt, Stmt *SubStmt) { 208 CaseStmt *CS = static_cast<CaseStmt*>(caseStmt); 209 CS->setSubStmt(SubStmt); 210} 211 212StmtResult 213Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc, 214 Stmt *SubStmt, Scope *CurScope) { 215 if (getCurFunction()->SwitchStack.empty()) { 216 Diag(DefaultLoc, diag::err_default_not_in_switch); 217 return Owned(SubStmt); 218 } 219 220 DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt); 221 getCurFunction()->SwitchStack.back()->addSwitchCase(DS); 222 return Owned(DS); 223} 224 225StmtResult 226Sema::ActOnLabelStmt(SourceLocation IdentLoc, IdentifierInfo *II, 227 SourceLocation ColonLoc, Stmt *SubStmt) { 228 // Look up the record for this label identifier. 229 LabelStmt *&LabelDecl = getCurFunction()->LabelMap[II]; 230 231 // If not forward referenced or defined already, just create a new LabelStmt. 232 if (LabelDecl == 0) 233 return Owned(LabelDecl = new (Context) LabelStmt(IdentLoc, II, SubStmt)); 234 235 assert(LabelDecl->getID() == II && "Label mismatch!"); 236 237 // Otherwise, this label was either forward reference or multiply defined. If 238 // multiply defined, reject it now. 239 if (LabelDecl->getSubStmt()) { 240 Diag(IdentLoc, diag::err_redefinition_of_label) << LabelDecl->getID(); 241 Diag(LabelDecl->getIdentLoc(), diag::note_previous_definition); 242 return Owned(SubStmt); 243 } 244 245 // Otherwise, this label was forward declared, and we just found its real 246 // definition. Fill in the forward definition and return it. 247 LabelDecl->setIdentLoc(IdentLoc); 248 LabelDecl->setSubStmt(SubStmt); 249 return Owned(LabelDecl); 250} 251 252StmtResult 253Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, Decl *CondVar, 254 Stmt *thenStmt, SourceLocation ElseLoc, 255 Stmt *elseStmt) { 256 ExprResult CondResult(CondVal.release()); 257 258 VarDecl *ConditionVar = 0; 259 if (CondVar) { 260 ConditionVar = cast<VarDecl>(CondVar); 261 CondResult = CheckConditionVariable(ConditionVar, IfLoc, true); 262 if (CondResult.isInvalid()) 263 return StmtError(); 264 } 265 Expr *ConditionExpr = CondResult.takeAs<Expr>(); 266 if (!ConditionExpr) 267 return StmtError(); 268 269 DiagnoseUnusedExprResult(thenStmt); 270 271 // Warn if the if block has a null body without an else value. 272 // this helps prevent bugs due to typos, such as 273 // if (condition); 274 // do_stuff(); 275 if (!elseStmt) { 276 if (NullStmt* stmt = dyn_cast<NullStmt>(thenStmt)) 277 Diag(stmt->getSemiLoc(), diag::warn_empty_if_body); 278 } 279 280 DiagnoseUnusedExprResult(elseStmt); 281 282 return Owned(new (Context) IfStmt(Context, IfLoc, ConditionVar, ConditionExpr, 283 thenStmt, ElseLoc, elseStmt)); 284} 285 286/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have 287/// the specified width and sign. If an overflow occurs, detect it and emit 288/// the specified diagnostic. 289void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val, 290 unsigned NewWidth, bool NewSign, 291 SourceLocation Loc, 292 unsigned DiagID) { 293 // Perform a conversion to the promoted condition type if needed. 294 if (NewWidth > Val.getBitWidth()) { 295 // If this is an extension, just do it. 296 Val.extend(NewWidth); 297 Val.setIsSigned(NewSign); 298 299 // If the input was signed and negative and the output is 300 // unsigned, don't bother to warn: this is implementation-defined 301 // behavior. 302 // FIXME: Introduce a second, default-ignored warning for this case? 303 } else if (NewWidth < Val.getBitWidth()) { 304 // If this is a truncation, check for overflow. 305 llvm::APSInt ConvVal(Val); 306 ConvVal.trunc(NewWidth); 307 ConvVal.setIsSigned(NewSign); 308 ConvVal.extend(Val.getBitWidth()); 309 ConvVal.setIsSigned(Val.isSigned()); 310 if (ConvVal != Val) 311 Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10); 312 313 // Regardless of whether a diagnostic was emitted, really do the 314 // truncation. 315 Val.trunc(NewWidth); 316 Val.setIsSigned(NewSign); 317 } else if (NewSign != Val.isSigned()) { 318 // Convert the sign to match the sign of the condition. This can cause 319 // overflow as well: unsigned(INTMIN) 320 // We don't diagnose this overflow, because it is implementation-defined 321 // behavior. 322 // FIXME: Introduce a second, default-ignored warning for this case? 323 llvm::APSInt OldVal(Val); 324 Val.setIsSigned(NewSign); 325 } 326} 327 328namespace { 329 struct CaseCompareFunctor { 330 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 331 const llvm::APSInt &RHS) { 332 return LHS.first < RHS; 333 } 334 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 335 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 336 return LHS.first < RHS.first; 337 } 338 bool operator()(const llvm::APSInt &LHS, 339 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 340 return LHS < RHS.first; 341 } 342 }; 343} 344 345/// CmpCaseVals - Comparison predicate for sorting case values. 346/// 347static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs, 348 const std::pair<llvm::APSInt, CaseStmt*>& rhs) { 349 if (lhs.first < rhs.first) 350 return true; 351 352 if (lhs.first == rhs.first && 353 lhs.second->getCaseLoc().getRawEncoding() 354 < rhs.second->getCaseLoc().getRawEncoding()) 355 return true; 356 return false; 357} 358 359/// CmpEnumVals - Comparison predicate for sorting enumeration values. 360/// 361static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 362 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 363{ 364 return lhs.first < rhs.first; 365} 366 367/// EqEnumVals - Comparison preficate for uniqing enumeration values. 