contrib/llvm/tools/clang/lib/Sema/SemaExprObjC.cpp

   1 //===--- SemaExprObjC.cpp - Semantic Analysis for ObjC Expressions --------===//
   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 Objective-C expressions.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "clang/Sema/SemaInternal.h"
  15 #include "clang/AST/ASTContext.h"
  16 #include "clang/AST/DeclObjC.h"
  17 #include "clang/AST/ExprObjC.h"
  18 #include "clang/AST/StmtVisitor.h"
  19 #include "clang/AST/TypeLoc.h"
  20 #include "clang/Analysis/DomainSpecific/CocoaConventions.h"
  21 #include "clang/Edit/Commit.h"
  22 #include "clang/Edit/Rewriters.h"
  23 #include "clang/Lex/Preprocessor.h"
  24 #include "clang/Sema/Initialization.h"
  25 #include "clang/Sema/Lookup.h"
  26 #include "clang/Sema/Scope.h"
  27 #include "clang/Sema/ScopeInfo.h"
  28 #include "llvm/ADT/SmallString.h"
  29
  30 using namespace clang;
  31 using namespace sema;
  32 using llvm::makeArrayRef;
  33
  34 ExprResult Sema::ParseObjCStringLiteral(SourceLocation *AtLocs,
  35                                         ArrayRef<Expr *> Strings) {
  36   // Most ObjC strings are formed out of a single piece.  However, we *can*
  37   // have strings formed out of multiple @ strings with multiple pptokens in
  38   // each one, e.g. @"foo" "bar" @"baz" "qux"   which need to be turned into one
  39   // StringLiteral for ObjCStringLiteral to hold onto.
  40   StringLiteral *S = cast<StringLiteral>(Strings[0]);
  41
  42   // If we have a multi-part string, merge it all together.
  43   if (Strings.size() != 1) {
  44     // Concatenate objc strings.
  45     SmallString<128> StrBuf;
  46     SmallVector<SourceLocation, 8> StrLocs;
  47
  48     for (Expr *E : Strings) {
  49       S = cast<StringLiteral>(E);
  50
  51       // ObjC strings can't be wide or UTF.
  52       if (!S->isAscii()) {
  53         Diag(S->getLocStart(), diag::err_cfstring_literal_not_string_constant)
  54           << S->getSourceRange();
  55         return true;
  56       }
  57
  58       // Append the string.
  59       StrBuf += S->getString();
  60
  61       // Get the locations of the string tokens.
  62       StrLocs.append(S->tokloc_begin(), S->tokloc_end());
  63     }
  64
  65     // Create the aggregate string with the appropriate content and location
  66     // information.
  67     const ConstantArrayType *CAT = Context.getAsConstantArrayType(S->getType());
  68     assert(CAT && "String literal not of constant array type!");
  69     QualType StrTy = Context.getConstantArrayType(
  70         CAT->getElementType(), llvm::APInt(32, StrBuf.size() + 1),
  71         CAT->getSizeModifier(), CAT->getIndexTypeCVRQualifiers());
  72     S = StringLiteral::Create(Context, StrBuf, StringLiteral::Ascii,
  73                               /*Pascal=*/false, StrTy, &StrLocs[0],
  74                               StrLocs.size());
  75   }
  76
  77   return BuildObjCStringLiteral(AtLocs[0], S);
  78 }
  79
  80 ExprResult Sema::BuildObjCStringLiteral(SourceLocation AtLoc, StringLiteral *S){
  81   // Verify that this composite string is acceptable for ObjC strings.
  82   if (CheckObjCString(S))
  83     return true;
  84
  85   // Initialize the constant string interface lazily. This assumes
  86   // the NSString interface is seen in this translation unit. Note: We
  87   // don't use NSConstantString, since the runtime team considers this
  88   // interface private (even though it appears in the header files).
  89   QualType Ty = Context.getObjCConstantStringInterface();
  90   if (!Ty.isNull()) {
  91     Ty = Context.getObjCObjectPointerType(Ty);
  92   } else if (getLangOpts().NoConstantCFStrings) {
  93     IdentifierInfo *NSIdent=nullptr;
  94     std::string StringClass(getLangOpts().ObjCConstantStringClass);
  95
  96     if (StringClass.empty())
  97       NSIdent = &Context.Idents.get("NSConstantString");
  98     else
  99       NSIdent = &Context.Idents.get(StringClass);
 100
 101     NamedDecl *IF = LookupSingleName(TUScope, NSIdent, AtLoc,
 102                                      LookupOrdinaryName);
 103     if (ObjCInterfaceDecl *StrIF = dyn_cast_or_null<ObjCInterfaceDecl>(IF)) {
 104       Context.setObjCConstantStringInterface(StrIF);
 105       Ty = Context.getObjCConstantStringInterface();
 106       Ty = Context.getObjCObjectPointerType(Ty);
 107     } else {
 108       // If there is no NSConstantString interface defined then treat this
 109       // as error and recover from it.
 110       Diag(S->getLocStart(), diag::err_no_nsconstant_string_class) << NSIdent
 111         << S->getSourceRange();
 112       Ty = Context.getObjCIdType();
 113     }
 114   } else {
 115     IdentifierInfo *NSIdent = NSAPIObj->getNSClassId(NSAPI::ClassId_NSString);
 116     NamedDecl *IF = LookupSingleName(TUScope, NSIdent, AtLoc,
 117                                      LookupOrdinaryName);
 118     if (ObjCInterfaceDecl *StrIF = dyn_cast_or_null<ObjCInterfaceDecl>(IF)) {
 119       Context.setObjCConstantStringInterface(StrIF);
 120       Ty = Context.getObjCConstantStringInterface();
 121       Ty = Context.getObjCObjectPointerType(Ty);
 122     } else {
 123       // If there is no NSString interface defined, implicitly declare
 124       // a @class NSString; and use that instead. This is to make sure
 125       // type of an NSString literal is represented correctly, instead of
 126       // being an 'id' type.
 127       Ty = Context.getObjCNSStringType();
 128       if (Ty.isNull()) {
 129         ObjCInterfaceDecl *NSStringIDecl =
 130           ObjCInterfaceDecl::Create (Context,
 131                                      Context.getTranslationUnitDecl(),
 132                                      SourceLocation(), NSIdent,
 133                                      nullptr, nullptr, SourceLocation());
 134         Ty = Context.getObjCInterfaceType(NSStringIDecl);
 135         Context.setObjCNSStringType(Ty);
 136       }
 137       Ty = Context.getObjCObjectPointerType(Ty);
 138     }
 139   }
 140
 141   return new (Context) ObjCStringLiteral(S, Ty, AtLoc);
 142 }
 143
 144 /// \brief Emits an error if the given method does not exist, or if the return
 145 /// type is not an Objective-C object.
 146 static bool validateBoxingMethod(Sema &S, SourceLocation Loc,
 147                                  const ObjCInterfaceDecl *Class,
 148                                  Selector Sel, const ObjCMethodDecl *Method) {
 149   if (!Method) {
 150     // FIXME: Is there a better way to avoid quotes than using getName()?
 151     S.Diag(Loc, diag::err_undeclared_boxing_method) << Sel << Class->getName();
 152     return false;
 153   }
 154
 155   // Make sure the return type is reasonable.
 156   QualType ReturnType = Method->getReturnType();
 157   if (!ReturnType->isObjCObjectPointerType()) {
 158     S.Diag(Loc, diag::err_objc_literal_method_sig)
 159       << Sel;
 160     S.Diag(Method->getLocation(), diag::note_objc_literal_method_return)
 161       << ReturnType;
 162     return false;
 163   }
 164
 165   return true;
 166 }
 167
 168 /// \brief Maps ObjCLiteralKind to NSClassIdKindKind
 169 static NSAPI::NSClassIdKindKind ClassKindFromLiteralKind(
 170                                             Sema::ObjCLiteralKind LiteralKind) {
 171   switch (LiteralKind) {
 172     case Sema::LK_Array:
 173       return NSAPI::ClassId_NSArray;
 174     case Sema::LK_Dictionary:
 175       return NSAPI::ClassId_NSDictionary;
 176     case Sema::LK_Numeric:
 177       return NSAPI::ClassId_NSNumber;
 178     case Sema::LK_String:
 179       return NSAPI::ClassId_NSString;
 180     case Sema::LK_Boxed:
 181       return NSAPI::ClassId_NSValue;
 182
 183     // there is no corresponding matching
 184     // between LK_None/LK_Block and NSClassIdKindKind
 185     case Sema::LK_Block:
 186     case Sema::LK_None:
 187       break;
 188   }
 189   llvm_unreachable("LiteralKind can't be converted into a ClassKind");
 190 }
 191
 192 /// \brief Validates ObjCInterfaceDecl availability.
 193 /// ObjCInterfaceDecl, used to create ObjC literals, should be defined
 194 /// if clang not in a debugger mode.
 195 static bool ValidateObjCLiteralInterfaceDecl(Sema &S, ObjCInterfaceDecl *Decl,
 196                                             SourceLocation Loc,
 197                                             Sema::ObjCLiteralKind LiteralKind) {
 198   if (!Decl) {
 199     NSAPI::NSClassIdKindKind Kind = ClassKindFromLiteralKind(LiteralKind);
 200     IdentifierInfo *II = S.NSAPIObj->getNSClassId(Kind);
 201     S.Diag(Loc, diag::err_undeclared_objc_literal_class)
 202       << II->getName() << LiteralKind;
 203     return false;
 204   } else if (!Decl->hasDefinition() && !S.getLangOpts().DebuggerObjCLiteral) {
 205     S.Diag(Loc, diag::err_undeclared_objc_literal_class)
 206       << Decl->getName() << LiteralKind;
 207     S.Diag(Decl->getLocation(), diag::note_forward_class);
 208     return false;
 209   }
 210
 211   return true;
 212 }
 213
 214 /// \brief Looks up ObjCInterfaceDecl of a given NSClassIdKindKind.
 215 /// Used to create ObjC literals, such as NSDictionary (@{}),
 216 /// NSArray (@[]) and Boxed Expressions (@())
 217 static ObjCInterfaceDecl *LookupObjCInterfaceDeclForLiteral(Sema &S,
 218                                             SourceLocation Loc,
 219                                             Sema::ObjCLiteralKind LiteralKind) {
 220   NSAPI::NSClassIdKindKind ClassKind = ClassKindFromLiteralKind(LiteralKind);
 221   IdentifierInfo *II = S.NSAPIObj->getNSClassId(ClassKind);
 222   NamedDecl *IF = S.LookupSingleName(S.TUScope, II, Loc,
 223                                      Sema::LookupOrdinaryName);
 224   ObjCInterfaceDecl *ID = dyn_cast_or_null<ObjCInterfaceDecl>(IF);
 225   if (!ID && S.getLangOpts().DebuggerObjCLiteral) {
 226     ASTContext &Context = S.Context;
 227     TranslationUnitDecl *TU = Context.getTranslationUnitDecl();
 228     ID = ObjCInterfaceDecl::Create (Context, TU, SourceLocation(), II,
 229                                     nullptr, nullptr, SourceLocation());
 230   }
 231
 232   if (!ValidateObjCLiteralInterfaceDecl(S, ID, Loc, LiteralKind)) {
 233     ID = nullptr;
 234   }
 235
 236   return ID;
 237 }
 238
 239 /// \brief Retrieve the NSNumber factory method that should be used to create
 240 /// an Objective-C literal for the given type.
 241 static ObjCMethodDecl *getNSNumberFactoryMethod(Sema &S, SourceLocation Loc,
 242                                                 QualType NumberType,
 243                                                 bool isLiteral = false,
 244                                                 SourceRange R = SourceRange()) {
 245   Optional<NSAPI::NSNumberLiteralMethodKind> Kind =
 246       S.NSAPIObj->getNSNumberFactoryMethodKind(NumberType);
 247
 248   if (!Kind) {
 249     if (isLiteral) {
 250       S.Diag(Loc, diag::err_invalid_nsnumber_type)
 251         << NumberType << R;
 252     }
 253     return nullptr;
 254   }
 255
 256   // If we already looked up this method, we're done.
 257   if (S.NSNumberLiteralMethods[*Kind])
 258     return S.NSNumberLiteralMethods[*Kind];
 259
 260   Selector Sel = S.NSAPIObj->getNSNumberLiteralSelector(*Kind,
 261                                                         /*Instance=*/false);
 262
 263   ASTContext &CX = S.Context;
 264
 265   // Look up the NSNumber class, if we haven't done so already. It's cached
 266   // in the Sema instance.
 267   if (!S.NSNumberDecl) {
 268     S.NSNumberDecl = LookupObjCInterfaceDeclForLiteral(S, Loc,
 269                                                        Sema::LK_Numeric);
 270     if (!S.NSNumberDecl) {
 271       return nullptr;
 272     }
 273   }
 274
 275   if (S.NSNumberPointer.isNull()) {
 276     // generate the pointer to NSNumber type.
 277     QualType NSNumberObject = CX.getObjCInterfaceType(S.NSNumberDecl);
 278     S.NSNumberPointer = CX.getObjCObjectPointerType(NSNumberObject);
 279   }
 280
 281   // Look for the appropriate method within NSNumber.
 282   ObjCMethodDecl *Method = S.NSNumberDecl->lookupClassMethod(Sel);
 283   if (!Method && S.getLangOpts().DebuggerObjCLiteral) {
 284     // create a stub definition this NSNumber factory method.
 285     TypeSourceInfo *ReturnTInfo = nullptr;
 286     Method =
 287         ObjCMethodDecl::Create(CX, SourceLocation(), SourceLocation(), Sel,
 288                                S.NSNumberPointer, ReturnTInfo, S.NSNumberDecl,
 289                                /*isInstance=*/false, /*isVariadic=*/false,
 290                                /*isPropertyAccessor=*/false,
 291                                /*isImplicitlyDeclared=*/true,
 292                                /*isDefined=*/false, ObjCMethodDecl::Required,
 293                                /*HasRelatedResultType=*/false);
 294     ParmVarDecl *value = ParmVarDecl::Create(S.Context, Method,
 295                                              SourceLocation(), SourceLocation(),
 296                                              &CX.Idents.get("value"),
 297                                              NumberType, /*TInfo=*/nullptr,
 298                                              SC_None, nullptr);
 299     Method->setMethodParams(S.Context, value, None);
 300   }
 301
 302   if (!validateBoxingMethod(S, Loc, S.NSNumberDecl, Sel, Method))
 303     return nullptr;
 304
 305   // Note: if the parameter type is out-of-line, we'll catch it later in the
 306   // implicit conversion.
 307
 308   S.NSNumberLiteralMethods[*Kind] = Method;
 309   return Method;
 310 }
 311
 312 /// BuildObjCNumericLiteral - builds an ObjCBoxedExpr AST node for the
 313 /// numeric literal expression. Type of the expression will be "NSNumber *".
 314 ExprResult Sema::BuildObjCNumericLiteral(SourceLocation AtLoc, Expr *Number) {
 315   // Determine the type of the literal.
 316   QualType NumberType = Number->getType();
 317   if (CharacterLiteral *Char = dyn_cast<CharacterLiteral>(Number)) {
 318     // In C, character literals have type 'int'. That's not the type we want
 319     // to use to determine the Objective-c literal kind.
 320     switch (Char->getKind()) {
 321     case CharacterLiteral::Ascii:
 322     case CharacterLiteral::UTF8:
 323       NumberType = Context.CharTy;
 324       break;
 325
 326     case CharacterLiteral::Wide:
 327       NumberType = Context.getWideCharType();
 328       break;
 329
 330     case CharacterLiteral::UTF16:
 331       NumberType = Context.Char16Ty;
 332       break;
 333
 334     case CharacterLiteral::UTF32:
 335       NumberType = Context.Char32Ty;
 336       break;
 337     }
 338   }
 339
 340   // Look for the appropriate method within NSNumber.
 341   // Construct the literal.
 342   SourceRange NR(Number->getSourceRange());
 343   ObjCMethodDecl *Method = getNSNumberFactoryMethod(*this, AtLoc, NumberType,
 344                                                     true, NR);
 345   if (!Method)
 346     return ExprError();
 347
 348   // Convert the number to the type that the parameter expects.
 349   ParmVarDecl *ParamDecl = Method->parameters()[0];
 350   InitializedEntity Entity = InitializedEntity::InitializeParameter(Context,
 351                                                                     ParamDecl);
 352   ExprResult ConvertedNumber = PerformCopyInitialization(Entity,
 353                                                          SourceLocation(),
 354                                                          Number);
 355   if (ConvertedNumber.isInvalid())
 356     return ExprError();
 357   Number = ConvertedNumber.get();
 358
 359   // Use the effective source range of the literal, including the leading '@'.
 360   return MaybeBindToTemporary(
 361            new (Context) ObjCBoxedExpr(Number, NSNumberPointer, Method,
 362                                        SourceRange(AtLoc, NR.getEnd())));
 363 }
 364
 365 ExprResult Sema::ActOnObjCBoolLiteral(SourceLocation AtLoc,
 366                                       SourceLocation ValueLoc,
 367                                       bool Value) {
 368   ExprResult Inner;
 369   if (getLangOpts().CPlusPlus) {
 370     Inner = ActOnCXXBoolLiteral(ValueLoc, Value? tok::kw_true : tok::kw_false);
 371   } else {
 372     // C doesn't actually have a way to represent literal values of type
 373     // _Bool. So, we'll use 0/1 and implicit cast to _Bool.
 374     Inner = ActOnIntegerConstant(ValueLoc, Value? 1 : 0);
 375     Inner = ImpCastExprToType(Inner.get(), Context.BoolTy,
 376                               CK_IntegralToBoolean);
 377   }
 378
 379   return BuildObjCNumericLiteral(AtLoc, Inner.get());
 380 }
 381
 382 /// \brief Check that the given expression is a valid element of an Objective-C
 383 /// collection literal.
 384 static ExprResult CheckObjCCollectionLiteralElement(Sema &S, Expr *Element,
 385                                                     QualType T,
 386                                                     bool ArrayLiteral = false) {
 387   // If the expression is type-dependent, there's nothing for us to do.
 388   if (Element->isTypeDependent())
 389     return Element;
 390
 391   ExprResult Result = S.CheckPlaceholderExpr(Element);
 392   if (Result.isInvalid())
 393     return ExprError();
 394   Element = Result.get();
 395
 396   // In C++, check for an implicit conversion to an Objective-C object pointer
 397   // type.
 398   if (S.getLangOpts().CPlusPlus && Element->getType()->isRecordType()) {
 399     InitializedEntity Entity
 400       = InitializedEntity::InitializeParameter(S.Context, T,
 401                                                /*Consumed=*/false);
 402     InitializationKind Kind
 403       = InitializationKind::CreateCopy(Element->getLocStart(),
 404                                        SourceLocation());
 405     InitializationSequence Seq(S, Entity, Kind, Element);
 406     if (!Seq.Failed())
 407       return Seq.Perform(S, Entity, Kind, Element);
 408   }
 409
 410   Expr *OrigElement = Element;
 411
 412   // Perform lvalue-to-rvalue conversion.
 413   Result = S.DefaultLvalueConversion(Element);
 414   if (Result.isInvalid())
 415     return ExprError();
 416   Element = Result.get();
 417
 418   // Make sure that we have an Objective-C pointer type or block.
 419   if (!Element->getType()->isObjCObjectPointerType() &&
 420       !Element->getType()->isBlockPointerType()) {
 421     bool Recovered = false;
 422
 423     // If this is potentially an Objective-C numeric literal, add the '@'.
 424     if (isa<IntegerLiteral>(OrigElement) ||
 425         isa<CharacterLiteral>(OrigElement) ||
 426         isa<FloatingLiteral>(OrigElement) ||
 427         isa<ObjCBoolLiteralExpr>(OrigElement) ||
 428         isa<CXXBoolLiteralExpr>(OrigElement)) {
 429       if (S.NSAPIObj->getNSNumberFactoryMethodKind(OrigElement->getType())) {
 430         int Which = isa<CharacterLiteral>(OrigElement) ? 1
 431                   : (isa<CXXBoolLiteralExpr>(OrigElement) ||
 432                      isa<ObjCBoolLiteralExpr>(OrigElement)) ? 2
 433                   : 3;
 434
 435         S.Diag(OrigElement->getLocStart(), diag::err_box_literal_collection)
 436           << Which << OrigElement->getSourceRange()
 437           << FixItHint::CreateInsertion(OrigElement->getLocStart(), "@");
 438
 439         Result = S.BuildObjCNumericLiteral(OrigElement->getLocStart(),
 440                                            OrigElement);
 441         if (Result.isInvalid())
 442           return ExprError();
 443
 444         Element = Result.get();
 445         Recovered = true;
 446       }
 447     }
 448     // If this is potentially an Objective-C string literal, add the '@'.
 449     else if (StringLiteral *String = dyn_cast<StringLiteral>(OrigElement)) {
 450       if (String->isAscii()) {
 451         S.Diag(OrigElement->getLocStart(), diag::err_box_literal_collection)
 452           << 0 << OrigElement->getSourceRange()
 453           << FixItHint::CreateInsertion(OrigElement->getLocStart(), "@");
 454
 455         Result = S.BuildObjCStringLiteral(OrigElement->getLocStart(), String);
 456         if (Result.isInvalid())
 457           return ExprError();
 458
 459         Element = Result.get();
 460         Recovered = true;
 461       }
 462     }
 463
 464     if (!Recovered) {
 465       S.Diag(Element->getLocStart(), diag::err_invalid_collection_element)
 466         << Element->getType();
 467       return ExprError();
 468     }
 469   }
 470   if (ArrayLiteral)
 471     if (ObjCStringLiteral *getString =
 472           dyn_cast<ObjCStringLiteral>(OrigElement)) {
 473       if (StringLiteral *SL = getString->getString()) {
 474         unsigned numConcat = SL->getNumConcatenated();
 475         if (numConcat > 1) {
 476           // Only warn if the concatenated string doesn't come from a macro.
 477           bool hasMacro = false;
 478           for (unsigned i = 0; i < numConcat ; ++i)
 479             if (SL->getStrTokenLoc(i).isMacroID()) {
 480               hasMacro = true;
 481               break;
 482             }
 483           if (!hasMacro)
 484             S.Diag(Element->getLocStart(),
 485                    diag::warn_concatenated_nsarray_literal)
 486               << Element->getType();
 487         }
 488       }
 489     }
 490
 491   // Make sure that the element has the type that the container factory
 492   // function expects.
