SemaStmt.cpp revision b5f9eb8a0709082bba8e8de3a6c643928570aaa0
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/Sema/Lookup.h" 19#include "clang/AST/ASTContext.h" 20#include "clang/AST/CharUnits.h" 21#include "clang/AST/DeclObjC.h" 22#include "clang/AST/EvaluatedExprVisitor.h" 23#include "clang/AST/ExprCXX.h" 24#include "clang/AST/ExprObjC.h" 25#include "clang/AST/StmtObjC.h" 26#include "clang/AST/StmtCXX.h" 27#include "clang/AST/TypeLoc.h" 28#include "clang/Lex/Preprocessor.h" 29#include "clang/Basic/TargetInfo.h" 30#include "llvm/ADT/ArrayRef.h" 31#include "llvm/ADT/STLExtras.h" 32#include "llvm/ADT/SmallPtrSet.h" 33#include "llvm/ADT/SmallString.h" 34#include "llvm/ADT/SmallVector.h" 35#include "llvm/ADT/Triple.h" 36#include "llvm/MC/MCAsmInfo.h" 37#include "llvm/MC/MCContext.h" 38#include "llvm/MC/MCInst.h" 39#include "llvm/MC/MCInstPrinter.h" 40#include "llvm/MC/MCInstrInfo.h" 41#include "llvm/MC/MCObjectFileInfo.h" 42#include "llvm/MC/MCRegisterInfo.h" 43#include "llvm/MC/MCStreamer.h" 44#include "llvm/MC/MCSubtargetInfo.h" 45#include "llvm/MC/MCTargetAsmParser.h" 46#include "llvm/MC/MCParser/MCAsmLexer.h" 47#include "llvm/MC/MCParser/MCAsmParser.h" 48#include "llvm/Support/SourceMgr.h" 49#include "llvm/Support/TargetRegistry.h" 50#include "llvm/Support/TargetSelect.h" 51using namespace clang; 52using namespace sema; 53 54StmtResult Sema::ActOnExprStmt(FullExprArg expr) { 55 Expr *E = expr.get(); 56 if (!E) // FIXME: FullExprArg has no error state? 57 return StmtError(); 58 59 // C99 6.8.3p2: The expression in an expression statement is evaluated as a 60 // void expression for its side effects. Conversion to void allows any 61 // operand, even incomplete types. 62 63 // Same thing in for stmt first clause (when expr) and third clause. 64 return Owned(static_cast<Stmt*>(E)); 65} 66 67 68StmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc, 69 bool HasLeadingEmptyMacro) { 70 return Owned(new (Context) NullStmt(SemiLoc, HasLeadingEmptyMacro)); 71} 72 73StmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, SourceLocation StartLoc, 74 SourceLocation EndLoc) { 75 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 76 77 // If we have an invalid decl, just return an error. 78 if (DG.isNull()) return StmtError(); 79 80 return Owned(new (Context) DeclStmt(DG, StartLoc, EndLoc)); 81} 82 83void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) { 84 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 85 86 // If we have an invalid decl, just return. 87 if (DG.isNull() || !DG.isSingleDecl()) return; 88 VarDecl *var = cast<VarDecl>(DG.getSingleDecl()); 89 90 // suppress any potential 'unused variable' warning. 91 var->setUsed(); 92 93 // foreach variables are never actually initialized in the way that 94 // the parser came up with. 95 var->setInit(0); 96 97 // In ARC, we don't need to retain the iteration variable of a fast 98 // enumeration loop. Rather than actually trying to catch that 99 // during declaration processing, we remove the consequences here. 100 if (getLangOpts().ObjCAutoRefCount) { 101 QualType type = var->getType(); 102 103 // Only do this if we inferred the lifetime. Inferred lifetime 104 // will show up as a local qualifier because explicit lifetime 105 // should have shown up as an AttributedType instead. 106 if (type.getLocalQualifiers().getObjCLifetime() == Qualifiers::OCL_Strong) { 107 // Add 'const' and mark the variable as pseudo-strong. 108 var->setType(type.withConst()); 109 var->setARCPseudoStrong(true); 110 } 111 } 112} 113 114/// \brief Diagnose unused '==' and '!=' as likely typos for '=' or '|='. 115/// 116/// Adding a cast to void (or other expression wrappers) will prevent the 117/// warning from firing. 118static bool DiagnoseUnusedComparison(Sema &S, const Expr *E) { 119 SourceLocation Loc; 120 bool IsNotEqual, CanAssign; 121 122 if (const BinaryOperator *Op = dyn_cast<BinaryOperator>(E)) { 123 if (Op->getOpcode() != BO_EQ && Op->getOpcode() != BO_NE) 124 return false; 125 126 Loc = Op->getOperatorLoc(); 127 IsNotEqual = Op->getOpcode() == BO_NE; 128 CanAssign = Op->getLHS()->IgnoreParenImpCasts()->isLValue(); 129 } else if (const CXXOperatorCallExpr *Op = dyn_cast<CXXOperatorCallExpr>(E)) { 130 if (Op->getOperator() != OO_EqualEqual && 131 Op->getOperator() != OO_ExclaimEqual) 132 return false; 133 134 Loc = Op->getOperatorLoc(); 135 IsNotEqual = Op->getOperator() == OO_ExclaimEqual; 136 CanAssign = Op->getArg(0)->IgnoreParenImpCasts()->isLValue(); 137 } else { 138 // Not a typo-prone comparison. 139 return false; 140 } 141 142 // Suppress warnings when the operator, suspicious as it may be, comes from 143 // a macro expansion. 144 if (Loc.isMacroID()) 145 return false; 146 147 S.Diag(Loc, diag::warn_unused_comparison) 148 << (unsigned)IsNotEqual << E->getSourceRange(); 149 150 // If the LHS is a plausible entity to assign to, provide a fixit hint to 151 // correct common typos. 152 if (CanAssign) { 153 if (IsNotEqual) 154 S.Diag(Loc, diag::note_inequality_comparison_to_or_assign) 155 << FixItHint::CreateReplacement(Loc, "|="); 156 else 157 S.Diag(Loc, diag::note_equality_comparison_to_assign) 158 << FixItHint::CreateReplacement(Loc, "="); 159 } 160 161 return true; 162} 163 164void Sema::DiagnoseUnusedExprResult(const Stmt *S) { 165 if (const LabelStmt *Label = dyn_cast_or_null<LabelStmt>(S)) 166 return DiagnoseUnusedExprResult(Label->getSubStmt()); 167 168 const Expr *E = dyn_cast_or_null<Expr>(S); 169 if (!E) 170 return; 171 172 const Expr *WarnExpr; 173 SourceLocation Loc; 174 SourceRange R1, R2; 175 if (SourceMgr.isInSystemMacro(E->getExprLoc()) || 176 !E->isUnusedResultAWarning(WarnExpr, Loc, R1, R2, Context)) 177 return; 178 179 // Okay, we have an unused result. Depending on what the base expression is, 180 // we might want to make a more specific diagnostic. Check for one of these 181 // cases now. 182 unsigned DiagID = diag::warn_unused_expr; 183 if (const ExprWithCleanups *Temps = dyn_cast<ExprWithCleanups>(E)) 184 E = Temps->getSubExpr(); 185 if (const CXXBindTemporaryExpr *TempExpr = dyn_cast<CXXBindTemporaryExpr>(E)) 186 E = TempExpr->getSubExpr(); 187 188 if (DiagnoseUnusedComparison(*this, E)) 189 return; 190 191 E = WarnExpr; 192 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 193 if (E->getType()->isVoidType()) 194 return; 195 196 // If the callee has attribute pure, const, or warn_unused_result, warn with 197 // a more specific message to make it clear what is happening. 198 if (const Decl *FD = CE->getCalleeDecl()) { 199 if (FD->getAttr<WarnUnusedResultAttr>()) { 200 Diag(Loc, diag::warn_unused_result) << R1 << R2; 201 return; 202 } 203 if (FD->getAttr<PureAttr>()) { 204 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure"; 205 return; 206 } 207 if (FD->getAttr<ConstAttr>()) { 208 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const"; 209 return; 210 } 211 } 212 } else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E)) { 213 if (getLangOpts().ObjCAutoRefCount && ME->isDelegateInitCall()) { 214 Diag(Loc, diag::err_arc_unused_init_message) << R1; 215 return; 216 } 217 const ObjCMethodDecl *MD = ME->getMethodDecl(); 218 if (MD && MD->getAttr<WarnUnusedResultAttr>()) { 219 Diag(Loc, diag::warn_unused_result) << R1 << R2; 220 return; 221 } 222 } else if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(E)) { 223 const Expr *Source = POE->getSyntacticForm(); 224 if (isa<ObjCSubscriptRefExpr>(Source)) 225 DiagID = diag::warn_unused_container_subscript_expr; 226 else 227 DiagID = diag::warn_unused_property_expr; 228 } else if (const CXXFunctionalCastExpr *FC 229 = dyn_cast<CXXFunctionalCastExpr>(E)) { 230 if (isa<CXXConstructExpr>(FC->getSubExpr()) || 231 isa<CXXTemporaryObjectExpr>(FC->getSubExpr())) 232 return; 233 } 234 // Diagnose "(void*) blah" as a typo for "(void) blah". 235 else if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(E)) { 236 TypeSourceInfo *TI = CE->getTypeInfoAsWritten(); 237 QualType T = TI->getType(); 238 239 // We really do want to use the non-canonical type here. 240 if (T == Context.VoidPtrTy) { 241 PointerTypeLoc TL = cast<PointerTypeLoc>(TI->getTypeLoc()); 242 243 Diag(Loc, diag::warn_unused_voidptr) 244 << FixItHint::CreateRemoval(TL.getStarLoc()); 245 return; 246 } 247 } 248 249 if (E->isGLValue() && E->getType().isVolatileQualified()) { 250 Diag(Loc, diag::warn_unused_volatile) << R1 << R2; 251 return; 252 } 253 254 DiagRuntimeBehavior(Loc, 0, PDiag(DiagID) << R1 << R2); 255} 256 257void Sema::ActOnStartOfCompoundStmt() { 258 PushCompoundScope(); 259} 260 261void Sema::ActOnFinishOfCompoundStmt() { 262 PopCompoundScope(); 263} 264 265sema::CompoundScopeInfo &Sema::getCurCompoundScope() const { 266 return getCurFunction()->CompoundScopes.back(); 267} 268 269StmtResult 270Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R, 271 MultiStmtArg elts, bool isStmtExpr) { 272 unsigned NumElts = elts.size(); 273 Stmt **Elts = reinterpret_cast<Stmt**>(elts.release()); 274 // If we're in C89 mode, check that we don't have any decls after stmts. If 275 // so, emit an extension diagnostic. 276 if (!getLangOpts().C99 && !getLangOpts().CPlusPlus) { 277 // Note that __extension__ can be around a decl. 278 unsigned i = 0; 279 // Skip over all declarations. 280 for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i) 281 /*empty*/; 282 283 // We found the end of the list or a statement. Scan for another declstmt. 284 for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i) 285 /*empty*/; 286 287 if (i != NumElts) { 288 Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin(); 289 Diag(D->getLocation(), diag::ext_mixed_decls_code); 290 } 291 } 292 // Warn about unused expressions in statements. 293 for (unsigned i = 0; i != NumElts; ++i) { 294 // Ignore statements that are last in a statement expression. 295 if (isStmtExpr && i == NumElts - 1) 296 continue; 297 298 DiagnoseUnusedExprResult(Elts[i]); 299 } 300 301 // Check for suspicious empty body (null statement) in `for' and `while' 302 // statements. Don't do anything for template instantiations, this just adds 303 // noise. 304 if (NumElts != 0 && !CurrentInstantiationScope && 305 getCurCompoundScope().HasEmptyLoopBodies) { 306 for (unsigned i = 0; i != NumElts - 1; ++i) 307 DiagnoseEmptyLoopBody(Elts[i], Elts[i + 1]); 308 } 309 310 return Owned(new (Context) CompoundStmt(Context, Elts, NumElts, L, R)); 311} 312 313StmtResult 314Sema::ActOnCaseStmt(SourceLocation CaseLoc, Expr *LHSVal, 315 SourceLocation DotDotDotLoc, Expr *RHSVal, 316 SourceLocation ColonLoc) { 317 assert((LHSVal != 0) && "missing expression in case statement"); 318 319 if (getCurFunction()->SwitchStack.empty()) { 320 Diag(CaseLoc, diag::err_case_not_in_switch); 321 return StmtError(); 322 } 323 324 if (!getLangOpts().CPlusPlus0x) { 325 // C99 6.8.4.2p3: The expression shall be an integer constant. 326 // However, GCC allows any evaluatable integer expression. 327 if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent()) { 328 LHSVal = VerifyIntegerConstantExpression(LHSVal).take(); 329 if (!LHSVal) 330 return StmtError(); 331 } 332 333 // GCC extension: The expression shall be an integer constant. 334 335 if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent()) { 336 RHSVal = VerifyIntegerConstantExpression(RHSVal).take(); 337 // Recover from an error by just forgetting about it. 338 } 339 } 340 341 CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc, 342 ColonLoc); 343 getCurFunction()->SwitchStack.back()->addSwitchCase(CS); 344 return Owned(CS); 345} 346 347/// ActOnCaseStmtBody - This installs a statement as the body of a case. 348void Sema::ActOnCaseStmtBody(Stmt *caseStmt, Stmt *SubStmt) { 349 DiagnoseUnusedExprResult(SubStmt); 350 351 CaseStmt *CS = static_cast<CaseStmt*>(caseStmt); 352 CS->setSubStmt(SubStmt); 353} 354 355StmtResult 356Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc, 357 Stmt *SubStmt, Scope *CurScope) { 358 DiagnoseUnusedExprResult(SubStmt); 359 360 if (getCurFunction()->SwitchStack.empty()) { 361 Diag(DefaultLoc, diag::err_default_not_in_switch); 362 return Owned(SubStmt); 363 } 364 365 DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt); 366 getCurFunction()->SwitchStack.back()->addSwitchCase(DS); 367 return Owned(DS); 368} 369 370StmtResult 371Sema::ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl, 372 SourceLocation ColonLoc, Stmt *SubStmt) { 373 // If the label was multiply defined, reject it now. 374 if (TheDecl->getStmt()) { 375 Diag(IdentLoc, diag::err_redefinition_of_label) << TheDecl->getDeclName(); 376 Diag(TheDecl->getLocation(), diag::note_previous_definition); 377 return Owned(SubStmt); 378 } 379 380 // Otherwise, things are good. Fill in the declaration and return it. 381 LabelStmt *LS = new (Context) LabelStmt(IdentLoc, TheDecl, SubStmt); 382 TheDecl->setStmt(LS); 383 if (!TheDecl->isGnuLocal()) 384 TheDecl->setLocation(IdentLoc); 385 return Owned(LS); 386} 387 388StmtResult Sema::ActOnAttributedStmt(SourceLocation AttrLoc, 389 ArrayRef<const Attr*> Attrs, 390 Stmt *SubStmt) { 391 // Fill in the declaration and return it. 392 AttributedStmt *LS = AttributedStmt::Create(Context, AttrLoc, Attrs, SubStmt); 393 return Owned(LS); 394} 395 396StmtResult 397Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, Decl *CondVar, 398 Stmt *thenStmt, SourceLocation ElseLoc, 399 Stmt *elseStmt) { 400 ExprResult CondResult(CondVal.release()); 401 402 VarDecl *ConditionVar = 0; 403 if (CondVar) { 404 ConditionVar = cast<VarDecl>(CondVar); 405 CondResult = CheckConditionVariable(ConditionVar, IfLoc, true); 406 if (CondResult.isInvalid()) 407 return StmtError(); 408 } 409 Expr *ConditionExpr = CondResult.takeAs<Expr>(); 410 if (!ConditionExpr) 411 return StmtError(); 412 413 DiagnoseUnusedExprResult(thenStmt); 414 415 if (!elseStmt) { 416 DiagnoseEmptyStmtBody(ConditionExpr->getLocEnd(), thenStmt, 417 diag::warn_empty_if_body); 418 } 419 420 DiagnoseUnusedExprResult(elseStmt); 421 422 return Owned(new (Context) IfStmt(Context, IfLoc, ConditionVar, ConditionExpr, 423 thenStmt, ElseLoc, elseStmt)); 424} 425 426/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have 427/// the specified width and sign. If an overflow occurs, detect it and emit 428/// the specified diagnostic. 429void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val, 430 unsigned NewWidth, bool NewSign, 431 SourceLocation Loc, 432 unsigned DiagID) { 433 // Perform a conversion to the promoted condition type if needed. 