368/// 369static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 370 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 371{ 372 return lhs.first == rhs.first; 373} 374 375/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of 376/// potentially integral-promoted expression @p expr. 377static QualType GetTypeBeforeIntegralPromotion(const Expr* expr) { 378 if (const CastExpr *ImplicitCast = dyn_cast<ImplicitCastExpr>(expr)) { 379 const Expr *ExprBeforePromotion = ImplicitCast->getSubExpr(); 380 QualType TypeBeforePromotion = ExprBeforePromotion->getType(); 381 if (TypeBeforePromotion->isIntegralOrEnumerationType()) { 382 return TypeBeforePromotion; 383 } 384 } 385 return expr->getType(); 386} 387 388StmtResult 389Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond, 390 Decl *CondVar) { 391 ExprResult CondResult; 392 393 VarDecl *ConditionVar = 0; 394 if (CondVar) { 395 ConditionVar = cast<VarDecl>(CondVar); 396 CondResult = CheckConditionVariable(ConditionVar, SourceLocation(), false); 397 if (CondResult.isInvalid()) 398 return StmtError(); 399 400 Cond = CondResult.release(); 401 } 402 403 if (!Cond) 404 return StmtError(); 405 406 CondResult 407 = ConvertToIntegralOrEnumerationType(SwitchLoc, Cond, 408 PDiag(diag::err_typecheck_statement_requires_integer), 409 PDiag(diag::err_switch_incomplete_class_type) 410 << Cond->getSourceRange(), 411 PDiag(diag::err_switch_explicit_conversion), 412 PDiag(diag::note_switch_conversion), 413 PDiag(diag::err_switch_multiple_conversions), 414 PDiag(diag::note_switch_conversion), 415 PDiag(0)); 416 if (CondResult.isInvalid()) return StmtError(); 417 Cond = CondResult.take(); 418 419 if (!CondVar) { 420 CondResult = MaybeCreateCXXExprWithTemporaries(Cond); 421 if (CondResult.isInvalid()) 422 return StmtError(); 423 Cond = CondResult.take(); 424 } 425 426 getCurFunction()->setHasBranchIntoScope(); 427 428 SwitchStmt *SS = new (Context) SwitchStmt(Context, ConditionVar, Cond); 429 getCurFunction()->SwitchStack.push_back(SS); 430 return Owned(SS); 431} 432 433StmtResult 434Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch, 435 Stmt *BodyStmt) { 436 SwitchStmt *SS = cast<SwitchStmt>(Switch); 437 assert(SS == getCurFunction()->SwitchStack.back() && 438 "switch stack missing push/pop!"); 439 440 SS->setBody(BodyStmt, SwitchLoc); 441 getCurFunction()->SwitchStack.pop_back(); 442 443 if (SS->getCond() == 0) 444 return StmtError(); 445 446 Expr *CondExpr = SS->getCond(); 447 Expr *CondExprBeforePromotion = CondExpr; 448 QualType CondTypeBeforePromotion = 449 GetTypeBeforeIntegralPromotion(CondExpr); 450 451 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr. 452 UsualUnaryConversions(CondExpr); 453 QualType CondType = CondExpr->getType(); 454 SS->setCond(CondExpr); 455 456 // C++ 6.4.2.p2: 457 // Integral promotions are performed (on the switch condition). 458 // 459 // A case value unrepresentable by the original switch condition 460 // type (before the promotion) doesn't make sense, even when it can 461 // be represented by the promoted type. Therefore we need to find 462 // the pre-promotion type of the switch condition. 463 if (!CondExpr->isTypeDependent()) { 464 // We have already converted the expression to an integral or enumeration 465 // type, when we started the switch statement. If we don't have an 466 // appropriate type now, just return an error. 467 if (!CondType->isIntegralOrEnumerationType()) 468 return StmtError(); 469 470 if (CondExpr->isKnownToHaveBooleanValue()) { 471 // switch(bool_expr) {...} is often a programmer error, e.g. 472 // switch(n && mask) { ... } // Doh - should be "n & mask". 473 // One can always use an if statement instead of switch(bool_expr). 474 Diag(SwitchLoc, diag::warn_bool_switch_condition) 475 << CondExpr->getSourceRange(); 476 } 477 } 478 479 // Get the bitwidth of the switched-on value before promotions. We must 480 // convert the integer case values to this width before comparison. 481 bool HasDependentValue 482 = CondExpr->isTypeDependent() || CondExpr->isValueDependent(); 483 unsigned CondWidth 484 = HasDependentValue? 0 485 : static_cast<unsigned>(Context.getTypeSize(CondTypeBeforePromotion)); 486 bool CondIsSigned = CondTypeBeforePromotion->isSignedIntegerType(); 487 488 // Accumulate all of the case values in a vector so that we can sort them 489 // and detect duplicates. This vector contains the APInt for the case after 490 // it has been converted to the condition type. 491 typedef llvm::SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy; 492 CaseValsTy CaseVals; 493 494 // Keep track of any GNU case ranges we see. The APSInt is the low value. 495 typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy; 496 CaseRangesTy CaseRanges; 497 498 DefaultStmt *TheDefaultStmt = 0; 499 500 bool CaseListIsErroneous = false; 501 502 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue; 503 SC = SC->getNextSwitchCase()) { 504 505 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) { 506 if (TheDefaultStmt) { 507 Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined); 508 Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev); 509 510 // FIXME: Remove the default statement from the switch block so that 511 // we'll return a valid AST. This requires recursing down the AST and 512 // finding it, not something we are set up to do right now. For now, 513 // just lop the entire switch stmt out of the AST. 514 CaseListIsErroneous = true; 515 } 516 TheDefaultStmt = DS; 517 518 } else { 519 CaseStmt *CS = cast<CaseStmt>(SC); 520 521 // We already verified that the expression has a i-c-e value (C99 522 // 6.8.4.2p3) - get that value now. 523 Expr *Lo = CS->getLHS(); 524 525 if (Lo->isTypeDependent() || Lo->isValueDependent()) { 526 HasDependentValue = true; 527 break; 528 } 529 530 llvm::APSInt LoVal = Lo->EvaluateAsInt(Context); 531 532 // Convert the value to the same width/sign as the condition. 533 ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned, 534 CS->getLHS()->getLocStart(), 535 diag::warn_case_value_overflow); 536 537 // If the LHS is not the same type as the condition, insert an implicit 538 // cast. 539 ImpCastExprToType(Lo, CondType, CK_IntegralCast); 540 CS->setLHS(Lo); 541 542 // If this is a case range, remember it in CaseRanges, otherwise CaseVals. 543 if (CS->getRHS()) { 544 if (CS->getRHS()->isTypeDependent() || 545 CS->getRHS()->isValueDependent()) { 546 HasDependentValue = true; 547 break; 548 } 549 CaseRanges.push_back(std::make_pair(LoVal, CS)); 550 } else 551 CaseVals.push_back(std::make_pair(LoVal, CS)); 552 } 553 } 554 555 if (!HasDependentValue) { 556 // If we don't have a default statement, check whether the 557 // condition is constant. 558 llvm::APSInt ConstantCondValue; 559 bool HasConstantCond = false; 560 bool ShouldCheckConstantCond = false; 561 if (!HasDependentValue && !TheDefaultStmt) { 562 Expr::EvalResult Result; 563 HasConstantCond = CondExprBeforePromotion->Evaluate(Result, Context); 564 if (HasConstantCond) { 565 assert(Result.Val.isInt() && "switch condition evaluated to non-int"); 566 ConstantCondValue = Result.Val.getInt(); 567 ShouldCheckConstantCond = true; 568 569 assert(ConstantCondValue.getBitWidth() == CondWidth && 570 ConstantCondValue.isSigned() == CondIsSigned); 571 } 572 } 573 574 // Sort all the scalar case values so we can easily detect duplicates. 