 493   return S.PerformCopyInitialization(
 494            InitializedEntity::InitializeParameter(S.Context, T,
 495                                                   /*Consumed=*/false),
 496            Element->getLocStart(), Element);
 497 }
 498
 499 ExprResult Sema::BuildObjCBoxedExpr(SourceRange SR, Expr *ValueExpr) {
 500   if (ValueExpr->isTypeDependent()) {
 501     ObjCBoxedExpr *BoxedExpr =
 502       new (Context) ObjCBoxedExpr(ValueExpr, Context.DependentTy, nullptr, SR);
 503     return BoxedExpr;
 504   }
 505   ObjCMethodDecl *BoxingMethod = nullptr;
 506   QualType BoxedType;
 507   // Convert the expression to an RValue, so we can check for pointer types...
 508   ExprResult RValue = DefaultFunctionArrayLvalueConversion(ValueExpr);
 509   if (RValue.isInvalid()) {
 510     return ExprError();
 511   }
 512   SourceLocation Loc = SR.getBegin();
 513   ValueExpr = RValue.get();
 514   QualType ValueType(ValueExpr->getType());
 515   if (const PointerType *PT = ValueType->getAs<PointerType>()) {
 516     QualType PointeeType = PT->getPointeeType();
 517     if (Context.hasSameUnqualifiedType(PointeeType, Context.CharTy)) {
 518
 519       if (!NSStringDecl) {
 520         NSStringDecl = LookupObjCInterfaceDeclForLiteral(*this, Loc,
 521                                                          Sema::LK_String);
 522         if (!NSStringDecl) {
 523           return ExprError();
 524         }
 525         QualType NSStringObject = Context.getObjCInterfaceType(NSStringDecl);
 526         NSStringPointer = Context.getObjCObjectPointerType(NSStringObject);
 527       }
 528
 529       if (!StringWithUTF8StringMethod) {
 530         IdentifierInfo *II = &Context.Idents.get("stringWithUTF8String");
 531         Selector stringWithUTF8String = Context.Selectors.getUnarySelector(II);
 532
 533         // Look for the appropriate method within NSString.
 534         BoxingMethod = NSStringDecl->lookupClassMethod(stringWithUTF8String);
 535         if (!BoxingMethod && getLangOpts().DebuggerObjCLiteral) {
 536           // Debugger needs to work even if NSString hasn't been defined.
 537           TypeSourceInfo *ReturnTInfo = nullptr;
 538           ObjCMethodDecl *M = ObjCMethodDecl::Create(
 539               Context, SourceLocation(), SourceLocation(), stringWithUTF8String,
 540               NSStringPointer, ReturnTInfo, NSStringDecl,
 541               /*isInstance=*/false, /*isVariadic=*/false,
 542               /*isPropertyAccessor=*/false,
 543               /*isImplicitlyDeclared=*/true,
 544               /*isDefined=*/false, ObjCMethodDecl::Required,
 545               /*HasRelatedResultType=*/false);
 546           QualType ConstCharType = Context.CharTy.withConst();
 547           ParmVarDecl *value =
 548             ParmVarDecl::Create(Context, M,
 549                                 SourceLocation(), SourceLocation(),
 550                                 &Context.Idents.get("value"),
 551                                 Context.getPointerType(ConstCharType),
 552                                 /*TInfo=*/nullptr,
 553                                 SC_None, nullptr);
 554           M->setMethodParams(Context, value, None);
 555           BoxingMethod = M;
 556         }
 557
 558         if (!validateBoxingMethod(*this, Loc, NSStringDecl,
 559                                   stringWithUTF8String, BoxingMethod))
 560            return ExprError();
 561
 562         StringWithUTF8StringMethod = BoxingMethod;
 563       }
 564
 565       BoxingMethod = StringWithUTF8StringMethod;
 566       BoxedType = NSStringPointer;
 567     }
 568   } else if (ValueType->isBuiltinType()) {
 569     // The other types we support are numeric, char and BOOL/bool. We could also
 570     // provide limited support for structure types, such as NSRange, NSRect, and
 571     // NSSize. See NSValue (NSValueGeometryExtensions) in <Foundation/NSGeometry.h>
 572     // for more details.
 573
 574     // Check for a top-level character literal.
 575     if (const CharacterLiteral *Char =
 576         dyn_cast<CharacterLiteral>(ValueExpr->IgnoreParens())) {
 577       // In C, character literals have type 'int'. That's not the type we want
 578       // to use to determine the Objective-c literal kind.
 579       switch (Char->getKind()) {
 580       case CharacterLiteral::Ascii:
 581       case CharacterLiteral::UTF8:
 582         ValueType = Context.CharTy;
 583         break;
 584
 585       case CharacterLiteral::Wide:
 586         ValueType = Context.getWideCharType();
 587         break;
 588
 589       case CharacterLiteral::UTF16:
 590         ValueType = Context.Char16Ty;
 591         break;
 592
 593       case CharacterLiteral::UTF32:
 594         ValueType = Context.Char32Ty;
 595         break;
 596       }
 597     }
 598     // FIXME:  Do I need to do anything special with BoolTy expressions?
 599
 600     // Look for the appropriate method within NSNumber.
 601     BoxingMethod = getNSNumberFactoryMethod(*this, Loc, ValueType);
 602     BoxedType = NSNumberPointer;
 603   } else if (const EnumType *ET = ValueType->getAs<EnumType>()) {
 604     if (!ET->getDecl()->isComplete()) {
 605       Diag(Loc, diag::err_objc_incomplete_boxed_expression_type)
 606         << ValueType << ValueExpr->getSourceRange();
 607       return ExprError();
 608     }
 609
 610     BoxingMethod = getNSNumberFactoryMethod(*this, Loc,
 611                                             ET->getDecl()->getIntegerType());
 612     BoxedType = NSNumberPointer;
 613   } else if (ValueType->isObjCBoxableRecordType()) {
 614     // Support for structure types, that marked as objc_boxable
 615     // struct __attribute__((objc_boxable)) s { ... };
 616
 617     // Look up the NSValue class, if we haven't done so already. It's cached
 618     // in the Sema instance.
 619     if (!NSValueDecl) {
 620       NSValueDecl = LookupObjCInterfaceDeclForLiteral(*this, Loc,
 621                                                       Sema::LK_Boxed);
 622       if (!NSValueDecl) {
 623         return ExprError();
 624       }
 625
 626       // generate the pointer to NSValue type.
 627       QualType NSValueObject = Context.getObjCInterfaceType(NSValueDecl);
 628       NSValuePointer = Context.getObjCObjectPointerType(NSValueObject);
 629     }
 630
 631     if (!ValueWithBytesObjCTypeMethod) {
 632       IdentifierInfo *II[] = {
 633         &Context.Idents.get("valueWithBytes"),
 634         &Context.Idents.get("objCType")
 635       };
 636       Selector ValueWithBytesObjCType = Context.Selectors.getSelector(2, II);
 637
 638       // Look for the appropriate method within NSValue.
 639       BoxingMethod = NSValueDecl->lookupClassMethod(ValueWithBytesObjCType);
 640       if (!BoxingMethod && getLangOpts().DebuggerObjCLiteral) {
 641         // Debugger needs to work even if NSValue hasn't been defined.
 642         TypeSourceInfo *ReturnTInfo = nullptr;
 643         ObjCMethodDecl *M = ObjCMethodDecl::Create(
 644                                                Context,
 645                                                SourceLocation(),
 646                                                SourceLocation(),
 647                                                ValueWithBytesObjCType,
 648                                                NSValuePointer,
 649                                                ReturnTInfo,
 650                                                NSValueDecl,
 651                                                /*isInstance=*/false,
 652                                                /*isVariadic=*/false,
 653                                                /*isPropertyAccessor=*/false,
 654                                                /*isImplicitlyDeclared=*/true,
 655                                                /*isDefined=*/false,
 656                                                ObjCMethodDecl::Required,
 657                                                /*HasRelatedResultType=*/false);
 658
 659         SmallVector<ParmVarDecl *, 2> Params;
 660
 661         ParmVarDecl *bytes =
 662         ParmVarDecl::Create(Context, M,
 663                             SourceLocation(), SourceLocation(),
 664                             &Context.Idents.get("bytes"),
 665                             Context.VoidPtrTy.withConst(),
 666                             /*TInfo=*/nullptr,
 667                             SC_None, nullptr);
 668         Params.push_back(bytes);
 669
 670         QualType ConstCharType = Context.CharTy.withConst();
 671         ParmVarDecl *type =
 672         ParmVarDecl::Create(Context, M,
 673                             SourceLocation(), SourceLocation(),
 674                             &Context.Idents.get("type"),
 675                             Context.getPointerType(ConstCharType),
 676                             /*TInfo=*/nullptr,
 677                             SC_None, nullptr);
 678         Params.push_back(type);
 679
 680         M->setMethodParams(Context, Params, None);
 681         BoxingMethod = M;
 682       }
 683
 684       if (!validateBoxingMethod(*this, Loc, NSValueDecl,
 685                                 ValueWithBytesObjCType, BoxingMethod))
 686         return ExprError();
 687
 688       ValueWithBytesObjCTypeMethod = BoxingMethod;
 689     }
 690
 691     if (!ValueType.isTriviallyCopyableType(Context)) {
 692       Diag(Loc, diag::err_objc_non_trivially_copyable_boxed_expression_type)
 693         << ValueType << ValueExpr->getSourceRange();
 694       return ExprError();
 695     }
 696
 697     BoxingMethod = ValueWithBytesObjCTypeMethod;
 698     BoxedType = NSValuePointer;
 699   }
 700
 701   if (!BoxingMethod) {
 702     Diag(Loc, diag::err_objc_illegal_boxed_expression_type)
 703       << ValueType << ValueExpr->getSourceRange();
 704     return ExprError();
 705   }
 706
 707   DiagnoseUseOfDecl(BoxingMethod, Loc);
 708
 709   ExprResult ConvertedValueExpr;
 710   if (ValueType->isObjCBoxableRecordType()) {
 711     InitializedEntity IE = InitializedEntity::InitializeTemporary(ValueType);
 712     ConvertedValueExpr = PerformCopyInitialization(IE, ValueExpr->getExprLoc(),
 713                                                    ValueExpr);
 714   } else {
 715     // Convert the expression to the type that the parameter requires.
 716     ParmVarDecl *ParamDecl = BoxingMethod->parameters()[0];
 717     InitializedEntity IE = InitializedEntity::InitializeParameter(Context,
 718                                                                   ParamDecl);
 719     ConvertedValueExpr = PerformCopyInitialization(IE, SourceLocation(),
 720                                                    ValueExpr);
 721   }
 722
 723   if (ConvertedValueExpr.isInvalid())
 724     return ExprError();
 725   ValueExpr = ConvertedValueExpr.get();
 726
 727   ObjCBoxedExpr *BoxedExpr =
 728     new (Context) ObjCBoxedExpr(ValueExpr, BoxedType,
 729                                       BoxingMethod, SR);
 730   return MaybeBindToTemporary(BoxedExpr);
 731 }
 732
 733 /// Build an ObjC subscript pseudo-object expression, given that
 734 /// that's supported by the runtime.
 735 ExprResult Sema::BuildObjCSubscriptExpression(SourceLocation RB, Expr *BaseExpr,
 736                                         Expr *IndexExpr,
 737                                         ObjCMethodDecl *getterMethod,
 738                                         ObjCMethodDecl *setterMethod) {
 739   assert(!LangOpts.isSubscriptPointerArithmetic());
 740
 741   // We can't get dependent types here; our callers should have
 742   // filtered them out.
 743   assert((!BaseExpr->isTypeDependent() && !IndexExpr->isTypeDependent()) &&
 744          "base or index cannot have dependent type here");
 745
 746   // Filter out placeholders in the index.  In theory, overloads could
 747   // be preserved here, although that might not actually work correctly.
 748   ExprResult Result = CheckPlaceholderExpr(IndexExpr);
 749   if (Result.isInvalid())
 750     return ExprError();
 751   IndexExpr = Result.get();
 752
 753   // Perform lvalue-to-rvalue conversion on the base.
 754   Result = DefaultLvalueConversion(BaseExpr);
 755   if (Result.isInvalid())
 756     return ExprError();
 757   BaseExpr = Result.get();
 758
 759   // Build the pseudo-object expression.
 760   return new (Context) ObjCSubscriptRefExpr(
 761       BaseExpr, IndexExpr, Context.PseudoObjectTy, VK_LValue, OK_ObjCSubscript,
 762       getterMethod, setterMethod, RB);
 763 }
 764
 765 ExprResult Sema::BuildObjCArrayLiteral(SourceRange SR, MultiExprArg Elements) {
 766   SourceLocation Loc = SR.getBegin();
 767
 768   if (!NSArrayDecl) {
 769     NSArrayDecl = LookupObjCInterfaceDeclForLiteral(*this, Loc,
 770                                                     Sema::LK_Array);
 771     if (!NSArrayDecl) {
 772       return ExprError();
 773     }
 774   }
 775
 776   // Find the arrayWithObjects:count: method, if we haven't done so already.
 777   QualType IdT = Context.getObjCIdType();
 778   if (!ArrayWithObjectsMethod) {
 779     Selector
 780       Sel = NSAPIObj->getNSArraySelector(NSAPI::NSArr_arrayWithObjectsCount);
 781     ObjCMethodDecl *Method = NSArrayDecl->lookupClassMethod(Sel);
 782     if (!Method && getLangOpts().DebuggerObjCLiteral) {
 783       TypeSourceInfo *ReturnTInfo = nullptr;
 784       Method = ObjCMethodDecl::Create(
 785           Context, SourceLocation(), SourceLocation(), Sel, IdT, ReturnTInfo,
 786           Context.getTranslationUnitDecl(), false /*Instance*/,
 787           false /*isVariadic*/,
 788           /*isPropertyAccessor=*/false,
 789           /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
 790           ObjCMethodDecl::Required, false);
 791       SmallVector<ParmVarDecl *, 2> Params;
 792       ParmVarDecl *objects = ParmVarDecl::Create(Context, Method,
 793                                                  SourceLocation(),
 794                                                  SourceLocation(),
 795                                                  &Context.Idents.get("objects"),
 796                                                  Context.getPointerType(IdT),
 797                                                  /*TInfo=*/nullptr,
 798                                                  SC_None, nullptr);
 799       Params.push_back(objects);
 800       ParmVarDecl *cnt = ParmVarDecl::Create(Context, Method,
 801                                              SourceLocation(),
 802                                              SourceLocation(),
 803                                              &Context.Idents.get("cnt"),
 804                                              Context.UnsignedLongTy,
 805                                              /*TInfo=*/nullptr, SC_None,
 806                                              nullptr);
 807       Params.push_back(cnt);
 808       Method->setMethodParams(Context, Params, None);
 809     }
 810
 811     if (!validateBoxingMethod(*this, Loc, NSArrayDecl, Sel, Method))
 812       return ExprError();
 813
 814     // Dig out the type that all elements should be converted to.
 815     QualType T = Method->parameters()[0]->getType();
 816     const PointerType *PtrT = T->getAs<PointerType>();
 817     if (!PtrT ||
 818         !Context.hasSameUnqualifiedType(PtrT->getPointeeType(), IdT)) {
 819       Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
 820         << Sel;
 821       Diag(Method->parameters()[0]->getLocation(),
 822            diag::note_objc_literal_method_param)
 823         << 0 << T
 824         << Context.getPointerType(IdT.withConst());
 825       return ExprError();
 826     }
 827
 828     // Check that the 'count' parameter is integral.
 829     if (!Method->parameters()[1]->getType()->isIntegerType()) {
 830       Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
 831         << Sel;
 832       Diag(Method->parameters()[1]->getLocation(),
 833            diag::note_objc_literal_method_param)
 834         << 1
 835         << Method->parameters()[1]->getType()
 836         << "integral";
 837       return ExprError();
 838     }
 839
 840     // We've found a good +arrayWithObjects:count: method. Save it!
 841     ArrayWithObjectsMethod = Method;
 842   }
 843
 844   QualType ObjectsType = ArrayWithObjectsMethod->parameters()[0]->getType();
 845   QualType RequiredType = ObjectsType->castAs<PointerType>()->getPointeeType();
 846
 847   // Check that each of the elements provided is valid in a collection literal,
 848   // performing conversions as necessary.
 849   Expr **ElementsBuffer = Elements.data();
 850   for (unsigned I = 0, N = Elements.size(); I != N; ++I) {
 851     ExprResult Converted = CheckObjCCollectionLiteralElement(*this,
 852                                                              ElementsBuffer[I],
 853                                                              RequiredType, true);
 854     if (Converted.isInvalid())
 855       return ExprError();
 856
 857     ElementsBuffer[I] = Converted.get();
 858   }
 859
 860   QualType Ty
 861     = Context.getObjCObjectPointerType(
 862                                     Context.getObjCInterfaceType(NSArrayDecl));
 863
 864   return MaybeBindToTemporary(
 865            ObjCArrayLiteral::Create(Context, Elements, Ty,
 866                                     ArrayWithObjectsMethod, SR));
 867 }
 868
 869 ExprResult Sema::BuildObjCDictionaryLiteral(SourceRange SR,
 870                               MutableArrayRef<ObjCDictionaryElement> Elements) {
 871   SourceLocation Loc = SR.getBegin();
 872
 873   if (!NSDictionaryDecl) {
 874     NSDictionaryDecl = LookupObjCInterfaceDeclForLiteral(*this, Loc,
 875                                                          Sema::LK_Dictionary);
 876     if (!NSDictionaryDecl) {
 877       return ExprError();
 878     }
 879   }
 880
 881   // Find the dictionaryWithObjects:forKeys:count: method, if we haven't done
 882   // so already.
 883   QualType IdT = Context.getObjCIdType();
 884   if (!DictionaryWithObjectsMethod) {
 885     Selector Sel = NSAPIObj->getNSDictionarySelector(
 886                                NSAPI::NSDict_dictionaryWithObjectsForKeysCount);
 887     ObjCMethodDecl *Method = NSDictionaryDecl->lookupClassMethod(Sel);
 888     if (!Method && getLangOpts().DebuggerObjCLiteral) {
 889       Method = ObjCMethodDecl::Create(Context,
 890                            SourceLocation(), SourceLocation(), Sel,
 891                            IdT,
 892                            nullptr /*TypeSourceInfo */,
 893                            Context.getTranslationUnitDecl(),
 894                            false /*Instance*/, false/*isVariadic*/,
 895                            /*isPropertyAccessor=*/false,
 896                            /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
 897                            ObjCMethodDecl::Required,
 898                            false);
 899       SmallVector<ParmVarDecl *, 3> Params;
 900       ParmVarDecl *objects = ParmVarDecl::Create(Context, Method,
 901                                                  SourceLocation(),
 902                                                  SourceLocation(),
 903                                                  &Context.Idents.get("objects"),
 904                                                  Context.getPointerType(IdT),
 905                                                  /*TInfo=*/nullptr, SC_None,
 906                                                  nullptr);
 907       Params.push_back(objects);
 908       ParmVarDecl *keys = ParmVarDecl::Create(Context, Method,
 909                                               SourceLocation(),
 910                                               SourceLocation(),
 911                                               &Context.Idents.get("keys"),
 912                                               Context.getPointerType(IdT),
 913                                               /*TInfo=*/nullptr, SC_None,
 914                                               nullptr);
 915       Params.push_back(keys);
 916       ParmVarDecl *cnt = ParmVarDecl::Create(Context, Method,
 917                                              SourceLocation(),
 918                                              SourceLocation(),
 919                                              &Context.Idents.get("cnt"),
 920                                              Context.UnsignedLongTy,
 921                                              /*TInfo=*/nullptr, SC_None,
 922                                              nullptr);
 923       Params.push_back(cnt);
 924       Method->setMethodParams(Context, Params, None);
 925     }
 926
 927     if (!validateBoxingMethod(*this, SR.getBegin(), NSDictionaryDecl, Sel,
 928                               Method))
 929        return ExprError();
 930
 931     // Dig out the type that all values should be converted to.
 932     QualType ValueT = Method->parameters()[0]->getType();
 933     const PointerType *PtrValue = ValueT->getAs<PointerType>();
 934     if (!PtrValue ||
 935         !Context.hasSameUnqualifiedType(PtrValue->getPointeeType(), IdT)) {
 936       Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
 937         << Sel;
 938       Diag(Method->parameters()[0]->getLocation(),
 939            diag::note_objc_literal_method_param)
 940         << 0 << ValueT
 941         << Context.getPointerType(IdT.withConst());
 942       return ExprError();
 943     }
 944
 945     // Dig out the type that all keys should be converted to.
 946     QualType KeyT = Method->parameters()[1]->getType();
 947     const PointerType *PtrKey = KeyT->getAs<PointerType>();
 948     if (!PtrKey ||
 949         !Context.hasSameUnqualifiedType(PtrKey->getPointeeType(),
 950                                         IdT)) {
 951       bool err = true;
 952       if (PtrKey) {
 953         if (QIDNSCopying.isNull()) {
 954           // key argument of selector is id<NSCopying>?
 955           if (ObjCProtocolDecl *NSCopyingPDecl =
 956               LookupProtocol(&Context.Idents.get("NSCopying"), SR.getBegin())) {
 957             ObjCProtocolDecl *PQ[] = {NSCopyingPDecl};
 958             QIDNSCopying =
 959               Context.getObjCObjectType(Context.ObjCBuiltinIdTy, { },
 960                                         llvm::makeArrayRef(
 961                                           (ObjCProtocolDecl**) PQ,
 962                                           1),
 963                                         false);
 964             QIDNSCopying = Context.getObjCObjectPointerType(QIDNSCopying);
 965           }
 966         }
 967         if (!QIDNSCopying.isNull())
 968           err = !Context.hasSameUnqualifiedType(PtrKey->getPointeeType(),
 969                                                 QIDNSCopying);
 970       }
 971
 972       if (err) {
 973         Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
 974           << Sel;
 975         Diag(Method->parameters()[1]->getLocation(),
 976              diag::note_objc_literal_method_param)
 977           << 1 << KeyT
 978           << Context.getPointerType(IdT.withConst());
 979         return ExprError();
 980       }
 981     }
 982
 983     // Check that the 'count' parameter is integral.
 984     QualType CountType = Method->parameters()[2]->getType();
 985     if (!CountType->isIntegerType()) {
 986       Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
 987         << Sel;
 988       Diag(Method->parameters()[2]->getLocation(),
 989            diag::note_objc_literal_method_param)
 990         << 2 << CountType
 991         << "integral";
 992       return ExprError();
 993     }
 994
 995     // We've found a good +dictionaryWithObjects:keys:count: method; save it!