434 if (NewWidth > Val.getBitWidth()) { 435 // If this is an extension, just do it. 436 Val = Val.extend(NewWidth); 437 Val.setIsSigned(NewSign); 438 439 // If the input was signed and negative and the output is 440 // unsigned, don't bother to warn: this is implementation-defined 441 // behavior. 442 // FIXME: Introduce a second, default-ignored warning for this case? 443 } else if (NewWidth < Val.getBitWidth()) { 444 // If this is a truncation, check for overflow. 445 llvm::APSInt ConvVal(Val); 446 ConvVal = ConvVal.trunc(NewWidth); 447 ConvVal.setIsSigned(NewSign); 448 ConvVal = ConvVal.extend(Val.getBitWidth()); 449 ConvVal.setIsSigned(Val.isSigned()); 450 if (ConvVal != Val) 451 Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10); 452 453 // Regardless of whether a diagnostic was emitted, really do the 454 // truncation. 455 Val = Val.trunc(NewWidth); 456 Val.setIsSigned(NewSign); 457 } else if (NewSign != Val.isSigned()) { 458 // Convert the sign to match the sign of the condition. This can cause 459 // overflow as well: unsigned(INTMIN) 460 // We don't diagnose this overflow, because it is implementation-defined 461 // behavior. 462 // FIXME: Introduce a second, default-ignored warning for this case? 463 llvm::APSInt OldVal(Val); 464 Val.setIsSigned(NewSign); 465 } 466} 467 468namespace { 469 struct CaseCompareFunctor { 470 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 471 const llvm::APSInt &RHS) { 472 return LHS.first < RHS; 473 } 474 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 475 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 476 return LHS.first < RHS.first; 477 } 478 bool operator()(const llvm::APSInt &LHS, 479 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 480 return LHS < RHS.first; 481 } 482 }; 483} 484 485/// CmpCaseVals - Comparison predicate for sorting case values. 486/// 487static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs, 488 const std::pair<llvm::APSInt, CaseStmt*>& rhs) { 489 if (lhs.first < rhs.first) 490 return true; 491 492 if (lhs.first == rhs.first && 493 lhs.second->getCaseLoc().getRawEncoding() 494 < rhs.second->getCaseLoc().getRawEncoding()) 495 return true; 496 return false; 497} 498 499/// CmpEnumVals - Comparison predicate for sorting enumeration values. 500/// 501static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 502 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 503{ 504 return lhs.first < rhs.first; 505} 506 507/// EqEnumVals - Comparison preficate for uniqing enumeration values. 508/// 509static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 510 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 511{ 512 return lhs.first == rhs.first; 513} 514 515/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of 516/// potentially integral-promoted expression @p expr. 517static QualType GetTypeBeforeIntegralPromotion(Expr *&expr) { 518 if (ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(expr)) 519 expr = cleanups->getSubExpr(); 520 while (ImplicitCastExpr *impcast = dyn_cast<ImplicitCastExpr>(expr)) { 521 if (impcast->getCastKind() != CK_IntegralCast) break; 522 expr = impcast->getSubExpr(); 523 } 524 return expr->getType(); 525} 526 527StmtResult 528Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond, 529 Decl *CondVar) { 530 ExprResult CondResult; 531 532 VarDecl *ConditionVar = 0; 533 if (CondVar) { 534 ConditionVar = cast<VarDecl>(CondVar); 535 CondResult = CheckConditionVariable(ConditionVar, SourceLocation(), false); 536 if (CondResult.isInvalid()) 537 return StmtError(); 538 539 Cond = CondResult.release(); 540 } 541 542 if (!Cond) 543 return StmtError(); 544 545 class SwitchConvertDiagnoser : public ICEConvertDiagnoser { 546 Expr *Cond; 547 548 public: 549 SwitchConvertDiagnoser(Expr *Cond) 550 : ICEConvertDiagnoser(false, true), Cond(Cond) { } 551 552 virtual DiagnosticBuilder diagnoseNotInt(Sema &S, SourceLocation Loc, 553 QualType T) { 554 return S.Diag(Loc, diag::err_typecheck_statement_requires_integer) << T; 555 } 556 557 virtual DiagnosticBuilder diagnoseIncomplete(Sema &S, SourceLocation Loc, 558 QualType T) { 559 return S.Diag(Loc, diag::err_switch_incomplete_class_type) 560 << T << Cond->getSourceRange(); 561 } 562 563 virtual DiagnosticBuilder diagnoseExplicitConv(Sema &S, SourceLocation Loc, 564 QualType T, 565 QualType ConvTy) { 566 return S.Diag(Loc, diag::err_switch_explicit_conversion) << T << ConvTy; 567 } 568 569 virtual DiagnosticBuilder noteExplicitConv(Sema &S, CXXConversionDecl *Conv, 570 QualType ConvTy) { 571 return S.Diag(Conv->getLocation(), diag::note_switch_conversion) 572 << ConvTy->isEnumeralType() << ConvTy; 573 } 574 575 virtual DiagnosticBuilder diagnoseAmbiguous(Sema &S, SourceLocation Loc, 576 QualType T) { 577 return S.Diag(Loc, diag::err_switch_multiple_conversions) << T; 578 } 579 580 virtual DiagnosticBuilder noteAmbiguous(Sema &S, CXXConversionDecl *Conv, 581 QualType ConvTy) { 582 return S.Diag(Conv->getLocation(), diag::note_switch_conversion) 583 << ConvTy->isEnumeralType() << ConvTy; 584 } 585 586 virtual DiagnosticBuilder diagnoseConversion(Sema &S, SourceLocation Loc, 587 QualType T, 588 QualType ConvTy) { 589 return DiagnosticBuilder::getEmpty(); 590 } 591 } SwitchDiagnoser(Cond); 592 593 CondResult 594 = ConvertToIntegralOrEnumerationType(SwitchLoc, Cond, SwitchDiagnoser, 595 /*AllowScopedEnumerations*/ true); 596 if (CondResult.isInvalid()) return StmtError(); 597 Cond = CondResult.take(); 598 599 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr. 600 CondResult = UsualUnaryConversions(Cond); 601 if (CondResult.isInvalid()) return StmtError(); 602 Cond = CondResult.take(); 603 604 if (!CondVar) { 605 CheckImplicitConversions(Cond, SwitchLoc); 606 CondResult = MaybeCreateExprWithCleanups(Cond); 607 if (CondResult.isInvalid()) 608 return StmtError(); 609 Cond = CondResult.take(); 610 } 611 612 getCurFunction()->setHasBranchIntoScope(); 613 614 SwitchStmt *SS = new (Context) SwitchStmt(Context, ConditionVar, Cond); 615 getCurFunction()->SwitchStack.push_back(SS); 616 return Owned(SS); 617} 618 619static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) { 620 if (Val.getBitWidth() < BitWidth) 621 Val = Val.extend(BitWidth); 622 else if (Val.getBitWidth() > BitWidth) 623 Val = Val.trunc(BitWidth); 624 Val.setIsSigned(IsSigned); 625} 626 627StmtResult 628Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch, 629 Stmt *BodyStmt) { 630 SwitchStmt *SS = cast<SwitchStmt>(Switch); 631 assert(SS == getCurFunction()->SwitchStack.back() && 632 "switch stack missing push/pop!"); 633 634 SS->setBody(BodyStmt, SwitchLoc); 635 getCurFunction()->SwitchStack.pop_back(); 636 637 Expr *CondExpr = SS->getCond(); 638 if (!CondExpr) return StmtError(); 639 640 QualType CondType = CondExpr->getType(); 641 642 Expr *CondExprBeforePromotion = CondExpr; 643 QualType CondTypeBeforePromotion = 644 GetTypeBeforeIntegralPromotion(CondExprBeforePromotion); 645 646 // C++ 6.4.2.p2: 647 // Integral promotions are performed (on the switch condition). 648 // 649 // A case value unrepresentable by the original switch condition 650 // type (before the promotion) doesn't make sense, even when it can 651 // be represented by the promoted type. Therefore we need to find 652 // the pre-promotion type of the switch condition. 653 if (!CondExpr->isTypeDependent()) { 654 // We have already converted the expression to an integral or enumeration 655 // type, when we started the switch statement. If we don't have an 656 // appropriate type now, just return an error. 657 if (!CondType->isIntegralOrEnumerationType()) 658 return StmtError(); 659 660 if (CondExpr->isKnownToHaveBooleanValue()) { 661 // switch(bool_expr) {...} is often a programmer error, e.g. 662 // switch(n && mask) { ... } // Doh - should be "n & mask". 663 // One can always use an if statement instead of switch(bool_expr). 664 Diag(SwitchLoc, diag::warn_bool_switch_condition) 665 << CondExpr->getSourceRange(); 666 } 667 } 668 669 // Get the bitwidth of the switched-on value before promotions. We must 670 // convert the integer case values to this width before comparison. 671 bool HasDependentValue 672 = CondExpr->isTypeDependent() || CondExpr->isValueDependent(); 673 unsigned CondWidth 674 = HasDependentValue ? 0 : Context.getIntWidth(CondTypeBeforePromotion); 675 bool CondIsSigned 676 = CondTypeBeforePromotion->isSignedIntegerOrEnumerationType(); 677 678 // Accumulate all of the case values in a vector so that we can sort them 679 // and detect duplicates. This vector contains the APInt for the case after 680 // it has been converted to the condition type. 681 typedef SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy; 682 CaseValsTy CaseVals; 683 684 // Keep track of any GNU case ranges we see. The APSInt is the low value. 685 typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy; 686 CaseRangesTy CaseRanges; 687 688 DefaultStmt *TheDefaultStmt = 0; 689 690 bool CaseListIsErroneous = false; 691 692 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue; 693 SC = SC->getNextSwitchCase()) { 694 695 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) { 696 if (TheDefaultStmt) { 697 Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined); 698 Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev); 699 700 // FIXME: Remove the default statement from the switch block so that 701 // we'll return a valid AST. This requires recursing down the AST and 702 // finding it, not something we are set up to do right now. For now, 703 // just lop the entire switch stmt out of the AST. 704 CaseListIsErroneous = true; 705 } 706 TheDefaultStmt = DS; 707 708 } else { 709 CaseStmt *CS = cast<CaseStmt>(SC); 710 711 Expr *Lo = CS->getLHS(); 712 713 if (Lo->isTypeDependent() || Lo->isValueDependent()) { 714 HasDependentValue = true; 715 break; 716 } 717 718 llvm::APSInt LoVal; 719 720 if (getLangOpts().CPlusPlus0x) { 721 // C++11 [stmt.switch]p2: the constant-expression shall be a converted 722 // constant expression of the promoted type of the switch condition. 723 ExprResult ConvLo = 724 CheckConvertedConstantExpression(Lo, CondType, LoVal, CCEK_CaseValue); 725 if (ConvLo.isInvalid()) { 726 CaseListIsErroneous = true; 727 continue; 728 } 729 Lo = ConvLo.take(); 730 } else { 731 // We already verified that the expression has a i-c-e value (C99 732 // 6.8.4.2p3) - get that value now. 733 LoVal = Lo->EvaluateKnownConstInt(Context); 734 735 // If the LHS is not the same type as the condition, insert an implicit 736 // cast. 737 Lo = DefaultLvalueConversion(Lo).take(); 738 Lo = ImpCastExprToType(Lo, CondType, CK_IntegralCast).take(); 739 } 740 741 // Convert the value to the same width/sign as the condition had prior to 742 // integral promotions. 743 // 744 // FIXME: This causes us to reject valid code: 745 // switch ((char)c) { case 256: case 0: return 0; } 746 // Here we claim there is a duplicated condition value, but there is not. 747 ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned, 748 Lo->getLocStart(), 749 diag::warn_case_value_overflow); 750 751 CS->setLHS(Lo); 752 753 // If this is a case range, remember it in CaseRanges, otherwise CaseVals. 754 if (CS->getRHS()) { 755 if (CS->getRHS()->isTypeDependent() || 756 CS->getRHS()->isValueDependent()) { 757 HasDependentValue = true; 758 break; 759 } 760 CaseRanges.push_back(std::make_pair(LoVal, CS)); 761 } else 762 CaseVals.push_back(std::make_pair(LoVal, CS)); 763 } 764 } 765 766 if (!HasDependentValue) { 767 // If we don't have a default statement, check whether the 768 // condition is constant. 769 llvm::APSInt ConstantCondValue; 770 bool HasConstantCond = false; 771 if (!HasDependentValue && !TheDefaultStmt) { 772 HasConstantCond 773 = CondExprBeforePromotion->EvaluateAsInt(ConstantCondValue, Context, 774 Expr::SE_AllowSideEffects); 775 assert(!HasConstantCond || 776 (ConstantCondValue.getBitWidth() == CondWidth && 777 ConstantCondValue.isSigned() == CondIsSigned)); 778 } 779 bool ShouldCheckConstantCond = HasConstantCond; 780 781 // Sort all the scalar case values so we can easily detect duplicates. 782 std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals); 783 784 if (!CaseVals.empty()) { 785 for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) { 786 if (ShouldCheckConstantCond && 787 CaseVals[i].first == ConstantCondValue) 788 ShouldCheckConstantCond = false; 789 790 if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) { 791 // If we have a duplicate, report it. 792 // First, determine if either case value has a name 793 StringRef PrevString, CurrString; 794 Expr *PrevCase = CaseVals[i-1].second->getLHS()->IgnoreParenCasts(); 795 Expr *CurrCase = CaseVals[i].second->getLHS()->IgnoreParenCasts(); 796 if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(PrevCase)) { 797 PrevString = DeclRef->getDecl()->getName(); 798 } 799 if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(CurrCase)) { 800 CurrString = DeclRef->getDecl()->getName(); 801 } 802 llvm::SmallString<16> CaseValStr; 803 CaseVals[i-1].first.toString(CaseValStr); 804 805 if (PrevString == CurrString) 806 Diag(CaseVals[i].second->getLHS()->getLocStart(), 807 diag::err_duplicate_case) << 808 (PrevString.empty() ? CaseValStr.str() : PrevString); 809 else 810 Diag(CaseVals[i].second->getLHS()->getLocStart(), 811 diag::err_duplicate_case_differing_expr) << 812 (PrevString.empty() ? CaseValStr.str() : PrevString) << 813 (CurrString.empty() ? CaseValStr.str() : CurrString) << 814 CaseValStr; 815 816 Diag(CaseVals[i-1].second->getLHS()->getLocStart(), 817 diag::note_duplicate_case_prev); 818 // FIXME: We really want to remove the bogus case stmt from the 819 // substmt, but we have no way to do this right now. 820 CaseListIsErroneous = true; 821 } 822 } 823 } 824 825 // Detect duplicate case ranges, which usually don't exist at all in 826 // the first place. 827 if (!CaseRanges.empty()) { 828 // Sort all the case ranges by their low value so we can easily detect 829 // overlaps between ranges. 830 std::stable_sort(CaseRanges.begin(), CaseRanges.end()); 831 832 // Scan the ranges, computing the high values and removing empty ranges. 833 std::vector<llvm::APSInt> HiVals; 834 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 835 llvm::APSInt &LoVal = CaseRanges[i].first; 836 CaseStmt *CR = CaseRanges[i].second; 837 Expr *Hi = CR->getRHS(); 838 llvm::APSInt HiVal; 839 840 if (getLangOpts().CPlusPlus0x) { 841 // C++11 [stmt.switch]p2: the constant-expression shall be a converted 842 // constant expression of the promoted type of the switch condition. 