575 std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals); 576 577 if (!CaseVals.empty()) { 578 for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) { 579 if (ShouldCheckConstantCond && 580 CaseVals[i].first == ConstantCondValue) 581 ShouldCheckConstantCond = false; 582 583 if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) { 584 // If we have a duplicate, report it. 585 Diag(CaseVals[i].second->getLHS()->getLocStart(), 586 diag::err_duplicate_case) << CaseVals[i].first.toString(10); 587 Diag(CaseVals[i-1].second->getLHS()->getLocStart(), 588 diag::note_duplicate_case_prev); 589 // FIXME: We really want to remove the bogus case stmt from the 590 // substmt, but we have no way to do this right now. 591 CaseListIsErroneous = true; 592 } 593 } 594 } 595 596 // Detect duplicate case ranges, which usually don't exist at all in 597 // the first place. 598 if (!CaseRanges.empty()) { 599 // Sort all the case ranges by their low value so we can easily detect 600 // overlaps between ranges. 601 std::stable_sort(CaseRanges.begin(), CaseRanges.end()); 602 603 // Scan the ranges, computing the high values and removing empty ranges. 604 std::vector<llvm::APSInt> HiVals; 605 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 606 llvm::APSInt &LoVal = CaseRanges[i].first; 607 CaseStmt *CR = CaseRanges[i].second; 608 Expr *Hi = CR->getRHS(); 609 llvm::APSInt HiVal = Hi->EvaluateAsInt(Context); 610 611 // Convert the value to the same width/sign as the condition. 612 ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned, 613 CR->getRHS()->getLocStart(), 614 diag::warn_case_value_overflow); 615 616 // If the LHS is not the same type as the condition, insert an implicit 617 // cast. 618 ImpCastExprToType(Hi, CondType, CK_IntegralCast); 619 CR->setRHS(Hi); 620 621 // If the low value is bigger than the high value, the case is empty. 622 if (LoVal > HiVal) { 623 Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range) 624 << SourceRange(CR->getLHS()->getLocStart(), 625 CR->getRHS()->getLocEnd()); 626 CaseRanges.erase(CaseRanges.begin()+i); 627 --i, --e; 628 continue; 629 } 630 631 if (ShouldCheckConstantCond && 632 LoVal <= ConstantCondValue && 633 ConstantCondValue <= HiVal) 634 ShouldCheckConstantCond = false; 635 636 HiVals.push_back(HiVal); 637 } 638 639 // Rescan the ranges, looking for overlap with singleton values and other 640 // ranges. Since the range list is sorted, we only need to compare case 641 // ranges with their neighbors. 642 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 643 llvm::APSInt &CRLo = CaseRanges[i].first; 644 llvm::APSInt &CRHi = HiVals[i]; 645 CaseStmt *CR = CaseRanges[i].second; 646 647 // Check to see whether the case range overlaps with any 648 // singleton cases. 649 CaseStmt *OverlapStmt = 0; 650 llvm::APSInt OverlapVal(32); 651 652 // Find the smallest value >= the lower bound. If I is in the 653 // case range, then we have overlap. 654 CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(), 655 CaseVals.end(), CRLo, 656 CaseCompareFunctor()); 657 if (I != CaseVals.end() && I->first < CRHi) { 658 OverlapVal = I->first; // Found overlap with scalar. 659 OverlapStmt = I->second; 660 } 661 662 // Find the smallest value bigger than the upper bound. 663 I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor()); 664 if (I != CaseVals.begin() && (I-1)->first >= CRLo) { 665 OverlapVal = (I-1)->first; // Found overlap with scalar. 666 OverlapStmt = (I-1)->second; 667 } 668 669 // Check to see if this case stmt overlaps with the subsequent 670 // case range. 671 if (i && CRLo <= HiVals[i-1]) { 672 OverlapVal = HiVals[i-1]; // Found overlap with range. 673 OverlapStmt = CaseRanges[i-1].second; 674 } 675 676 if (OverlapStmt) { 677 // If we have a duplicate, report it. 678 Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case) 679 << OverlapVal.toString(10); 680 Diag(OverlapStmt->getLHS()->getLocStart(), 681 diag::note_duplicate_case_prev); 682 // FIXME: We really want to remove the bogus case stmt from the 683 // substmt, but we have no way to do this right now. 684 CaseListIsErroneous = true; 685 } 686 } 687 } 688 689 // Complain if we have a constant condition and we didn't find a match. 690 if (!CaseListIsErroneous && ShouldCheckConstantCond) { 691 // TODO: it would be nice if we printed enums as enums, chars as 692 // chars, etc. 693 Diag(CondExpr->getExprLoc(), diag::warn_missing_case_for_condition) 694 << ConstantCondValue.toString(10) 695 << CondExpr->getSourceRange(); 696 } 697 698 // Check to see if switch is over an Enum and handles all of its 699 // values. We only issue a warning if there is not 'default:', but 700 // we still do the analysis to preserve this information in the AST 701 // (which can be used by flow-based analyes). 702 // 703 const EnumType* ET = CondTypeBeforePromotion->getAs<EnumType>(); 704 705 // If switch has default case, then ignore it. 706 if (!CaseListIsErroneous && !HasConstantCond && ET) { 707 const EnumDecl *ED = ET->getDecl(); 708 typedef llvm::SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> EnumValsTy; 709 EnumValsTy EnumVals; 710 711 // Gather all enum values, set their type and sort them, 712 // allowing easier comparison with CaseVals. 713 for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin(); 714 EDI != ED->enumerator_end(); EDI++) { 715 llvm::APSInt Val = (*EDI)->getInitVal(); 716 if(Val.getBitWidth() < CondWidth) 717 Val.extend(CondWidth); 718 else if (Val.getBitWidth() > CondWidth) 719 Val.trunc(CondWidth); 720 Val.setIsSigned(CondIsSigned); 721 EnumVals.push_back(std::make_pair(Val, (*EDI))); 722 } 723 std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals); 724 EnumValsTy::iterator EIend = 725 std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals); 726 727 // See which case values aren't in enum. 728 // TODO: we might want to check whether case values are out of the 729 // enum even if we don't want to check whether all cases are handled. 