 996     DictionaryWithObjectsMethod = Method;
 997   }
 998
 999   QualType ValuesT = DictionaryWithObjectsMethod->parameters()[0]->getType();
1000   QualType ValueT = ValuesT->castAs<PointerType>()->getPointeeType();
1001   QualType KeysT = DictionaryWithObjectsMethod->parameters()[1]->getType();
1002   QualType KeyT = KeysT->castAs<PointerType>()->getPointeeType();
1003
1004   // Check that each of the keys and values provided is valid in a collection
1005   // literal, performing conversions as necessary.
1006   bool HasPackExpansions = false;
1007   for (ObjCDictionaryElement &Element : Elements) {
1008     // Check the key.
1009     ExprResult Key = CheckObjCCollectionLiteralElement(*this, Element.Key,
1010                                                        KeyT);
1011     if (Key.isInvalid())
1012       return ExprError();
1013
1014     // Check the value.
1015     ExprResult Value
1016       = CheckObjCCollectionLiteralElement(*this, Element.Value, ValueT);
1017     if (Value.isInvalid())
1018       return ExprError();
1019
1020     Element.Key = Key.get();
1021     Element.Value = Value.get();
1022
1023     if (Element.EllipsisLoc.isInvalid())
1024       continue;
1025
1026     if (!Element.Key->containsUnexpandedParameterPack() &&
1027         !Element.Value->containsUnexpandedParameterPack()) {
1028       Diag(Element.EllipsisLoc,
1029            diag::err_pack_expansion_without_parameter_packs)
1030         << SourceRange(Element.Key->getLocStart(),
1031                        Element.Value->getLocEnd());
1032       return ExprError();
1033     }
1034
1035     HasPackExpansions = true;
1036   }
1037
1038   QualType Ty
1039     = Context.getObjCObjectPointerType(
1040                                 Context.getObjCInterfaceType(NSDictionaryDecl));
1041   return MaybeBindToTemporary(ObjCDictionaryLiteral::Create(
1042       Context, Elements, HasPackExpansions, Ty,
1043       DictionaryWithObjectsMethod, SR));
1044 }
1045
1046 ExprResult Sema::BuildObjCEncodeExpression(SourceLocation AtLoc,
1047                                       TypeSourceInfo *EncodedTypeInfo,
1048                                       SourceLocation RParenLoc) {
1049   QualType EncodedType = EncodedTypeInfo->getType();
1050   QualType StrTy;
1051   if (EncodedType->isDependentType())
1052     StrTy = Context.DependentTy;
1053   else {
1054     if (!EncodedType->getAsArrayTypeUnsafe() && //// Incomplete array is handled.
1055         !EncodedType->isVoidType()) // void is handled too.
1056       if (RequireCompleteType(AtLoc, EncodedType,
1057                               diag::err_incomplete_type_objc_at_encode,
1058                               EncodedTypeInfo->getTypeLoc()))
1059         return ExprError();
1060
1061     std::string Str;
1062     QualType NotEncodedT;
1063     Context.getObjCEncodingForType(EncodedType, Str, nullptr, &NotEncodedT);
1064     if (!NotEncodedT.isNull())
1065       Diag(AtLoc, diag::warn_incomplete_encoded_type)
1066         << EncodedType << NotEncodedT;
1067
1068     // The type of @encode is the same as the type of the corresponding string,
1069     // which is an array type.
1070     StrTy = Context.CharTy;
1071     // A C++ string literal has a const-qualified element type (C++ 2.13.4p1).
1072     if (getLangOpts().CPlusPlus || getLangOpts().ConstStrings)
1073       StrTy.addConst();
1074     StrTy = Context.getConstantArrayType(StrTy, llvm::APInt(32, Str.size()+1),
1075                                          ArrayType::Normal, 0);
1076   }
1077
1078   return new (Context) ObjCEncodeExpr(StrTy, EncodedTypeInfo, AtLoc, RParenLoc);
1079 }
1080
1081 ExprResult Sema::ParseObjCEncodeExpression(SourceLocation AtLoc,
1082                                            SourceLocation EncodeLoc,
1083                                            SourceLocation LParenLoc,
1084                                            ParsedType ty,
1085                                            SourceLocation RParenLoc) {
1086   // FIXME: Preserve type source info ?
1087   TypeSourceInfo *TInfo;
1088   QualType EncodedType = GetTypeFromParser(ty, &TInfo);
1089   if (!TInfo)
1090     TInfo = Context.getTrivialTypeSourceInfo(EncodedType,
1091                                              getLocForEndOfToken(LParenLoc));
1092
1093   return BuildObjCEncodeExpression(AtLoc, TInfo, RParenLoc);
1094 }
1095
1096 static bool HelperToDiagnoseMismatchedMethodsInGlobalPool(Sema &S,
1097                                                SourceLocation AtLoc,
1098                                                SourceLocation LParenLoc,
1099                                                SourceLocation RParenLoc,
1100                                                ObjCMethodDecl *Method,
1101                                                ObjCMethodList &MethList) {
1102   ObjCMethodList *M = &MethList;
1103   bool Warned = false;
1104   for (M = M->getNext(); M; M=M->getNext()) {
1105     ObjCMethodDecl *MatchingMethodDecl = M->getMethod();
1106     if (MatchingMethodDecl == Method ||
1107         isa<ObjCImplDecl>(MatchingMethodDecl->getDeclContext()) ||
1108         MatchingMethodDecl->getSelector() != Method->getSelector())
1109       continue;
1110     if (!S.MatchTwoMethodDeclarations(Method,
1111                                       MatchingMethodDecl, Sema::MMS_loose)) {
1112       if (!Warned) {
1113         Warned = true;
1114         S.Diag(AtLoc, diag::warn_multiple_selectors)
1115           << Method->getSelector() << FixItHint::CreateInsertion(LParenLoc, "(")
1116           << FixItHint::CreateInsertion(RParenLoc, ")");
1117         S.Diag(Method->getLocation(), diag::note_method_declared_at)
1118           << Method->getDeclName();
1119       }
1120       S.Diag(MatchingMethodDecl->getLocation(), diag::note_method_declared_at)
1121         << MatchingMethodDecl->getDeclName();
1122     }
1123   }
1124   return Warned;
1125 }
1126
1127 static void DiagnoseMismatchedSelectors(Sema &S, SourceLocation AtLoc,
1128                                         ObjCMethodDecl *Method,
1129                                         SourceLocation LParenLoc,
1130                                         SourceLocation RParenLoc,
1131                                         bool WarnMultipleSelectors) {
1132   if (!WarnMultipleSelectors ||
1133       S.Diags.isIgnored(diag::warn_multiple_selectors, SourceLocation()))
1134     return;
1135   bool Warned = false;
1136   for (Sema::GlobalMethodPool::iterator b = S.MethodPool.begin(),
1137        e = S.MethodPool.end(); b != e; b++) {
1138     // first, instance methods
1139     ObjCMethodList &InstMethList = b->second.first;
1140     if (HelperToDiagnoseMismatchedMethodsInGlobalPool(S, AtLoc, LParenLoc, RParenLoc,
1141                                                       Method, InstMethList))
1142       Warned = true;
1143
1144     // second, class methods
1145     ObjCMethodList &ClsMethList = b->second.second;
1146     if (HelperToDiagnoseMismatchedMethodsInGlobalPool(S, AtLoc, LParenLoc, RParenLoc,
1147                                                       Method, ClsMethList) || Warned)
1148       return;
1149   }
1150 }
1151
1152 ExprResult Sema::ParseObjCSelectorExpression(Selector Sel,
1153                                              SourceLocation AtLoc,
1154                                              SourceLocation SelLoc,
1155                                              SourceLocation LParenLoc,
1156                                              SourceLocation RParenLoc,
1157                                              bool WarnMultipleSelectors) {
1158   ObjCMethodDecl *Method = LookupInstanceMethodInGlobalPool(Sel,
1159                              SourceRange(LParenLoc, RParenLoc));
1160   if (!Method)
1161     Method = LookupFactoryMethodInGlobalPool(Sel,
1162                                           SourceRange(LParenLoc, RParenLoc));
1163   if (!Method) {
1164     if (const ObjCMethodDecl *OM = SelectorsForTypoCorrection(Sel)) {
1165       Selector MatchedSel = OM->getSelector();
1166       SourceRange SelectorRange(LParenLoc.getLocWithOffset(1),
1167                                 RParenLoc.getLocWithOffset(-1));
1168       Diag(SelLoc, diag::warn_undeclared_selector_with_typo)
1169         << Sel << MatchedSel
1170         << FixItHint::CreateReplacement(SelectorRange, MatchedSel.getAsString());
1171
1172     } else
1173         Diag(SelLoc, diag::warn_undeclared_selector) << Sel;
1174   } else
1175     DiagnoseMismatchedSelectors(*this, AtLoc, Method, LParenLoc, RParenLoc,
1176                                 WarnMultipleSelectors);
1177
1178   if (Method &&
1179       Method->getImplementationControl() != ObjCMethodDecl::Optional &&
1180       !getSourceManager().isInSystemHeader(Method->getLocation()))
1181     ReferencedSelectors.insert(std::make_pair(Sel, AtLoc));
1182
1183   // In ARC, forbid the user from using @selector for
1184   // retain/release/autorelease/dealloc/retainCount.
1185   if (getLangOpts().ObjCAutoRefCount) {
1186     switch (Sel.getMethodFamily()) {
1187     case OMF_retain:
1188     case OMF_release:
1189     case OMF_autorelease:
1190     case OMF_retainCount:
1191     case OMF_dealloc:
1192       Diag(AtLoc, diag::err_arc_illegal_selector) <<
1193         Sel << SourceRange(LParenLoc, RParenLoc);
1194       break;
1195
1196     case OMF_None:
1197     case OMF_alloc:
1198     case OMF_copy:
1199     case OMF_finalize:
1200     case OMF_init:
1201     case OMF_mutableCopy:
1202     case OMF_new:
1203     case OMF_self:
1204     case OMF_initialize:
1205     case OMF_performSelector:
1206       break;
1207     }
1208   }
1209   QualType Ty = Context.getObjCSelType();
1210   return new (Context) ObjCSelectorExpr(Ty, Sel, AtLoc, RParenLoc);
1211 }
1212
1213 ExprResult Sema::ParseObjCProtocolExpression(IdentifierInfo *ProtocolId,
1214                                              SourceLocation AtLoc,
1215                                              SourceLocation ProtoLoc,
1216                                              SourceLocation LParenLoc,
1217                                              SourceLocation ProtoIdLoc,
1218                                              SourceLocation RParenLoc) {
1219   ObjCProtocolDecl* PDecl = LookupProtocol(ProtocolId, ProtoIdLoc);
1220   if (!PDecl) {
1221     Diag(ProtoLoc, diag::err_undeclared_protocol) << ProtocolId;
1222     return true;
1223   }
1224   if (PDecl->hasDefinition())
1225     PDecl = PDecl->getDefinition();
1226
1227   QualType Ty = Context.getObjCProtoType();
1228   if (Ty.isNull())
1229     return true;
1230   Ty = Context.getObjCObjectPointerType(Ty);
1231   return new (Context) ObjCProtocolExpr(Ty, PDecl, AtLoc, ProtoIdLoc, RParenLoc);
1232 }
1233
1234 /// Try to capture an implicit reference to 'self'.
1235 ObjCMethodDecl *Sema::tryCaptureObjCSelf(SourceLocation Loc) {
1236   DeclContext *DC = getFunctionLevelDeclContext();
1237
1238   // If we're not in an ObjC method, error out.  Note that, unlike the
1239   // C++ case, we don't require an instance method --- class methods
1240   // still have a 'self', and we really do still need to capture it!
1241   ObjCMethodDecl *method = dyn_cast<ObjCMethodDecl>(DC);
1242   if (!method)
1243     return nullptr;
1244
1245   tryCaptureVariable(method->getSelfDecl(), Loc);
1246
1247   return method;
1248 }
1249
1250 static QualType stripObjCInstanceType(ASTContext &Context, QualType T) {
1251   QualType origType = T;
1252   if (auto nullability = AttributedType::stripOuterNullability(T)) {
1253     if (T == Context.getObjCInstanceType()) {
1254       return Context.getAttributedType(
1255                AttributedType::getNullabilityAttrKind(*nullability),
1256                Context.getObjCIdType(),
1257                Context.getObjCIdType());
1258     }
1259
1260     return origType;
1261   }
1262
1263   if (T == Context.getObjCInstanceType())
1264     return Context.getObjCIdType();
1265
1266   return origType;
1267 }
1268
1269 /// Determine the result type of a message send based on the receiver type,
1270 /// method, and the kind of message send.
1271 ///
1272 /// This is the "base" result type, which will still need to be adjusted
1273 /// to account for nullability.
1274 static QualType getBaseMessageSendResultType(Sema &S,
1275                                              QualType ReceiverType,
1276                                              ObjCMethodDecl *Method,
1277                                              bool isClassMessage,
1278                                              bool isSuperMessage) {
1279   assert(Method && "Must have a method");
1280   if (!Method->hasRelatedResultType())
1281     return Method->getSendResultType(ReceiverType);
1282
1283   ASTContext &Context = S.Context;
1284
1285   // Local function that transfers the nullability of the method's
1286   // result type to the returned result.
1287   auto transferNullability = [&](QualType type) -> QualType {
1288     // If the method's result type has nullability, extract it.
1289     if (auto nullability = Method->getSendResultType(ReceiverType)
1290                              ->getNullability(Context)){
1291       // Strip off any outer nullability sugar from the provided type.
1292       (void)AttributedType::stripOuterNullability(type);
1293
1294       // Form a new attributed type using the method result type's nullability.
1295       return Context.getAttributedType(
1296                AttributedType::getNullabilityAttrKind(*nullability),
1297                type,
1298                type);
1299     }
1300
1301     return type;
1302   };
1303
1304   // If a method has a related return type:
1305   //   - if the method found is an instance method, but the message send
1306   //     was a class message send, T is the declared return type of the method
1307   //     found
1308   if (Method->isInstanceMethod() && isClassMessage)
1309     return stripObjCInstanceType(Context,
1310                                  Method->getSendResultType(ReceiverType));
1311
1312   //   - if the receiver is super, T is a pointer to the class of the
1313   //     enclosing method definition
1314   if (isSuperMessage) {
1315     if (ObjCMethodDecl *CurMethod = S.getCurMethodDecl())
1316       if (ObjCInterfaceDecl *Class = CurMethod->getClassInterface()) {
1317         return transferNullability(
1318                  Context.getObjCObjectPointerType(
1319                    Context.getObjCInterfaceType(Class)));
1320       }
1321   }
1322
1323   //   - if the receiver is the name of a class U, T is a pointer to U
1324   if (ReceiverType->getAsObjCInterfaceType())
1325     return transferNullability(Context.getObjCObjectPointerType(ReceiverType));
1326   //   - if the receiver is of type Class or qualified Class type,
1327   //     T is the declared return type of the method.
1328   if (ReceiverType->isObjCClassType() ||
1329       ReceiverType->isObjCQualifiedClassType())
1330     return stripObjCInstanceType(Context,
1331                                  Method->getSendResultType(ReceiverType));
1332
1333   //   - if the receiver is id, qualified id, Class, or qualified Class, T
1334   //     is the receiver type, otherwise
1335   //   - T is the type of the receiver expression.
1336   return transferNullability(ReceiverType);
1337 }
1338
1339 QualType Sema::getMessageSendResultType(QualType ReceiverType,
1340                                         ObjCMethodDecl *Method,
1341                                         bool isClassMessage,
1342                                         bool isSuperMessage) {
1343   // Produce the result type.
1344   QualType resultType = getBaseMessageSendResultType(*this, ReceiverType,
1345                                                      Method,
1346                                                      isClassMessage,
1347                                                      isSuperMessage);
1348
1349   // If this is a class message, ignore the nullability of the receiver.
1350   if (isClassMessage)
1351     return resultType;
1352
1353   // Map the nullability of the result into a table index.
1354   unsigned receiverNullabilityIdx = 0;
1355   if (auto nullability = ReceiverType->getNullability(Context))
1356     receiverNullabilityIdx = 1 + static_cast<unsigned>(*nullability);
1357
1358   unsigned resultNullabilityIdx = 0;
1359   if (auto nullability = resultType->getNullability(Context))
1360     resultNullabilityIdx = 1 + static_cast<unsigned>(*nullability);
1361
1362   // The table of nullability mappings, indexed by the receiver's nullability
1363   // and then the result type's nullability.
1364   static const uint8_t None = 0;
1365   static const uint8_t NonNull = 1;
1366   static const uint8_t Nullable = 2;
1367   static const uint8_t Unspecified = 3;
1368   static const uint8_t nullabilityMap[4][4] = {
1369     //                  None        NonNull       Nullable    Unspecified
1370     /* None */        { None,       None,         Nullable,   None },
1371     /* NonNull */     { None,       NonNull,      Nullable,   Unspecified },
1372     /* Nullable */    { Nullable,   Nullable,     Nullable,   Nullable },
1373     /* Unspecified */ { None,       Unspecified,  Nullable,   Unspecified }
1374   };
1375
1376   unsigned newResultNullabilityIdx
1377     = nullabilityMap[receiverNullabilityIdx][resultNullabilityIdx];
1378   if (newResultNullabilityIdx == resultNullabilityIdx)
1379     return resultType;
1380
1381   // Strip off the existing nullability. This removes as little type sugar as
1382   // possible.
1383   do {
1384     if (auto attributed = dyn_cast<AttributedType>(resultType.getTypePtr())) {
1385       resultType = attributed->getModifiedType();
1386     } else {
1387       resultType = resultType.getDesugaredType(Context);
1388     }
1389   } while (resultType->getNullability(Context));
1390
1391   // Add nullability back if needed.
1392   if (newResultNullabilityIdx > 0) {
1393     auto newNullability
1394       = static_cast<NullabilityKind>(newResultNullabilityIdx-1);
1395     return Context.getAttributedType(
1396              AttributedType::getNullabilityAttrKind(newNullability),
1397              resultType, resultType);
1398   }
1399
1400   return resultType;
1401 }
1402
1403 /// Look for an ObjC method whose result type exactly matches the given type.
1404 static const ObjCMethodDecl *
1405 findExplicitInstancetypeDeclarer(const ObjCMethodDecl *MD,
1406                                  QualType instancetype) {
1407   if (MD->getReturnType() == instancetype)
1408     return MD;
1409
1410   // For these purposes, a method in an @implementation overrides a
1411   // declaration in the @interface.
1412   if (const ObjCImplDecl *impl =
1413         dyn_cast<ObjCImplDecl>(MD->getDeclContext())) {
1414     const ObjCContainerDecl *iface;
1415     if (const ObjCCategoryImplDecl *catImpl =
1416           dyn_cast<ObjCCategoryImplDecl>(impl)) {
1417       iface = catImpl->getCategoryDecl();
1418     } else {
1419       iface = impl->getClassInterface();
1420     }
1421
1422     const ObjCMethodDecl *ifaceMD =
1423       iface->getMethod(MD->getSelector(), MD->isInstanceMethod());
1424     if (ifaceMD) return findExplicitInstancetypeDeclarer(ifaceMD, instancetype);
1425   }
1426
1427   SmallVector<const ObjCMethodDecl *, 4> overrides;
1428   MD->getOverriddenMethods(overrides);
1429   for (unsigned i = 0, e = overrides.size(); i != e; ++i) {
1430     if (const ObjCMethodDecl *result =
1431           findExplicitInstancetypeDeclarer(overrides[i], instancetype))
1432       return result;
1433   }
1434
1435   return nullptr;
1436 }
1437
1438 void Sema::EmitRelatedResultTypeNoteForReturn(QualType destType) {
1439   // Only complain if we're in an ObjC method and the required return
1440   // type doesn't match the method's declared return type.
1441   ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(CurContext);
1442   if (!MD || !MD->hasRelatedResultType() ||
1443       Context.hasSameUnqualifiedType(destType, MD->getReturnType()))
1444     return;
1445
1446   // Look for a method overridden by this method which explicitly uses
1447   // 'instancetype'.
1448   if (const ObjCMethodDecl *overridden =
1449         findExplicitInstancetypeDeclarer(MD, Context.getObjCInstanceType())) {
1450     SourceRange range = overridden->getReturnTypeSourceRange();
1451     SourceLocation loc = range.getBegin();
1452     if (loc.isInvalid())
1453       loc = overridden->getLocation();
1454     Diag(loc, diag::note_related_result_type_explicit)
1455       << /*current method*/ 1 << range;
1456     return;
1457   }
1458
1459   // Otherwise, if we have an interesting method family, note that.
1460   // This should always trigger if the above didn't.
1461   if (ObjCMethodFamily family = MD->getMethodFamily())
1462     Diag(MD->getLocation(), diag::note_related_result_type_family)
1463       << /*current method*/ 1
1464       << family;
1465 }
1466
1467 void Sema::EmitRelatedResultTypeNote(const Expr *E) {
1468   E = E->IgnoreParenImpCasts();
1469   const ObjCMessageExpr *MsgSend = dyn_cast<ObjCMessageExpr>(E);
1470   if (!MsgSend)
1471     return;
1472
1473   const ObjCMethodDecl *Method = MsgSend->getMethodDecl();
1474   if (!Method)
1475     return;
1476
1477   if (!Method->hasRelatedResultType())
1478     return;
1479
1480   if (Context.hasSameUnqualifiedType(
1481           Method->getReturnType().getNonReferenceType(), MsgSend->getType()))
1482     return;
1483
1484   if (!Context.hasSameUnqualifiedType(Method->getReturnType(),
1485                                       Context.getObjCInstanceType()))
1486     return;
1487
1488   Diag(Method->getLocation(), diag::note_related_result_type_inferred)
1489     << Method->isInstanceMethod() << Method->getSelector()
1490     << MsgSend->getType();
1491 }
1492
1493 bool Sema::CheckMessageArgumentTypes(QualType ReceiverType,
1494                                      MultiExprArg Args,
1495                                      Selector Sel,
1496                                      ArrayRef<SourceLocation> SelectorLocs,
1497                                      ObjCMethodDecl *Method,
1498                                      bool isClassMessage, bool isSuperMessage,
1499                                      SourceLocation lbrac, SourceLocation rbrac,
1500                                      SourceRange RecRange,
1501                                      QualType &ReturnType, ExprValueKind &VK) {
1502   SourceLocation SelLoc;
1503   if (!SelectorLocs.empty() && SelectorLocs.front().isValid())
1504     SelLoc = SelectorLocs.front();
1505   else
1506     SelLoc = lbrac;
1507
1508   if (!Method) {
1509     // Apply default argument promotion as for (C99 6.5.2.2p6).