843 ExprResult ConvHi = 844 CheckConvertedConstantExpression(Hi, CondType, HiVal, 845 CCEK_CaseValue); 846 if (ConvHi.isInvalid()) { 847 CaseListIsErroneous = true; 848 continue; 849 } 850 Hi = ConvHi.take(); 851 } else { 852 HiVal = Hi->EvaluateKnownConstInt(Context); 853 854 // If the RHS is not the same type as the condition, insert an 855 // implicit cast. 856 Hi = DefaultLvalueConversion(Hi).take(); 857 Hi = ImpCastExprToType(Hi, CondType, CK_IntegralCast).take(); 858 } 859 860 // Convert the value to the same width/sign as the condition. 861 ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned, 862 Hi->getLocStart(), 863 diag::warn_case_value_overflow); 864 865 CR->setRHS(Hi); 866 867 // If the low value is bigger than the high value, the case is empty. 868 if (LoVal > HiVal) { 869 Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range) 870 << SourceRange(CR->getLHS()->getLocStart(), 871 Hi->getLocEnd()); 872 CaseRanges.erase(CaseRanges.begin()+i); 873 --i, --e; 874 continue; 875 } 876 877 if (ShouldCheckConstantCond && 878 LoVal <= ConstantCondValue && 879 ConstantCondValue <= HiVal) 880 ShouldCheckConstantCond = false; 881 882 HiVals.push_back(HiVal); 883 } 884 885 // Rescan the ranges, looking for overlap with singleton values and other 886 // ranges. Since the range list is sorted, we only need to compare case 887 // ranges with their neighbors. 888 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 889 llvm::APSInt &CRLo = CaseRanges[i].first; 890 llvm::APSInt &CRHi = HiVals[i]; 891 CaseStmt *CR = CaseRanges[i].second; 892 893 // Check to see whether the case range overlaps with any 894 // singleton cases. 895 CaseStmt *OverlapStmt = 0; 896 llvm::APSInt OverlapVal(32); 897 898 // Find the smallest value >= the lower bound. If I is in the 899 // case range, then we have overlap. 900 CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(), 901 CaseVals.end(), CRLo, 902 CaseCompareFunctor()); 903 if (I != CaseVals.end() && I->first < CRHi) { 904 OverlapVal = I->first; // Found overlap with scalar. 905 OverlapStmt = I->second; 906 } 907 908 // Find the smallest value bigger than the upper bound. 909 I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor()); 910 if (I != CaseVals.begin() && (I-1)->first >= CRLo) { 911 OverlapVal = (I-1)->first; // Found overlap with scalar. 912 OverlapStmt = (I-1)->second; 913 } 914 915 // Check to see if this case stmt overlaps with the subsequent 916 // case range. 917 if (i && CRLo <= HiVals[i-1]) { 918 OverlapVal = HiVals[i-1]; // Found overlap with range. 919 OverlapStmt = CaseRanges[i-1].second; 920 } 921 922 if (OverlapStmt) { 923 // If we have a duplicate, report it. 924 Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case) 925 << OverlapVal.toString(10); 926 Diag(OverlapStmt->getLHS()->getLocStart(), 927 diag::note_duplicate_case_prev); 928 // FIXME: We really want to remove the bogus case stmt from the 929 // substmt, but we have no way to do this right now. 930 CaseListIsErroneous = true; 931 } 932 } 933 } 934 935 // Complain if we have a constant condition and we didn't find a match. 936 if (!CaseListIsErroneous && ShouldCheckConstantCond) { 937 // TODO: it would be nice if we printed enums as enums, chars as 938 // chars, etc. 939 Diag(CondExpr->getExprLoc(), diag::warn_missing_case_for_condition) 940 << ConstantCondValue.toString(10) 941 << CondExpr->getSourceRange(); 942 } 943 944 // Check to see if switch is over an Enum and handles all of its 945 // values. We only issue a warning if there is not 'default:', but 946 // we still do the analysis to preserve this information in the AST 947 // (which can be used by flow-based analyes). 948 // 949 const EnumType *ET = CondTypeBeforePromotion->getAs<EnumType>(); 950 951 // If switch has default case, then ignore it. 952 if (!CaseListIsErroneous && !HasConstantCond && ET) { 953 const EnumDecl *ED = ET->getDecl(); 954 typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> 955 EnumValsTy; 956 EnumValsTy EnumVals; 957 958 // Gather all enum values, set their type and sort them, 959 // allowing easier comparison with CaseVals. 960 for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin(); 961 EDI != ED->enumerator_end(); ++EDI) { 962 llvm::APSInt Val = EDI->getInitVal(); 963 AdjustAPSInt(Val, CondWidth, CondIsSigned); 964 EnumVals.push_back(std::make_pair(Val, *EDI)); 965 } 966 std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals); 967 EnumValsTy::iterator EIend = 968 std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals); 969 970 // See which case values aren't in enum. 971 EnumValsTy::const_iterator EI = EnumVals.begin(); 972 for (CaseValsTy::const_iterator CI = CaseVals.begin(); 973 CI != CaseVals.end(); CI++) { 974 while (EI != EIend && EI->first < CI->first) 975 EI++; 976 if (EI == EIend || EI->first > CI->first) 977 Diag(CI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 978 << CondTypeBeforePromotion; 979 } 980 // See which of case ranges aren't in enum 981 EI = EnumVals.begin(); 982 for (CaseRangesTy::const_iterator RI = CaseRanges.begin(); 983 RI != CaseRanges.end() && EI != EIend; RI++) { 984 while (EI != EIend && EI->first < RI->first) 985 EI++; 986 987 if (EI == EIend || EI->first != RI->first) { 988 Diag(RI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 989 << CondTypeBeforePromotion; 990 } 991 992 llvm::APSInt Hi = 993 RI->second->getRHS()->EvaluateKnownConstInt(Context); 994 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 995 while (EI != EIend && EI->first < Hi) 996 EI++; 997 if (EI == EIend || EI->first != Hi) 998 Diag(RI->second->getRHS()->getExprLoc(), diag::warn_not_in_enum) 999 << CondTypeBeforePromotion; 1000 } 1001 1002 // Check which enum vals aren't in switch 1003 CaseValsTy::const_iterator CI = CaseVals.begin(); 1004 CaseRangesTy::const_iterator RI = CaseRanges.begin(); 1005 bool hasCasesNotInSwitch = false; 1006 1007 SmallVector<DeclarationName,8> UnhandledNames; 1008 1009 for (EI = EnumVals.begin(); EI != EIend; EI++){ 1010 // Drop unneeded case values 1011 llvm::APSInt CIVal; 1012 while (CI != CaseVals.end() && CI->first < EI->first) 1013 CI++; 1014 1015 if (CI != CaseVals.end() && CI->first == EI->first) 1016 continue; 1017 1018 // Drop unneeded case ranges 1019 for (; RI != CaseRanges.end(); RI++) { 1020 llvm::APSInt Hi = 1021 RI->second->getRHS()->EvaluateKnownConstInt(Context); 1022 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 1023 if (EI->first <= Hi) 1024 break; 1025 } 1026 1027 if (RI == CaseRanges.end() || EI->first < RI->first) { 1028 hasCasesNotInSwitch = true; 1029 UnhandledNames.push_back(EI->second->getDeclName()); 1030 } 1031 } 1032 1033 if (TheDefaultStmt && UnhandledNames.empty()) 1034 Diag(TheDefaultStmt->getDefaultLoc(), diag::warn_unreachable_default); 1035 1036 // Produce a nice diagnostic if multiple values aren't handled. 1037 switch (UnhandledNames.size()) { 1038 case 0: break; 1039 case 1: 1040 Diag(CondExpr->getExprLoc(), TheDefaultStmt 1041 ? diag::warn_def_missing_case1 : diag::warn_missing_case1) 1042 << UnhandledNames[0]; 1043 break; 1044 case 2: 1045 Diag(CondExpr->getExprLoc(), TheDefaultStmt 1046 ? diag::warn_def_missing_case2 : diag::warn_missing_case2) 1047 << UnhandledNames[0] << UnhandledNames[1]; 1048 break; 1049 case 3: 1050 Diag(CondExpr->getExprLoc(), TheDefaultStmt 1051 ? diag::warn_def_missing_case3 : diag::warn_missing_case3) 1052 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 1053 break; 1054 default: 1055 Diag(CondExpr->getExprLoc(), TheDefaultStmt 1056 ? diag::warn_def_missing_cases : diag::warn_missing_cases) 1057 << (unsigned)UnhandledNames.size() 1058 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 1059 break; 1060 } 1061 1062 if (!hasCasesNotInSwitch) 1063 SS->setAllEnumCasesCovered(); 1064 } 1065 } 1066 1067 DiagnoseEmptyStmtBody(CondExpr->getLocEnd(), BodyStmt, 1068 diag::warn_empty_switch_body); 1069 1070 // FIXME: If the case list was broken is some way, we don't have a good system 1071 // to patch it up. Instead, just return the whole substmt as broken. 1072 if (CaseListIsErroneous) 1073 return StmtError(); 1074 1075 return Owned(SS); 1076} 1077 1078void 1079Sema::DiagnoseAssignmentEnum(QualType DstType, QualType SrcType, 1080 Expr *SrcExpr) { 1081 unsigned DIAG = diag::warn_not_in_enum_assignement; 1082 if (Diags.getDiagnosticLevel(DIAG, SrcExpr->getExprLoc()) 1083 == DiagnosticsEngine::Ignored) 1084 return; 1085 1086 if (const EnumType *ET = DstType->getAs<EnumType>()) 1087 if (!Context.hasSameType(SrcType, DstType) && 1088 SrcType->isIntegerType()) { 1089 if (!SrcExpr->isTypeDependent() && !SrcExpr->isValueDependent() && 1090 SrcExpr->isIntegerConstantExpr(Context)) { 1091 // Get the bitwidth of the enum value before promotions. 1092 unsigned DstWith = Context.getIntWidth(DstType); 1093 bool DstIsSigned = DstType->isSignedIntegerOrEnumerationType(); 1094 1095 llvm::APSInt RhsVal = SrcExpr->EvaluateKnownConstInt(Context); 1096 const EnumDecl *ED = ET->getDecl(); 1097 typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> 1098 EnumValsTy; 1099 EnumValsTy EnumVals; 1100 1101 // Gather all enum values, set their type and sort them, 1102 // allowing easier comparison with rhs constant. 1103 for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin(); 1104 EDI != ED->enumerator_end(); ++EDI) { 1105 llvm::APSInt Val = EDI->getInitVal(); 1106 AdjustAPSInt(Val, DstWith, DstIsSigned); 1107 EnumVals.push_back(std::make_pair(Val, *EDI)); 1108 } 1109 if (EnumVals.empty()) 1110 return; 1111 std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals); 1112 EnumValsTy::iterator EIend = 1113 std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals); 1114 1115 // See which case values aren't in enum. 1116 EnumValsTy::const_iterator EI = EnumVals.begin(); 1117 while (EI != EIend && EI->first < RhsVal) 1118 EI++; 1119 if (EI == EIend || EI->first != RhsVal) { 1120 Diag(SrcExpr->getExprLoc(), diag::warn_not_in_enum_assignement) 1121 << DstType; 1122 } 1123 } 1124 } 1125} 1126 1127StmtResult 1128Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond, 1129 Decl *CondVar, Stmt *Body) { 1130 ExprResult CondResult(Cond.release()); 1131 1132 VarDecl *ConditionVar = 0; 1133 if (CondVar) { 1134 ConditionVar = cast<VarDecl>(CondVar); 1135 CondResult = CheckConditionVariable(ConditionVar, WhileLoc, true); 1136 if (CondResult.isInvalid()) 1137 return StmtError(); 1138 } 1139 Expr *ConditionExpr = CondResult.take(); 1140 if (!ConditionExpr) 1141 return StmtError(); 1142 1143 DiagnoseUnusedExprResult(Body); 1144 1145 if (isa<NullStmt>(Body)) 1146 getCurCompoundScope().setHasEmptyLoopBodies(); 1147 1148 return Owned(new (Context) WhileStmt(Context, ConditionVar, ConditionExpr, 1149 Body, WhileLoc)); 1150} 1151 1152StmtResult 1153Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body, 1154 SourceLocation WhileLoc, SourceLocation CondLParen, 1155 Expr *Cond, SourceLocation CondRParen) { 1156 assert(Cond && "ActOnDoStmt(): missing expression"); 1157 1158 ExprResult CondResult = CheckBooleanCondition(Cond, DoLoc); 1159 if (CondResult.isInvalid() || CondResult.isInvalid()) 1160 return StmtError(); 1161 Cond = CondResult.take(); 1162 1163 CheckImplicitConversions(Cond, DoLoc); 1164 CondResult = MaybeCreateExprWithCleanups(Cond); 1165 if (CondResult.isInvalid()) 1166 return StmtError(); 1167 Cond = CondResult.take(); 1168 1169 DiagnoseUnusedExprResult(Body); 1170 1171 return Owned(new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen)); 1172} 1173 1174namespace { 1175 // This visitor will traverse a conditional statement and store all 1176 // the evaluated decls into a vector. Simple is set to true if none 1177 // of the excluded constructs are used. 1178 class DeclExtractor : public EvaluatedExprVisitor<DeclExtractor> { 1179 llvm::SmallPtrSet<VarDecl*, 8> &Decls; 1180 llvm::SmallVector<SourceRange, 10> &Ranges; 1181 bool Simple; 1182public: 1183 typedef EvaluatedExprVisitor<DeclExtractor> Inherited; 1184 1185 DeclExtractor(Sema &S, llvm::SmallPtrSet<VarDecl*, 8> &Decls, 1186 llvm::SmallVector<SourceRange, 10> &Ranges) : 1187 Inherited(S.Context), 1188 Decls(Decls), 1189 Ranges(Ranges), 1190 Simple(true) {} 1191 1192 bool isSimple() { return Simple; } 1193 1194 // Replaces the method in EvaluatedExprVisitor. 1195 void VisitMemberExpr(MemberExpr* E) { 1196 Simple = false; 1197 } 1198 1199 // Any Stmt not whitelisted will cause the condition to be marked complex. 1200 void VisitStmt(Stmt *S) { 1201 Simple = false; 1202 } 1203 1204 void VisitBinaryOperator(BinaryOperator *E) { 1205 Visit(E->getLHS()); 1206 Visit(E->getRHS()); 1207 } 1208 1209 void VisitCastExpr(CastExpr *E) { 1210 Visit(E->getSubExpr()); 1211 } 1212 1213 void VisitUnaryOperator(UnaryOperator *E) { 1214 // Skip checking conditionals with derefernces. 1215 if (E->getOpcode() == UO_Deref) 1216 Simple = false; 1217 else 1218 Visit(E->getSubExpr()); 1219 } 1220 1221 void VisitConditionalOperator(ConditionalOperator *E) { 1222 Visit(E->getCond()); 1223 Visit(E->getTrueExpr()); 1224 Visit(E->getFalseExpr()); 1225 } 1226 1227 void VisitParenExpr(ParenExpr *E) { 1228 Visit(E->getSubExpr()); 1229 } 1230 1231 void VisitBinaryConditionalOperator(BinaryConditionalOperator *E) { 1232 Visit(E->getOpaqueValue()->getSourceExpr()); 1233 Visit(E->getFalseExpr()); 1234 } 1235 1236 void VisitIntegerLiteral(IntegerLiteral *E) { } 1237 void VisitFloatingLiteral(FloatingLiteral *E) { } 1238 void VisitCXXBoolLiteralExpr(CXXBoolLiteralExpr *E) { } 1239 void VisitCharacterLiteral(CharacterLiteral *E) { } 1240 void VisitGNUNullExpr(GNUNullExpr *E) { } 1241 void VisitImaginaryLiteral(ImaginaryLiteral *E) { } 1242 1243 void VisitDeclRefExpr(DeclRefExpr *E) { 1244 VarDecl *VD = dyn_cast<VarDecl>(E->getDecl()); 1245 if (!VD) return; 1246 1247 Ranges.push_back(E->getSourceRange()); 1248 1249 Decls.insert(VD); 1250 } 1251 1252 }; // end class DeclExtractor 1253 1254 // DeclMatcher checks to see if the decls are used in a non-evauluated 1255 // context. 