730 if (!TheDefaultStmt) { 731 EnumValsTy::const_iterator EI = EnumVals.begin(); 732 for (CaseValsTy::const_iterator CI = CaseVals.begin(); 733 CI != CaseVals.end(); CI++) { 734 while (EI != EIend && EI->first < CI->first) 735 EI++; 736 if (EI == EIend || EI->first > CI->first) 737 Diag(CI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 738 << ED->getDeclName(); 739 } 740 // See which of case ranges aren't in enum 741 EI = EnumVals.begin(); 742 for (CaseRangesTy::const_iterator RI = CaseRanges.begin(); 743 RI != CaseRanges.end() && EI != EIend; RI++) { 744 while (EI != EIend && EI->first < RI->first) 745 EI++; 746 747 if (EI == EIend || EI->first != RI->first) { 748 Diag(RI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 749 << ED->getDeclName(); 750 } 751 752 llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context); 753 while (EI != EIend && EI->first < Hi) 754 EI++; 755 if (EI == EIend || EI->first != Hi) 756 Diag(RI->second->getRHS()->getExprLoc(), diag::warn_not_in_enum) 757 << ED->getDeclName(); 758 } 759 } 760 // Check which enum vals aren't in switch 761 CaseValsTy::const_iterator CI = CaseVals.begin(); 762 CaseRangesTy::const_iterator RI = CaseRanges.begin(); 763 bool hasCasesNotInSwitch = false; 764 765 for (EnumValsTy::const_iterator EI = EnumVals.begin(); EI != EIend; EI++){ 766 //Drop unneeded case values 767 llvm::APSInt CIVal; 768 while (CI != CaseVals.end() && CI->first < EI->first) 769 CI++; 770 771 if (CI != CaseVals.end() && CI->first == EI->first) 772 continue; 773 774 // Drop unneeded case ranges 775 for (; RI != CaseRanges.end(); RI++) { 776 llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context); 777 if (EI->first <= Hi) 778 break; 779 } 780 781 if (RI == CaseRanges.end() || EI->first < RI->first) { 782 hasCasesNotInSwitch = true; 783 if (!TheDefaultStmt) 784 Diag(CondExpr->getExprLoc(), diag::warn_missing_cases) 785 << EI->second->getDeclName(); 786 } 787 } 788 789 if (!hasCasesNotInSwitch) 790 SS->setAllEnumCasesCovered(); 791 } 792 } 793 794 // FIXME: If the case list was broken is some way, we don't have a good system 795 // to patch it up. Instead, just return the whole substmt as broken. 796 if (CaseListIsErroneous) 797 return StmtError(); 798 799 return Owned(SS); 800} 801 802StmtResult 803Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond, 804 Decl *CondVar, Stmt *Body) { 805 ExprResult CondResult(Cond.release()); 806 807 VarDecl *ConditionVar = 0; 808 if (CondVar) { 809 ConditionVar = cast<VarDecl>(CondVar); 810 CondResult = CheckConditionVariable(ConditionVar, WhileLoc, true); 811 if (CondResult.isInvalid()) 812 return StmtError(); 813 } 814 Expr *ConditionExpr = CondResult.take(); 815 if (!ConditionExpr) 816 return StmtError(); 817 818 DiagnoseUnusedExprResult(Body); 819 820 return Owned(new (Context) WhileStmt(Context, ConditionVar, ConditionExpr, 821 Body, WhileLoc)); 822} 823 824StmtResult 825Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body, 826 SourceLocation WhileLoc, SourceLocation CondLParen, 827 Expr *Cond, SourceLocation CondRParen) { 828 assert(Cond && "ActOnDoStmt(): missing expression"); 829 830 if (CheckBooleanCondition(Cond, DoLoc)) 831 return StmtError(); 832 833 ExprResult CondResult = MaybeCreateCXXExprWithTemporaries(Cond); 834 if (CondResult.isInvalid()) 835 return StmtError(); 836 Cond = CondResult.take(); 837 838 DiagnoseUnusedExprResult(Body); 839 840 return Owned(new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen)); 841} 842 843StmtResult 844Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 845 Stmt *First, FullExprArg second, Decl *secondVar, 846 FullExprArg third, 847 SourceLocation RParenLoc, Stmt *Body) { 848 if (!getLangOptions().CPlusPlus) { 849 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) { 850 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 851 // declare identifiers for objects having storage class 'auto' or 852 // 'register'. 853 for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end(); 854 DI!=DE; ++DI) { 855 VarDecl *VD = dyn_cast<VarDecl>(*DI); 856 if (VD && VD->isBlockVarDecl() && !VD->hasLocalStorage()) 857 VD = 0; 858 if (VD == 0) 859 Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for); 860 // FIXME: mark decl erroneous! 861 } 862 } 863 } 864 865 ExprResult SecondResult(second.release()); 866 VarDecl *ConditionVar = 0; 867 if (secondVar) { 868 ConditionVar = cast<VarDecl>(secondVar); 869 SecondResult = CheckConditionVariable(ConditionVar, ForLoc, true); 870 if (SecondResult.isInvalid()) 871 return StmtError(); 872 } 873 874 Expr *Third = third.release().takeAs<Expr>(); 875 876 DiagnoseUnusedExprResult(First); 877 DiagnoseUnusedExprResult(Third); 878 DiagnoseUnusedExprResult(Body); 879 880 return Owned(new (Context) ForStmt(Context, First, 881 SecondResult.take(), ConditionVar, 882 Third, Body, ForLoc, LParenLoc, 883 RParenLoc)); 884} 885 886StmtResult 887Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc, 888 SourceLocation LParenLoc, 889 Stmt *First, Expr *Second, 890 SourceLocation RParenLoc, Stmt *Body) { 891 if (First) { 892 QualType FirstType; 893 if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) { 894 if (!DS->isSingleDecl()) 895 return StmtError(Diag((*DS->decl_begin())->getLocation(), 896 diag::err_toomany_element_decls)); 897 898 Decl *D = DS->getSingleDecl(); 899 FirstType = cast<ValueDecl>(D)->getType(); 900 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 901 // declare identifiers for objects having storage class 'auto' or 902 // 'register'. 903 VarDecl *VD = cast<VarDecl>(D); 904 if (VD->isBlockVarDecl() && !VD->hasLocalStorage()) 905 return StmtError(Diag(VD->getLocation(), 906 diag::err_non_variable_decl_in_for)); 907 } else { 908 Expr *FirstE = cast<Expr>(First); 909 if (!FirstE->isTypeDependent() && 910 FirstE->isLvalue(Context) != Expr::LV_Valid) 911 return StmtError(Diag(First->getLocStart(), 912 diag::err_selector_element_not_lvalue) 913 << First->getSourceRange()); 914 915 FirstType = static_cast<Expr*>(First)->getType(); 916 } 917 if (!FirstType->isDependentType() && 918 !FirstType->isObjCObjectPointerType() && 919 !FirstType->isBlockPointerType()) 920 Diag(ForLoc, diag::err_selector_element_type) 921 << FirstType << First->getSourceRange(); 922 } 923 if (Second && !Second->isTypeDependent()) { 924 DefaultFunctionArrayLvalueConversion(Second); 925 QualType SecondType = Second->getType(); 926 if (!SecondType->isObjCObjectPointerType()) 927 Diag(ForLoc, diag::err_collection_expr_type) 928 << SecondType << Second->getSourceRange(); 929 else if (const ObjCObjectPointerType *OPT = 930 SecondType->getAsObjCInterfacePointerType()) { 931 llvm::SmallVector<IdentifierInfo *, 4> KeyIdents; 932 IdentifierInfo* selIdent = 933 &Context.Idents.get("countByEnumeratingWithState"); 934 KeyIdents.push_back(selIdent); 935 selIdent = &Context.Idents.get("objects"); 936 KeyIdents.push_back(selIdent); 937 selIdent = &Context.Idents.get("count"); 938 KeyIdents.push_back(selIdent); 939 Selector CSelector = Context.Selectors.getSelector(3, &KeyIdents[0]); 940 if (ObjCInterfaceDecl *IDecl = OPT->getInterfaceDecl()) { 941 if (!IDecl->isForwardDecl() && 942 !IDecl->lookupInstanceMethod(CSelector)) { 943 // Must further look into private implementation methods. 