1510     for (unsigned i = 0, e = Args.size(); i != e; i++) {
1511       if (Args[i]->isTypeDependent())
1512         continue;
1513
1514       ExprResult result;
1515       if (getLangOpts().DebuggerSupport) {
1516         QualType paramTy; // ignored
1517         result = checkUnknownAnyArg(SelLoc, Args[i], paramTy);
1518       } else {
1519         result = DefaultArgumentPromotion(Args[i]);
1520       }
1521       if (result.isInvalid())
1522         return true;
1523       Args[i] = result.get();
1524     }
1525
1526     unsigned DiagID;
1527     if (getLangOpts().ObjCAutoRefCount)
1528       DiagID = diag::err_arc_method_not_found;
1529     else
1530       DiagID = isClassMessage ? diag::warn_class_method_not_found
1531                               : diag::warn_inst_method_not_found;
1532     if (!getLangOpts().DebuggerSupport) {
1533       const ObjCMethodDecl *OMD = SelectorsForTypoCorrection(Sel, ReceiverType);
1534       if (OMD && !OMD->isInvalidDecl()) {
1535         if (getLangOpts().ObjCAutoRefCount)
1536           DiagID = diag::err_method_not_found_with_typo;
1537         else
1538           DiagID = isClassMessage ? diag::warn_class_method_not_found_with_typo
1539                                   : diag::warn_instance_method_not_found_with_typo;
1540         Selector MatchedSel = OMD->getSelector();
1541         SourceRange SelectorRange(SelectorLocs.front(), SelectorLocs.back());
1542         if (MatchedSel.isUnarySelector())
1543           Diag(SelLoc, DiagID)
1544             << Sel<< isClassMessage << MatchedSel
1545             << FixItHint::CreateReplacement(SelectorRange, MatchedSel.getAsString());
1546         else
1547           Diag(SelLoc, DiagID) << Sel<< isClassMessage << MatchedSel;
1548       }
1549       else
1550         Diag(SelLoc, DiagID)
1551           << Sel << isClassMessage << SourceRange(SelectorLocs.front(),
1552                                                 SelectorLocs.back());
1553       // Find the class to which we are sending this message.
1554       if (ReceiverType->isObjCObjectPointerType()) {
1555         if (ObjCInterfaceDecl *ThisClass =
1556             ReceiverType->getAs<ObjCObjectPointerType>()->getInterfaceDecl()) {
1557           Diag(ThisClass->getLocation(), diag::note_receiver_class_declared);
1558           if (!RecRange.isInvalid())
1559             if (ThisClass->lookupClassMethod(Sel))
1560               Diag(RecRange.getBegin(),diag::note_receiver_expr_here)
1561                 << FixItHint::CreateReplacement(RecRange,
1562                                                 ThisClass->getNameAsString());
1563         }
1564       }
1565     }
1566
1567     // In debuggers, we want to use __unknown_anytype for these
1568     // results so that clients can cast them.
1569     if (getLangOpts().DebuggerSupport) {
1570       ReturnType = Context.UnknownAnyTy;
1571     } else {
1572       ReturnType = Context.getObjCIdType();
1573     }
1574     VK = VK_RValue;
1575     return false;
1576   }
1577
1578   ReturnType = getMessageSendResultType(ReceiverType, Method, isClassMessage,
1579                                         isSuperMessage);
1580   VK = Expr::getValueKindForType(Method->getReturnType());
1581
1582   unsigned NumNamedArgs = Sel.getNumArgs();
1583   // Method might have more arguments than selector indicates. This is due
1584   // to addition of c-style arguments in method.
1585   if (Method->param_size() > Sel.getNumArgs())
1586     NumNamedArgs = Method->param_size();
1587   // FIXME. This need be cleaned up.
1588   if (Args.size() < NumNamedArgs) {
1589     Diag(SelLoc, diag::err_typecheck_call_too_few_args)
1590       << 2 << NumNamedArgs << static_cast<unsigned>(Args.size());
1591     return false;
1592   }
1593
1594   // Compute the set of type arguments to be substituted into each parameter
1595   // type.
1596   Optional<ArrayRef<QualType>> typeArgs
1597     = ReceiverType->getObjCSubstitutions(Method->getDeclContext());
1598   bool IsError = false;
1599   for (unsigned i = 0; i < NumNamedArgs; i++) {
1600     // We can't do any type-checking on a type-dependent argument.
1601     if (Args[i]->isTypeDependent())
1602       continue;
1603
1604     Expr *argExpr = Args[i];
1605
1606     ParmVarDecl *param = Method->parameters()[i];
1607     assert(argExpr && "CheckMessageArgumentTypes(): missing expression");
1608
1609     // Strip the unbridged-cast placeholder expression off unless it's
1610     // a consumed argument.
1611     if (argExpr->hasPlaceholderType(BuiltinType::ARCUnbridgedCast) &&
1612         !param->hasAttr<CFConsumedAttr>())
1613       argExpr = stripARCUnbridgedCast(argExpr);
1614
1615     // If the parameter is __unknown_anytype, infer its type
1616     // from the argument.
1617     if (param->getType() == Context.UnknownAnyTy) {
1618       QualType paramType;
1619       ExprResult argE = checkUnknownAnyArg(SelLoc, argExpr, paramType);
1620       if (argE.isInvalid()) {
1621         IsError = true;
1622       } else {
1623         Args[i] = argE.get();
1624
1625         // Update the parameter type in-place.
1626         param->setType(paramType);
1627       }
1628       continue;
1629     }
1630
1631     QualType origParamType = param->getType();
1632     QualType paramType = param->getType();
1633     if (typeArgs)
1634       paramType = paramType.substObjCTypeArgs(
1635                     Context,
1636                     *typeArgs,
1637                     ObjCSubstitutionContext::Parameter);
1638
1639     if (RequireCompleteType(argExpr->getSourceRange().getBegin(),
1640                             paramType,
1641                             diag::err_call_incomplete_argument, argExpr))
1642       return true;
1643
1644     InitializedEntity Entity
1645       = InitializedEntity::InitializeParameter(Context, param, paramType);
1646     ExprResult ArgE = PerformCopyInitialization(Entity, SourceLocation(), argExpr);
1647     if (ArgE.isInvalid())
1648       IsError = true;
1649     else {
1650       Args[i] = ArgE.getAs<Expr>();
1651
1652       // If we are type-erasing a block to a block-compatible
1653       // Objective-C pointer type, we may need to extend the lifetime
1654       // of the block object.
1655       if (typeArgs && Args[i]->isRValue() && paramType->isBlockPointerType() &&
1656           Args[i]->getType()->isBlockPointerType() &&
1657           origParamType->isObjCObjectPointerType()) {
1658         ExprResult arg = Args[i];
1659         maybeExtendBlockObject(arg);
1660         Args[i] = arg.get();
1661       }
1662     }
1663   }
1664
1665   // Promote additional arguments to variadic methods.
1666   if (Method->isVariadic()) {
1667     for (unsigned i = NumNamedArgs, e = Args.size(); i < e; ++i) {
1668       if (Args[i]->isTypeDependent())
1669         continue;
1670
1671       ExprResult Arg = DefaultVariadicArgumentPromotion(Args[i], VariadicMethod,
1672                                                         nullptr);
1673       IsError |= Arg.isInvalid();
1674       Args[i] = Arg.get();
1675     }
1676   } else {
1677     // Check for extra arguments to non-variadic methods.
1678     if (Args.size() != NumNamedArgs) {
1679       Diag(Args[NumNamedArgs]->getLocStart(),
1680            diag::err_typecheck_call_too_many_args)
1681         << 2 /*method*/ << NumNamedArgs << static_cast<unsigned>(Args.size())
1682         << Method->getSourceRange()
1683         << SourceRange(Args[NumNamedArgs]->getLocStart(),
1684                        Args.back()->getLocEnd());
1685     }
1686   }
1687
1688   DiagnoseSentinelCalls(Method, SelLoc, Args);
1689
1690   // Do additional checkings on method.
1691   IsError |= CheckObjCMethodCall(
1692       Method, SelLoc, makeArrayRef(Args.data(), Args.size()));
1693
1694   return IsError;
1695 }
1696
1697 bool Sema::isSelfExpr(Expr *RExpr) {
1698   // 'self' is objc 'self' in an objc method only.
1699   ObjCMethodDecl *Method =
1700       dyn_cast_or_null<ObjCMethodDecl>(CurContext->getNonClosureAncestor());
1701   return isSelfExpr(RExpr, Method);
1702 }
1703
1704 bool Sema::isSelfExpr(Expr *receiver, const ObjCMethodDecl *method) {
1705   if (!method) return false;
1706
1707   receiver = receiver->IgnoreParenLValueCasts();
1708   if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(receiver))
1709     if (DRE->getDecl() == method->getSelfDecl())
1710       return true;
1711   return false;
1712 }
1713
1714 /// LookupMethodInType - Look up a method in an ObjCObjectType.
1715 ObjCMethodDecl *Sema::LookupMethodInObjectType(Selector sel, QualType type,
1716                                                bool isInstance) {
1717   const ObjCObjectType *objType = type->castAs<ObjCObjectType>();
1718   if (ObjCInterfaceDecl *iface = objType->getInterface()) {
1719     // Look it up in the main interface (and categories, etc.)
1720     if (ObjCMethodDecl *method = iface->lookupMethod(sel, isInstance))
1721       return method;
1722
1723     // Okay, look for "private" methods declared in any
1724     // @implementations we've seen.
1725     if (ObjCMethodDecl *method = iface->lookupPrivateMethod(sel, isInstance))
1726       return method;
1727   }
1728
1729   // Check qualifiers.
1730   for (const auto *I : objType->quals())
1731     if (ObjCMethodDecl *method = I->lookupMethod(sel, isInstance))
1732       return method;
1733
1734   return nullptr;
1735 }
1736
1737 /// LookupMethodInQualifiedType - Lookups up a method in protocol qualifier
1738 /// list of a qualified objective pointer type.
1739 ObjCMethodDecl *Sema::LookupMethodInQualifiedType(Selector Sel,
1740                                               const ObjCObjectPointerType *OPT,
1741                                               bool Instance)
1742 {
1743   ObjCMethodDecl *MD = nullptr;
1744   for (const auto *PROTO : OPT->quals()) {
1745     if ((MD = PROTO->lookupMethod(Sel, Instance))) {
1746       return MD;
1747     }
1748   }
1749   return nullptr;
1750 }
1751
1752 /// HandleExprPropertyRefExpr - Handle foo.bar where foo is a pointer to an
1753 /// objective C interface.  This is a property reference expression.
1754 ExprResult Sema::
1755 HandleExprPropertyRefExpr(const ObjCObjectPointerType *OPT,
1756                           Expr *BaseExpr, SourceLocation OpLoc,
1757                           DeclarationName MemberName,
1758                           SourceLocation MemberLoc,
1759                           SourceLocation SuperLoc, QualType SuperType,
1760                           bool Super) {
1761   const ObjCInterfaceType *IFaceT = OPT->getInterfaceType();
1762   ObjCInterfaceDecl *IFace = IFaceT->getDecl();
1763
1764   if (!MemberName.isIdentifier()) {
1765     Diag(MemberLoc, diag::err_invalid_property_name)
1766       << MemberName << QualType(OPT, 0);
1767     return ExprError();
1768   }
1769
1770   IdentifierInfo *Member = MemberName.getAsIdentifierInfo();
1771
1772   SourceRange BaseRange = Super? SourceRange(SuperLoc)
1773                                : BaseExpr->getSourceRange();
1774   if (RequireCompleteType(MemberLoc, OPT->getPointeeType(),
1775                           diag::err_property_not_found_forward_class,
1776                           MemberName, BaseRange))
1777     return ExprError();
1778
1779   if (ObjCPropertyDecl *PD = IFace->FindPropertyDeclaration(
1780           Member, ObjCPropertyQueryKind::OBJC_PR_query_instance)) {
1781     // Check whether we can reference this property.
1782     if (DiagnoseUseOfDecl(PD, MemberLoc))
1783       return ExprError();
1784     if (Super)
1785       return new (Context)
1786           ObjCPropertyRefExpr(PD, Context.PseudoObjectTy, VK_LValue,
1787                               OK_ObjCProperty, MemberLoc, SuperLoc, SuperType);
1788     else
1789       return new (Context)
1790           ObjCPropertyRefExpr(PD, Context.PseudoObjectTy, VK_LValue,
1791                               OK_ObjCProperty, MemberLoc, BaseExpr);
1792   }
1793   // Check protocols on qualified interfaces.
1794   for (const auto *I : OPT->quals())
1795     if (ObjCPropertyDecl *PD = I->FindPropertyDeclaration(
1796             Member, ObjCPropertyQueryKind::OBJC_PR_query_instance)) {
1797       // Check whether we can reference this property.
1798       if (DiagnoseUseOfDecl(PD, MemberLoc))
1799         return ExprError();
1800
1801       if (Super)
1802         return new (Context) ObjCPropertyRefExpr(
1803             PD, Context.PseudoObjectTy, VK_LValue, OK_ObjCProperty, MemberLoc,
1804             SuperLoc, SuperType);
1805       else
1806         return new (Context)
1807             ObjCPropertyRefExpr(PD, Context.PseudoObjectTy, VK_LValue,
1808                                 OK_ObjCProperty, MemberLoc, BaseExpr);
1809     }
1810   // If that failed, look for an "implicit" property by seeing if the nullary
1811   // selector is implemented.
1812
1813   // FIXME: The logic for looking up nullary and unary selectors should be
1814   // shared with the code in ActOnInstanceMessage.
1815
1816   Selector Sel = PP.getSelectorTable().getNullarySelector(Member);
1817   ObjCMethodDecl *Getter = IFace->lookupInstanceMethod(Sel);
1818
1819   // May be found in property's qualified list.
1820   if (!Getter)
1821     Getter = LookupMethodInQualifiedType(Sel, OPT, true);
1822
1823   // If this reference is in an @implementation, check for 'private' methods.
1824   if (!Getter)
1825     Getter = IFace->lookupPrivateMethod(Sel);
1826
1827   if (Getter) {
1828     // Check if we can reference this property.
1829     if (DiagnoseUseOfDecl(Getter, MemberLoc))
1830       return ExprError();
1831   }
1832   // If we found a getter then this may be a valid dot-reference, we
1833   // will look for the matching setter, in case it is needed.
1834   Selector SetterSel =
1835     SelectorTable::constructSetterSelector(PP.getIdentifierTable(),
1836                                            PP.getSelectorTable(), Member);
1837   ObjCMethodDecl *Setter = IFace->lookupInstanceMethod(SetterSel);
1838
1839   // May be found in property's qualified list.
1840   if (!Setter)
1841     Setter = LookupMethodInQualifiedType(SetterSel, OPT, true);
1842
1843   if (!Setter) {
1844     // If this reference is in an @implementation, also check for 'private'
1845     // methods.
1846     Setter = IFace->lookupPrivateMethod(SetterSel);
1847   }
1848
1849   if (Setter && DiagnoseUseOfDecl(Setter, MemberLoc))
1850     return ExprError();
1851
1852   // Special warning if member name used in a property-dot for a setter accessor
1853   // does not use a property with same name; e.g. obj.X = ... for a property with
1854   // name 'x'.
1855   if (Setter && Setter->isImplicit() && Setter->isPropertyAccessor() &&
1856       !IFace->FindPropertyDeclaration(
1857           Member, ObjCPropertyQueryKind::OBJC_PR_query_instance)) {
1858       if (const ObjCPropertyDecl *PDecl = Setter->findPropertyDecl()) {
1859         // Do not warn if user is using property-dot syntax to make call to
1860         // user named setter.
1861         if (!(PDecl->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_setter))
1862           Diag(MemberLoc,
1863                diag::warn_property_access_suggest)
1864           << MemberName << QualType(OPT, 0) << PDecl->getName()
1865           << FixItHint::CreateReplacement(MemberLoc, PDecl->getName());
1866       }
1867   }
1868
1869   if (Getter || Setter) {
1870     if (Super)
1871       return new (Context)
1872           ObjCPropertyRefExpr(Getter, Setter, Context.PseudoObjectTy, VK_LValue,
1873                               OK_ObjCProperty, MemberLoc, SuperLoc, SuperType);
1874     else
1875       return new (Context)
1876           ObjCPropertyRefExpr(Getter, Setter, Context.PseudoObjectTy, VK_LValue,
1877                               OK_ObjCProperty, MemberLoc, BaseExpr);
1878
1879   }
1880
1881   // Attempt to correct for typos in property names.
1882   if (TypoCorrection Corrected =
1883           CorrectTypo(DeclarationNameInfo(MemberName, MemberLoc),
1884                       LookupOrdinaryName, nullptr, nullptr,
1885                       llvm::make_unique<DeclFilterCCC<ObjCPropertyDecl>>(),
1886                       CTK_ErrorRecovery, IFace, false, OPT)) {
1887     DeclarationName TypoResult = Corrected.getCorrection();
1888     if (TypoResult.isIdentifier() &&
1889         TypoResult.getAsIdentifierInfo() == Member) {
1890       // There is no need to try the correction if it is the same.
1891       NamedDecl *ChosenDecl =
1892         Corrected.isKeyword() ? nullptr : Corrected.getFoundDecl();
1893       if (ChosenDecl && isa<ObjCPropertyDecl>(ChosenDecl))
1894         if (cast<ObjCPropertyDecl>(ChosenDecl)->isClassProperty()) {
1895           // This is a class property, we should not use the instance to
1896           // access it.
1897           Diag(MemberLoc, diag::err_class_property_found) << MemberName
1898           << OPT->getInterfaceDecl()->getName()
1899           << FixItHint::CreateReplacement(BaseExpr->getSourceRange(),
1900                                           OPT->getInterfaceDecl()->getName());
1901           return ExprError();
1902         }
1903     } else {
1904       diagnoseTypo(Corrected, PDiag(diag::err_property_not_found_suggest)
1905                                 << MemberName << QualType(OPT, 0));
1906       return HandleExprPropertyRefExpr(OPT, BaseExpr, OpLoc,
1907                                        TypoResult, MemberLoc,
1908                                        SuperLoc, SuperType, Super);
1909     }
1910   }
1911   ObjCInterfaceDecl *ClassDeclared;
1912   if (ObjCIvarDecl *Ivar =
1913       IFace->lookupInstanceVariable(Member, ClassDeclared)) {
1914     QualType T = Ivar->getType();
1915     if (const ObjCObjectPointerType * OBJPT =
1916         T->getAsObjCInterfacePointerType()) {
1917       if (RequireCompleteType(MemberLoc, OBJPT->getPointeeType(),
1918                               diag::err_property_not_as_forward_class,
1919                               MemberName, BaseExpr))
1920         return ExprError();
1921     }
1922     Diag(MemberLoc,
1923          diag::err_ivar_access_using_property_syntax_suggest)
1924     << MemberName << QualType(OPT, 0) << Ivar->getDeclName()
1925     << FixItHint::CreateReplacement(OpLoc, "->");
1926     return ExprError();
1927   }
1928
1929   Diag(MemberLoc, diag::err_property_not_found)
1930     << MemberName << QualType(OPT, 0);
1931   if (Setter)
1932     Diag(Setter->getLocation(), diag::note_getter_unavailable)
1933           << MemberName << BaseExpr->getSourceRange();
1934   return ExprError();
1935 }
1936
1937 ExprResult Sema::
1938 ActOnClassPropertyRefExpr(IdentifierInfo &receiverName,
1939                           IdentifierInfo &propertyName,
1940                           SourceLocation receiverNameLoc,
1941                           SourceLocation propertyNameLoc) {
1942
1943   IdentifierInfo *receiverNamePtr = &receiverName;
1944   ObjCInterfaceDecl *IFace = getObjCInterfaceDecl(receiverNamePtr,
1945                                                   receiverNameLoc);
1946
1947   QualType SuperType;
1948   if (!IFace) {
1949     // If the "receiver" is 'super' in a method, handle it as an expression-like
1950     // property reference.
1951     if (receiverNamePtr->isStr("super")) {
1952       if (ObjCMethodDecl *CurMethod = tryCaptureObjCSelf(receiverNameLoc)) {
1953         if (auto classDecl = CurMethod->getClassInterface()) {
1954           SuperType = QualType(classDecl->getSuperClassType(), 0);
1955           if (CurMethod->isInstanceMethod()) {
1956             if (SuperType.isNull()) {
1957               // The current class does not have a superclass.
1958               Diag(receiverNameLoc, diag::err_root_class_cannot_use_super)
1959                 << CurMethod->getClassInterface()->getIdentifier();
1960               return ExprError();
1961             }
1962             QualType T = Context.getObjCObjectPointerType(SuperType);
1963
1964             return HandleExprPropertyRefExpr(T->castAs<ObjCObjectPointerType>(),
1965                                              /*BaseExpr*/nullptr,
1966                                              SourceLocation()/*OpLoc*/,
1967                                              &propertyName,
1968                                              propertyNameLoc,
1969                                              receiverNameLoc, T, true);
1970           }
1971
1972           // Otherwise, if this is a class method, try dispatching to our
1973           // superclass.
1974           IFace = CurMethod->getClassInterface()->getSuperClass();
1975         }
1976       }
1977     }
1978
1979     if (!IFace) {
1980       Diag(receiverNameLoc, diag::err_expected_either) << tok::identifier
1981                                                        << tok::l_paren;
1982       return ExprError();
1983     }
1984   }
1985
1986   Selector GetterSel;
1987   Selector SetterSel;
1988   if (auto PD = IFace->FindPropertyDeclaration(
1989           &propertyName, ObjCPropertyQueryKind::OBJC_PR_query_class)) {
1990     GetterSel = PD->getGetterName();
1991     SetterSel = PD->getSetterName();
1992   } else {
1993     GetterSel = PP.getSelectorTable().getNullarySelector(&propertyName);
1994     SetterSel = SelectorTable::constructSetterSelector(
1995         PP.getIdentifierTable(), PP.getSelectorTable(), &propertyName);
1996   }
1997
1998   // Search for a declared property first.
1999   ObjCMethodDecl *Getter = IFace->lookupClassMethod(GetterSel);
2000
2001   // If this reference is in an @implementation, check for 'private' methods.
2002   if (!Getter)
2003     Getter = IFace->lookupPrivateClassMethod(GetterSel);
2004
2005   if (Getter) {
2006     // FIXME: refactor/share with ActOnMemberReference().
2007     // Check if we can reference this property.
2008     if (DiagnoseUseOfDecl(Getter, propertyNameLoc))
2009       return ExprError();
2010   }
2011
2012   // Look for the matching setter, in case it is needed.