1256 class DeclMatcher : public EvaluatedExprVisitor<DeclMatcher> { 1257 llvm::SmallPtrSet<VarDecl*, 8> &Decls; 1258 bool FoundDecl; 1259 1260public: 1261 typedef EvaluatedExprVisitor<DeclMatcher> Inherited; 1262 1263 DeclMatcher(Sema &S, llvm::SmallPtrSet<VarDecl*, 8> &Decls, Stmt *Statement) : 1264 Inherited(S.Context), Decls(Decls), FoundDecl(false) { 1265 if (!Statement) return; 1266 1267 Visit(Statement); 1268 } 1269 1270 void VisitReturnStmt(ReturnStmt *S) { 1271 FoundDecl = true; 1272 } 1273 1274 void VisitBreakStmt(BreakStmt *S) { 1275 FoundDecl = true; 1276 } 1277 1278 void VisitGotoStmt(GotoStmt *S) { 1279 FoundDecl = true; 1280 } 1281 1282 void VisitCastExpr(CastExpr *E) { 1283 if (E->getCastKind() == CK_LValueToRValue) 1284 CheckLValueToRValueCast(E->getSubExpr()); 1285 else 1286 Visit(E->getSubExpr()); 1287 } 1288 1289 void CheckLValueToRValueCast(Expr *E) { 1290 E = E->IgnoreParenImpCasts(); 1291 1292 if (isa<DeclRefExpr>(E)) { 1293 return; 1294 } 1295 1296 if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) { 1297 Visit(CO->getCond()); 1298 CheckLValueToRValueCast(CO->getTrueExpr()); 1299 CheckLValueToRValueCast(CO->getFalseExpr()); 1300 return; 1301 } 1302 1303 if (BinaryConditionalOperator *BCO = 1304 dyn_cast<BinaryConditionalOperator>(E)) { 1305 CheckLValueToRValueCast(BCO->getOpaqueValue()->getSourceExpr()); 1306 CheckLValueToRValueCast(BCO->getFalseExpr()); 1307 return; 1308 } 1309 1310 Visit(E); 1311 } 1312 1313 void VisitDeclRefExpr(DeclRefExpr *E) { 1314 if (VarDecl *VD = dyn_cast<VarDecl>(E->getDecl())) 1315 if (Decls.count(VD)) 1316 FoundDecl = true; 1317 } 1318 1319 bool FoundDeclInUse() { return FoundDecl; } 1320 1321 }; // end class DeclMatcher 1322 1323 void CheckForLoopConditionalStatement(Sema &S, Expr *Second, 1324 Expr *Third, Stmt *Body) { 1325 // Condition is empty 1326 if (!Second) return; 1327 1328 if (S.Diags.getDiagnosticLevel(diag::warn_variables_not_in_loop_body, 1329 Second->getLocStart()) 1330 == DiagnosticsEngine::Ignored) 1331 return; 1332 1333 PartialDiagnostic PDiag = S.PDiag(diag::warn_variables_not_in_loop_body); 1334 llvm::SmallPtrSet<VarDecl*, 8> Decls; 1335 llvm::SmallVector<SourceRange, 10> Ranges; 1336 DeclExtractor DE(S, Decls, Ranges); 1337 DE.Visit(Second); 1338 1339 // Don't analyze complex conditionals. 1340 if (!DE.isSimple()) return; 1341 1342 // No decls found. 1343 if (Decls.size() == 0) return; 1344 1345 // Don't warn on volatile, static, or global variables. 1346 for (llvm::SmallPtrSet<VarDecl*, 8>::iterator I = Decls.begin(), 1347 E = Decls.end(); 1348 I != E; ++I) 1349 if ((*I)->getType().isVolatileQualified() || 1350 (*I)->hasGlobalStorage()) return; 1351 1352 if (DeclMatcher(S, Decls, Second).FoundDeclInUse() || 1353 DeclMatcher(S, Decls, Third).FoundDeclInUse() || 1354 DeclMatcher(S, Decls, Body).FoundDeclInUse()) 1355 return; 1356 1357 // Load decl names into diagnostic. 1358 if (Decls.size() > 4) 1359 PDiag << 0; 1360 else { 1361 PDiag << Decls.size(); 1362 for (llvm::SmallPtrSet<VarDecl*, 8>::iterator I = Decls.begin(), 1363 E = Decls.end(); 1364 I != E; ++I) 1365 PDiag << (*I)->getDeclName(); 1366 } 1367 1368 // Load SourceRanges into diagnostic if there is room. 1369 // Otherwise, load the SourceRange of the conditional expression. 1370 if (Ranges.size() <= PartialDiagnostic::MaxArguments) 1371 for (llvm::SmallVector<SourceRange, 10>::iterator I = Ranges.begin(), 1372 E = Ranges.end(); 1373 I != E; ++I) 1374 PDiag << *I; 1375 else 1376 PDiag << Second->getSourceRange(); 1377 1378 S.Diag(Ranges.begin()->getBegin(), PDiag); 1379 } 1380 1381} // end namespace 1382 1383StmtResult 1384Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 1385 Stmt *First, FullExprArg second, Decl *secondVar, 1386 FullExprArg third, 1387 SourceLocation RParenLoc, Stmt *Body) { 1388 if (!getLangOpts().CPlusPlus) { 1389 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) { 1390 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 1391 // declare identifiers for objects having storage class 'auto' or 1392 // 'register'. 1393 for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end(); 1394 DI!=DE; ++DI) { 1395 VarDecl *VD = dyn_cast<VarDecl>(*DI); 1396 if (VD && VD->isLocalVarDecl() && !VD->hasLocalStorage()) 1397 VD = 0; 1398 if (VD == 0) 1399 Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for); 1400 // FIXME: mark decl erroneous! 1401 } 1402 } 1403 } 1404 1405 CheckForLoopConditionalStatement(*this, second.get(), third.get(), Body); 1406 1407 ExprResult SecondResult(second.release()); 1408 VarDecl *ConditionVar = 0; 1409 if (secondVar) { 1410 ConditionVar = cast<VarDecl>(secondVar); 1411 SecondResult = CheckConditionVariable(ConditionVar, ForLoc, true); 1412 if (SecondResult.isInvalid()) 1413 return StmtError(); 1414 } 1415 1416 Expr *Third = third.release().takeAs<Expr>(); 1417 1418 DiagnoseUnusedExprResult(First); 1419 DiagnoseUnusedExprResult(Third); 1420 DiagnoseUnusedExprResult(Body); 1421 1422 if (isa<NullStmt>(Body)) 1423 getCurCompoundScope().setHasEmptyLoopBodies(); 1424 1425 return Owned(new (Context) ForStmt(Context, First, 1426 SecondResult.take(), ConditionVar, 1427 Third, Body, ForLoc, LParenLoc, 1428 RParenLoc)); 1429} 1430 1431/// In an Objective C collection iteration statement: 1432/// for (x in y) 1433/// x can be an arbitrary l-value expression. Bind it up as a 1434/// full-expression. 1435StmtResult Sema::ActOnForEachLValueExpr(Expr *E) { 1436 // Reduce placeholder expressions here. Note that this rejects the 1437 // use of pseudo-object l-values in this position. 1438 ExprResult result = CheckPlaceholderExpr(E); 1439 if (result.isInvalid()) return StmtError(); 1440 E = result.take(); 1441 1442 CheckImplicitConversions(E); 1443 1444 result = MaybeCreateExprWithCleanups(E); 1445 if (result.isInvalid()) return StmtError(); 1446 1447 return Owned(static_cast<Stmt*>(result.take())); 1448} 1449 1450ExprResult 1451Sema::CheckObjCForCollectionOperand(SourceLocation forLoc, Expr *collection) { 1452 if (!collection) 1453 return ExprError(); 1454 1455 // Bail out early if we've got a type-dependent expression. 1456 if (collection->isTypeDependent()) return Owned(collection); 1457 1458 // Perform normal l-value conversion. 1459 ExprResult result = DefaultFunctionArrayLvalueConversion(collection); 1460 if (result.isInvalid()) 1461 return ExprError(); 1462 collection = result.take(); 1463 1464 // The operand needs to have object-pointer type. 1465 // TODO: should we do a contextual conversion? 1466 const ObjCObjectPointerType *pointerType = 1467 collection->getType()->getAs<ObjCObjectPointerType>(); 1468 if (!pointerType) 1469 return Diag(forLoc, diag::err_collection_expr_type) 1470 << collection->getType() << collection->getSourceRange(); 1471 1472 // Check that the operand provides 1473 // - countByEnumeratingWithState:objects:count: 1474 const ObjCObjectType *objectType = pointerType->getObjectType(); 1475 ObjCInterfaceDecl *iface = objectType->getInterface(); 1476 1477 // If we have a forward-declared type, we can't do this check. 1478 // Under ARC, it is an error not to have a forward-declared class. 1479 if (iface && 1480 RequireCompleteType(forLoc, QualType(objectType, 0), 1481 getLangOpts().ObjCAutoRefCount 1482 ? diag::err_arc_collection_forward 1483 : 0, 1484 collection)) { 1485 // Otherwise, if we have any useful type information, check that 1486 // the type declares the appropriate method. 1487 } else if (iface || !objectType->qual_empty()) { 1488 IdentifierInfo *selectorIdents[] = { 1489 &Context.Idents.get("countByEnumeratingWithState"), 1490 &Context.Idents.get("objects"), 1491 &Context.Idents.get("count") 1492 }; 1493 Selector selector = Context.Selectors.getSelector(3, &selectorIdents[0]); 1494 1495 ObjCMethodDecl *method = 0; 1496 1497 // If there's an interface, look in both the public and private APIs. 1498 if (iface) { 1499 method = iface->lookupInstanceMethod(selector); 1500 if (!method) method = iface->lookupPrivateMethod(selector); 1501 } 1502 1503 // Also check protocol qualifiers. 1504 if (!method) 1505 method = LookupMethodInQualifiedType(selector, pointerType, 1506 /*instance*/ true); 1507 1508 // If we didn't find it anywhere, give up. 1509 if (!method) { 1510 Diag(forLoc, diag::warn_collection_expr_type) 1511 << collection->getType() << selector << collection->getSourceRange(); 1512 } 1513 1514 // TODO: check for an incompatible signature? 1515 } 1516 1517 // Wrap up any cleanups in the expression. 1518 return Owned(MaybeCreateExprWithCleanups(collection)); 1519} 1520 1521StmtResult 1522Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc, 1523 SourceLocation LParenLoc, 1524 Stmt *First, Expr *collection, 1525 SourceLocation RParenLoc) { 1526 1527 ExprResult CollectionExprResult = 1528 CheckObjCForCollectionOperand(ForLoc, collection); 1529 1530 if (First) { 1531 QualType FirstType; 1532 if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) { 1533 if (!DS->isSingleDecl()) 1534 return StmtError(Diag((*DS->decl_begin())->getLocation(), 1535 diag::err_toomany_element_decls)); 1536 1537 VarDecl *D = cast<VarDecl>(DS->getSingleDecl()); 1538 FirstType = D->getType(); 1539 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 1540 // declare identifiers for objects having storage class 'auto' or 1541 // 'register'. 1542 if (!D->hasLocalStorage()) 1543 return StmtError(Diag(D->getLocation(), 1544 diag::err_non_variable_decl_in_for)); 1545 } else { 1546 Expr *FirstE = cast<Expr>(First); 1547 if (!FirstE->isTypeDependent() && !FirstE->isLValue()) 1548 return StmtError(Diag(First->getLocStart(), 1549 diag::err_selector_element_not_lvalue) 1550 << First->getSourceRange()); 1551 1552 FirstType = static_cast<Expr*>(First)->getType(); 1553 } 1554 if (!FirstType->isDependentType() && 1555 !FirstType->isObjCObjectPointerType() && 1556 !FirstType->isBlockPointerType()) 1557 return StmtError(Diag(ForLoc, diag::err_selector_element_type) 1558 << FirstType << First->getSourceRange()); 1559 } 1560 1561 if (CollectionExprResult.isInvalid()) 1562 return StmtError(); 1563 1564 return Owned(new (Context) ObjCForCollectionStmt(First, 1565 CollectionExprResult.take(), 0, 1566 ForLoc, RParenLoc)); 1567} 1568 1569namespace { 1570 1571enum BeginEndFunction { 1572 BEF_begin, 1573 BEF_end 1574}; 1575 1576/// Build a variable declaration for a for-range statement. 1577static VarDecl *BuildForRangeVarDecl(Sema &SemaRef, SourceLocation Loc, 1578 QualType Type, const char *Name) { 1579 DeclContext *DC = SemaRef.CurContext; 1580 IdentifierInfo *II = &SemaRef.PP.getIdentifierTable().get(Name); 1581 TypeSourceInfo *TInfo = SemaRef.Context.getTrivialTypeSourceInfo(Type, Loc); 1582 VarDecl *Decl = VarDecl::Create(SemaRef.Context, DC, Loc, Loc, II, Type, 1583 TInfo, SC_Auto, SC_None); 1584 Decl->setImplicit(); 1585 return Decl; 1586} 1587 1588/// Finish building a variable declaration for a for-range statement. 1589/// \return true if an error occurs. 1590static bool FinishForRangeVarDecl(Sema &SemaRef, VarDecl *Decl, Expr *Init, 1591 SourceLocation Loc, int diag) { 1592 // Deduce the type for the iterator variable now rather than leaving it to 1593 // AddInitializerToDecl, so we can produce a more suitable diagnostic. 1594 TypeSourceInfo *InitTSI = 0; 1595 if ((!isa<InitListExpr>(Init) && Init->getType()->isVoidType()) || 1596 SemaRef.DeduceAutoType(Decl->getTypeSourceInfo(), Init, InitTSI) == 1597 Sema::DAR_Failed) 1598 SemaRef.Diag(Loc, diag) << Init->getType(); 1599 if (!InitTSI) { 1600 Decl->setInvalidDecl(); 1601 return true; 1602 } 1603 Decl->setTypeSourceInfo(InitTSI); 1604 Decl->setType(InitTSI->getType()); 1605 1606 // In ARC, infer lifetime. 1607 // FIXME: ARC may want to turn this into 'const __unsafe_unretained' if 1608 // we're doing the equivalent of fast iteration. 1609 if (SemaRef.getLangOpts().ObjCAutoRefCount && 1610 SemaRef.inferObjCARCLifetime(Decl)) 1611 Decl->setInvalidDecl(); 1612 1613 SemaRef.AddInitializerToDecl(Decl, Init, /*DirectInit=*/false, 1614 /*TypeMayContainAuto=*/false); 1615 SemaRef.FinalizeDeclaration(Decl); 1616 SemaRef.CurContext->addHiddenDecl(Decl); 1617 return false; 1618} 1619 1620/// Produce a note indicating which begin/end function was implicitly called 1621/// by a C++0x for-range statement. This is often not obvious from the code, 1622/// nor from the diagnostics produced when analysing the implicit expressions 1623/// required in a for-range statement. 1624void NoteForRangeBeginEndFunction(Sema &SemaRef, Expr *E, 1625 BeginEndFunction BEF) { 1626 CallExpr *CE = dyn_cast<CallExpr>(E); 1627 if (!CE) 1628 return; 1629 FunctionDecl *D = dyn_cast<FunctionDecl>(CE->getCalleeDecl()); 1630 if (!D) 1631 return; 1632 SourceLocation Loc = D->getLocation(); 1633 1634 std::string Description; 1635 bool IsTemplate = false; 1636 if (FunctionTemplateDecl *FunTmpl = D->getPrimaryTemplate()) { 1637 Description = SemaRef.getTemplateArgumentBindingsText( 1638 FunTmpl->getTemplateParameters(), *D->getTemplateSpecializationArgs()); 1639 IsTemplate = true; 1640 } 1641 1642 SemaRef.Diag(Loc, diag::note_for_range_begin_end) 1643 << BEF << IsTemplate << Description << E->getType(); 1644} 1645 1646/// Build a call to 'begin' or 'end' for a C++0x for-range statement. If the 1647/// given LookupResult is non-empty, it is assumed to describe a member which 1648/// will be invoked. Otherwise, the function will be found via argument 1649/// dependent lookup. 1650static ExprResult BuildForRangeBeginEndCall(Sema &SemaRef, Scope *S, 1651 SourceLocation Loc, 1652 VarDecl *Decl, 1653 BeginEndFunction BEF, 1654 const DeclarationNameInfo &NameInfo, 1655 LookupResult &MemberLookup, 1656 Expr *Range) { 1657 ExprResult CallExpr; 1658 if (!MemberLookup.empty()) { 1659 ExprResult MemberRef = 1660 SemaRef.BuildMemberReferenceExpr(Range, Range->getType(), Loc, 1661 /*IsPtr=*/false, CXXScopeSpec(), 1662 /*TemplateKWLoc=*/SourceLocation(), 1663 /*FirstQualifierInScope=*/0, 1664 MemberLookup, 1665 /*TemplateArgs=*/0); 1666 if (MemberRef.isInvalid()) 1667 return ExprError(); 1668 CallExpr = SemaRef.ActOnCallExpr(S, MemberRef.get(), Loc, MultiExprArg(), 1669 Loc, 0); 1670 if (CallExpr.isInvalid()) 1671 return ExprError(); 1672 } else { 1673 UnresolvedSet<0> FoundNames; 1674 // C++0x [stmt.ranged]p1: For the purposes of this name lookup, namespace 1675 // std is an associated namespace. 1676 UnresolvedLookupExpr *Fn = 1677 UnresolvedLookupExpr::Create(SemaRef.Context, /*NamingClass=*/0, 1678 NestedNameSpecifierLoc(), NameInfo, 1679 /*NeedsADL=*/true, /*Overloaded=*/false, 1680 FoundNames.begin(), FoundNames.end(), 1681 /*LookInStdNamespace=*/true); 1682 CallExpr = SemaRef.BuildOverloadedCallExpr(S, Fn, Fn, Loc, &Range, 1, Loc, 1683 0, /*AllowTypoCorrection=*/false); 1684 if (CallExpr.isInvalid()) { 1685 SemaRef.Diag(Range->getLocStart(), diag::note_for_range_type) 1686 << Range->getType(); 1687 return ExprError(); 1688 } 1689 } 1690 if (FinishForRangeVarDecl(SemaRef, Decl, CallExpr.get(), Loc, 1691 diag::err_for_range_iter_deduction_failure)) { 1692 NoteForRangeBeginEndFunction(SemaRef, CallExpr.get(), BEF); 1693 return ExprError(); 1694 } 1695 return CallExpr; 1696} 1697 1698} 1699 1700static bool ObjCEnumerationCollection(Expr *Collection) { 1701 return !Collection->isTypeDependent() 1702 && Collection->getType()->getAs<ObjCObjectPointerType>() != 0; 1703} 1704 1705/// ActOnCXXForRangeStmt - Check and build a C++0x for-range statement. 