944 if (!LookupPrivateInstanceMethod(CSelector, IDecl)) 945 Diag(ForLoc, diag::warn_collection_expr_type) 946 << SecondType << CSelector << Second->getSourceRange(); 947 } 948 } 949 } 950 } 951 return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body, 952 ForLoc, RParenLoc)); 953} 954 955StmtResult 956Sema::ActOnGotoStmt(SourceLocation GotoLoc, SourceLocation LabelLoc, 957 IdentifierInfo *LabelII) { 958 // Look up the record for this label identifier. 959 LabelStmt *&LabelDecl = getCurFunction()->LabelMap[LabelII]; 960 961 getCurFunction()->setHasBranchIntoScope(); 962 963 // If we haven't seen this label yet, create a forward reference. 964 if (LabelDecl == 0) 965 LabelDecl = new (Context) LabelStmt(LabelLoc, LabelII, 0); 966 967 return Owned(new (Context) GotoStmt(LabelDecl, GotoLoc, LabelLoc)); 968} 969 970StmtResult 971Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc, 972 Expr *E) { 973 // Convert operand to void* 974 if (!E->isTypeDependent()) { 975 QualType ETy = E->getType(); 976 QualType DestTy = Context.getPointerType(Context.VoidTy.withConst()); 977 AssignConvertType ConvTy = 978 CheckSingleAssignmentConstraints(DestTy, E); 979 if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing)) 980 return StmtError(); 981 } 982 983 getCurFunction()->setHasIndirectGoto(); 984 985 return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E)); 986} 987 988StmtResult 989Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) { 990 Scope *S = CurScope->getContinueParent(); 991 if (!S) { 992 // C99 6.8.6.2p1: A break shall appear only in or as a loop body. 993 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop)); 994 } 995 996 return Owned(new (Context) ContinueStmt(ContinueLoc)); 997} 998 999StmtResult 1000Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) { 1001 Scope *S = CurScope->getBreakParent(); 1002 if (!S) { 1003 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body. 1004 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch)); 1005 } 1006 1007 return Owned(new (Context) BreakStmt(BreakLoc)); 1008} 1009 1010/// \brief Determine whether a return statement is a candidate for the named 1011/// return value optimization (C++0x 12.8p34, bullet 1). 1012/// 1013/// \param Ctx The context in which the return expression and type occur. 1014/// 1015/// \param RetType The return type of the function or block. 1016/// 1017/// \param RetExpr The expression being returned from the function or block. 1018/// 1019/// \returns The NRVO candidate variable, if the return statement may use the 1020/// NRVO, or NULL if there is no such candidate. 1021static const VarDecl *getNRVOCandidate(ASTContext &Ctx, QualType RetType, 1022 Expr *RetExpr) { 1023 QualType ExprType = RetExpr->getType(); 1024 // - in a return statement in a function with ... 1025 // ... a class return type ... 1026 if (!RetType->isRecordType()) 1027 return 0; 1028 // ... the same cv-unqualified type as the function return type ... 1029 if (!Ctx.hasSameUnqualifiedType(RetType, ExprType)) 1030 return 0; 1031 // ... the expression is the name of a non-volatile automatic object ... 1032 // We ignore parentheses here. 1033 // FIXME: Is this compliant? (Everyone else does it) 1034 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(RetExpr->IgnoreParens()); 1035 if (!DR) 1036 return 0; 1037 const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()); 1038 if (!VD) 1039 return 0; 1040 1041 if (VD->getKind() == Decl::Var && VD->hasLocalStorage() && 1042 !VD->getType()->isReferenceType() && !VD->hasAttr<BlocksAttr>() && 1043 !VD->getType().isVolatileQualified()) 1044 return VD; 1045 1046 return 0; 1047} 1048 1049/// ActOnBlockReturnStmt - Utility routine to figure out block's return type. 1050/// 1051StmtResult 1052Sema::ActOnBlockReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1053 // If this is the first return we've seen in the block, infer the type of 1054 // the block from it. 1055 BlockScopeInfo *CurBlock = getCurBlock(); 1056 if (CurBlock->ReturnType.isNull()) { 1057 if (RetValExp) { 1058 // Don't call UsualUnaryConversions(), since we don't want to do 1059 // integer promotions here. 1060 DefaultFunctionArrayLvalueConversion(RetValExp); 1061 CurBlock->ReturnType = RetValExp->getType(); 1062 if (BlockDeclRefExpr *CDRE = dyn_cast<BlockDeclRefExpr>(RetValExp)) { 1063 // We have to remove a 'const' added to copied-in variable which was 1064 // part of the implementation spec. and not the actual qualifier for 1065 // the variable. 1066 if (CDRE->isConstQualAdded()) 1067 CurBlock->ReturnType.removeConst(); 1068 } 1069 } else 1070 CurBlock->ReturnType = Context.VoidTy; 1071 } 1072 QualType FnRetType = CurBlock->ReturnType; 1073 1074 if (CurBlock->TheDecl->hasAttr<NoReturnAttr>()) { 1075 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr) 1076 << getCurFunctionOrMethodDecl()->getDeclName(); 1077 return StmtError(); 1078 } 1079 1080 // Otherwise, verify that this result type matches the previous one. We are 1081 // pickier with blocks than for normal functions because we don't have GCC 1082 // compatibility to worry about here. 1083 ReturnStmt *Result = 0; 1084 if (CurBlock->ReturnType->isVoidType()) { 1085 if (RetValExp) { 1086 Diag(ReturnLoc, diag::err_return_block_has_expr); 1087 RetValExp = 0; 1088 } 1089 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 1090 } else if (!RetValExp) { 1091 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr)); 1092 } else { 1093 const VarDecl *NRVOCandidate = 0; 1094 1095 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1096 // we have a non-void block with an expression, continue checking 1097 1098 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1099 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1100 // function return. 1101 1102 // In C++ the return statement is handled via a copy initialization. 1103 // the C version of which boils down to CheckSingleAssignmentConstraints. 1104 NRVOCandidate = getNRVOCandidate(Context, FnRetType, RetValExp); 1105 ExprResult Res = PerformCopyInitialization( 1106 InitializedEntity::InitializeResult(ReturnLoc, 1107 FnRetType, 1108 NRVOCandidate != 0), 1109 SourceLocation(), 1110 Owned(RetValExp)); 1111 if (Res.isInvalid()) { 1112 // FIXME: Cleanup temporaries here, anyway? 