2013   ObjCMethodDecl *Setter = IFace->lookupClassMethod(SetterSel);
2014   if (!Setter) {
2015     // If this reference is in an @implementation, also check for 'private'
2016     // methods.
2017     Setter = IFace->lookupPrivateClassMethod(SetterSel);
2018   }
2019   // Look through local category implementations associated with the class.
2020   if (!Setter)
2021     Setter = IFace->getCategoryClassMethod(SetterSel);
2022
2023   if (Setter && DiagnoseUseOfDecl(Setter, propertyNameLoc))
2024     return ExprError();
2025
2026   if (Getter || Setter) {
2027     if (!SuperType.isNull())
2028       return new (Context)
2029           ObjCPropertyRefExpr(Getter, Setter, Context.PseudoObjectTy, VK_LValue,
2030                               OK_ObjCProperty, propertyNameLoc, receiverNameLoc,
2031                               SuperType);
2032
2033     return new (Context) ObjCPropertyRefExpr(
2034         Getter, Setter, Context.PseudoObjectTy, VK_LValue, OK_ObjCProperty,
2035         propertyNameLoc, receiverNameLoc, IFace);
2036   }
2037   return ExprError(Diag(propertyNameLoc, diag::err_property_not_found)
2038                      << &propertyName << Context.getObjCInterfaceType(IFace));
2039 }
2040
2041 namespace {
2042
2043 class ObjCInterfaceOrSuperCCC : public CorrectionCandidateCallback {
2044  public:
2045   ObjCInterfaceOrSuperCCC(ObjCMethodDecl *Method) {
2046     // Determine whether "super" is acceptable in the current context.
2047     if (Method && Method->getClassInterface())
2048       WantObjCSuper = Method->getClassInterface()->getSuperClass();
2049   }
2050
2051   bool ValidateCandidate(const TypoCorrection &candidate) override {
2052     return candidate.getCorrectionDeclAs<ObjCInterfaceDecl>() ||
2053         candidate.isKeyword("super");
2054   }
2055 };
2056
2057 } // end anonymous namespace
2058
2059 Sema::ObjCMessageKind Sema::getObjCMessageKind(Scope *S,
2060                                                IdentifierInfo *Name,
2061                                                SourceLocation NameLoc,
2062                                                bool IsSuper,
2063                                                bool HasTrailingDot,
2064                                                ParsedType &ReceiverType) {
2065   ReceiverType = nullptr;
2066
2067   // If the identifier is "super" and there is no trailing dot, we're
2068   // messaging super. If the identifier is "super" and there is a
2069   // trailing dot, it's an instance message.
2070   if (IsSuper && S->isInObjcMethodScope())
2071     return HasTrailingDot? ObjCInstanceMessage : ObjCSuperMessage;
2072
2073   LookupResult Result(*this, Name, NameLoc, LookupOrdinaryName);
2074   LookupName(Result, S);
2075
2076   switch (Result.getResultKind()) {
2077   case LookupResult::NotFound:
2078     // Normal name lookup didn't find anything. If we're in an
2079     // Objective-C method, look for ivars. If we find one, we're done!
2080     // FIXME: This is a hack. Ivar lookup should be part of normal
2081     // lookup.
2082     if (ObjCMethodDecl *Method = getCurMethodDecl()) {
2083       if (!Method->getClassInterface()) {
2084         // Fall back: let the parser try to parse it as an instance message.
2085         return ObjCInstanceMessage;
2086       }
2087
2088       ObjCInterfaceDecl *ClassDeclared;
2089       if (Method->getClassInterface()->lookupInstanceVariable(Name,
2090                                                               ClassDeclared))
2091         return ObjCInstanceMessage;
2092     }
2093
2094     // Break out; we'll perform typo correction below.
2095     break;
2096
2097   case LookupResult::NotFoundInCurrentInstantiation:
2098   case LookupResult::FoundOverloaded:
2099   case LookupResult::FoundUnresolvedValue:
2100   case LookupResult::Ambiguous:
2101     Result.suppressDiagnostics();
2102     return ObjCInstanceMessage;
2103
2104   case LookupResult::Found: {
2105     // If the identifier is a class or not, and there is a trailing dot,
2106     // it's an instance message.
2107     if (HasTrailingDot)
2108       return ObjCInstanceMessage;
2109     // We found something. If it's a type, then we have a class
2110     // message. Otherwise, it's an instance message.
2111     NamedDecl *ND = Result.getFoundDecl();
2112     QualType T;
2113     if (ObjCInterfaceDecl *Class = dyn_cast<ObjCInterfaceDecl>(ND))
2114       T = Context.getObjCInterfaceType(Class);
2115     else if (TypeDecl *Type = dyn_cast<TypeDecl>(ND)) {
2116       T = Context.getTypeDeclType(Type);
2117       DiagnoseUseOfDecl(Type, NameLoc);
2118     }
2119     else
2120       return ObjCInstanceMessage;
2121
2122     //  We have a class message, and T is the type we're
2123     //  messaging. Build source-location information for it.
2124     TypeSourceInfo *TSInfo = Context.getTrivialTypeSourceInfo(T, NameLoc);
2125     ReceiverType = CreateParsedType(T, TSInfo);
2126     return ObjCClassMessage;
2127   }
2128   }
2129
2130   if (TypoCorrection Corrected = CorrectTypo(
2131           Result.getLookupNameInfo(), Result.getLookupKind(), S, nullptr,
2132           llvm::make_unique<ObjCInterfaceOrSuperCCC>(getCurMethodDecl()),
2133           CTK_ErrorRecovery, nullptr, false, nullptr, false)) {
2134     if (Corrected.isKeyword()) {
2135       // If we've found the keyword "super" (the only keyword that would be
2136       // returned by CorrectTypo), this is a send to super.
2137       diagnoseTypo(Corrected,
2138                    PDiag(diag::err_unknown_receiver_suggest) << Name);
2139       return ObjCSuperMessage;
2140     } else if (ObjCInterfaceDecl *Class =
2141                    Corrected.getCorrectionDeclAs<ObjCInterfaceDecl>()) {
2142       // If we found a declaration, correct when it refers to an Objective-C
2143       // class.
2144       diagnoseTypo(Corrected,
2145                    PDiag(diag::err_unknown_receiver_suggest) << Name);
2146       QualType T = Context.getObjCInterfaceType(Class);
2147       TypeSourceInfo *TSInfo = Context.getTrivialTypeSourceInfo(T, NameLoc);
2148       ReceiverType = CreateParsedType(T, TSInfo);
2149       return ObjCClassMessage;
2150     }
2151   }
2152
2153   // Fall back: let the parser try to parse it as an instance message.
2154   return ObjCInstanceMessage;
2155 }
2156
2157 ExprResult Sema::ActOnSuperMessage(Scope *S,
2158                                    SourceLocation SuperLoc,
2159                                    Selector Sel,
2160                                    SourceLocation LBracLoc,
2161                                    ArrayRef<SourceLocation> SelectorLocs,
2162                                    SourceLocation RBracLoc,
2163                                    MultiExprArg Args) {
2164   // Determine whether we are inside a method or not.
2165   ObjCMethodDecl *Method = tryCaptureObjCSelf(SuperLoc);
2166   if (!Method) {
2167     Diag(SuperLoc, diag::err_invalid_receiver_to_message_super);
2168     return ExprError();
2169   }
2170
2171   ObjCInterfaceDecl *Class = Method->getClassInterface();
2172   if (!Class) {
2173     Diag(SuperLoc, diag::err_no_super_class_message)
2174       << Method->getDeclName();
2175     return ExprError();
2176   }
2177
2178   QualType SuperTy(Class->getSuperClassType(), 0);
2179   if (SuperTy.isNull()) {
2180     // The current class does not have a superclass.
2181     Diag(SuperLoc, diag::err_root_class_cannot_use_super)
2182       << Class->getIdentifier();
2183     return ExprError();
2184   }
2185
2186   // We are in a method whose class has a superclass, so 'super'
2187   // is acting as a keyword.
2188   if (Method->getSelector() == Sel)
2189     getCurFunction()->ObjCShouldCallSuper = false;
2190
2191   if (Method->isInstanceMethod()) {
2192     // Since we are in an instance method, this is an instance
2193     // message to the superclass instance.
2194     SuperTy = Context.getObjCObjectPointerType(SuperTy);
2195     return BuildInstanceMessage(nullptr, SuperTy, SuperLoc,
2196                                 Sel, /*Method=*/nullptr,
2197                                 LBracLoc, SelectorLocs, RBracLoc, Args);
2198   }
2199
2200   // Since we are in a class method, this is a class message to
2201   // the superclass.
2202   return BuildClassMessage(/*ReceiverTypeInfo=*/nullptr,
2203                            SuperTy,
2204                            SuperLoc, Sel, /*Method=*/nullptr,
2205                            LBracLoc, SelectorLocs, RBracLoc, Args);
2206 }
2207
2208 ExprResult Sema::BuildClassMessageImplicit(QualType ReceiverType,
2209                                            bool isSuperReceiver,
2210                                            SourceLocation Loc,
2211                                            Selector Sel,
2212                                            ObjCMethodDecl *Method,
2213                                            MultiExprArg Args) {
2214   TypeSourceInfo *receiverTypeInfo = nullptr;
2215   if (!ReceiverType.isNull())
2216     receiverTypeInfo = Context.getTrivialTypeSourceInfo(ReceiverType);
2217
2218   return BuildClassMessage(receiverTypeInfo, ReceiverType,
2219                           /*SuperLoc=*/isSuperReceiver ? Loc : SourceLocation(),
2220                            Sel, Method, Loc, Loc, Loc, Args,
2221                            /*isImplicit=*/true);
2222 }
2223
2224 static void applyCocoaAPICheck(Sema &S, const ObjCMessageExpr *Msg,
2225                                unsigned DiagID,
2226                                bool (*refactor)(const ObjCMessageExpr *,
2227                                               const NSAPI &, edit::Commit &)) {
2228   SourceLocation MsgLoc = Msg->getExprLoc();
2229   if (S.Diags.isIgnored(DiagID, MsgLoc))
2230     return;
2231
2232   SourceManager &SM = S.SourceMgr;
2233   edit::Commit ECommit(SM, S.LangOpts);
2234   if (refactor(Msg,*S.NSAPIObj, ECommit)) {
2235     DiagnosticBuilder Builder = S.Diag(MsgLoc, DiagID)
2236                         << Msg->getSelector() << Msg->getSourceRange();
2237     // FIXME: Don't emit diagnostic at all if fixits are non-commitable.
2238     if (!ECommit.isCommitable())
2239       return;
2240     for (edit::Commit::edit_iterator
2241            I = ECommit.edit_begin(), E = ECommit.edit_end(); I != E; ++I) {
2242       const edit::Commit::Edit &Edit = *I;
2243       switch (Edit.Kind) {
2244       case edit::Commit::Act_Insert:
2245         Builder.AddFixItHint(FixItHint::CreateInsertion(Edit.OrigLoc,
2246                                                         Edit.Text,
2247                                                         Edit.BeforePrev));
2248         break;
2249       case edit::Commit::Act_InsertFromRange:
2250         Builder.AddFixItHint(
2251             FixItHint::CreateInsertionFromRange(Edit.OrigLoc,
2252                                                 Edit.getInsertFromRange(SM),
2253                                                 Edit.BeforePrev));
2254         break;
2255       case edit::Commit::Act_Remove:
2256         Builder.AddFixItHint(FixItHint::CreateRemoval(Edit.getFileRange(SM)));
2257         break;
2258       }
2259     }
2260   }
2261 }
2262
2263 static void checkCocoaAPI(Sema &S, const ObjCMessageExpr *Msg) {
2264   applyCocoaAPICheck(S, Msg, diag::warn_objc_redundant_literal_use,
2265                      edit::rewriteObjCRedundantCallWithLiteral);
2266 }
2267
2268 static void checkFoundationAPI(Sema &S, SourceLocation Loc,
2269                                const ObjCMethodDecl *Method,
2270                                ArrayRef<Expr *> Args, QualType ReceiverType,
2271                                bool IsClassObjectCall) {
2272   // Check if this is a performSelector method that uses a selector that returns
2273   // a record or a vector type.
2274   if (Method->getSelector().getMethodFamily() != OMF_performSelector ||
2275       Args.empty())
2276     return;
2277   const auto *SE = dyn_cast<ObjCSelectorExpr>(Args[0]->IgnoreParens());
2278   if (!SE)
2279     return;
2280   ObjCMethodDecl *ImpliedMethod;
2281   if (!IsClassObjectCall) {
2282     const auto *OPT = ReceiverType->getAs<ObjCObjectPointerType>();
2283     if (!OPT || !OPT->getInterfaceDecl())
2284       return;
2285     ImpliedMethod =
2286         OPT->getInterfaceDecl()->lookupInstanceMethod(SE->getSelector());
2287     if (!ImpliedMethod)
2288       ImpliedMethod =
2289           OPT->getInterfaceDecl()->lookupPrivateMethod(SE->getSelector());
2290   } else {
2291     const auto *IT = ReceiverType->getAs<ObjCInterfaceType>();
2292     if (!IT)
2293       return;
2294     ImpliedMethod = IT->getDecl()->lookupClassMethod(SE->getSelector());
2295     if (!ImpliedMethod)
2296       ImpliedMethod =
2297           IT->getDecl()->lookupPrivateClassMethod(SE->getSelector());
2298   }
2299   if (!ImpliedMethod)
2300     return;
2301   QualType Ret = ImpliedMethod->getReturnType();
2302   if (Ret->isRecordType() || Ret->isVectorType() || Ret->isExtVectorType()) {
2303     QualType Ret = ImpliedMethod->getReturnType();
2304     S.Diag(Loc, diag::warn_objc_unsafe_perform_selector)
2305         << Method->getSelector()
2306         << (!Ret->isRecordType()
2307                 ? /*Vector*/ 2
2308                 : Ret->isUnionType() ? /*Union*/ 1 : /*Struct*/ 0);
2309     S.Diag(ImpliedMethod->getLocStart(),
2310            diag::note_objc_unsafe_perform_selector_method_declared_here)
2311         << ImpliedMethod->getSelector() << Ret;
2312   }
2313 }
2314
2315 /// \brief Diagnose use of %s directive in an NSString which is being passed
2316 /// as formatting string to formatting method.
2317 static void
2318 DiagnoseCStringFormatDirectiveInObjCAPI(Sema &S,
2319                                         ObjCMethodDecl *Method,
2320                                         Selector Sel,
2321                                         Expr **Args, unsigned NumArgs) {
2322   unsigned Idx = 0;
2323   bool Format = false;
2324   ObjCStringFormatFamily SFFamily = Sel.getStringFormatFamily();
2325   if (SFFamily == ObjCStringFormatFamily::SFF_NSString) {
2326     Idx = 0;
2327     Format = true;
2328   }
2329   else if (Method) {
2330     for (const auto *I : Method->specific_attrs<FormatAttr>()) {
2331       if (S.GetFormatNSStringIdx(I, Idx)) {
2332         Format = true;
2333         break;
2334       }
2335     }
2336   }
2337   if (!Format || NumArgs <= Idx)
2338     return;
2339
2340   Expr *FormatExpr = Args[Idx];
2341   if (ObjCStringLiteral *OSL =
2342       dyn_cast<ObjCStringLiteral>(FormatExpr->IgnoreParenImpCasts())) {
2343     StringLiteral *FormatString = OSL->getString();
2344     if (S.FormatStringHasSArg(FormatString)) {
2345       S.Diag(FormatExpr->getExprLoc(), diag::warn_objc_cdirective_format_string)
2346         << "%s" << 0 << 0;
2347       if (Method)
2348         S.Diag(Method->getLocation(), diag::note_method_declared_at)
2349           << Method->getDeclName();
2350     }
2351   }
2352 }
2353
2354 /// \brief Build an Objective-C class message expression.
2355 ///
2356 /// This routine takes care of both normal class messages and
2357 /// class messages to the superclass.
2358 ///
2359 /// \param ReceiverTypeInfo Type source information that describes the
2360 /// receiver of this message. This may be NULL, in which case we are
2361 /// sending to the superclass and \p SuperLoc must be a valid source
2362 /// location.
2363
2364 /// \param ReceiverType The type of the object receiving the
2365 /// message. When \p ReceiverTypeInfo is non-NULL, this is the same
2366 /// type as that refers to. For a superclass send, this is the type of
2367 /// the superclass.
2368 ///
2369 /// \param SuperLoc The location of the "super" keyword in a
2370 /// superclass message.
2371 ///
2372 /// \param Sel The selector to which the message is being sent.
2373 ///
2374 /// \param Method The method that this class message is invoking, if
2375 /// already known.
2376 ///
2377 /// \param LBracLoc The location of the opening square bracket ']'.
2378 ///
2379 /// \param RBracLoc The location of the closing square bracket ']'.
2380 ///
2381 /// \param ArgsIn The message arguments.
2382 ExprResult Sema::BuildClassMessage(TypeSourceInfo *ReceiverTypeInfo,
2383                                    QualType ReceiverType,
2384                                    SourceLocation SuperLoc,
2385                                    Selector Sel,
2386                                    ObjCMethodDecl *Method,
2387                                    SourceLocation LBracLoc,
2388                                    ArrayRef<SourceLocation> SelectorLocs,
2389                                    SourceLocation RBracLoc,
2390                                    MultiExprArg ArgsIn,
2391                                    bool isImplicit) {
2392   SourceLocation Loc = SuperLoc.isValid()? SuperLoc
2393     : ReceiverTypeInfo->getTypeLoc().getSourceRange().getBegin();
2394   if (LBracLoc.isInvalid()) {
2395     Diag(Loc, diag::err_missing_open_square_message_send)
2396       << FixItHint::CreateInsertion(Loc, "[");
2397     LBracLoc = Loc;
2398   }
2399   SourceLocation SelLoc;
2400   if (!SelectorLocs.empty() && SelectorLocs.front().isValid())
2401     SelLoc = SelectorLocs.front();
2402   else
2403     SelLoc = Loc;
2404
2405   if (ReceiverType->isDependentType()) {
2406     // If the receiver type is dependent, we can't type-check anything
2407     // at this point. Build a dependent expression.
2408     unsigned NumArgs = ArgsIn.size();
2409     Expr **Args = ArgsIn.data();
2410     assert(SuperLoc.isInvalid() && "Message to super with dependent type");
2411     return ObjCMessageExpr::Create(
2412         Context, ReceiverType, VK_RValue, LBracLoc, ReceiverTypeInfo, Sel,
2413         SelectorLocs, /*Method=*/nullptr, makeArrayRef(Args, NumArgs), RBracLoc,
2414         isImplicit);
2415   }
2416
2417   // Find the class to which we are sending this message.
2418   ObjCInterfaceDecl *Class = nullptr;
2419   const ObjCObjectType *ClassType = ReceiverType->getAs<ObjCObjectType>();
2420   if (!ClassType || !(Class = ClassType->getInterface())) {
2421     Diag(Loc, diag::err_invalid_receiver_class_message)
2422       << ReceiverType;
2423     return ExprError();
2424   }
2425   assert(Class && "We don't know which class we're messaging?");
2426   // objc++ diagnoses during typename annotation.
2427   if (!getLangOpts().CPlusPlus)
2428     (void)DiagnoseUseOfDecl(Class, SelLoc);
2429   // Find the method we are messaging.
2430   if (!Method) {
2431     SourceRange TypeRange
2432       = SuperLoc.isValid()? SourceRange(SuperLoc)
2433                           : ReceiverTypeInfo->getTypeLoc().getSourceRange();
2434     if (RequireCompleteType(Loc, Context.getObjCInterfaceType(Class),
2435                             (getLangOpts().ObjCAutoRefCount
2436                                ? diag::err_arc_receiver_forward_class
2437                                : diag::warn_receiver_forward_class),
2438                             TypeRange)) {
2439       // A forward class used in messaging is treated as a 'Class'
2440       Method = LookupFactoryMethodInGlobalPool(Sel,
2441                                                SourceRange(LBracLoc, RBracLoc));
2442       if (Method && !getLangOpts().ObjCAutoRefCount)
2443         Diag(Method->getLocation(), diag::note_method_sent_forward_class)
2444           << Method->getDeclName();
2445     }
2446     if (!Method)
2447       Method = Class->lookupClassMethod(Sel);
2448
2449     // If we have an implementation in scope, check "private" methods.
2450     if (!Method)
2451       Method = Class->lookupPrivateClassMethod(Sel);
2452
2453     if (Method && DiagnoseUseOfDecl(Method, SelLoc))
2454       return ExprError();
2455   }
2456
2457   // Check the argument types and determine the result type.
2458   QualType ReturnType;
2459   ExprValueKind VK = VK_RValue;
2460
2461   unsigned NumArgs = ArgsIn.size();
2462   Expr **Args = ArgsIn.data();
2463   if (CheckMessageArgumentTypes(ReceiverType, MultiExprArg(Args, NumArgs),
2464                                 Sel, SelectorLocs,
2465                                 Method, true,
2466                                 SuperLoc.isValid(), LBracLoc, RBracLoc,
2467                                 SourceRange(),
2468                                 ReturnType, VK))
2469     return ExprError();
2470
2471   if (Method && !Method->getReturnType()->isVoidType() &&
2472       RequireCompleteType(LBracLoc, Method->getReturnType(),
2473                           diag::err_illegal_message_expr_incomplete_type))
2474     return ExprError();
2475
2476   // Warn about explicit call of +initialize on its own class. But not on 'super'.
2477   if (Method && Method->getMethodFamily() == OMF_initialize) {
2478     if (!SuperLoc.isValid()) {
2479       const ObjCInterfaceDecl *ID =
2480         dyn_cast<ObjCInterfaceDecl>(Method->getDeclContext());
2481       if (ID == Class) {
2482         Diag(Loc, diag::warn_direct_initialize_call);
2483         Diag(Method->getLocation(), diag::note_method_declared_at)
2484           << Method->getDeclName();
2485       }
2486     }
2487     else if (ObjCMethodDecl *CurMeth = getCurMethodDecl()) {
2488       // [super initialize] is allowed only within an +initialize implementation
2489       if (CurMeth->getMethodFamily() != OMF_initialize) {
2490         Diag(Loc, diag::warn_direct_super_initialize_call);
2491         Diag(Method->getLocation(), diag::note_method_declared_at)
2492           << Method->getDeclName();
2493         Diag(CurMeth->getLocation(), diag::note_method_declared_at)
2494         << CurMeth->getDeclName();
2495       }
2496     }
2497   }
2498
2499   DiagnoseCStringFormatDirectiveInObjCAPI(*this, Method, Sel, Args, NumArgs);
2500
2501   // Construct the appropriate ObjCMessageExpr.