1706/// 1707/// C++0x [stmt.ranged]: 1708/// A range-based for statement is equivalent to 1709/// 1710/// { 1711/// auto && __range = range-init; 1712/// for ( auto __begin = begin-expr, 1713/// __end = end-expr; 1714/// __begin != __end; 1715/// ++__begin ) { 1716/// for-range-declaration = *__begin; 1717/// statement 1718/// } 1719/// } 1720/// 1721/// The body of the loop is not available yet, since it cannot be analysed until 1722/// we have determined the type of the for-range-declaration. 1723StmtResult 1724Sema::ActOnCXXForRangeStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 1725 Stmt *First, SourceLocation ColonLoc, Expr *Range, 1726 SourceLocation RParenLoc) { 1727 if (!First || !Range) 1728 return StmtError(); 1729 1730 if (ObjCEnumerationCollection(Range)) 1731 return ActOnObjCForCollectionStmt(ForLoc, LParenLoc, First, Range, 1732 RParenLoc); 1733 1734 DeclStmt *DS = dyn_cast<DeclStmt>(First); 1735 assert(DS && "first part of for range not a decl stmt"); 1736 1737 if (!DS->isSingleDecl()) { 1738 Diag(DS->getStartLoc(), diag::err_type_defined_in_for_range); 1739 return StmtError(); 1740 } 1741 if (DS->getSingleDecl()->isInvalidDecl()) 1742 return StmtError(); 1743 1744 if (DiagnoseUnexpandedParameterPack(Range, UPPC_Expression)) 1745 return StmtError(); 1746 1747 // Build auto && __range = range-init 1748 SourceLocation RangeLoc = Range->getLocStart(); 1749 VarDecl *RangeVar = BuildForRangeVarDecl(*this, RangeLoc, 1750 Context.getAutoRRefDeductType(), 1751 "__range"); 1752 if (FinishForRangeVarDecl(*this, RangeVar, Range, RangeLoc, 1753 diag::err_for_range_deduction_failure)) 1754 return StmtError(); 1755 1756 // Claim the type doesn't contain auto: we've already done the checking. 1757 DeclGroupPtrTy RangeGroup = 1758 BuildDeclaratorGroup((Decl**)&RangeVar, 1, /*TypeMayContainAuto=*/false); 1759 StmtResult RangeDecl = ActOnDeclStmt(RangeGroup, RangeLoc, RangeLoc); 1760 if (RangeDecl.isInvalid()) 1761 return StmtError(); 1762 1763 return BuildCXXForRangeStmt(ForLoc, ColonLoc, RangeDecl.get(), 1764 /*BeginEndDecl=*/0, /*Cond=*/0, /*Inc=*/0, DS, 1765 RParenLoc); 1766} 1767 1768/// BuildCXXForRangeStmt - Build or instantiate a C++0x for-range statement. 1769StmtResult 1770Sema::BuildCXXForRangeStmt(SourceLocation ForLoc, SourceLocation ColonLoc, 1771 Stmt *RangeDecl, Stmt *BeginEnd, Expr *Cond, 1772 Expr *Inc, Stmt *LoopVarDecl, 1773 SourceLocation RParenLoc) { 1774 Scope *S = getCurScope(); 1775 1776 DeclStmt *RangeDS = cast<DeclStmt>(RangeDecl); 1777 VarDecl *RangeVar = cast<VarDecl>(RangeDS->getSingleDecl()); 1778 QualType RangeVarType = RangeVar->getType(); 1779 1780 DeclStmt *LoopVarDS = cast<DeclStmt>(LoopVarDecl); 1781 VarDecl *LoopVar = cast<VarDecl>(LoopVarDS->getSingleDecl()); 1782 1783 StmtResult BeginEndDecl = BeginEnd; 1784 ExprResult NotEqExpr = Cond, IncrExpr = Inc; 1785 1786 if (!BeginEndDecl.get() && !RangeVarType->isDependentType()) { 1787 SourceLocation RangeLoc = RangeVar->getLocation(); 1788 1789 const QualType RangeVarNonRefType = RangeVarType.getNonReferenceType(); 1790 1791 ExprResult BeginRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType, 1792 VK_LValue, ColonLoc); 1793 if (BeginRangeRef.isInvalid()) 1794 return StmtError(); 1795 1796 ExprResult EndRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType, 1797 VK_LValue, ColonLoc); 1798 if (EndRangeRef.isInvalid()) 1799 return StmtError(); 1800 1801 QualType AutoType = Context.getAutoDeductType(); 1802 Expr *Range = RangeVar->getInit(); 1803 if (!Range) 1804 return StmtError(); 1805 QualType RangeType = Range->getType(); 1806 1807 if (RequireCompleteType(RangeLoc, RangeType, 1808 diag::err_for_range_incomplete_type)) 1809 return StmtError(); 1810 1811 // Build auto __begin = begin-expr, __end = end-expr. 1812 VarDecl *BeginVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType, 1813 "__begin"); 1814 VarDecl *EndVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType, 1815 "__end"); 1816 1817 // Build begin-expr and end-expr and attach to __begin and __end variables. 1818 ExprResult BeginExpr, EndExpr; 1819 if (const ArrayType *UnqAT = RangeType->getAsArrayTypeUnsafe()) { 1820 // - if _RangeT is an array type, begin-expr and end-expr are __range and 1821 // __range + __bound, respectively, where __bound is the array bound. If 1822 // _RangeT is an array of unknown size or an array of incomplete type, 1823 // the program is ill-formed; 1824 1825 // begin-expr is __range. 1826 BeginExpr = BeginRangeRef; 1827 if (FinishForRangeVarDecl(*this, BeginVar, BeginRangeRef.get(), ColonLoc, 1828 diag::err_for_range_iter_deduction_failure)) { 1829 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1830 return StmtError(); 1831 } 1832 1833 // Find the array bound. 1834 ExprResult BoundExpr; 1835 if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(UnqAT)) 1836 BoundExpr = Owned(IntegerLiteral::Create(Context, CAT->getSize(), 1837 Context.getPointerDiffType(), 1838 RangeLoc)); 1839 else if (const VariableArrayType *VAT = 1840 dyn_cast<VariableArrayType>(UnqAT)) 1841 BoundExpr = VAT->getSizeExpr(); 1842 else { 1843 // Can't be a DependentSizedArrayType or an IncompleteArrayType since 1844 // UnqAT is not incomplete and Range is not type-dependent. 1845 llvm_unreachable("Unexpected array type in for-range"); 1846 } 1847 1848 // end-expr is __range + __bound. 1849 EndExpr = ActOnBinOp(S, ColonLoc, tok::plus, EndRangeRef.get(), 1850 BoundExpr.get()); 1851 if (EndExpr.isInvalid()) 1852 return StmtError(); 1853 if (FinishForRangeVarDecl(*this, EndVar, EndExpr.get(), ColonLoc, 1854 diag::err_for_range_iter_deduction_failure)) { 1855 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1856 return StmtError(); 1857 } 1858 } else { 1859 DeclarationNameInfo BeginNameInfo(&PP.getIdentifierTable().get("begin"), 1860 ColonLoc); 1861 DeclarationNameInfo EndNameInfo(&PP.getIdentifierTable().get("end"), 1862 ColonLoc); 1863 1864 LookupResult BeginMemberLookup(*this, BeginNameInfo, LookupMemberName); 1865 LookupResult EndMemberLookup(*this, EndNameInfo, LookupMemberName); 1866 1867 if (CXXRecordDecl *D = RangeType->getAsCXXRecordDecl()) { 1868 // - if _RangeT is a class type, the unqualified-ids begin and end are 1869 // looked up in the scope of class _RangeT as if by class member access 1870 // lookup (3.4.5), and if either (or both) finds at least one 1871 // declaration, begin-expr and end-expr are __range.begin() and 1872 // __range.end(), respectively; 1873 LookupQualifiedName(BeginMemberLookup, D); 1874 LookupQualifiedName(EndMemberLookup, D); 1875 1876 if (BeginMemberLookup.empty() != EndMemberLookup.empty()) { 1877 Diag(ColonLoc, diag::err_for_range_member_begin_end_mismatch) 1878 << RangeType << BeginMemberLookup.empty(); 1879 return StmtError(); 1880 } 1881 } else { 1882 // - otherwise, begin-expr and end-expr are begin(__range) and 1883 // end(__range), respectively, where begin and end are looked up with 1884 // argument-dependent lookup (3.4.2). For the purposes of this name 1885 // lookup, namespace std is an associated namespace. 1886 } 1887 1888 BeginExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, BeginVar, 1889 BEF_begin, BeginNameInfo, 1890 BeginMemberLookup, 1891 BeginRangeRef.get()); 1892 if (BeginExpr.isInvalid()) 1893 return StmtError(); 1894 1895 EndExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, EndVar, 1896 BEF_end, EndNameInfo, 1897 EndMemberLookup, EndRangeRef.get()); 1898 if (EndExpr.isInvalid()) 1899 return StmtError(); 1900 } 1901 1902 // C++0x [decl.spec.auto]p6: BeginType and EndType must be the same. 1903 QualType BeginType = BeginVar->getType(), EndType = EndVar->getType(); 1904 if (!Context.hasSameType(BeginType, EndType)) { 1905 Diag(RangeLoc, diag::err_for_range_begin_end_types_differ) 1906 << BeginType << EndType; 1907 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1908 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1909 } 1910 1911 Decl *BeginEndDecls[] = { BeginVar, EndVar }; 1912 // Claim the type doesn't contain auto: we've already done the checking. 1913 DeclGroupPtrTy BeginEndGroup = 1914 BuildDeclaratorGroup(BeginEndDecls, 2, /*TypeMayContainAuto=*/false); 1915 BeginEndDecl = ActOnDeclStmt(BeginEndGroup, ColonLoc, ColonLoc); 1916 1917 const QualType BeginRefNonRefType = BeginType.getNonReferenceType(); 1918 ExprResult BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, 1919 VK_LValue, ColonLoc); 1920 if (BeginRef.isInvalid()) 1921 return StmtError(); 1922 1923 ExprResult EndRef = BuildDeclRefExpr(EndVar, EndType.getNonReferenceType(), 1924 VK_LValue, ColonLoc); 1925 if (EndRef.isInvalid()) 1926 return StmtError(); 1927 1928 // Build and check __begin != __end expression. 1929 NotEqExpr = ActOnBinOp(S, ColonLoc, tok::exclaimequal, 1930 BeginRef.get(), EndRef.get()); 1931 NotEqExpr = ActOnBooleanCondition(S, ColonLoc, NotEqExpr.get()); 1932 NotEqExpr = ActOnFinishFullExpr(NotEqExpr.get()); 1933 if (NotEqExpr.isInvalid()) { 1934 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1935 if (!Context.hasSameType(BeginType, EndType)) 1936 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1937 return StmtError(); 1938 } 1939 1940 // Build and check ++__begin expression. 1941 BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, 1942 VK_LValue, ColonLoc); 1943 if (BeginRef.isInvalid()) 1944 return StmtError(); 1945 1946 IncrExpr = ActOnUnaryOp(S, ColonLoc, tok::plusplus, BeginRef.get()); 1947 IncrExpr = ActOnFinishFullExpr(IncrExpr.get()); 1948 if (IncrExpr.isInvalid()) { 1949 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1950 return StmtError(); 1951 } 1952 1953 // Build and check *__begin expression. 1954 BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, 1955 VK_LValue, ColonLoc); 1956 if (BeginRef.isInvalid()) 1957 return StmtError(); 1958 1959 ExprResult DerefExpr = ActOnUnaryOp(S, ColonLoc, tok::star, BeginRef.get()); 1960 if (DerefExpr.isInvalid()) { 1961 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1962 return StmtError(); 1963 } 1964 1965 // Attach *__begin as initializer for VD. 1966 if (!LoopVar->isInvalidDecl()) { 1967 AddInitializerToDecl(LoopVar, DerefExpr.get(), /*DirectInit=*/false, 1968 /*TypeMayContainAuto=*/true); 1969 if (LoopVar->isInvalidDecl()) 1970 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1971 } 1972 } else { 1973 // The range is implicitly used as a placeholder when it is dependent. 1974 RangeVar->setUsed(); 1975 } 1976 1977 return Owned(new (Context) CXXForRangeStmt(RangeDS, 1978 cast_or_null<DeclStmt>(BeginEndDecl.get()), 1979 NotEqExpr.take(), IncrExpr.take(), 1980 LoopVarDS, /*Body=*/0, ForLoc, 1981 ColonLoc, RParenLoc)); 1982} 1983 1984/// FinishObjCForCollectionStmt - Attach the body to a objective-C foreach 1985/// statement. 1986StmtResult Sema::FinishObjCForCollectionStmt(Stmt *S, Stmt *B) { 1987 if (!S || !B) 1988 return StmtError(); 1989 ObjCForCollectionStmt * ForStmt = cast<ObjCForCollectionStmt>(S); 1990 1991 ForStmt->setBody(B); 1992 return S; 1993} 1994 1995/// FinishCXXForRangeStmt - Attach the body to a C++0x for-range statement. 1996/// This is a separate step from ActOnCXXForRangeStmt because analysis of the 1997/// body cannot be performed until after the type of the range variable is 1998/// determined. 1999StmtResult Sema::FinishCXXForRangeStmt(Stmt *S, Stmt *B) { 2000 if (!S || !B) 2001 return StmtError(); 2002 2003 if (isa<ObjCForCollectionStmt>(S)) 2004 return FinishObjCForCollectionStmt(S, B); 2005 2006 CXXForRangeStmt *ForStmt = cast<CXXForRangeStmt>(S); 2007 ForStmt->setBody(B); 2008 2009 DiagnoseEmptyStmtBody(ForStmt->getRParenLoc(), B, 2010 diag::warn_empty_range_based_for_body); 2011 2012 return S; 2013} 2014 2015StmtResult Sema::ActOnGotoStmt(SourceLocation GotoLoc, 2016 SourceLocation LabelLoc, 2017 LabelDecl *TheDecl) { 2018 getCurFunction()->setHasBranchIntoScope(); 2019 TheDecl->setUsed(); 2020 return Owned(new (Context) GotoStmt(TheDecl, GotoLoc, LabelLoc)); 2021} 2022 2023StmtResult 2024Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc, 2025 Expr *E) { 2026 // Convert operand to void* 2027 if (!E->isTypeDependent()) { 2028 QualType ETy = E->getType(); 2029 QualType DestTy = Context.getPointerType(Context.VoidTy.withConst()); 2030 ExprResult ExprRes = Owned(E); 2031 AssignConvertType ConvTy = 2032 CheckSingleAssignmentConstraints(DestTy, ExprRes); 2033 if (ExprRes.isInvalid()) 2034 return StmtError(); 2035 E = ExprRes.take(); 2036 if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing)) 2037 return StmtError(); 2038 E = MaybeCreateExprWithCleanups(E); 2039 } 2040 2041 getCurFunction()->setHasIndirectGoto(); 2042 2043 return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E)); 2044} 2045 2046StmtResult 2047Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) { 2048 Scope *S = CurScope->getContinueParent(); 2049 if (!S) { 2050 // C99 6.8.6.2p1: A break shall appear only in or as a loop body. 2051 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop)); 2052 } 2053 2054 return Owned(new (Context) ContinueStmt(ContinueLoc)); 2055} 2056 2057StmtResult 2058Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) { 2059 Scope *S = CurScope->getBreakParent(); 2060 if (!S) { 2061 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body. 2062 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch)); 2063 } 2064 2065 return Owned(new (Context) BreakStmt(BreakLoc)); 2066} 2067 2068/// \brief Determine whether the given expression is a candidate for 2069/// copy elision in either a return statement or a throw expression. 2070/// 2071/// \param ReturnType If we're determining the copy elision candidate for 2072/// a return statement, this is the return type of the function. If we're 2073/// determining the copy elision candidate for a throw expression, this will 2074/// be a NULL type. 2075/// 2076/// \param E The expression being returned from the function or block, or 2077/// being thrown. 2078/// 2079/// \param AllowFunctionParameter Whether we allow function parameters to 2080/// be considered NRVO candidates. C++ prohibits this for NRVO itself, but 2081/// we re-use this logic to determine whether we should try to move as part of 2082/// a return or throw (which does allow function parameters). 