1113 return StmtError(); 1114 } 1115 1116 if (RetValExp) 1117 RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp); 1118 1119 RetValExp = Res.takeAs<Expr>(); 1120 if (RetValExp) 1121 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1122 } 1123 1124 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 1125 } 1126 1127 // If we need to check for the named return value optimization, save the 1128 // return statement in our scope for later processing. 1129 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 1130 !CurContext->isDependentContext()) 1131 FunctionScopes.back()->Returns.push_back(Result); 1132 1133 return Owned(Result); 1134} 1135 1136StmtResult 1137Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1138 if (getCurBlock()) 1139 return ActOnBlockReturnStmt(ReturnLoc, RetValExp); 1140 1141 QualType FnRetType; 1142 if (const FunctionDecl *FD = getCurFunctionDecl()) { 1143 FnRetType = FD->getResultType(); 1144 if (FD->hasAttr<NoReturnAttr>() || 1145 FD->getType()->getAs<FunctionType>()->getNoReturnAttr()) 1146 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) 1147 << getCurFunctionOrMethodDecl()->getDeclName(); 1148 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) 1149 FnRetType = MD->getResultType(); 1150 else // If we don't have a function/method context, bail. 1151 return StmtError(); 1152 1153 ReturnStmt *Result = 0; 1154 if (FnRetType->isVoidType()) { 1155 if (RetValExp && !RetValExp->isTypeDependent()) { 1156 // C99 6.8.6.4p1 (ext_ since GCC warns) 1157 unsigned D = diag::ext_return_has_expr; 1158 if (RetValExp->getType()->isVoidType()) 1159 D = diag::ext_return_has_void_expr; 1160 1161 // return (some void expression); is legal in C++. 1162 if (D != diag::ext_return_has_void_expr || 1163 !getLangOptions().CPlusPlus) { 1164 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 1165 Diag(ReturnLoc, D) 1166 << CurDecl->getDeclName() << isa<ObjCMethodDecl>(CurDecl) 1167 << RetValExp->getSourceRange(); 1168 } 1169 1170 RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp); 1171 } 1172 1173 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 1174 } else if (!RetValExp && !FnRetType->isDependentType()) { 1175 unsigned DiagID = diag::warn_return_missing_expr; // C90 6.6.6.4p4 1176 // C99 6.8.6.4p1 (ext_ since GCC warns) 1177 if (getLangOptions().C99) DiagID = diag::ext_return_missing_expr; 1178 1179 if (FunctionDecl *FD = getCurFunctionDecl()) 1180 Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/; 1181 else 1182 Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/; 1183 Result = new (Context) ReturnStmt(ReturnLoc); 1184 } else { 1185 const VarDecl *NRVOCandidate = 0; 1186 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1187 // we have a non-void function with an expression, continue checking 1188 1189 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1190 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1191 // function return. 1192 1193 // In C++ the return statement is handled via a copy initialization. 1194 // the C version of which boils down to CheckSingleAssignmentConstraints. 1195 NRVOCandidate = getNRVOCandidate(Context, FnRetType, RetValExp); 1196 ExprResult Res = PerformCopyInitialization( 1197 InitializedEntity::InitializeResult(ReturnLoc, 1198 FnRetType, 1199 NRVOCandidate != 0), 1200 SourceLocation(), 1201 Owned(RetValExp)); 1202 if (Res.isInvalid()) { 1203 // FIXME: Cleanup temporaries here, anyway? 1204 return StmtError(); 1205 } 1206 1207 RetValExp = Res.takeAs<Expr>(); 1208 if (RetValExp) 1209 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1210 } 1211 1212 if (RetValExp) 1213 RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp); 1214 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 1215 } 1216 1217 // If we need to check for the named return value optimization, save the 1218 // return statement in our scope for later processing. 1219 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 1220 !CurContext->isDependentContext()) 1221 FunctionScopes.back()->Returns.push_back(Result); 1222 1223 return Owned(Result); 1224} 1225 1226/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently 1227/// ignore "noop" casts in places where an lvalue is required by an inline asm. 1228/// We emulate this behavior when -fheinous-gnu-extensions is specified, but 1229/// provide a strong guidance to not use it. 1230/// 1231/// This method checks to see if the argument is an acceptable l-value and 1232/// returns false if it is a case we can handle. 1233static bool CheckAsmLValue(const Expr *E, Sema &S) { 1234 // Type dependent expressions will be checked during instantiation. 1235 if (E->isTypeDependent()) 1236 return false; 1237 1238 if (E->isLvalue(S.Context) == Expr::LV_Valid) 1239 return false; // Cool, this is an lvalue. 1240 1241 // Okay, this is not an lvalue, but perhaps it is the result of a cast that we 1242 // are supposed to allow. 1243 const Expr *E2 = E->IgnoreParenNoopCasts(S.Context); 1244 if (E != E2 && E2->isLvalue(S.Context) == Expr::LV_Valid) { 1245 if (!S.getLangOptions().HeinousExtensions) 1246 S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue) 1247 << E->getSourceRange(); 1248 else 1249 S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue) 1250 << E->getSourceRange(); 1251 // Accept, even if we emitted an error diagnostic. 1252 return false; 1253 } 1254 1255 // None of the above, just randomly invalid non-lvalue. 1256 return true; 1257} 1258 1259 1260StmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, 1261 bool IsSimple, 1262 bool IsVolatile, 1263 unsigned NumOutputs, 1264 unsigned NumInputs, 1265 IdentifierInfo **Names, 1266 MultiExprArg constraints, 1267 MultiExprArg exprs, 1268 Expr *asmString, 1269 MultiExprArg clobbers, 1270 SourceLocation RParenLoc, 1271 bool MSAsm) { 1272 unsigned NumClobbers = clobbers.size(); 1273 StringLiteral **Constraints = 1274 reinterpret_cast<StringLiteral**>(constraints.get()); 1275 Expr **Exprs = exprs.get(); 1276 StringLiteral *AsmString = cast<StringLiteral>(asmString); 1277 StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get()); 1278 1279 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; 1280 1281 // The parser verifies that there is a string literal here. 1282 if (AsmString->isWide()) 1283 return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character) 1284 << AsmString->getSourceRange()); 1285 1286 for (unsigned i = 0; i != NumOutputs; i++) { 1287 StringLiteral *Literal = Constraints[i]; 1288 if (Literal->isWide()) 1289 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1290 << Literal->getSourceRange()); 1291 1292 llvm::StringRef OutputName; 1293 if (Names[i]) 1294 OutputName = Names[i]->getName(); 1295 1296 TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName); 1297 if (!Context.Target.validateOutputConstraint(Info)) 1298 return StmtError(Diag(Literal->getLocStart(), 1299 diag::err_asm_invalid_output_constraint) 1300 << Info.getConstraintStr()); 1301 1302 // Check that the output exprs are valid lvalues. 