2502   ObjCMessageExpr *Result;
2503   if (SuperLoc.isValid())
2504     Result = ObjCMessageExpr::Create(Context, ReturnType, VK, LBracLoc,
2505                                      SuperLoc, /*IsInstanceSuper=*/false,
2506                                      ReceiverType, Sel, SelectorLocs,
2507                                      Method, makeArrayRef(Args, NumArgs),
2508                                      RBracLoc, isImplicit);
2509   else {
2510     Result = ObjCMessageExpr::Create(Context, ReturnType, VK, LBracLoc,
2511                                      ReceiverTypeInfo, Sel, SelectorLocs,
2512                                      Method, makeArrayRef(Args, NumArgs),
2513                                      RBracLoc, isImplicit);
2514     if (!isImplicit)
2515       checkCocoaAPI(*this, Result);
2516   }
2517   if (Method)
2518     checkFoundationAPI(*this, SelLoc, Method, makeArrayRef(Args, NumArgs),
2519                        ReceiverType, /*IsClassObjectCall=*/true);
2520   return MaybeBindToTemporary(Result);
2521 }
2522
2523 // ActOnClassMessage - used for both unary and keyword messages.
2524 // ArgExprs is optional - if it is present, the number of expressions
2525 // is obtained from Sel.getNumArgs().
2526 ExprResult Sema::ActOnClassMessage(Scope *S,
2527                                    ParsedType Receiver,
2528                                    Selector Sel,
2529                                    SourceLocation LBracLoc,
2530                                    ArrayRef<SourceLocation> SelectorLocs,
2531                                    SourceLocation RBracLoc,
2532                                    MultiExprArg Args) {
2533   TypeSourceInfo *ReceiverTypeInfo;
2534   QualType ReceiverType = GetTypeFromParser(Receiver, &ReceiverTypeInfo);
2535   if (ReceiverType.isNull())
2536     return ExprError();
2537
2538   if (!ReceiverTypeInfo)
2539     ReceiverTypeInfo = Context.getTrivialTypeSourceInfo(ReceiverType, LBracLoc);
2540
2541   return BuildClassMessage(ReceiverTypeInfo, ReceiverType,
2542                            /*SuperLoc=*/SourceLocation(), Sel,
2543                            /*Method=*/nullptr, LBracLoc, SelectorLocs, RBracLoc,
2544                            Args);
2545 }
2546
2547 ExprResult Sema::BuildInstanceMessageImplicit(Expr *Receiver,
2548                                               QualType ReceiverType,
2549                                               SourceLocation Loc,
2550                                               Selector Sel,
2551                                               ObjCMethodDecl *Method,
2552                                               MultiExprArg Args) {
2553   return BuildInstanceMessage(Receiver, ReceiverType,
2554                               /*SuperLoc=*/!Receiver ? Loc : SourceLocation(),
2555                               Sel, Method, Loc, Loc, Loc, Args,
2556                               /*isImplicit=*/true);
2557 }
2558
2559 static bool isMethodDeclaredInRootProtocol(Sema &S, const ObjCMethodDecl *M) {
2560   if (!S.NSAPIObj)
2561     return false;
2562   const auto *Protocol = dyn_cast<ObjCProtocolDecl>(M->getDeclContext());
2563   if (!Protocol)
2564     return false;
2565   const IdentifierInfo *II = S.NSAPIObj->getNSClassId(NSAPI::ClassId_NSObject);
2566   if (const auto *RootClass = dyn_cast_or_null<ObjCInterfaceDecl>(
2567           S.LookupSingleName(S.TUScope, II, Protocol->getLocStart(),
2568                              Sema::LookupOrdinaryName))) {
2569     for (const ObjCProtocolDecl *P : RootClass->all_referenced_protocols()) {
2570       if (P->getCanonicalDecl() == Protocol->getCanonicalDecl())
2571         return true;
2572     }
2573   }
2574   return false;
2575 }
2576
2577 /// \brief Build an Objective-C instance message expression.
2578 ///
2579 /// This routine takes care of both normal instance messages and
2580 /// instance messages to the superclass instance.
2581 ///
2582 /// \param Receiver The expression that computes the object that will
2583 /// receive this message. This may be empty, in which case we are
2584 /// sending to the superclass instance and \p SuperLoc must be a valid
2585 /// source location.
2586 ///
2587 /// \param ReceiverType The (static) type of the object receiving the
2588 /// message. When a \p Receiver expression is provided, this is the
2589 /// same type as that expression. For a superclass instance send, this
2590 /// is a pointer to the type of the superclass.
2591 ///
2592 /// \param SuperLoc The location of the "super" keyword in a
2593 /// superclass instance message.
2594 ///
2595 /// \param Sel The selector to which the message is being sent.
2596 ///
2597 /// \param Method The method that this instance message is invoking, if
2598 /// already known.
2599 ///
2600 /// \param LBracLoc The location of the opening square bracket ']'.
2601 ///
2602 /// \param RBracLoc The location of the closing square bracket ']'.
2603 ///
2604 /// \param ArgsIn The message arguments.
2605 ExprResult Sema::BuildInstanceMessage(Expr *Receiver,
2606                                       QualType ReceiverType,
2607                                       SourceLocation SuperLoc,
2608                                       Selector Sel,
2609                                       ObjCMethodDecl *Method,
2610                                       SourceLocation LBracLoc,
2611                                       ArrayRef<SourceLocation> SelectorLocs,
2612                                       SourceLocation RBracLoc,
2613                                       MultiExprArg ArgsIn,
2614                                       bool isImplicit) {
2615   assert((Receiver || SuperLoc.isValid()) && "If the Receiver is null, the "
2616                                              "SuperLoc must be valid so we can "
2617                                              "use it instead.");
2618
2619   // The location of the receiver.
2620   SourceLocation Loc = SuperLoc.isValid()? SuperLoc : Receiver->getLocStart();
2621   SourceRange RecRange =
2622       SuperLoc.isValid()? SuperLoc : Receiver->getSourceRange();
2623   SourceLocation SelLoc;
2624   if (!SelectorLocs.empty() && SelectorLocs.front().isValid())
2625     SelLoc = SelectorLocs.front();
2626   else
2627     SelLoc = Loc;
2628
2629   if (LBracLoc.isInvalid()) {
2630     Diag(Loc, diag::err_missing_open_square_message_send)
2631       << FixItHint::CreateInsertion(Loc, "[");
2632     LBracLoc = Loc;
2633   }
2634
2635   // If we have a receiver expression, perform appropriate promotions
2636   // and determine receiver type.
2637   if (Receiver) {
2638     if (Receiver->hasPlaceholderType()) {
2639       ExprResult Result;
2640       if (Receiver->getType() == Context.UnknownAnyTy)
2641         Result = forceUnknownAnyToType(Receiver, Context.getObjCIdType());
2642       else
2643         Result = CheckPlaceholderExpr(Receiver);
2644       if (Result.isInvalid()) return ExprError();
2645       Receiver = Result.get();
2646     }
2647
2648     if (Receiver->isTypeDependent()) {
2649       // If the receiver is type-dependent, we can't type-check anything
2650       // at this point. Build a dependent expression.
2651       unsigned NumArgs = ArgsIn.size();
2652       Expr **Args = ArgsIn.data();
2653       assert(SuperLoc.isInvalid() && "Message to super with dependent type");
2654       return ObjCMessageExpr::Create(
2655           Context, Context.DependentTy, VK_RValue, LBracLoc, Receiver, Sel,
2656           SelectorLocs, /*Method=*/nullptr, makeArrayRef(Args, NumArgs),
2657           RBracLoc, isImplicit);
2658     }
2659
2660     // If necessary, apply function/array conversion to the receiver.
2661     // C99 6.7.5.3p[7,8].
2662     ExprResult Result = DefaultFunctionArrayLvalueConversion(Receiver);
2663     if (Result.isInvalid())
2664       return ExprError();
2665     Receiver = Result.get();
2666     ReceiverType = Receiver->getType();
2667
2668     // If the receiver is an ObjC pointer, a block pointer, or an
2669     // __attribute__((NSObject)) pointer, we don't need to do any
2670     // special conversion in order to look up a receiver.
2671     if (ReceiverType->isObjCRetainableType()) {
2672       // do nothing
2673     } else if (!getLangOpts().ObjCAutoRefCount &&
2674                !Context.getObjCIdType().isNull() &&
2675                (ReceiverType->isPointerType() ||
2676                 ReceiverType->isIntegerType())) {
2677       // Implicitly convert integers and pointers to 'id' but emit a warning.
2678       // But not in ARC.
2679       Diag(Loc, diag::warn_bad_receiver_type)
2680         << ReceiverType
2681         << Receiver->getSourceRange();
2682       if (ReceiverType->isPointerType()) {
2683         Receiver = ImpCastExprToType(Receiver, Context.getObjCIdType(),
2684                                      CK_CPointerToObjCPointerCast).get();
2685       } else {
2686         // TODO: specialized warning on null receivers?
2687         bool IsNull = Receiver->isNullPointerConstant(Context,
2688                                               Expr::NPC_ValueDependentIsNull);
2689         CastKind Kind = IsNull ? CK_NullToPointer : CK_IntegralToPointer;
2690         Receiver = ImpCastExprToType(Receiver, Context.getObjCIdType(),
2691                                      Kind).get();
2692       }
2693       ReceiverType = Receiver->getType();
2694     } else if (getLangOpts().CPlusPlus) {
2695       // The receiver must be a complete type.
2696       if (RequireCompleteType(Loc, Receiver->getType(),
2697                               diag::err_incomplete_receiver_type))
2698         return ExprError();
2699
2700       ExprResult result = PerformContextuallyConvertToObjCPointer(Receiver);
2701       if (result.isUsable()) {
2702         Receiver = result.get();
2703         ReceiverType = Receiver->getType();
2704       }
2705     }
2706   }
2707
2708   // There's a somewhat weird interaction here where we assume that we
2709   // won't actually have a method unless we also don't need to do some
2710   // of the more detailed type-checking on the receiver.
2711
2712   if (!Method) {
2713     // Handle messages to id and __kindof types (where we use the
2714     // global method pool).
2715     const ObjCObjectType *typeBound = nullptr;
2716     bool receiverIsIdLike = ReceiverType->isObjCIdOrObjectKindOfType(Context,
2717                                                                      typeBound);
2718     if (receiverIsIdLike || ReceiverType->isBlockPointerType() ||
2719         (Receiver && Context.isObjCNSObjectType(Receiver->getType()))) {
2720       SmallVector<ObjCMethodDecl*, 4> Methods;
2721       // If we have a type bound, further filter the methods.
2722       CollectMultipleMethodsInGlobalPool(Sel, Methods, true/*InstanceFirst*/,
2723                                          true/*CheckTheOther*/, typeBound);
2724       if (!Methods.empty()) {
2725         // We choose the first method as the initial candidate, then try to
2726         // select a better one.
2727         Method = Methods[0];
2728
2729         if (ObjCMethodDecl *BestMethod =
2730             SelectBestMethod(Sel, ArgsIn, Method->isInstanceMethod(), Methods))
2731           Method = BestMethod;
2732
2733         if (!AreMultipleMethodsInGlobalPool(Sel, Method,
2734                                             SourceRange(LBracLoc, RBracLoc),
2735                                             receiverIsIdLike, Methods))
2736            DiagnoseUseOfDecl(Method, SelLoc);
2737       }
2738     } else if (ReceiverType->isObjCClassOrClassKindOfType() ||
2739                ReceiverType->isObjCQualifiedClassType()) {
2740       // Handle messages to Class.
2741       // We allow sending a message to a qualified Class ("Class<foo>"), which
2742       // is ok as long as one of the protocols implements the selector (if not,
2743       // warn).
2744       if (!ReceiverType->isObjCClassOrClassKindOfType()) {
2745         const ObjCObjectPointerType *QClassTy
2746           = ReceiverType->getAsObjCQualifiedClassType();
2747         // Search protocols for class methods.
2748         Method = LookupMethodInQualifiedType(Sel, QClassTy, false);
2749         if (!Method) {
2750           Method = LookupMethodInQualifiedType(Sel, QClassTy, true);
2751           // warn if instance method found for a Class message.
2752           if (Method && !isMethodDeclaredInRootProtocol(*this, Method)) {
2753             Diag(SelLoc, diag::warn_instance_method_on_class_found)
2754               << Method->getSelector() << Sel;
2755             Diag(Method->getLocation(), diag::note_method_declared_at)
2756               << Method->getDeclName();
2757           }
2758         }
2759       } else {
2760         if (ObjCMethodDecl *CurMeth = getCurMethodDecl()) {
2761           if (ObjCInterfaceDecl *ClassDecl = CurMeth->getClassInterface()) {
2762             // First check the public methods in the class interface.
2763             Method = ClassDecl->lookupClassMethod(Sel);
2764
2765             if (!Method)
2766               Method = ClassDecl->lookupPrivateClassMethod(Sel);
2767           }
2768           if (Method && DiagnoseUseOfDecl(Method, SelLoc))
2769             return ExprError();
2770         }
2771         if (!Method) {
2772           // If not messaging 'self', look for any factory method named 'Sel'.
2773           if (!Receiver || !isSelfExpr(Receiver)) {
2774             // If no class (factory) method was found, check if an _instance_
2775             // method of the same name exists in the root class only.
2776             SmallVector<ObjCMethodDecl*, 4> Methods;
2777             CollectMultipleMethodsInGlobalPool(Sel, Methods,
2778                                                false/*InstanceFirst*/,
2779                                                true/*CheckTheOther*/);
2780             if (!Methods.empty()) {
2781               // We choose the first method as the initial candidate, then try
2782               // to select a better one.
2783               Method = Methods[0];
2784
2785               // If we find an instance method, emit waring.
2786               if (Method->isInstanceMethod()) {
2787                 if (const ObjCInterfaceDecl *ID =
2788                     dyn_cast<ObjCInterfaceDecl>(Method->getDeclContext())) {
2789                   if (ID->getSuperClass())
2790                     Diag(SelLoc, diag::warn_root_inst_method_not_found)
2791                         << Sel << SourceRange(LBracLoc, RBracLoc);
2792                 }
2793               }
2794
2795              if (ObjCMethodDecl *BestMethod =
2796                  SelectBestMethod(Sel, ArgsIn, Method->isInstanceMethod(),
2797                                   Methods))
2798                Method = BestMethod;
2799             }
2800           }
2801         }
2802       }
2803     } else {
2804       ObjCInterfaceDecl *ClassDecl = nullptr;
2805
2806       // We allow sending a message to a qualified ID ("id<foo>"), which is ok as
2807       // long as one of the protocols implements the selector (if not, warn).
2808       // And as long as message is not deprecated/unavailable (warn if it is).
2809       if (const ObjCObjectPointerType *QIdTy
2810                                    = ReceiverType->getAsObjCQualifiedIdType()) {
2811         // Search protocols for instance methods.
2812         Method = LookupMethodInQualifiedType(Sel, QIdTy, true);
2813         if (!Method)
2814           Method = LookupMethodInQualifiedType(Sel, QIdTy, false);
2815         if (Method && DiagnoseUseOfDecl(Method, SelLoc))
2816           return ExprError();
2817       } else if (const ObjCObjectPointerType *OCIType
2818                    = ReceiverType->getAsObjCInterfacePointerType()) {
2819         // We allow sending a message to a pointer to an interface (an object).
2820         ClassDecl = OCIType->getInterfaceDecl();
2821
2822         // Try to complete the type. Under ARC, this is a hard error from which
2823         // we don't try to recover.
2824         // FIXME: In the non-ARC case, this will still be a hard error if the
2825         // definition is found in a module that's not visible.
2826         const ObjCInterfaceDecl *forwardClass = nullptr;
2827         if (RequireCompleteType(Loc, OCIType->getPointeeType(),
2828               getLangOpts().ObjCAutoRefCount
2829                 ? diag::err_arc_receiver_forward_instance
2830                 : diag::warn_receiver_forward_instance,
2831                                 Receiver? Receiver->getSourceRange()
2832                                         : SourceRange(SuperLoc))) {
2833           if (getLangOpts().ObjCAutoRefCount)
2834             return ExprError();
2835
2836           forwardClass = OCIType->getInterfaceDecl();
2837           Diag(Receiver ? Receiver->getLocStart()
2838                         : SuperLoc, diag::note_receiver_is_id);
2839           Method = nullptr;
2840         } else {
2841           Method = ClassDecl->lookupInstanceMethod(Sel);
2842         }
2843
2844         if (!Method)
2845           // Search protocol qualifiers.
2846           Method = LookupMethodInQualifiedType(Sel, OCIType, true);
2847
2848         if (!Method) {
2849           // If we have implementations in scope, check "private" methods.
2850           Method = ClassDecl->lookupPrivateMethod(Sel);
2851
2852           if (!Method && getLangOpts().ObjCAutoRefCount) {
2853             Diag(SelLoc, diag::err_arc_may_not_respond)
2854               << OCIType->getPointeeType() << Sel << RecRange
2855               << SourceRange(SelectorLocs.front(), SelectorLocs.back());
2856             return ExprError();
2857           }
2858
2859           if (!Method && (!Receiver || !isSelfExpr(Receiver))) {
2860             // If we still haven't found a method, look in the global pool. This
2861             // behavior isn't very desirable, however we need it for GCC
2862             // compatibility. FIXME: should we deviate??
2863             if (OCIType->qual_empty()) {
2864               SmallVector<ObjCMethodDecl*, 4> Methods;
2865               CollectMultipleMethodsInGlobalPool(Sel, Methods,
2866                                                  true/*InstanceFirst*/,
2867                                                  false/*CheckTheOther*/);
2868               if (!Methods.empty()) {
2869                 // We choose the first method as the initial candidate, then try
2870                 // to select a better one.
2871                 Method = Methods[0];
2872
2873                 if (ObjCMethodDecl *BestMethod =
2874                     SelectBestMethod(Sel, ArgsIn, Method->isInstanceMethod(),
2875                                      Methods))
2876                   Method = BestMethod;
2877
2878                 AreMultipleMethodsInGlobalPool(Sel, Method,
2879                                                SourceRange(LBracLoc, RBracLoc),
2880                                                true/*receiverIdOrClass*/,
2881                                                Methods);
2882               }
2883               if (Method && !forwardClass)
2884                 Diag(SelLoc, diag::warn_maynot_respond)
2885                   << OCIType->getInterfaceDecl()->getIdentifier()
2886                   << Sel << RecRange;
2887             }
2888           }
2889         }
2890         if (Method && DiagnoseUseOfDecl(Method, SelLoc, forwardClass))
2891           return ExprError();
2892       } else {
2893         // Reject other random receiver types (e.g. structs).
2894         Diag(Loc, diag::err_bad_receiver_type)
2895           << ReceiverType << Receiver->getSourceRange();
2896         return ExprError();
2897       }
2898     }
2899   }
2900
2901   FunctionScopeInfo *DIFunctionScopeInfo =
2902     (Method && Method->getMethodFamily() == OMF_init)
2903       ? getEnclosingFunction() : nullptr;
2904
2905   if (DIFunctionScopeInfo &&
2906       DIFunctionScopeInfo->ObjCIsDesignatedInit &&
2907       (SuperLoc.isValid() || isSelfExpr(Receiver))) {
2908     bool isDesignatedInitChain = false;
2909     if (SuperLoc.isValid()) {
2910       if (const ObjCObjectPointerType *
2911             OCIType = ReceiverType->getAsObjCInterfacePointerType()) {
2912         if (const ObjCInterfaceDecl *ID = OCIType->getInterfaceDecl()) {
2913           // Either we know this is a designated initializer or we
2914           // conservatively assume it because we don't know for sure.
2915           if (!ID->declaresOrInheritsDesignatedInitializers() ||
2916               ID->isDesignatedInitializer(Sel)) {
2917             isDesignatedInitChain = true;
2918             DIFunctionScopeInfo->ObjCWarnForNoDesignatedInitChain = false;
2919           }
2920         }
2921       }
2922     }
2923     if (!isDesignatedInitChain) {
2924       const ObjCMethodDecl *InitMethod = nullptr;
2925       bool isDesignated =
2926         getCurMethodDecl()->isDesignatedInitializerForTheInterface(&InitMethod);
2927       assert(isDesignated && InitMethod);
2928       (void)isDesignated;
2929       Diag(SelLoc, SuperLoc.isValid() ?
2930              diag::warn_objc_designated_init_non_designated_init_call :
2931              diag::warn_objc_designated_init_non_super_designated_init_call);
2932       Diag(InitMethod->getLocation(),
2933            diag::note_objc_designated_init_marked_here);
2934     }
2935   }
2936
2937   if (DIFunctionScopeInfo &&
2938       DIFunctionScopeInfo->ObjCIsSecondaryInit &&
2939       (SuperLoc.isValid() || isSelfExpr(Receiver))) {
2940     if (SuperLoc.isValid()) {
2941       Diag(SelLoc, diag::warn_objc_secondary_init_super_init_call);
2942     } else {
2943       DIFunctionScopeInfo->ObjCWarnForNoInitDelegation = false;
2944     }
2945   }
2946
2947   // Check the message arguments.
2948   unsigned NumArgs = ArgsIn.size();
2949   Expr **Args = ArgsIn.data();
2950   QualType ReturnType;
2951   ExprValueKind VK = VK_RValue;
2952   bool ClassMessage = (ReceiverType->isObjCClassType() ||
2953                        ReceiverType->isObjCQualifiedClassType());
2954   if (CheckMessageArgumentTypes(ReceiverType, MultiExprArg(Args, NumArgs),
2955                                 Sel, SelectorLocs, Method,
2956                                 ClassMessage, SuperLoc.isValid(),
2957                                 LBracLoc, RBracLoc, RecRange, ReturnType, VK))
2958     return ExprError();
2959
2960   if (Method && !Method->getReturnType()->isVoidType() &&
2961       RequireCompleteType(LBracLoc, Method->getReturnType(),
2962                           diag::err_illegal_message_expr_incomplete_type))
2963     return ExprError();
2964
2965   // In ARC, forbid the user from sending messages to
2966   // retain/release/autorelease/dealloc/retainCount explicitly.