2083/// 2084/// \returns The NRVO candidate variable, if the return statement may use the 2085/// NRVO, or NULL if there is no such candidate. 2086const VarDecl *Sema::getCopyElisionCandidate(QualType ReturnType, 2087 Expr *E, 2088 bool AllowFunctionParameter) { 2089 QualType ExprType = E->getType(); 2090 // - in a return statement in a function with ... 2091 // ... a class return type ... 2092 if (!ReturnType.isNull()) { 2093 if (!ReturnType->isRecordType()) 2094 return 0; 2095 // ... the same cv-unqualified type as the function return type ... 2096 if (!Context.hasSameUnqualifiedType(ReturnType, ExprType)) 2097 return 0; 2098 } 2099 2100 // ... the expression is the name of a non-volatile automatic object 2101 // (other than a function or catch-clause parameter)) ... 2102 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(E->IgnoreParens()); 2103 if (!DR || DR->refersToEnclosingLocal()) 2104 return 0; 2105 const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()); 2106 if (!VD) 2107 return 0; 2108 2109 // ...object (other than a function or catch-clause parameter)... 2110 if (VD->getKind() != Decl::Var && 2111 !(AllowFunctionParameter && VD->getKind() == Decl::ParmVar)) 2112 return 0; 2113 if (VD->isExceptionVariable()) return 0; 2114 2115 // ...automatic... 2116 if (!VD->hasLocalStorage()) return 0; 2117 2118 // ...non-volatile... 2119 if (VD->getType().isVolatileQualified()) return 0; 2120 if (VD->getType()->isReferenceType()) return 0; 2121 2122 // __block variables can't be allocated in a way that permits NRVO. 2123 if (VD->hasAttr<BlocksAttr>()) return 0; 2124 2125 // Variables with higher required alignment than their type's ABI 2126 // alignment cannot use NRVO. 2127 if (VD->hasAttr<AlignedAttr>() && 2128 Context.getDeclAlign(VD) > Context.getTypeAlignInChars(VD->getType())) 2129 return 0; 2130 2131 return VD; 2132} 2133 2134/// \brief Perform the initialization of a potentially-movable value, which 2135/// is the result of return value. 2136/// 2137/// This routine implements C++0x [class.copy]p33, which attempts to treat 2138/// returned lvalues as rvalues in certain cases (to prefer move construction), 2139/// then falls back to treating them as lvalues if that failed. 2140ExprResult 2141Sema::PerformMoveOrCopyInitialization(const InitializedEntity &Entity, 2142 const VarDecl *NRVOCandidate, 2143 QualType ResultType, 2144 Expr *Value, 2145 bool AllowNRVO) { 2146 // C++0x [class.copy]p33: 2147 // When the criteria for elision of a copy operation are met or would 2148 // be met save for the fact that the source object is a function 2149 // parameter, and the object to be copied is designated by an lvalue, 2150 // overload resolution to select the constructor for the copy is first 2151 // performed as if the object were designated by an rvalue. 2152 ExprResult Res = ExprError(); 2153 if (AllowNRVO && 2154 (NRVOCandidate || getCopyElisionCandidate(ResultType, Value, true))) { 2155 ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack, 2156 Value->getType(), CK_NoOp, Value, VK_XValue); 2157 2158 Expr *InitExpr = &AsRvalue; 2159 InitializationKind Kind 2160 = InitializationKind::CreateCopy(Value->getLocStart(), 2161 Value->getLocStart()); 2162 InitializationSequence Seq(*this, Entity, Kind, &InitExpr, 1); 2163 2164 // [...] If overload resolution fails, or if the type of the first 2165 // parameter of the selected constructor is not an rvalue reference 2166 // to the object's type (possibly cv-qualified), overload resolution 2167 // is performed again, considering the object as an lvalue. 2168 if (Seq) { 2169 for (InitializationSequence::step_iterator Step = Seq.step_begin(), 2170 StepEnd = Seq.step_end(); 2171 Step != StepEnd; ++Step) { 2172 if (Step->Kind != InitializationSequence::SK_ConstructorInitialization) 2173 continue; 2174 2175 CXXConstructorDecl *Constructor 2176 = cast<CXXConstructorDecl>(Step->Function.Function); 2177 2178 const RValueReferenceType *RRefType 2179 = Constructor->getParamDecl(0)->getType() 2180 ->getAs<RValueReferenceType>(); 2181 2182 // If we don't meet the criteria, break out now. 2183 if (!RRefType || 2184 !Context.hasSameUnqualifiedType(RRefType->getPointeeType(), 2185 Context.getTypeDeclType(Constructor->getParent()))) 2186 break; 2187 2188 // Promote "AsRvalue" to the heap, since we now need this 2189 // expression node to persist. 2190 Value = ImplicitCastExpr::Create(Context, Value->getType(), 2191 CK_NoOp, Value, 0, VK_XValue); 2192 2193 // Complete type-checking the initialization of the return type 2194 // using the constructor we found. 2195 Res = Seq.Perform(*this, Entity, Kind, MultiExprArg(&Value, 1)); 2196 } 2197 } 2198 } 2199 2200 // Either we didn't meet the criteria for treating an lvalue as an rvalue, 2201 // above, or overload resolution failed. Either way, we need to try 2202 // (again) now with the return value expression as written. 2203 if (Res.isInvalid()) 2204 Res = PerformCopyInitialization(Entity, SourceLocation(), Value); 2205 2206 return Res; 2207} 2208 2209/// ActOnCapScopeReturnStmt - Utility routine to type-check return statements 2210/// for capturing scopes. 2211/// 2212StmtResult 2213Sema::ActOnCapScopeReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 2214 // If this is the first return we've seen, infer the return type. 2215 // [expr.prim.lambda]p4 in C++11; block literals follow a superset of those 2216 // rules which allows multiple return statements. 2217 CapturingScopeInfo *CurCap = cast<CapturingScopeInfo>(getCurFunction()); 2218 QualType FnRetType = CurCap->ReturnType; 2219 2220 // For blocks/lambdas with implicit return types, we check each return 2221 // statement individually, and deduce the common return type when the block 2222 // or lambda is completed. 2223 if (CurCap->HasImplicitReturnType) { 2224 if (RetValExp && !isa<InitListExpr>(RetValExp)) { 2225 ExprResult Result = DefaultFunctionArrayLvalueConversion(RetValExp); 2226 if (Result.isInvalid()) 2227 return StmtError(); 2228 RetValExp = Result.take(); 2229 2230 if (!RetValExp->isTypeDependent()) 2231 FnRetType = RetValExp->getType(); 2232 else 2233 FnRetType = CurCap->ReturnType = Context.DependentTy; 2234 } else { 2235 if (RetValExp) { 2236 // C++11 [expr.lambda.prim]p4 bans inferring the result from an 2237 // initializer list, because it is not an expression (even 2238 // though we represent it as one). We still deduce 'void'. 2239 Diag(ReturnLoc, diag::err_lambda_return_init_list) 2240 << RetValExp->getSourceRange(); 2241 } 2242 2243 FnRetType = Context.VoidTy; 2244 } 2245 2246 // Although we'll properly infer the type of the block once it's completed, 2247 // make sure we provide a return type now for better error recovery. 2248 if (CurCap->ReturnType.isNull()) 2249 CurCap->ReturnType = FnRetType; 2250 } 2251 assert(!FnRetType.isNull()); 2252 2253 if (BlockScopeInfo *CurBlock = dyn_cast<BlockScopeInfo>(CurCap)) { 2254 if (CurBlock->FunctionType->getAs<FunctionType>()->getNoReturnAttr()) { 2255 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr); 2256 return StmtError(); 2257 } 2258 } else { 2259 LambdaScopeInfo *LSI = cast<LambdaScopeInfo>(CurCap); 2260 if (LSI->CallOperator->getType()->getAs<FunctionType>()->getNoReturnAttr()){ 2261 Diag(ReturnLoc, diag::err_noreturn_lambda_has_return_expr); 2262 return StmtError(); 2263 } 2264 } 2265 2266 // Otherwise, verify that this result type matches the previous one. We are 2267 // pickier with blocks than for normal functions because we don't have GCC 2268 // compatibility to worry about here. 2269 const VarDecl *NRVOCandidate = 0; 2270 if (FnRetType->isDependentType()) { 2271 // Delay processing for now. TODO: there are lots of dependent 2272 // types we can conclusively prove aren't void. 2273 } else if (FnRetType->isVoidType()) { 2274 if (RetValExp && !isa<InitListExpr>(RetValExp) && 2275 !(getLangOpts().CPlusPlus && 2276 (RetValExp->isTypeDependent() || 2277 RetValExp->getType()->isVoidType()))) { 2278 if (!getLangOpts().CPlusPlus && 2279 RetValExp->getType()->isVoidType()) 2280 Diag(ReturnLoc, diag::ext_return_has_void_expr) << "literal" << 2; 2281 else { 2282 Diag(ReturnLoc, diag::err_return_block_has_expr); 2283 RetValExp = 0; 2284 } 2285 } 2286 } else if (!RetValExp) { 2287 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr)); 2288 } else if (!RetValExp->isTypeDependent()) { 2289 // we have a non-void block with an expression, continue checking 2290 2291 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 2292 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 2293 // function return. 2294 2295 // In C++ the return statement is handled via a copy initialization. 2296 // the C version of which boils down to CheckSingleAssignmentConstraints. 2297 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 2298 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 2299 FnRetType, 2300 NRVOCandidate != 0); 2301 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, 2302 FnRetType, RetValExp); 2303 if (Res.isInvalid()) { 2304 // FIXME: Cleanup temporaries here, anyway? 2305 return StmtError(); 2306 } 2307 RetValExp = Res.take(); 2308 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 2309 } 2310 2311 if (RetValExp) { 2312 CheckImplicitConversions(RetValExp, ReturnLoc); 2313 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 2314 } 2315 ReturnStmt *Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 2316 NRVOCandidate); 2317 2318 // If we need to check for the named return value optimization, 2319 // or if we need to infer the return type, 2320 // save the return statement in our scope for later processing. 2321 if (CurCap->HasImplicitReturnType || 2322 (getLangOpts().CPlusPlus && FnRetType->isRecordType() && 2323 !CurContext->isDependentContext())) 2324 FunctionScopes.back()->Returns.push_back(Result); 2325 2326 return Owned(Result); 2327} 2328 2329StmtResult 2330Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 2331 // Check for unexpanded parameter packs. 2332 if (RetValExp && DiagnoseUnexpandedParameterPack(RetValExp)) 2333 return StmtError(); 2334 2335 if (isa<CapturingScopeInfo>(getCurFunction())) 2336 return ActOnCapScopeReturnStmt(ReturnLoc, RetValExp); 2337 2338 QualType FnRetType; 2339 QualType RelatedRetType; 2340 if (const FunctionDecl *FD = getCurFunctionDecl()) { 2341 FnRetType = FD->getResultType(); 2342 if (FD->hasAttr<NoReturnAttr>() || 2343 FD->getType()->getAs<FunctionType>()->getNoReturnAttr()) 2344 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) 2345 << FD->getDeclName(); 2346 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) { 2347 FnRetType = MD->getResultType(); 2348 if (MD->hasRelatedResultType() && MD->getClassInterface()) { 2349 // In the implementation of a method with a related return type, the 2350 // type used to type-check the validity of return statements within the 2351 // method body is a pointer to the type of the class being implemented. 2352 RelatedRetType = Context.getObjCInterfaceType(MD->getClassInterface()); 2353 RelatedRetType = Context.getObjCObjectPointerType(RelatedRetType); 2354 } 2355 } else // If we don't have a function/method context, bail. 2356 return StmtError(); 2357 2358 ReturnStmt *Result = 0; 2359 if (FnRetType->isVoidType()) { 2360 if (RetValExp) { 2361 if (isa<InitListExpr>(RetValExp)) { 2362 // We simply never allow init lists as the return value of void 2363 // functions. This is compatible because this was never allowed before, 2364 // so there's no legacy code to deal with. 2365 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 2366 int FunctionKind = 0; 2367 if (isa<ObjCMethodDecl>(CurDecl)) 2368 FunctionKind = 1; 2369 else if (isa<CXXConstructorDecl>(CurDecl)) 2370 FunctionKind = 2; 2371 else if (isa<CXXDestructorDecl>(CurDecl)) 2372 FunctionKind = 3; 2373 2374 Diag(ReturnLoc, diag::err_return_init_list) 2375 << CurDecl->getDeclName() << FunctionKind 2376 << RetValExp->getSourceRange(); 2377 2378 // Drop the expression. 2379 RetValExp = 0; 2380 } else if (!RetValExp->isTypeDependent()) { 2381 // C99 6.8.6.4p1 (ext_ since GCC warns) 2382 unsigned D = diag::ext_return_has_expr; 2383 if (RetValExp->getType()->isVoidType()) 2384 D = diag::ext_return_has_void_expr; 2385 else { 2386 ExprResult Result = Owned(RetValExp); 2387 Result = IgnoredValueConversions(Result.take()); 2388 if (Result.isInvalid()) 2389 return StmtError(); 2390 RetValExp = Result.take(); 2391 RetValExp = ImpCastExprToType(RetValExp, 2392 Context.VoidTy, CK_ToVoid).take(); 2393 } 2394 2395 // return (some void expression); is legal in C++. 2396 if (D != diag::ext_return_has_void_expr || 2397 !getLangOpts().CPlusPlus) { 2398 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 2399 2400 int FunctionKind = 0; 2401 if (isa<ObjCMethodDecl>(CurDecl)) 2402 FunctionKind = 1; 2403 else if (isa<CXXConstructorDecl>(CurDecl)) 2404 FunctionKind = 2; 2405 else if (isa<CXXDestructorDecl>(CurDecl)) 2406 FunctionKind = 3; 2407 2408 Diag(ReturnLoc, D) 2409 << CurDecl->getDeclName() << FunctionKind 2410 << RetValExp->getSourceRange(); 2411 } 2412 } 2413 2414 if (RetValExp) { 2415 CheckImplicitConversions(RetValExp, ReturnLoc); 2416 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 2417 } 2418 } 2419 2420 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 2421 } else if (!RetValExp && !FnRetType->isDependentType()) { 2422 unsigned DiagID = diag::warn_return_missing_expr; // C90 6.6.6.4p4 2423 // C99 6.8.6.4p1 (ext_ since GCC warns) 2424 if (getLangOpts().C99) DiagID = diag::ext_return_missing_expr; 2425 2426 if (FunctionDecl *FD = getCurFunctionDecl()) 2427 Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/; 2428 else 2429 Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/; 2430 Result = new (Context) ReturnStmt(ReturnLoc); 2431 } else { 2432 const VarDecl *NRVOCandidate = 0; 2433 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 2434 // we have a non-void function with an expression, continue checking 2435 2436 if (!RelatedRetType.isNull()) { 2437 // If we have a related result type, perform an extra conversion here. 2438 // FIXME: The diagnostics here don't really describe what is happening. 2439 InitializedEntity Entity = 2440 InitializedEntity::InitializeTemporary(RelatedRetType); 2441 2442 ExprResult Res = PerformCopyInitialization(Entity, SourceLocation(), 2443 RetValExp); 2444 if (Res.isInvalid()) { 2445 // FIXME: Cleanup temporaries here, anyway? 2446 return StmtError(); 2447 } 2448 RetValExp = Res.takeAs<Expr>(); 2449 } 2450 2451 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 2452 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 2453 // function return. 