1303 Expr *OutputExpr = Exprs[i]; 1304 if (CheckAsmLValue(OutputExpr, *this)) { 1305 return StmtError(Diag(OutputExpr->getLocStart(), 1306 diag::err_asm_invalid_lvalue_in_output) 1307 << OutputExpr->getSourceRange()); 1308 } 1309 1310 OutputConstraintInfos.push_back(Info); 1311 } 1312 1313 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; 1314 1315 for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { 1316 StringLiteral *Literal = Constraints[i]; 1317 if (Literal->isWide()) 1318 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1319 << Literal->getSourceRange()); 1320 1321 llvm::StringRef InputName; 1322 if (Names[i]) 1323 InputName = Names[i]->getName(); 1324 1325 TargetInfo::ConstraintInfo Info(Literal->getString(), InputName); 1326 if (!Context.Target.validateInputConstraint(OutputConstraintInfos.data(), 1327 NumOutputs, Info)) { 1328 return StmtError(Diag(Literal->getLocStart(), 1329 diag::err_asm_invalid_input_constraint) 1330 << Info.getConstraintStr()); 1331 } 1332 1333 Expr *InputExpr = Exprs[i]; 1334 1335 // Only allow void types for memory constraints. 1336 if (Info.allowsMemory() && !Info.allowsRegister()) { 1337 if (CheckAsmLValue(InputExpr, *this)) 1338 return StmtError(Diag(InputExpr->getLocStart(), 1339 diag::err_asm_invalid_lvalue_in_input) 1340 << Info.getConstraintStr() 1341 << InputExpr->getSourceRange()); 1342 } 1343 1344 if (Info.allowsRegister()) { 1345 if (InputExpr->getType()->isVoidType()) { 1346 return StmtError(Diag(InputExpr->getLocStart(), 1347 diag::err_asm_invalid_type_in_input) 1348 << InputExpr->getType() << Info.getConstraintStr() 1349 << InputExpr->getSourceRange()); 1350 } 1351 } 1352 1353 DefaultFunctionArrayLvalueConversion(Exprs[i]); 1354 1355 InputConstraintInfos.push_back(Info); 1356 } 1357 1358 // Check that the clobbers are valid. 1359 for (unsigned i = 0; i != NumClobbers; i++) { 1360 StringLiteral *Literal = Clobbers[i]; 1361 if (Literal->isWide()) 1362 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1363 << Literal->getSourceRange()); 1364 1365 llvm::StringRef Clobber = Literal->getString(); 1366 1367 if (!Context.Target.isValidGCCRegisterName(Clobber)) 1368 return StmtError(Diag(Literal->getLocStart(), 1369 diag::err_asm_unknown_register_name) << Clobber); 1370 } 1371 1372 AsmStmt *NS = 1373 new (Context) AsmStmt(Context, AsmLoc, IsSimple, IsVolatile, MSAsm, 1374 NumOutputs, NumInputs, Names, Constraints, Exprs, 1375 AsmString, NumClobbers, Clobbers, RParenLoc); 1376 // Validate the asm string, ensuring it makes sense given the operands we 1377 // have. 1378 llvm::SmallVector<AsmStmt::AsmStringPiece, 8> Pieces; 1379 unsigned DiagOffs; 1380 if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) { 1381 Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID) 1382 << AsmString->getSourceRange(); 1383 return StmtError(); 1384 } 1385 1386 // Validate tied input operands for type mismatches. 1387 for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) { 1388 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; 1389 1390 // If this is a tied constraint, verify that the output and input have 1391 // either exactly the same type, or that they are int/ptr operands with the 1392 // same size (int/long, int*/long, are ok etc). 1393 if (!Info.hasTiedOperand()) continue; 1394 1395 unsigned TiedTo = Info.getTiedOperand(); 1396 Expr *OutputExpr = Exprs[TiedTo]; 1397 Expr *InputExpr = Exprs[i+NumOutputs]; 1398 QualType InTy = InputExpr->getType(); 1399 QualType OutTy = OutputExpr->getType(); 1400 if (Context.hasSameType(InTy, OutTy)) 1401 continue; // All types can be tied to themselves. 1402 1403 // Decide if the input and output are in the same domain (integer/ptr or 1404 // floating point. 1405 enum AsmDomain { 1406 AD_Int, AD_FP, AD_Other 1407 } InputDomain, OutputDomain; 1408 1409 if (InTy->isIntegerType() || InTy->isPointerType()) 1410 InputDomain = AD_Int; 1411 else if (InTy->isRealFloatingType()) 1412 InputDomain = AD_FP; 1413 else 1414 InputDomain = AD_Other; 1415 1416 if (OutTy->isIntegerType() || OutTy->isPointerType()) 1417 OutputDomain = AD_Int; 1418 else if (OutTy->isRealFloatingType()) 1419 OutputDomain = AD_FP; 1420 else 1421 OutputDomain = AD_Other; 1422 1423 // They are ok if they are the same size and in the same domain. This 1424 // allows tying things like: 1425 // void* to int* 1426 // void* to int if they are the same size. 1427 // double to long double if they are the same size. 1428 // 1429 uint64_t OutSize = Context.getTypeSize(OutTy); 1430 uint64_t InSize = Context.getTypeSize(InTy); 1431 if (OutSize == InSize && InputDomain == OutputDomain && 1432 InputDomain != AD_Other) 1433 continue; 1434 1435 // If the smaller input/output operand is not mentioned in the asm string, 1436 // then we can promote it and the asm string won't notice. Check this 1437 // case now. 1438 bool SmallerValueMentioned = false; 1439 for (unsigned p = 0, e = Pieces.size(); p != e; ++p) { 1440 AsmStmt::AsmStringPiece &Piece = Pieces[p]; 1441 if (!Piece.isOperand()) continue; 1442 1443 // If this is a reference to the input and if the input was the smaller 1444 // one, then we have to reject this asm. 1445 if (Piece.getOperandNo() == i+NumOutputs) { 1446 if (InSize < OutSize) { 1447 SmallerValueMentioned = true; 1448 break; 1449 } 1450 } 1451 1452 // If this is a reference to the input and if the input was the smaller 1453 // one, then we have to reject this asm. 1454 if (Piece.getOperandNo() == TiedTo) { 1455 if (InSize > OutSize) { 1456 SmallerValueMentioned = true; 1457 break; 1458 } 1459 } 1460 } 1461 1462 // If the smaller value wasn't mentioned in the asm string, and if the 1463 // output was a register, just extend the shorter one to the size of the 1464 // larger one. 1465 if (!SmallerValueMentioned && InputDomain != AD_Other && 1466 OutputConstraintInfos[TiedTo].allowsRegister()) 1467 continue; 1468 1469 Diag(InputExpr->getLocStart(), 1470 