2967   if (getLangOpts().ObjCAutoRefCount) {
2968     ObjCMethodFamily family =
2969       (Method ? Method->getMethodFamily() : Sel.getMethodFamily());
2970     switch (family) {
2971     case OMF_init:
2972       if (Method)
2973         checkInitMethod(Method, ReceiverType);
2974
2975     case OMF_None:
2976     case OMF_alloc:
2977     case OMF_copy:
2978     case OMF_finalize:
2979     case OMF_mutableCopy:
2980     case OMF_new:
2981     case OMF_self:
2982     case OMF_initialize:
2983       break;
2984
2985     case OMF_dealloc:
2986     case OMF_retain:
2987     case OMF_release:
2988     case OMF_autorelease:
2989     case OMF_retainCount:
2990       Diag(SelLoc, diag::err_arc_illegal_explicit_message)
2991         << Sel << RecRange;
2992       break;
2993
2994     case OMF_performSelector:
2995       if (Method && NumArgs >= 1) {
2996         if (const auto *SelExp =
2997                 dyn_cast<ObjCSelectorExpr>(Args[0]->IgnoreParens())) {
2998           Selector ArgSel = SelExp->getSelector();
2999           ObjCMethodDecl *SelMethod =
3000             LookupInstanceMethodInGlobalPool(ArgSel,
3001                                              SelExp->getSourceRange());
3002           if (!SelMethod)
3003             SelMethod =
3004               LookupFactoryMethodInGlobalPool(ArgSel,
3005                                               SelExp->getSourceRange());
3006           if (SelMethod) {
3007             ObjCMethodFamily SelFamily = SelMethod->getMethodFamily();
3008             switch (SelFamily) {
3009               case OMF_alloc:
3010               case OMF_copy:
3011               case OMF_mutableCopy:
3012               case OMF_new:
3013               case OMF_init:
3014                 // Issue error, unless ns_returns_not_retained.
3015                 if (!SelMethod->hasAttr<NSReturnsNotRetainedAttr>()) {
3016                   // selector names a +1 method
3017                   Diag(SelLoc,
3018                        diag::err_arc_perform_selector_retains);
3019                   Diag(SelMethod->getLocation(), diag::note_method_declared_at)
3020                     << SelMethod->getDeclName();
3021                 }
3022                 break;
3023               default:
3024                 // +0 call. OK. unless ns_returns_retained.
3025                 if (SelMethod->hasAttr<NSReturnsRetainedAttr>()) {
3026                   // selector names a +1 method
3027                   Diag(SelLoc,
3028                        diag::err_arc_perform_selector_retains);
3029                   Diag(SelMethod->getLocation(), diag::note_method_declared_at)
3030                     << SelMethod->getDeclName();
3031                 }
3032                 break;
3033             }
3034           }
3035         } else {
3036           // error (may leak).
3037           Diag(SelLoc, diag::warn_arc_perform_selector_leaks);
3038           Diag(Args[0]->getExprLoc(), diag::note_used_here);
3039         }
3040       }
3041       break;
3042     }
3043   }
3044
3045   DiagnoseCStringFormatDirectiveInObjCAPI(*this, Method, Sel, Args, NumArgs);
3046
3047   // Construct the appropriate ObjCMessageExpr instance.
3048   ObjCMessageExpr *Result;
3049   if (SuperLoc.isValid())
3050     Result = ObjCMessageExpr::Create(Context, ReturnType, VK, LBracLoc,
3051                                      SuperLoc,  /*IsInstanceSuper=*/true,
3052                                      ReceiverType, Sel, SelectorLocs, Method,
3053                                      makeArrayRef(Args, NumArgs), RBracLoc,
3054                                      isImplicit);
3055   else {
3056     Result = ObjCMessageExpr::Create(Context, ReturnType, VK, LBracLoc,
3057                                      Receiver, Sel, SelectorLocs, Method,
3058                                      makeArrayRef(Args, NumArgs), RBracLoc,
3059                                      isImplicit);
3060     if (!isImplicit)
3061       checkCocoaAPI(*this, Result);
3062   }
3063   if (Method) {
3064     bool IsClassObjectCall = ClassMessage;
3065     // 'self' message receivers in class methods should be treated as message
3066     // sends to the class object in order for the semantic checks to be
3067     // performed correctly. Messages to 'super' already count as class messages,
3068     // so they don't need to be handled here.
3069     if (Receiver && isSelfExpr(Receiver)) {
3070       if (const auto *OPT = ReceiverType->getAs<ObjCObjectPointerType>()) {
3071         if (OPT->getObjectType()->isObjCClass()) {
3072           if (const auto *CurMeth = getCurMethodDecl()) {
3073             IsClassObjectCall = true;
3074             ReceiverType =
3075                 Context.getObjCInterfaceType(CurMeth->getClassInterface());
3076           }
3077         }
3078       }
3079     }
3080     checkFoundationAPI(*this, SelLoc, Method, makeArrayRef(Args, NumArgs),
3081                        ReceiverType, IsClassObjectCall);
3082   }
3083
3084   if (getLangOpts().ObjCAutoRefCount) {
3085     // In ARC, annotate delegate init calls.
3086     if (Result->getMethodFamily() == OMF_init &&
3087         (SuperLoc.isValid() || isSelfExpr(Receiver))) {
3088       // Only consider init calls *directly* in init implementations,
3089       // not within blocks.
3090       ObjCMethodDecl *method = dyn_cast<ObjCMethodDecl>(CurContext);
3091       if (method && method->getMethodFamily() == OMF_init) {
3092         // The implicit assignment to self means we also don't want to
3093         // consume the result.
3094         Result->setDelegateInitCall(true);
3095         return Result;
3096       }
3097     }
3098
3099     // In ARC, check for message sends which are likely to introduce
3100     // retain cycles.
3101     checkRetainCycles(Result);
3102   }
3103
3104   if (getLangOpts().ObjCWeak) {
3105     if (!isImplicit && Method) {
3106       if (const ObjCPropertyDecl *Prop = Method->findPropertyDecl()) {
3107         bool IsWeak =
3108           Prop->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_weak;
3109         if (!IsWeak && Sel.isUnarySelector())
3110           IsWeak = ReturnType.getObjCLifetime() & Qualifiers::OCL_Weak;
3111         if (IsWeak &&
3112             !Diags.isIgnored(diag::warn_arc_repeated_use_of_weak, LBracLoc))
3113           getCurFunction()->recordUseOfWeak(Result, Prop);
3114       }
3115     }
3116   }
3117
3118   CheckObjCCircularContainer(Result);
3119
3120   return MaybeBindToTemporary(Result);
3121 }
3122
3123 static void RemoveSelectorFromWarningCache(Sema &S, Expr* Arg) {
3124   if (ObjCSelectorExpr *OSE =
3125       dyn_cast<ObjCSelectorExpr>(Arg->IgnoreParenCasts())) {
3126     Selector Sel = OSE->getSelector();
3127     SourceLocation Loc = OSE->getAtLoc();
3128     auto Pos = S.ReferencedSelectors.find(Sel);
3129     if (Pos != S.ReferencedSelectors.end() && Pos->second == Loc)
3130       S.ReferencedSelectors.erase(Pos);
3131   }
3132 }
3133
3134 // ActOnInstanceMessage - used for both unary and keyword messages.
3135 // ArgExprs is optional - if it is present, the number of expressions
3136 // is obtained from Sel.getNumArgs().
3137 ExprResult Sema::ActOnInstanceMessage(Scope *S,
3138                                       Expr *Receiver,
3139                                       Selector Sel,
3140                                       SourceLocation LBracLoc,
3141                                       ArrayRef<SourceLocation> SelectorLocs,
3142                                       SourceLocation RBracLoc,
3143                                       MultiExprArg Args) {
3144   if (!Receiver)
3145     return ExprError();
3146
3147   // A ParenListExpr can show up while doing error recovery with invalid code.
3148   if (isa<ParenListExpr>(Receiver)) {
3149     ExprResult Result = MaybeConvertParenListExprToParenExpr(S, Receiver);
3150     if (Result.isInvalid()) return ExprError();
3151     Receiver = Result.get();
3152   }
3153
3154   if (RespondsToSelectorSel.isNull()) {
3155     IdentifierInfo *SelectorId = &Context.Idents.get("respondsToSelector");
3156     RespondsToSelectorSel = Context.Selectors.getUnarySelector(SelectorId);
3157   }
3158   if (Sel == RespondsToSelectorSel)
3159     RemoveSelectorFromWarningCache(*this, Args[0]);
3160
3161   return BuildInstanceMessage(Receiver, Receiver->getType(),
3162                               /*SuperLoc=*/SourceLocation(), Sel,
3163                               /*Method=*/nullptr, LBracLoc, SelectorLocs,
3164                               RBracLoc, Args);
3165 }
3166
3167 enum ARCConversionTypeClass {
3168   /// int, void, struct A
3169   ACTC_none,
3170
3171   /// id, void (^)()
3172   ACTC_retainable,
3173
3174   /// id*, id***, void (^*)(),
3175   ACTC_indirectRetainable,
3176
3177   /// void* might be a normal C type, or it might a CF type.
3178   ACTC_voidPtr,
3179
3180   /// struct A*
3181   ACTC_coreFoundation
3182 };
3183
3184 static bool isAnyRetainable(ARCConversionTypeClass ACTC) {
3185   return (ACTC == ACTC_retainable ||
3186           ACTC == ACTC_coreFoundation ||
3187           ACTC == ACTC_voidPtr);
3188 }
3189
3190 static bool isAnyCLike(ARCConversionTypeClass ACTC) {
3191   return ACTC == ACTC_none ||
3192          ACTC == ACTC_voidPtr ||
3193          ACTC == ACTC_coreFoundation;
3194 }
3195
3196 static ARCConversionTypeClass classifyTypeForARCConversion(QualType type) {
3197   bool isIndirect = false;
3198
3199   // Ignore an outermost reference type.
3200   if (const ReferenceType *ref = type->getAs<ReferenceType>()) {
3201     type = ref->getPointeeType();
3202     isIndirect = true;
3203   }
3204
3205   // Drill through pointers and arrays recursively.
3206   while (true) {
3207     if (const PointerType *ptr = type->getAs<PointerType>()) {
3208       type = ptr->getPointeeType();
3209
3210       // The first level of pointer may be the innermost pointer on a CF type.
3211       if (!isIndirect) {
3212         if (type->isVoidType()) return ACTC_voidPtr;
3213         if (type->isRecordType()) return ACTC_coreFoundation;
3214       }
3215     } else if (const ArrayType *array = type->getAsArrayTypeUnsafe()) {
3216       type = QualType(array->getElementType()->getBaseElementTypeUnsafe(), 0);
3217     } else {
3218       break;
3219     }
3220     isIndirect = true;
3221   }
3222
3223   if (isIndirect) {
3224     if (type->isObjCARCBridgableType())
3225       return ACTC_indirectRetainable;
3226     return ACTC_none;
3227   }
3228
3229   if (type->isObjCARCBridgableType())
3230     return ACTC_retainable;
3231
3232   return ACTC_none;
3233 }
3234
3235 namespace {
3236   /// A result from the cast checker.
3237   enum ACCResult {
3238     /// Cannot be casted.
3239     ACC_invalid,
3240
3241     /// Can be safely retained or not retained.
3242     ACC_bottom,
3243
3244     /// Can be casted at +0.
3245     ACC_plusZero,
3246
3247     /// Can be casted at +1.
3248     ACC_plusOne
3249   };
3250   ACCResult merge(ACCResult left, ACCResult right) {
3251     if (left == right) return left;
3252     if (left == ACC_bottom) return right;
3253     if (right == ACC_bottom) return left;
3254     return ACC_invalid;
3255   }
3256
3257   /// A checker which white-lists certain expressions whose conversion
3258   /// to or from retainable type would otherwise be forbidden in ARC.
3259   class ARCCastChecker : public StmtVisitor<ARCCastChecker, ACCResult> {
3260     typedef StmtVisitor<ARCCastChecker, ACCResult> super;
3261
3262     ASTContext &Context;
3263     ARCConversionTypeClass SourceClass;
3264     ARCConversionTypeClass TargetClass;
3265     bool Diagnose;
3266
3267     static bool isCFType(QualType type) {
3268       // Someday this can use ns_bridged.  For now, it has to do this.
3269       return type->isCARCBridgableType();
3270     }
3271
3272   public:
3273     ARCCastChecker(ASTContext &Context, ARCConversionTypeClass source,
3274                    ARCConversionTypeClass target, bool diagnose)
3275       : Context(Context), SourceClass(source), TargetClass(target),
3276         Diagnose(diagnose) {}
3277
3278     using super::Visit;
3279     ACCResult Visit(Expr *e) {
3280       return super::Visit(e->IgnoreParens());
3281     }
3282
3283     ACCResult VisitStmt(Stmt *s) {
3284       return ACC_invalid;
3285     }
3286
3287     /// Null pointer constants can be casted however you please.
3288     ACCResult VisitExpr(Expr *e) {
3289       if (e->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNotNull))
3290         return ACC_bottom;
3291       return ACC_invalid;
3292     }
3293
3294     /// Objective-C string literals can be safely casted.
3295     ACCResult VisitObjCStringLiteral(ObjCStringLiteral *e) {
3296       // If we're casting to any retainable type, go ahead.  Global
3297       // strings are immune to retains, so this is bottom.
3298       if (isAnyRetainable(TargetClass)) return ACC_bottom;
3299
3300       return ACC_invalid;
3301     }
3302
3303     /// Look through certain implicit and explicit casts.
3304     ACCResult VisitCastExpr(CastExpr *e) {
3305       switch (e->getCastKind()) {
3306         case CK_NullToPointer:
3307           return ACC_bottom;
3308
3309         case CK_NoOp:
3310         case CK_LValueToRValue:
3311         case CK_BitCast:
3312         case CK_CPointerToObjCPointerCast:
3313         case CK_BlockPointerToObjCPointerCast:
3314         case CK_AnyPointerToBlockPointerCast:
3315           return Visit(e->getSubExpr());
3316
3317         default:
3318           return ACC_invalid;
3319       }
3320     }
3321
3322     /// Look through unary extension.
3323     ACCResult VisitUnaryExtension(UnaryOperator *e) {
3324       return Visit(e->getSubExpr());
3325     }
3326
3327     /// Ignore the LHS of a comma operator.
3328     ACCResult VisitBinComma(BinaryOperator *e) {
3329       return Visit(e->getRHS());
3330     }
3331
3332     /// Conditional operators are okay if both sides are okay.
3333     ACCResult VisitConditionalOperator(ConditionalOperator *e) {
3334       ACCResult left = Visit(e->getTrueExpr());
3335       if (left == ACC_invalid) return ACC_invalid;
3336       return merge(left, Visit(e->getFalseExpr()));
3337     }
3338
3339     /// Look through pseudo-objects.
3340     ACCResult VisitPseudoObjectExpr(PseudoObjectExpr *e) {
3341       // If we're getting here, we should always have a result.
3342       return Visit(e->getResultExpr());
3343     }
3344
3345     /// Statement expressions are okay if their result expression is okay.
3346     ACCResult VisitStmtExpr(StmtExpr *e) {
3347       return Visit(e->getSubStmt()->body_back());
3348     }
3349
3350     /// Some declaration references are okay.
3351     ACCResult VisitDeclRefExpr(DeclRefExpr *e) {
3352       VarDecl *var = dyn_cast<VarDecl>(e->getDecl());
3353       // References to global constants are okay.
3354       if (isAnyRetainable(TargetClass) &&
3355           isAnyRetainable(SourceClass) &&
3356           var &&
3357           !var->hasDefinition(Context) &&
3358           var->getType().isConstQualified()) {
3359
3360         // In system headers, they can also be assumed to be immune to retains.
3361         // These are things like 'kCFStringTransformToLatin'.
3362         if (Context.getSourceManager().isInSystemHeader(var->getLocation()))
3363           return ACC_bottom;
3364
3365         return ACC_plusZero;
3366       }
3367
3368       // Nothing else.
3369       return ACC_invalid;
3370     }
3371
3372     /// Some calls are okay.
3373     ACCResult VisitCallExpr(CallExpr *e) {
3374       if (FunctionDecl *fn = e->getDirectCallee())
3375         if (ACCResult result = checkCallToFunction(fn))
3376           return result;
3377
3378       return super::VisitCallExpr(e);
3379     }
3380
3381     ACCResult checkCallToFunction(FunctionDecl *fn) {
3382       // Require a CF*Ref return type.
3383       if (!isCFType(fn->getReturnType()))
3384         return ACC_invalid;
3385
3386       if (!isAnyRetainable(TargetClass))
3387         return ACC_invalid;
3388
3389       // Honor an explicit 'not retained' attribute.
3390       if (fn->hasAttr<CFReturnsNotRetainedAttr>())
3391         return ACC_plusZero;
3392
3393       // Honor an explicit 'retained' attribute, except that for
3394       // now we're not going to permit implicit handling of +1 results,
3395       // because it's a bit frightening.
3396       if (fn->hasAttr<CFReturnsRetainedAttr>())
3397         return Diagnose ? ACC_plusOne
3398                         : ACC_invalid; // ACC_plusOne if we start accepting this
3399
3400       // Recognize this specific builtin function, which is used by CFSTR.
3401       unsigned builtinID = fn->getBuiltinID();
3402       if (builtinID == Builtin::BI__builtin___CFStringMakeConstantString)
3403         return ACC_bottom;
3404
3405       // Otherwise, don't do anything implicit with an unaudited function.
3406       if (!fn->hasAttr<CFAuditedTransferAttr>())
3407         return ACC_invalid;
3408
3409       // Otherwise, it's +0 unless it follows the create convention.
3410       if (ento::coreFoundation::followsCreateRule(fn))
3411         return Diagnose ? ACC_plusOne
3412                         : ACC_invalid; // ACC_plusOne if we start accepting this
3413
3414       return ACC_plusZero;
3415     }
3416
3417     ACCResult VisitObjCMessageExpr(ObjCMessageExpr *e) {
3418       return checkCallToMethod(e->getMethodDecl());
3419     }
3420
3421     ACCResult VisitObjCPropertyRefExpr(ObjCPropertyRefExpr *e) {
3422       ObjCMethodDecl *method;
3423       if (e->isExplicitProperty())
3424         method = e->getExplicitProperty()->getGetterMethodDecl();
3425       else
3426         method = e->getImplicitPropertyGetter();
3427       return checkCallToMethod(method);
3428     }
3429
3430     ACCResult checkCallToMethod(ObjCMethodDecl *method) {
3431       if (!method) return ACC_invalid;
3432
3433       // Check for message sends to functions returning CF types.  We
3434       // just obey the Cocoa conventions with these, even though the
3435       // return type is CF.
3436       if (!isAnyRetainable(TargetClass) || !isCFType(method->getReturnType()))
3437         return ACC_invalid;
3438
3439       // If the method is explicitly marked not-retained, it's +0.
3440       if (method->hasAttr<CFReturnsNotRetainedAttr>())
3441         return ACC_plusZero;
3442
3443       // If the method is explicitly marked as returning retained, or its
3444       // selector follows a +1 Cocoa convention, treat it as +1.
3445       if (method->hasAttr<CFReturnsRetainedAttr>())
3446         return ACC_plusOne;
3447
3448       switch (method->getSelector().getMethodFamily()) {
3449       case OMF_alloc:
3450       case OMF_copy:
3451       case OMF_mutableCopy:
3452       case OMF_new:
3453         return ACC_plusOne;
3454
3455       default:
3456         // Otherwise, treat it as +0.
3457         return ACC_plusZero;
3458       }
3459     }
3460   };
3461 } // end anonymous namespace
3462
3463 bool Sema::isKnownName(StringRef name) {
3464   if (name.empty())
3465     return false;
3466   LookupResult R(*this, &Context.Idents.get(name), SourceLocation(),
3467                  Sema::LookupOrdinaryName);
3468   return LookupName(R, TUScope, false);
3469 }
3470
3471 static void addFixitForObjCARCConversion(Sema &S,
3472                                          DiagnosticBuilder &DiagB,
3473                                          Sema::CheckedConversionKind CCK,
3474                                          SourceLocation afterLParen,
3475                                          QualType castType,
3476                                          Expr *castExpr,
3477                                          Expr *realCast,
3478                                          const char *bridgeKeyword,
3479                                          const char *CFBridgeName) {
3480   // We handle C-style and implicit casts here.