2454 2455 // In C++ the return statement is handled via a copy initialization, 2456 // the C version of which boils down to CheckSingleAssignmentConstraints. 2457 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 2458 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 2459 FnRetType, 2460 NRVOCandidate != 0); 2461 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, 2462 FnRetType, RetValExp); 2463 if (Res.isInvalid()) { 2464 // FIXME: Cleanup temporaries here, anyway? 2465 return StmtError(); 2466 } 2467 2468 RetValExp = Res.takeAs<Expr>(); 2469 if (RetValExp) 2470 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 2471 } 2472 2473 if (RetValExp) { 2474 CheckImplicitConversions(RetValExp, ReturnLoc); 2475 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 2476 } 2477 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 2478 } 2479 2480 // If we need to check for the named return value optimization, save the 2481 // return statement in our scope for later processing. 2482 if (getLangOpts().CPlusPlus && FnRetType->isRecordType() && 2483 !CurContext->isDependentContext()) 2484 FunctionScopes.back()->Returns.push_back(Result); 2485 2486 return Owned(Result); 2487} 2488 2489/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently 2490/// ignore "noop" casts in places where an lvalue is required by an inline asm. 2491/// We emulate this behavior when -fheinous-gnu-extensions is specified, but 2492/// provide a strong guidance to not use it. 2493/// 2494/// This method checks to see if the argument is an acceptable l-value and 2495/// returns false if it is a case we can handle. 2496static bool CheckAsmLValue(const Expr *E, Sema &S) { 2497 // Type dependent expressions will be checked during instantiation. 2498 if (E->isTypeDependent()) 2499 return false; 2500 2501 if (E->isLValue()) 2502 return false; // Cool, this is an lvalue. 2503 2504 // Okay, this is not an lvalue, but perhaps it is the result of a cast that we 2505 // are supposed to allow. 2506 const Expr *E2 = E->IgnoreParenNoopCasts(S.Context); 2507 if (E != E2 && E2->isLValue()) { 2508 if (!S.getLangOpts().HeinousExtensions) 2509 S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue) 2510 << E->getSourceRange(); 2511 else 2512 S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue) 2513 << E->getSourceRange(); 2514 // Accept, even if we emitted an error diagnostic. 2515 return false; 2516 } 2517 2518 // None of the above, just randomly invalid non-lvalue. 2519 return true; 2520} 2521 2522/// isOperandMentioned - Return true if the specified operand # is mentioned 2523/// anywhere in the decomposed asm string. 2524static bool isOperandMentioned(unsigned OpNo, 2525 ArrayRef<AsmStmt::AsmStringPiece> AsmStrPieces) { 2526 for (unsigned p = 0, e = AsmStrPieces.size(); p != e; ++p) { 2527 const AsmStmt::AsmStringPiece &Piece = AsmStrPieces[p]; 2528 if (!Piece.isOperand()) continue; 2529 2530 // If this is a reference to the input and if the input was the smaller 2531 // one, then we have to reject this asm. 2532 if (Piece.getOperandNo() == OpNo) 2533 return true; 2534 } 2535 return false; 2536} 2537 2538StmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, bool IsSimple, 2539 bool IsVolatile, unsigned NumOutputs, 2540 unsigned NumInputs, IdentifierInfo **Names, 2541 MultiExprArg constraints, MultiExprArg exprs, 2542 Expr *asmString, MultiExprArg clobbers, 2543 SourceLocation RParenLoc, bool MSAsm) { 2544 unsigned NumClobbers = clobbers.size(); 2545 StringLiteral **Constraints = 2546 reinterpret_cast<StringLiteral**>(constraints.get()); 2547 Expr **Exprs = exprs.get(); 2548 StringLiteral *AsmString = cast<StringLiteral>(asmString); 2549 StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get()); 2550 2551 SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; 2552 2553 // The parser verifies that there is a string literal here. 2554 if (!AsmString->isAscii()) 2555 return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character) 2556 << AsmString->getSourceRange()); 2557 2558 for (unsigned i = 0; i != NumOutputs; i++) { 2559 StringLiteral *Literal = Constraints[i]; 2560 if (!Literal->isAscii()) 2561 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 2562 << Literal->getSourceRange()); 2563 2564 StringRef OutputName; 2565 if (Names[i]) 2566 OutputName = Names[i]->getName(); 2567 2568 TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName); 2569 if (!Context.getTargetInfo().validateOutputConstraint(Info)) 2570 return StmtError(Diag(Literal->getLocStart(), 2571 diag::err_asm_invalid_output_constraint) 2572 << Info.getConstraintStr()); 2573 2574 // Check that the output exprs are valid lvalues. 2575 Expr *OutputExpr = Exprs[i]; 2576 if (CheckAsmLValue(OutputExpr, *this)) { 2577 return StmtError(Diag(OutputExpr->getLocStart(), 2578 diag::err_asm_invalid_lvalue_in_output) 2579 << OutputExpr->getSourceRange()); 2580 } 2581 2582 OutputConstraintInfos.push_back(Info); 2583 } 2584 2585 SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; 2586 2587 for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { 2588 StringLiteral *Literal = Constraints[i]; 2589 if (!Literal->isAscii()) 2590 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 2591 << Literal->getSourceRange()); 2592 2593 StringRef InputName; 2594 if (Names[i]) 2595 InputName = Names[i]->getName(); 2596 2597 TargetInfo::ConstraintInfo Info(Literal->getString(), InputName); 2598 if (!Context.getTargetInfo().validateInputConstraint(OutputConstraintInfos.data(), 2599 NumOutputs, Info)) { 2600 return StmtError(Diag(Literal->getLocStart(), 2601 diag::err_asm_invalid_input_constraint) 2602 << Info.getConstraintStr()); 2603 } 2604 2605 Expr *InputExpr = Exprs[i]; 2606 2607 // Only allow void types for memory constraints. 2608 if (Info.allowsMemory() && !Info.allowsRegister()) { 2609 if (CheckAsmLValue(InputExpr, *this)) 2610 return StmtError(Diag(InputExpr->getLocStart(), 2611 diag::err_asm_invalid_lvalue_in_input) 2612 << Info.getConstraintStr() 2613 << InputExpr->getSourceRange()); 2614 } 2615 2616 if (Info.allowsRegister()) { 2617 if (InputExpr->getType()->isVoidType()) { 2618 return StmtError(Diag(InputExpr->getLocStart(), 2619 diag::err_asm_invalid_type_in_input) 2620 << InputExpr->getType() << Info.getConstraintStr() 2621 << InputExpr->getSourceRange()); 2622 } 2623 } 2624 2625 ExprResult Result = DefaultFunctionArrayLvalueConversion(Exprs[i]); 2626 if (Result.isInvalid()) 2627 return StmtError(); 2628 2629 Exprs[i] = Result.take(); 2630 InputConstraintInfos.push_back(Info); 2631 } 2632 2633 // Check that the clobbers are valid. 2634 for (unsigned i = 0; i != NumClobbers; i++) { 2635 StringLiteral *Literal = Clobbers[i]; 2636 if (!Literal->isAscii()) 2637 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 2638 << Literal->getSourceRange()); 2639 2640 StringRef Clobber = Literal->getString(); 2641 2642 if (!Context.getTargetInfo().isValidClobber(Clobber)) 2643 return StmtError(Diag(Literal->getLocStart(), 2644 diag::err_asm_unknown_register_name) << Clobber); 2645 } 2646 2647 AsmStmt *NS = 2648 new (Context) AsmStmt(Context, AsmLoc, IsSimple, IsVolatile, MSAsm, 2649 NumOutputs, NumInputs, Names, Constraints, Exprs, 2650 AsmString, NumClobbers, Clobbers, RParenLoc); 2651 // Validate the asm string, ensuring it makes sense given the operands we 2652 // have. 2653 SmallVector<AsmStmt::AsmStringPiece, 8> Pieces; 2654 unsigned DiagOffs; 2655 if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) { 2656 Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID) 2657 << AsmString->getSourceRange(); 2658 return StmtError(); 2659 } 2660 2661 // Validate tied input operands for type mismatches. 2662 for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) { 2663 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; 2664 2665 // If this is a tied constraint, verify that the output and input have 2666 // either exactly the same type, or that they are int/ptr operands with the 2667 // same size (int/long, int*/long, are ok etc). 2668 if (!Info.hasTiedOperand()) continue; 2669 2670 unsigned TiedTo = Info.getTiedOperand(); 2671 unsigned InputOpNo = i+NumOutputs; 2672 Expr *OutputExpr = Exprs[TiedTo]; 2673 Expr *InputExpr = Exprs[InputOpNo]; 2674 2675 if (OutputExpr->isTypeDependent() || InputExpr->isTypeDependent()) 2676 continue; 2677 2678 QualType InTy = InputExpr->getType(); 2679 QualType OutTy = OutputExpr->getType(); 2680 if (Context.hasSameType(InTy, OutTy)) 2681 continue; // All types can be tied to themselves. 2682 2683 // Decide if the input and output are in the same domain (integer/ptr or 2684 // floating point. 2685 enum AsmDomain { 2686 AD_Int, AD_FP, AD_Other 2687 } InputDomain, OutputDomain; 2688 2689 if (InTy->isIntegerType() || InTy->isPointerType()) 2690 InputDomain = AD_Int; 2691 else if (InTy->isRealFloatingType()) 2692 InputDomain = AD_FP; 2693 else 2694 InputDomain = AD_Other; 2695 2696 if (OutTy->isIntegerType() || OutTy->isPointerType()) 2697 OutputDomain = AD_Int; 2698 else if (OutTy->isRealFloatingType()) 2699 OutputDomain = AD_FP; 2700 else 2701 OutputDomain = AD_Other; 2702 2703 // They are ok if they are the same size and in the same domain. This 2704 // allows tying things like: 2705 // void* to int* 2706 // void* to int if they are the same size. 2707 // double to long double if they are the same size. 2708 // 2709 uint64_t OutSize = Context.getTypeSize(OutTy); 2710 uint64_t InSize = Context.getTypeSize(InTy); 2711 if (OutSize == InSize && InputDomain == OutputDomain && 2712 InputDomain != AD_Other) 2713 continue; 2714 2715 // If the smaller input/output operand is not mentioned in the asm string, 2716 // then we can promote the smaller one to a larger input and the asm string 2717 // won't notice. 2718 bool SmallerValueMentioned = false; 2719 2720 // If this is a reference to the input and if the input was the smaller 2721 // one, then we have to reject this asm. 2722 if (isOperandMentioned(InputOpNo, Pieces)) { 2723 // This is a use in the asm string of the smaller operand. Since we 2724 // codegen this by promoting to a wider value, the asm will get printed 2725 // "wrong". 2726 SmallerValueMentioned |= InSize < OutSize; 2727 } 2728 if (isOperandMentioned(TiedTo, Pieces)) { 2729 // If this is a reference to the output, and if the output is the larger 2730 // value, then it's ok because we'll promote the input to the larger type. 2731 SmallerValueMentioned |= OutSize < InSize; 2732 } 2733 2734 // If the smaller value wasn't mentioned in the asm string, and if the 2735 // output was a register, just extend the shorter one to the size of the 2736 // larger one. 2737 if (!SmallerValueMentioned && InputDomain != AD_Other && 2738 OutputConstraintInfos[TiedTo].allowsRegister()) 2739 continue; 2740 2741 // Either both of the operands were mentioned or the smaller one was 2742 // mentioned. One more special case that we'll allow: if the tied input is 2743 // integer, unmentioned, and is a constant, then we'll allow truncating it 2744 // down to the size of the destination. 2745 if (InputDomain == AD_Int && OutputDomain == AD_Int && 2746 !isOperandMentioned(InputOpNo, Pieces) && 2747 InputExpr->isEvaluatable(Context)) { 2748 CastKind castKind = 2749 (OutTy->isBooleanType() ? CK_IntegralToBoolean : CK_IntegralCast); 2750 InputExpr = ImpCastExprToType(InputExpr, OutTy, castKind).take(); 2751 Exprs[InputOpNo] = InputExpr; 2752 NS->setInputExpr(i, InputExpr); 2753 continue; 2754 } 2755 2756 Diag(InputExpr->getLocStart(), 2757 diag::err_asm_tying_incompatible_types) 2758 << InTy << OutTy << OutputExpr->getSourceRange() 2759 << InputExpr->getSourceRange(); 2760 return StmtError(); 2761 } 2762 2763 return Owned(NS); 2764} 2765 2766static void patchMSAsmStrings(Sema &SemaRef, bool &IsSimple, 2767 SourceLocation AsmLoc, 2768 ArrayRef<Token> AsmToks, 2769 const TargetInfo &TI, 2770 std::vector<std::string> &AsmStrings) { 2771 assert (!AsmToks.empty() && "Didn't expect an empty AsmToks!"); 2772 2773 // Assume simple asm stmt until we parse a non-register identifer. 2774 IsSimple = true; 2775 2776 SmallString<512> Asm; 2777 unsigned NumAsmStrings = 0; 2778 for (unsigned i = 0, e = AsmToks.size(); i != e; ++i) { 2779 2780 // Determine if this should be considered a new asm. 2781 bool isNewAsm = i == 0 || AsmToks[i].isAtStartOfLine() || 2782 AsmToks[i].is(tok::kw_asm); 2783 2784 // Emit the previous asm string. 2785 if (i && isNewAsm) { 2786 AsmStrings[NumAsmStrings++] = Asm.c_str(); 2787 if (AsmToks[i].is(tok::kw_asm)) { 2788 ++i; // Skip __asm 2789 assert (i != e && "Expected another token."); 2790 } 2791 } 2792 2793 // Start a new asm string with the opcode. 2794 if (isNewAsm) { 2795 Asm = AsmToks[i].getIdentifierInfo()->getName().str(); 2796 continue; 2797 } 2798 2799 if (i && AsmToks[i].hasLeadingSpace()) 2800 Asm += ' '; 2801 2802 // Check the operand(s). 2803 switch (AsmToks[i].getKind()) { 2804 default: 2805 //llvm_unreachable("Unknown token."); 2806 break; 2807 case tok::comma: Asm += ","; break; 2808 case tok::colon: Asm += ":"; break; 2809 case tok::l_square: Asm += "["; break; 2810 case tok::r_square: Asm += "]"; break; 2811 case tok::l_brace: Asm += "{"; break; 2812 case tok::r_brace: Asm += "}"; break; 2813 case tok::numeric_constant: { 2814 SmallString<32> TokenBuf; 2815 TokenBuf.resize(32); 2816 bool StringInvalid = false; 2817 Asm += SemaRef.PP.getSpelling(AsmToks[i], TokenBuf, &StringInvalid); 2818 assert (!StringInvalid && "Expected valid string!"); 2819 break; 2820 } 2821 case tok::identifier: { 2822 StringRef Name = AsmToks[i].getIdentifierInfo()->getName(); 2823 2824 // Valid registers don't need modification. 2825 if (TI.isValidGCCRegisterName(Name)) { 2826 Asm += Name; 2827 break; 2828 } 2829 2830 // TODO: Lookup the identifier. 2831 IsSimple = false; 2832 break; 2833 } 2834 } // AsmToks[i].getKind() 2835 } 2836 2837 // Emit the final (and possibly only) asm string. 2838 AsmStrings[NumAsmStrings] = Asm.c_str(); 2839} 2840 2841// Build the unmodified MSAsmString. 