diag::err_asm_tying_incompatible_types) 1471 << InTy << OutTy << OutputExpr->getSourceRange() 1472 << InputExpr->getSourceRange(); 1473 return StmtError(); 1474 } 1475 1476 return Owned(NS); 1477} 1478 1479StmtResult 1480Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc, 1481 SourceLocation RParen, Decl *Parm, 1482 Stmt *Body) { 1483 VarDecl *Var = cast_or_null<VarDecl>(Parm); 1484 if (Var && Var->isInvalidDecl()) 1485 return StmtError(); 1486 1487 return Owned(new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, Body)); 1488} 1489 1490StmtResult 1491Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body) { 1492 return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, Body)); 1493} 1494 1495StmtResult 1496Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try, 1497 MultiStmtArg CatchStmts, Stmt *Finally) { 1498 getCurFunction()->setHasBranchProtectedScope(); 1499 unsigned NumCatchStmts = CatchStmts.size(); 1500 return Owned(ObjCAtTryStmt::Create(Context, AtLoc, Try, 1501 CatchStmts.release(), 1502 NumCatchStmts, 1503 Finally)); 1504} 1505 1506StmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc, 1507 Expr *Throw) { 1508 if (Throw) { 1509 QualType ThrowType = Throw->getType(); 1510 // Make sure the expression type is an ObjC pointer or "void *". 1511 if (!ThrowType->isDependentType() && 1512 !ThrowType->isObjCObjectPointerType()) { 1513 const PointerType *PT = ThrowType->getAs<PointerType>(); 1514 if (!PT || !PT->getPointeeType()->isVoidType()) 1515 return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object) 1516 << Throw->getType() << Throw->getSourceRange()); 1517 } 1518 } 1519 1520 return Owned(new (Context) ObjCAtThrowStmt(AtLoc, Throw)); 1521} 1522 1523StmtResult 1524Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw, 1525 Scope *CurScope) { 1526 if (!Throw) { 1527 // @throw without an expression designates a rethrow (which much occur 1528 // in the context of an @catch clause). 1529 Scope *AtCatchParent = CurScope; 1530 while (AtCatchParent && !AtCatchParent->isAtCatchScope()) 1531 AtCatchParent = AtCatchParent->getParent(); 1532 if (!AtCatchParent) 1533 return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch)); 1534 } 1535 1536 return BuildObjCAtThrowStmt(AtLoc, Throw); 1537} 1538 1539StmtResult 1540Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, Expr *SyncExpr, 1541 Stmt *SyncBody) { 1542 getCurFunction()->setHasBranchProtectedScope(); 1543 1544 // Make sure the expression type is an ObjC pointer or "void *". 1545 if (!SyncExpr->getType()->isDependentType() && 1546 !SyncExpr->getType()->isObjCObjectPointerType()) { 1547 const PointerType *PT = SyncExpr->getType()->getAs<PointerType>(); 1548 if (!PT || !PT->getPointeeType()->isVoidType()) 1549 return StmtError(Diag(AtLoc, diag::error_objc_synchronized_expects_object) 1550 << SyncExpr->getType() << SyncExpr->getSourceRange()); 1551 } 1552 1553 return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, SyncExpr, SyncBody)); 1554} 1555 1556/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block 1557/// and creates a proper catch handler from them. 1558StmtResult 1559Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl, 1560 Stmt *HandlerBlock) { 1561 // There's nothing to test that ActOnExceptionDecl didn't already test. 1562 return Owned(new (Context) CXXCatchStmt(CatchLoc, 1563 cast_or_null<VarDecl>(ExDecl), 1564 HandlerBlock)); 1565} 1566 1567namespace { 1568 1569class TypeWithHandler { 1570 QualType t; 1571 CXXCatchStmt *stmt; 1572public: 1573 TypeWithHandler(const QualType &type, CXXCatchStmt *statement) 1574 : t(type), stmt(statement) {} 1575 1576 // An arbitrary order is fine as long as it places identical 1577 // types next to each other. 1578 bool operator<(const TypeWithHandler &y) const { 1579 if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr()) 1580 return true; 1581 if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr()) 1582 return false; 1583 else 1584 return getTypeSpecStartLoc() < y.getTypeSpecStartLoc(); 1585 } 1586 1587 bool operator==(const TypeWithHandler& other) const { 1588 return t == other.t; 1589 } 1590 1591 CXXCatchStmt *getCatchStmt() const { return stmt; } 1592 SourceLocation getTypeSpecStartLoc() const { 1593 return stmt->getExceptionDecl()->getTypeSpecStartLoc(); 1594 } 1595}; 1596 1597} 1598 1599/// ActOnCXXTryBlock - Takes a try compound-statement and a number of 1600/// handlers and creates a try statement from them. 1601StmtResult 1602Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock, 1603 MultiStmtArg RawHandlers) { 1604 unsigned NumHandlers = RawHandlers.size(); 1605 assert(NumHandlers > 0 && 1606 "The parser shouldn't call this if there are no handlers."); 1607 Stmt **Handlers = RawHandlers.get(); 1608 1609 llvm::SmallVector<TypeWithHandler, 8> TypesWithHandlers; 1610 1611 for (unsigned i = 0; i < NumHandlers; ++i) { 1612 CXXCatchStmt *Handler = llvm::cast<CXXCatchStmt>(Handlers[i]); 1613 if (!Handler->getExceptionDecl()) { 1614 if (i < NumHandlers - 1) 1615 return StmtError(Diag(Handler->getLocStart(), 1616 diag::err_early_catch_all)); 1617 1618 continue; 1619 } 1620 1621 const QualType CaughtType = Handler->getCaughtType(); 1622 const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType); 1623 TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler)); 1624 } 1625 1626 // Detect handlers for the same type as an earlier one. 1627 if (NumHandlers > 1) { 1628 llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end()); 1629 1630 TypeWithHandler prev = TypesWithHandlers[0]; 1631 for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) { 1632 TypeWithHandler curr = TypesWithHandlers[i]; 1633 1634 if (curr == prev) { 1635 Diag(curr.getTypeSpecStartLoc(), 1636 diag::warn_exception_caught_by_earlier_handler) 1637 << curr.getCatchStmt()->getCaughtType().getAsString(); 1638 Diag(prev.getTypeSpecStartLoc(), 1639 diag::note_previous_exception_handler) 1640 << prev.getCatchStmt()->getCaughtType().getAsString(); 1641 } 1642 1643 prev = curr; 1644 } 1645 } 1646 1647 getCurFunction()->setHasBranchProtectedScope(); 1648 1649 // FIXME: We should detect handlers that cannot catch anything because an 1650 // earlier handler catches a superclass. Need to find a method that is not 1651 // quadratic for this. 1652 // Neither of these are explicitly forbidden, but every compiler detects them 1653 // and warns. 1654 1655 return Owned(CXXTryStmt::Create(Context, TryLoc, TryBlock, 1656 Handlers, NumHandlers)); 1657} 1658