2842static std::string buildMSAsmString(Sema &SemaRef, 2843 ArrayRef<Token> AsmToks, 2844 unsigned &NumAsmStrings) { 2845 assert (!AsmToks.empty() && "Didn't expect an empty AsmToks!"); 2846 SmallString<512> Asm; 2847 SmallString<512> TokenBuf; 2848 TokenBuf.resize(512); 2849 2850 NumAsmStrings = 0; 2851 for (unsigned i = 0, e = AsmToks.size(); i < e; ++i) { 2852 bool isNewAsm = i == 0 || AsmToks[i].isAtStartOfLine() || 2853 AsmToks[i].is(tok::kw_asm); 2854 2855 if (isNewAsm) { 2856 ++NumAsmStrings; 2857 if (i) 2858 Asm += '\n'; 2859 if (AsmToks[i].is(tok::kw_asm)) { 2860 i++; // Skip __asm 2861 assert (i != e && "Expected another token"); 2862 } 2863 } 2864 2865 if (i && AsmToks[i].hasLeadingSpace() && !isNewAsm) 2866 Asm += ' '; 2867 2868 bool StringInvalid = false; 2869 Asm += SemaRef.PP.getSpelling(AsmToks[i], TokenBuf, &StringInvalid); 2870 assert (!StringInvalid && "Expected valid string!"); 2871 } 2872 return Asm.c_str(); 2873} 2874 2875StmtResult Sema::ActOnMSAsmStmt(SourceLocation AsmLoc, 2876 SourceLocation LBraceLoc, 2877 ArrayRef<Token> AsmToks, 2878 SourceLocation EndLoc) { 2879 // MS-style inline assembly is not fully supported, so emit a warning. 2880 Diag(AsmLoc, diag::warn_unsupported_msasm); 2881 SmallVector<StringRef,4> Clobbers; 2882 std::set<std::string> ClobberRegs; 2883 2884 // Empty asm statements don't need to instantiate the AsmParser, etc. 2885 if (AsmToks.empty()) { 2886 StringRef AsmString; 2887 MSAsmStmt *NS = 2888 new (Context) MSAsmStmt(Context, AsmLoc, LBraceLoc, 2889 /* IsSimple */ true, /* IsVolatile */ true, 2890 AsmToks, AsmString, Clobbers, EndLoc); 2891 return Owned(NS); 2892 } 2893 2894 unsigned NumAsmStrings; 2895 std::string AsmString = buildMSAsmString(*this, AsmToks, NumAsmStrings); 2896 2897 bool IsSimple; 2898 std::vector<std::string> PatchedAsmStrings; 2899 PatchedAsmStrings.resize(NumAsmStrings); 2900 2901 // Rewrite operands to appease the AsmParser. 2902 patchMSAsmStrings(*this, IsSimple, AsmLoc, AsmToks, Context.getTargetInfo(), 2903 PatchedAsmStrings); 2904 2905 // patchMSAsmStrings doesn't correctly patch non-simple asm statements. 2906 if (!IsSimple) { 2907 MSAsmStmt *NS = 2908 new (Context) MSAsmStmt(Context, AsmLoc, LBraceLoc, 2909 /* IsSimple */ true, /* IsVolatile */ true, 2910 AsmToks, AsmString, Clobbers, EndLoc); 2911 return Owned(NS); 2912 } 2913 2914 // Initialize targets and assembly printers/parsers. 2915 llvm::InitializeAllTargetInfos(); 2916 llvm::InitializeAllTargetMCs(); 2917 llvm::InitializeAllAsmParsers(); 2918 2919 // Get the target specific parser. 2920 std::string Error; 2921 const std::string &TT = Context.getTargetInfo().getTriple().getTriple(); 2922 const llvm::Target *TheTarget(llvm::TargetRegistry::lookupTarget(TT, Error)); 2923 2924 OwningPtr<llvm::MCAsmInfo> MAI(TheTarget->createMCAsmInfo(TT)); 2925 OwningPtr<llvm::MCRegisterInfo> MRI(TheTarget->createMCRegInfo(TT)); 2926 OwningPtr<llvm::MCObjectFileInfo> MOFI(new llvm::MCObjectFileInfo()); 2927 OwningPtr<llvm::MCSubtargetInfo> 2928 STI(TheTarget->createMCSubtargetInfo(TT, "", "")); 2929 2930 for (unsigned i = 0, e = PatchedAsmStrings.size(); i != e; ++i) { 2931 llvm::SourceMgr SrcMgr; 2932 llvm::MCContext Ctx(*MAI, *MRI, MOFI.get(), &SrcMgr); 2933 llvm::MemoryBuffer *Buffer = 2934 llvm::MemoryBuffer::getMemBuffer(PatchedAsmStrings[i], "<inline asm>"); 2935 2936 // Tell SrcMgr about this buffer, which is what the parser will pick up. 2937 SrcMgr.AddNewSourceBuffer(Buffer, llvm::SMLoc()); 2938 2939 OwningPtr<llvm::MCStreamer> Str; 2940 OwningPtr<llvm::MCAsmParser> 2941 Parser(createMCAsmParser(SrcMgr, Ctx, *Str.get(), *MAI)); 2942 OwningPtr<llvm::MCTargetAsmParser> 2943 TargetParser(TheTarget->createMCAsmParser(*STI, *Parser)); 2944 // Change to the Intel dialect. 2945 Parser->setAssemblerDialect(1); 2946 Parser->setTargetParser(*TargetParser.get()); 2947 2948 // Prime the lexer. 2949 Parser->Lex(); 2950 2951 // Parse the opcode. 2952 StringRef IDVal; 2953 Parser->ParseIdentifier(IDVal); 2954 2955 // Canonicalize the opcode to lower case. 2956 SmallString<128> Opcode; 2957 for (unsigned i = 0, e = IDVal.size(); i != e; ++i) 2958 Opcode.push_back(tolower(IDVal[i])); 2959 2960 // Parse the operands. 2961 llvm::SMLoc IDLoc; 2962 SmallVector<llvm::MCParsedAsmOperand*, 8> Operands; 2963 bool HadError = TargetParser->ParseInstruction(Opcode.str(), IDLoc, 2964 Operands); 2965 assert (!HadError && "Unexpected error parsing instruction"); 2966 2967 // Match the MCInstr. 2968 SmallVector<llvm::MCInst, 2> Instrs; 2969 HadError = TargetParser->MatchInstruction(IDLoc, Operands, Instrs); 2970 assert (!HadError && "Unexpected error matching instruction"); 2971 assert ((Instrs.size() == 1) && "Expected only a single instruction."); 2972 2973 // Get the instruction descriptor. 2974 llvm::MCInst Inst = Instrs[0]; 2975 const llvm::MCInstrInfo *MII = TheTarget->createMCInstrInfo(); 2976 const llvm::MCInstrDesc &Desc = MII->get(Inst.getOpcode()); 2977 llvm::MCInstPrinter *IP = 2978 TheTarget->createMCInstPrinter(1, *MAI, *MII, *MRI, *STI); 2979 2980 // Build the list of clobbers. 2981 for (unsigned i = 0, e = Desc.getNumDefs(); i != e; ++i) { 2982 const llvm::MCOperand &Op = Inst.getOperand(i); 2983 if (!Op.isReg()) 2984 continue; 2985 2986 std::string Reg; 2987 llvm::raw_string_ostream OS(Reg); 2988 IP->printRegName(OS, Op.getReg()); 2989 2990 StringRef Clobber(OS.str()); 2991 if (!Context.getTargetInfo().isValidClobber(Clobber)) 2992 return StmtError(Diag(AsmLoc, diag::err_asm_unknown_register_name) << 2993 Clobber); 2994 ClobberRegs.insert(Reg); 2995 } 2996 } 2997 for (std::set<std::string>::iterator I = ClobberRegs.begin(), 2998 E = ClobberRegs.end(); I != E; ++I) 2999 Clobbers.push_back(*I); 3000 3001 MSAsmStmt *NS = 3002 new (Context) MSAsmStmt(Context, AsmLoc, LBraceLoc, 3003 IsSimple, /* IsVolatile */ true, 3004 AsmToks, AsmString, Clobbers, EndLoc); 3005 3006 return Owned(NS); 3007} 3008 3009StmtResult 3010Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc, 3011 SourceLocation RParen, Decl *Parm, 3012 Stmt *Body) { 3013 VarDecl *Var = cast_or_null<VarDecl>(Parm); 3014 if (Var && Var->isInvalidDecl()) 3015 return StmtError(); 3016 3017 return Owned(new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, Body)); 3018} 3019 3020StmtResult 3021Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body) { 3022 return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, Body)); 3023} 3024 3025StmtResult 3026Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try, 3027 MultiStmtArg CatchStmts, Stmt *Finally) { 3028 if (!getLangOpts().ObjCExceptions) 3029 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@try"; 3030 3031 getCurFunction()->setHasBranchProtectedScope(); 3032 unsigned NumCatchStmts = CatchStmts.size(); 3033 return Owned(ObjCAtTryStmt::Create(Context, AtLoc, Try, 3034 CatchStmts.release(), 3035 NumCatchStmts, 3036 Finally)); 3037} 3038 3039StmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw) { 3040 if (Throw) { 3041 ExprResult Result = DefaultLvalueConversion(Throw); 3042 if (Result.isInvalid()) 3043 return StmtError(); 3044 3045 Throw = MaybeCreateExprWithCleanups(Result.take()); 3046 QualType ThrowType = Throw->getType(); 3047 // Make sure the expression type is an ObjC pointer or "void *". 3048 if (!ThrowType->isDependentType() && 3049 !ThrowType->isObjCObjectPointerType()) { 3050 const PointerType *PT = ThrowType->getAs<PointerType>(); 3051 if (!PT || !PT->getPointeeType()->isVoidType()) 3052 return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object) 3053 << Throw->getType() << Throw->getSourceRange()); 3054 } 3055 } 3056 3057 return Owned(new (Context) ObjCAtThrowStmt(AtLoc, Throw)); 3058} 3059 3060StmtResult 3061Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw, 3062 Scope *CurScope) { 3063 if (!getLangOpts().ObjCExceptions) 3064 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@throw"; 3065 3066 if (!Throw) { 3067 // @throw without an expression designates a rethrow (which much occur 3068 // in the context of an @catch clause). 3069 Scope *AtCatchParent = CurScope; 3070 while (AtCatchParent && !AtCatchParent->isAtCatchScope()) 3071 AtCatchParent = AtCatchParent->getParent(); 3072 if (!AtCatchParent) 3073 return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch)); 3074 } 3075 return BuildObjCAtThrowStmt(AtLoc, Throw); 3076} 3077 3078ExprResult 3079Sema::ActOnObjCAtSynchronizedOperand(SourceLocation atLoc, Expr *operand) { 3080 ExprResult result = DefaultLvalueConversion(operand); 3081 if (result.isInvalid()) 3082 return ExprError(); 3083 operand = result.take(); 3084 3085 // Make sure the expression type is an ObjC pointer or "void *". 3086 QualType type = operand->getType(); 3087 if (!type->isDependentType() && 3088 !type->isObjCObjectPointerType()) { 3089 const PointerType *pointerType = type->getAs<PointerType>(); 3090 if (!pointerType || !pointerType->getPointeeType()->isVoidType()) 3091 return Diag(atLoc, diag::error_objc_synchronized_expects_object) 3092 << type << operand->getSourceRange(); 3093 } 3094 3095 // The operand to @synchronized is a full-expression. 3096 return MaybeCreateExprWithCleanups(operand); 3097} 3098 3099StmtResult 3100Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, Expr *SyncExpr, 3101 Stmt *SyncBody) { 3102 // We can't jump into or indirect-jump out of a @synchronized block. 3103 getCurFunction()->setHasBranchProtectedScope(); 3104 return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, SyncExpr, SyncBody)); 3105} 3106 3107/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block 3108/// and creates a proper catch handler from them. 3109StmtResult 3110Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl, 3111 Stmt *HandlerBlock) { 3112 // There's nothing to test that ActOnExceptionDecl didn't already test. 3113 return Owned(new (Context) CXXCatchStmt(CatchLoc, 3114 cast_or_null<VarDecl>(ExDecl), 3115 HandlerBlock)); 3116} 3117 3118StmtResult 3119Sema::ActOnObjCAutoreleasePoolStmt(SourceLocation AtLoc, Stmt *Body) { 3120 getCurFunction()->setHasBranchProtectedScope(); 3121 return Owned(new (Context) ObjCAutoreleasePoolStmt(AtLoc, Body)); 3122} 3123 3124namespace { 3125 3126class TypeWithHandler { 3127 QualType t; 3128 CXXCatchStmt *stmt; 3129public: 3130 TypeWithHandler(const QualType &type, CXXCatchStmt *statement) 3131 : t(type), stmt(statement) {} 3132 3133 // An arbitrary order is fine as long as it places identical 3134 // types next to each other. 3135 bool operator<(const TypeWithHandler &y) const { 3136 if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr()) 3137 return true; 3138 if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr()) 3139 return false; 3140 else 3141 return getTypeSpecStartLoc() < y.getTypeSpecStartLoc(); 3142 } 3143 3144 bool operator==(const TypeWithHandler& other) const { 3145 return t == other.t; 3146 } 3147 3148 CXXCatchStmt *getCatchStmt() const { return stmt; } 3149 SourceLocation getTypeSpecStartLoc() const { 3150 return stmt->getExceptionDecl()->getTypeSpecStartLoc(); 3151 } 3152}; 3153 3154} 3155 3156/// ActOnCXXTryBlock - Takes a try compound-statement and a number of 3157/// handlers and creates a try statement from them. 3158StmtResult 3159Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock, 3160 MultiStmtArg RawHandlers) { 3161 // Don't report an error if 'try' is used in system headers. 3162 if (!getLangOpts().CXXExceptions && 3163 !getSourceManager().isInSystemHeader(TryLoc)) 3164 Diag(TryLoc, diag::err_exceptions_disabled) << "try"; 3165 3166 unsigned NumHandlers = RawHandlers.size(); 3167 assert(NumHandlers > 0 && 3168 "The parser shouldn't call this if there are no handlers."); 3169 Stmt **Handlers = RawHandlers.get(); 3170 3171 SmallVector<TypeWithHandler, 8> TypesWithHandlers; 3172 3173 for (unsigned i = 0; i < NumHandlers; ++i) { 3174 CXXCatchStmt *Handler = cast<CXXCatchStmt>(Handlers[i]); 3175 if (!Handler->getExceptionDecl()) { 3176 if (i < NumHandlers - 1) 3177 return StmtError(Diag(Handler->getLocStart(), 3178 diag::err_early_catch_all)); 3179 3180 continue; 3181 } 3182 3183 const QualType CaughtType = Handler->getCaughtType(); 3184 const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType); 3185 TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler)); 3186 } 3187 3188 // Detect handlers for the same type as an earlier one. 3189 if (NumHandlers > 1) { 3190 llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end()); 3191 3192 TypeWithHandler prev = TypesWithHandlers[0]; 3193 for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) { 3194 TypeWithHandler curr = TypesWithHandlers[i]; 3195 3196 if (curr == prev) { 3197 Diag(curr.getTypeSpecStartLoc(), 3198 diag::warn_exception_caught_by_earlier_handler) 3199 << curr.getCatchStmt()->getCaughtType().getAsString(); 3200 Diag(prev.getTypeSpecStartLoc(), 3201 diag::note_previous_exception_handler) 3202 << prev.getCatchStmt()->getCaughtType().getAsString(); 3203 } 3204 3205 prev = curr; 3206 } 3207 } 3208 3209 getCurFunction()->setHasBranchProtectedScope(); 3210 3211 // FIXME: We should detect handlers that cannot catch anything because an 3212 // earlier handler catches a superclass. Need to find a method that is not 3213 // quadratic for this. 3214 // Neither of these are explicitly forbidden, but every compiler detects them 3215 // and warns. 3216 3217 return Owned(CXXTryStmt::Create(Context, TryLoc, TryBlock, 3218 Handlers, NumHandlers)); 3219} 3220 3221StmtResult 3222Sema::ActOnSEHTryBlock(bool IsCXXTry, 3223 SourceLocation TryLoc, 3224 Stmt *TryBlock, 3225 Stmt *Handler) { 3226 assert(TryBlock && Handler); 3227 3228 getCurFunction()->setHasBranchProtectedScope(); 3229 3230 return Owned(SEHTryStmt::Create(Context,IsCXXTry,TryLoc,TryBlock,Handler)); 3231} 3232 3233StmtResult 3234Sema::ActOnSEHExceptBlock(SourceLocation Loc, 3235 Expr *FilterExpr, 3236 Stmt *Block) { 3237 assert(FilterExpr && Block); 3238 3239 if(!FilterExpr->getType()->isIntegerType()) { 3240 return StmtError(Diag(FilterExpr->getExprLoc(), 3241 diag::err_filter_expression_integral) 3242 << FilterExpr->getType()); 3243 } 3244 3245 return Owned(SEHExceptStmt::Create(Context,Loc,FilterExpr,Block)); 3246} 3247 3248StmtResult 3249Sema::ActOnSEHFinallyBlock(SourceLocation Loc, 3250 Stmt *Block) { 3251 assert(Block); 3252 return Owned(SEHFinallyStmt::Create(Context,Loc,Block)); 3253} 3254 3255StmtResult Sema::BuildMSDependentExistsStmt(SourceLocation KeywordLoc, 3256 bool IsIfExists, 3257 NestedNameSpecifierLoc QualifierLoc, 3258 DeclarationNameInfo NameInfo, 3259 Stmt *Nested) 3260{ 3261 return new (Context) MSDependentExistsStmt(KeywordLoc, IsIfExists, 3262 QualifierLoc, NameInfo, 3263 cast<CompoundStmt>(Nested)); 3264} 3265 3266 3267StmtResult Sema::ActOnMSDependentExistsStmt(SourceLocation KeywordLoc, 3268 bool IsIfExists, 3269 CXXScopeSpec &SS, 3270 UnqualifiedId &Name, 3271 Stmt *Nested) { 3272 return BuildMSDependentExistsStmt(KeywordLoc, IsIfExists, 3273 SS.getWithLocInContext(Context), 3274 GetNameFromUnqualifiedId(Name), 3275 Nested); 3276} 3277