3481   switch (CCK) {
3482   case Sema::CCK_ImplicitConversion:
3483   case Sema::CCK_CStyleCast:
3484   case Sema::CCK_OtherCast:
3485     break;
3486   case Sema::CCK_FunctionalCast:
3487     return;
3488   }
3489
3490   if (CFBridgeName) {
3491     if (CCK == Sema::CCK_OtherCast) {
3492       if (const CXXNamedCastExpr *NCE = dyn_cast<CXXNamedCastExpr>(realCast)) {
3493         SourceRange range(NCE->getOperatorLoc(),
3494                           NCE->getAngleBrackets().getEnd());
3495         SmallString<32> BridgeCall;
3496
3497         SourceManager &SM = S.getSourceManager();
3498         char PrevChar = *SM.getCharacterData(range.getBegin().getLocWithOffset(-1));
3499         if (Lexer::isIdentifierBodyChar(PrevChar, S.getLangOpts()))
3500           BridgeCall += ' ';
3501
3502         BridgeCall += CFBridgeName;
3503         DiagB.AddFixItHint(FixItHint::CreateReplacement(range, BridgeCall));
3504       }
3505       return;
3506     }
3507     Expr *castedE = castExpr;
3508     if (CStyleCastExpr *CCE = dyn_cast<CStyleCastExpr>(castedE))
3509       castedE = CCE->getSubExpr();
3510     castedE = castedE->IgnoreImpCasts();
3511     SourceRange range = castedE->getSourceRange();
3512
3513     SmallString<32> BridgeCall;
3514
3515     SourceManager &SM = S.getSourceManager();
3516     char PrevChar = *SM.getCharacterData(range.getBegin().getLocWithOffset(-1));
3517     if (Lexer::isIdentifierBodyChar(PrevChar, S.getLangOpts()))
3518       BridgeCall += ' ';
3519
3520     BridgeCall += CFBridgeName;
3521
3522     if (isa<ParenExpr>(castedE)) {
3523       DiagB.AddFixItHint(FixItHint::CreateInsertion(range.getBegin(),
3524                          BridgeCall));
3525     } else {
3526       BridgeCall += '(';
3527       DiagB.AddFixItHint(FixItHint::CreateInsertion(range.getBegin(),
3528                                                     BridgeCall));
3529       DiagB.AddFixItHint(FixItHint::CreateInsertion(
3530                                        S.getLocForEndOfToken(range.getEnd()),
3531                                        ")"));
3532     }
3533     return;
3534   }
3535
3536   if (CCK == Sema::CCK_CStyleCast) {
3537     DiagB.AddFixItHint(FixItHint::CreateInsertion(afterLParen, bridgeKeyword));
3538   } else if (CCK == Sema::CCK_OtherCast) {
3539     if (const CXXNamedCastExpr *NCE = dyn_cast<CXXNamedCastExpr>(realCast)) {
3540       std::string castCode = "(";
3541       castCode += bridgeKeyword;
3542       castCode += castType.getAsString();
3543       castCode += ")";
3544       SourceRange Range(NCE->getOperatorLoc(),
3545                         NCE->getAngleBrackets().getEnd());
3546       DiagB.AddFixItHint(FixItHint::CreateReplacement(Range, castCode));
3547     }
3548   } else {
3549     std::string castCode = "(";
3550     castCode += bridgeKeyword;
3551     castCode += castType.getAsString();
3552     castCode += ")";
3553     Expr *castedE = castExpr->IgnoreImpCasts();
3554     SourceRange range = castedE->getSourceRange();
3555     if (isa<ParenExpr>(castedE)) {
3556       DiagB.AddFixItHint(FixItHint::CreateInsertion(range.getBegin(),
3557                          castCode));
3558     } else {
3559       castCode += "(";
3560       DiagB.AddFixItHint(FixItHint::CreateInsertion(range.getBegin(),
3561                                                     castCode));
3562       DiagB.AddFixItHint(FixItHint::CreateInsertion(
3563                                        S.getLocForEndOfToken(range.getEnd()),
3564                                        ")"));
3565     }
3566   }
3567 }
3568
3569 template <typename T>
3570 static inline T *getObjCBridgeAttr(const TypedefType *TD) {
3571   TypedefNameDecl *TDNDecl = TD->getDecl();
3572   QualType QT = TDNDecl->getUnderlyingType();
3573   if (QT->isPointerType()) {
3574     QT = QT->getPointeeType();
3575     if (const RecordType *RT = QT->getAs<RecordType>())
3576       if (RecordDecl *RD = RT->getDecl()->getMostRecentDecl())
3577         return RD->getAttr<T>();
3578   }
3579   return nullptr;
3580 }
3581
3582 static ObjCBridgeRelatedAttr *ObjCBridgeRelatedAttrFromType(QualType T,
3583                                                             TypedefNameDecl *&TDNDecl) {
3584   while (const TypedefType *TD = dyn_cast<TypedefType>(T.getTypePtr())) {
3585     TDNDecl = TD->getDecl();
3586     if (ObjCBridgeRelatedAttr *ObjCBAttr =
3587         getObjCBridgeAttr<ObjCBridgeRelatedAttr>(TD))
3588       return ObjCBAttr;
3589     T = TDNDecl->getUnderlyingType();
3590   }
3591   return nullptr;
3592 }
3593
3594 static void
3595 diagnoseObjCARCConversion(Sema &S, SourceRange castRange,
3596                           QualType castType, ARCConversionTypeClass castACTC,
3597                           Expr *castExpr, Expr *realCast,
3598                           ARCConversionTypeClass exprACTC,
3599                           Sema::CheckedConversionKind CCK) {
3600   SourceLocation loc =
3601     (castRange.isValid() ? castRange.getBegin() : castExpr->getExprLoc());
3602
3603   if (S.makeUnavailableInSystemHeader(loc,
3604                                  UnavailableAttr::IR_ARCForbiddenConversion))
3605     return;
3606
3607   QualType castExprType = castExpr->getType();
3608   // Defer emitting a diagnostic for bridge-related casts; that will be
3609   // handled by CheckObjCBridgeRelatedConversions.
3610   TypedefNameDecl *TDNDecl = nullptr;
3611   if ((castACTC == ACTC_coreFoundation &&  exprACTC == ACTC_retainable &&
3612        ObjCBridgeRelatedAttrFromType(castType, TDNDecl)) ||
3613       (exprACTC == ACTC_coreFoundation && castACTC == ACTC_retainable &&
3614        ObjCBridgeRelatedAttrFromType(castExprType, TDNDecl)))
3615     return;
3616
3617   unsigned srcKind = 0;
3618   switch (exprACTC) {
3619   case ACTC_none:
3620   case ACTC_coreFoundation:
3621   case ACTC_voidPtr:
3622     srcKind = (castExprType->isPointerType() ? 1 : 0);
3623     break;
3624   case ACTC_retainable:
3625     srcKind = (castExprType->isBlockPointerType() ? 2 : 3);
3626     break;
3627   case ACTC_indirectRetainable:
3628     srcKind = 4;
3629     break;
3630   }
3631
3632   // Check whether this could be fixed with a bridge cast.
3633   SourceLocation afterLParen = S.getLocForEndOfToken(castRange.getBegin());
3634   SourceLocation noteLoc = afterLParen.isValid() ? afterLParen : loc;
3635
3636   // Bridge from an ARC type to a CF type.
3637   if (castACTC == ACTC_retainable && isAnyRetainable(exprACTC)) {
3638
3639     S.Diag(loc, diag::err_arc_cast_requires_bridge)
3640       << unsigned(CCK == Sema::CCK_ImplicitConversion) // cast|implicit
3641       << 2 // of C pointer type
3642       << castExprType
3643       << unsigned(castType->isBlockPointerType()) // to ObjC|block type
3644       << castType
3645       << castRange
3646       << castExpr->getSourceRange();
3647     bool br = S.isKnownName("CFBridgingRelease");
3648     ACCResult CreateRule =
3649       ARCCastChecker(S.Context, exprACTC, castACTC, true).Visit(castExpr);
3650     assert(CreateRule != ACC_bottom && "This cast should already be accepted.");
3651     if (CreateRule != ACC_plusOne)
3652     {
3653       DiagnosticBuilder DiagB =
3654         (CCK != Sema::CCK_OtherCast) ? S.Diag(noteLoc, diag::note_arc_bridge)
3655                               : S.Diag(noteLoc, diag::note_arc_cstyle_bridge);
3656
3657       addFixitForObjCARCConversion(S, DiagB, CCK, afterLParen,
3658                                    castType, castExpr, realCast, "__bridge ",
3659                                    nullptr);
3660     }
3661     if (CreateRule != ACC_plusZero)
3662     {
3663       DiagnosticBuilder DiagB =
3664         (CCK == Sema::CCK_OtherCast && !br) ?
3665           S.Diag(noteLoc, diag::note_arc_cstyle_bridge_transfer) << castExprType :
3666           S.Diag(br ? castExpr->getExprLoc() : noteLoc,
3667                  diag::note_arc_bridge_transfer)
3668             << castExprType << br;
3669
3670       addFixitForObjCARCConversion(S, DiagB, CCK, afterLParen,
3671                                    castType, castExpr, realCast, "__bridge_transfer ",
3672                                    br ? "CFBridgingRelease" : nullptr);
3673     }
3674
3675     return;
3676   }
3677
3678   // Bridge from a CF type to an ARC type.
3679   if (exprACTC == ACTC_retainable && isAnyRetainable(castACTC)) {
3680     bool br = S.isKnownName("CFBridgingRetain");
3681     S.Diag(loc, diag::err_arc_cast_requires_bridge)
3682       << unsigned(CCK == Sema::CCK_ImplicitConversion) // cast|implicit
3683       << unsigned(castExprType->isBlockPointerType()) // of ObjC|block type
3684       << castExprType
3685       << 2 // to C pointer type
3686       << castType
3687       << castRange
3688       << castExpr->getSourceRange();
3689     ACCResult CreateRule =
3690       ARCCastChecker(S.Context, exprACTC, castACTC, true).Visit(castExpr);
3691     assert(CreateRule != ACC_bottom && "This cast should already be accepted.");
3692     if (CreateRule != ACC_plusOne)
3693     {
3694       DiagnosticBuilder DiagB =
3695       (CCK != Sema::CCK_OtherCast) ? S.Diag(noteLoc, diag::note_arc_bridge)
3696                                : S.Diag(noteLoc, diag::note_arc_cstyle_bridge);
3697       addFixitForObjCARCConversion(S, DiagB, CCK, afterLParen,
3698                                    castType, castExpr, realCast, "__bridge ",
3699                                    nullptr);
3700     }
3701     if (CreateRule != ACC_plusZero)
3702     {
3703       DiagnosticBuilder DiagB =
3704         (CCK == Sema::CCK_OtherCast && !br) ?
3705           S.Diag(noteLoc, diag::note_arc_cstyle_bridge_retained) << castType :
3706           S.Diag(br ? castExpr->getExprLoc() : noteLoc,
3707                  diag::note_arc_bridge_retained)
3708             << castType << br;
3709
3710       addFixitForObjCARCConversion(S, DiagB, CCK, afterLParen,
3711                                    castType, castExpr, realCast, "__bridge_retained ",
3712                                    br ? "CFBridgingRetain" : nullptr);
3713     }
3714
3715     return;
3716   }
3717
3718   S.Diag(loc, diag::err_arc_mismatched_cast)
3719     << (CCK != Sema::CCK_ImplicitConversion)
3720     << srcKind << castExprType << castType
3721     << castRange << castExpr->getSourceRange();
3722 }
3723
3724 template <typename TB>
3725 static bool CheckObjCBridgeNSCast(Sema &S, QualType castType, Expr *castExpr,
3726                                   bool &HadTheAttribute, bool warn) {
3727   QualType T = castExpr->getType();
3728   HadTheAttribute = false;
3729   while (const TypedefType *TD = dyn_cast<TypedefType>(T.getTypePtr())) {
3730     TypedefNameDecl *TDNDecl = TD->getDecl();
3731     if (TB *ObjCBAttr = getObjCBridgeAttr<TB>(TD)) {
3732       if (IdentifierInfo *Parm = ObjCBAttr->getBridgedType()) {
3733         HadTheAttribute = true;
3734         if (Parm->isStr("id"))
3735           return true;
3736
3737         NamedDecl *Target = nullptr;
3738         // Check for an existing type with this name.
3739         LookupResult R(S, DeclarationName(Parm), SourceLocation(),
3740                        Sema::LookupOrdinaryName);
3741         if (S.LookupName(R, S.TUScope)) {
3742           Target = R.getFoundDecl();
3743           if (Target && isa<ObjCInterfaceDecl>(Target)) {
3744             ObjCInterfaceDecl *ExprClass = cast<ObjCInterfaceDecl>(Target);
3745             if (const ObjCObjectPointerType *InterfacePointerType =
3746                   castType->getAsObjCInterfacePointerType()) {
3747               ObjCInterfaceDecl *CastClass
3748                 = InterfacePointerType->getObjectType()->getInterface();
3749               if ((CastClass == ExprClass) ||
3750                   (CastClass && CastClass->isSuperClassOf(ExprClass)))
3751                 return true;
3752               if (warn)
3753                 S.Diag(castExpr->getLocStart(), diag::warn_objc_invalid_bridge)
3754                   << T << Target->getName() << castType->getPointeeType();
3755               return false;
3756             } else if (castType->isObjCIdType() ||
3757                        (S.Context.ObjCObjectAdoptsQTypeProtocols(
3758                           castType, ExprClass)))
3759               // ok to cast to 'id'.
3760               // casting to id<p-list> is ok if bridge type adopts all of
3761               // p-list protocols.
3762               return true;
3763             else {
3764               if (warn) {
3765                 S.Diag(castExpr->getLocStart(), diag::warn_objc_invalid_bridge)
3766                   << T << Target->getName() << castType;
3767                 S.Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3768                 S.Diag(Target->getLocStart(), diag::note_declared_at);
3769               }
3770               return false;
3771            }
3772           }
3773         } else if (!castType->isObjCIdType()) {
3774           S.Diag(castExpr->getLocStart(), diag::err_objc_cf_bridged_not_interface)
3775             << castExpr->getType() << Parm;
3776           S.Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3777           if (Target)
3778             S.Diag(Target->getLocStart(), diag::note_declared_at);
3779         }
3780         return true;
3781       }
3782       return false;
3783     }
3784     T = TDNDecl->getUnderlyingType();
3785   }
3786   return true;
3787 }
3788
3789 template <typename TB>
3790 static bool CheckObjCBridgeCFCast(Sema &S, QualType castType, Expr *castExpr,
3791                                   bool &HadTheAttribute, bool warn) {
3792   QualType T = castType;
3793   HadTheAttribute = false;
3794   while (const TypedefType *TD = dyn_cast<TypedefType>(T.getTypePtr())) {
3795     TypedefNameDecl *TDNDecl = TD->getDecl();
3796     if (TB *ObjCBAttr = getObjCBridgeAttr<TB>(TD)) {
3797       if (IdentifierInfo *Parm = ObjCBAttr->getBridgedType()) {
3798         HadTheAttribute = true;
3799         if (Parm->isStr("id"))
3800           return true;
3801
3802         NamedDecl *Target = nullptr;
3803         // Check for an existing type with this name.
3804         LookupResult R(S, DeclarationName(Parm), SourceLocation(),
3805                        Sema::LookupOrdinaryName);
3806         if (S.LookupName(R, S.TUScope)) {
3807           Target = R.getFoundDecl();
3808           if (Target && isa<ObjCInterfaceDecl>(Target)) {
3809             ObjCInterfaceDecl *CastClass = cast<ObjCInterfaceDecl>(Target);
3810             if (const ObjCObjectPointerType *InterfacePointerType =
3811                   castExpr->getType()->getAsObjCInterfacePointerType()) {
3812               ObjCInterfaceDecl *ExprClass
3813                 = InterfacePointerType->getObjectType()->getInterface();
3814               if ((CastClass == ExprClass) ||
3815                   (ExprClass && CastClass->isSuperClassOf(ExprClass)))
3816                 return true;
3817               if (warn) {
3818                 S.Diag(castExpr->getLocStart(), diag::warn_objc_invalid_bridge_to_cf)
3819                   << castExpr->getType()->getPointeeType() << T;
3820                 S.Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3821               }
3822               return false;
3823             } else if (castExpr->getType()->isObjCIdType() ||
3824                        (S.Context.QIdProtocolsAdoptObjCObjectProtocols(
3825                           castExpr->getType(), CastClass)))
3826               // ok to cast an 'id' expression to a CFtype.
3827               // ok to cast an 'id<plist>' expression to CFtype provided plist
3828               // adopts all of CFtype's ObjetiveC's class plist.
3829               return true;
3830             else {
3831               if (warn) {
3832                 S.Diag(castExpr->getLocStart(), diag::warn_objc_invalid_bridge_to_cf)
3833                   << castExpr->getType() << castType;
3834                 S.Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3835                 S.Diag(Target->getLocStart(), diag::note_declared_at);
3836               }
3837               return false;
3838             }
3839           }
3840         }
3841         S.Diag(castExpr->getLocStart(), diag::err_objc_ns_bridged_invalid_cfobject)
3842         << castExpr->getType() << castType;
3843         S.Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3844         if (Target)
3845           S.Diag(Target->getLocStart(), diag::note_declared_at);
3846         return true;
3847       }
3848       return false;
3849     }
3850     T = TDNDecl->getUnderlyingType();
3851   }
3852   return true;
3853 }
3854
3855 void Sema::CheckTollFreeBridgeCast(QualType castType, Expr *castExpr) {
3856   if (!getLangOpts().ObjC1)
3857     return;
3858   // warn in presence of __bridge casting to or from a toll free bridge cast.
3859   ARCConversionTypeClass exprACTC = classifyTypeForARCConversion(castExpr->getType());
3860   ARCConversionTypeClass castACTC = classifyTypeForARCConversion(castType);
3861   if (castACTC == ACTC_retainable && exprACTC == ACTC_coreFoundation) {
3862     bool HasObjCBridgeAttr;
3863     bool ObjCBridgeAttrWillNotWarn =
3864       CheckObjCBridgeNSCast<ObjCBridgeAttr>(*this, castType, castExpr, HasObjCBridgeAttr,
3865                                             false);
3866     if (ObjCBridgeAttrWillNotWarn && HasObjCBridgeAttr)
3867       return;
3868     bool HasObjCBridgeMutableAttr;
3869     bool ObjCBridgeMutableAttrWillNotWarn =
3870       CheckObjCBridgeNSCast<ObjCBridgeMutableAttr>(*this, castType, castExpr,
3871                                                    HasObjCBridgeMutableAttr, false);
3872     if (ObjCBridgeMutableAttrWillNotWarn && HasObjCBridgeMutableAttr)
3873       return;
3874
3875     if (HasObjCBridgeAttr)
3876       CheckObjCBridgeNSCast<ObjCBridgeAttr>(*this, castType, castExpr, HasObjCBridgeAttr,
3877                                             true);
3878     else if (HasObjCBridgeMutableAttr)
3879       CheckObjCBridgeNSCast<ObjCBridgeMutableAttr>(*this, castType, castExpr,
3880                                                    HasObjCBridgeMutableAttr, true);
3881   }
3882   else if (castACTC == ACTC_coreFoundation && exprACTC == ACTC_retainable) {
3883     bool HasObjCBridgeAttr;
3884     bool ObjCBridgeAttrWillNotWarn =
3885       CheckObjCBridgeCFCast<ObjCBridgeAttr>(*this, castType, castExpr, HasObjCBridgeAttr,
3886                                             false);
3887     if (ObjCBridgeAttrWillNotWarn && HasObjCBridgeAttr)
3888       return;
3889     bool HasObjCBridgeMutableAttr;
3890     bool ObjCBridgeMutableAttrWillNotWarn =
3891       CheckObjCBridgeCFCast<ObjCBridgeMutableAttr>(*this, castType, castExpr,
3892                                                    HasObjCBridgeMutableAttr, false);
3893     if (ObjCBridgeMutableAttrWillNotWarn && HasObjCBridgeMutableAttr)
3894       return;
3895
3896     if (HasObjCBridgeAttr)
3897       CheckObjCBridgeCFCast<ObjCBridgeAttr>(*this, castType, castExpr, HasObjCBridgeAttr,
3898                                             true);
3899     else if (HasObjCBridgeMutableAttr)
3900       CheckObjCBridgeCFCast<ObjCBridgeMutableAttr>(*this, castType, castExpr,
3901                                                    HasObjCBridgeMutableAttr, true);
3902   }
3903 }
3904
3905 void Sema::CheckObjCBridgeRelatedCast(QualType castType, Expr *castExpr) {
3906   QualType SrcType = castExpr->getType();
3907   if (ObjCPropertyRefExpr *PRE = dyn_cast<ObjCPropertyRefExpr>(castExpr)) {
3908     if (PRE->isExplicitProperty()) {
3909       if (ObjCPropertyDecl *PDecl = PRE->getExplicitProperty())
3910         SrcType = PDecl->getType();
3911     }
3912     else if (PRE->isImplicitProperty()) {
3913       if (ObjCMethodDecl *Getter = PRE->getImplicitPropertyGetter())
3914         SrcType = Getter->getReturnType();
3915     }
3916   }
3917
3918   ARCConversionTypeClass srcExprACTC = classifyTypeForARCConversion(SrcType);
3919   ARCConversionTypeClass castExprACTC = classifyTypeForARCConversion(castType);
3920   if (srcExprACTC != ACTC_retainable || castExprACTC != ACTC_coreFoundation)
3921     return;
3922   CheckObjCBridgeRelatedConversions(castExpr->getLocStart(),
3923                                     castType, SrcType, castExpr);
3924 }
3925
3926 bool Sema::CheckTollFreeBridgeStaticCast(QualType castType, Expr *castExpr,
3927                                          CastKind &Kind) {
3928   if (!getLangOpts().ObjC1)
3929     return false;
3930   ARCConversionTypeClass exprACTC =
3931     classifyTypeForARCConversion(castExpr->getType());
3932   ARCConversionTypeClass castACTC = classifyTypeForARCConversion(castType);
3933   if ((castACTC == ACTC_retainable && exprACTC == ACTC_coreFoundation) ||
3934       (castACTC == ACTC_coreFoundation && exprACTC == ACTC_retainable)) {
3935     CheckTollFreeBridgeCast(castType, castExpr);
3936     Kind = (castACTC == ACTC_coreFoundation) ? CK_BitCast
3937                                              : CK_CPointerToObjCPointerCast;
3938     return true;
3939   }
3940   return false;
3941 }
3942
3943 bool Sema::checkObjCBridgeRelatedComponents(SourceLocation Loc,
3944                                             QualType DestType, QualType SrcType,
3945                                             ObjCInterfaceDecl *&RelatedClass,
3946                                             ObjCMethodDecl *&ClassMethod,
3947                                             ObjCMethodDecl *&InstanceMethod,
3948                                             TypedefNameDecl *&TDNDecl,
3949                                             bool CfToNs, bool Diagnose) {
3950   QualType T = CfToNs ? SrcType : DestType;
3951   ObjCBridgeRelatedAttr *ObjCBAttr = ObjCBridgeRelatedAttrFromType(T, TDNDecl);
3952   if (!ObjCBAttr)
3953     return false;
3954
3955   IdentifierInfo *RCId = ObjCBAttr->getRelatedClass();
3956   IdentifierInfo *CMId = ObjCBAttr->getClassMethod();
3957   IdentifierInfo *IMId = ObjCBAttr->getInstanceMethod();
3958   if (!RCId)
3959     return false;
3960   NamedDecl *Target = nullptr;
3961   // Check for an existing type with this name.
3962   LookupResult R(*this, DeclarationName(RCId), SourceLocation(),
3963                  Sema::LookupOrdinaryName);
3964   if (!LookupName(R, TUScope)) {
3965     if (Diagnose) {
3966       Diag(Loc, diag::err_objc_bridged_related_invalid_class) << RCId
3967             << SrcType << DestType;
3968       Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3969     }
3970     return false;
3971   }
3972   Target = R.getFoundDecl();
3973   if (Target && isa<ObjCInterfaceDecl>(Target))
3974     RelatedClass = cast<ObjCInterfaceDecl>(Target);
3975   else {
3976     if (Diagnose) {
3977       Diag(Loc, diag::err_objc_bridged_related_invalid_class_name) << RCId
3978             << SrcType << DestType;
3979       Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3980       if (Target)
3981         Diag(Target->getLocStart(), diag::note_declared_at);
3982     }
3983     return false;
3984   }
3985
3986   // Check for an existing class method with the given selector name.
3987   if (CfToNs && CMId) {
3988     Selector Sel = Context.Selectors.getUnarySelector(CMId);
3989     ClassMethod = RelatedClass->lookupMethod(Sel, false);
3990     if (!ClassMethod) {
3991       if (Diagnose) {
3992         Diag(Loc, diag::err_objc_bridged_related_known_method)
3993               << SrcType << DestType << Sel << false;
3994         Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3995       }
3996       return false;
3997     }
3998   }
3999
4000   // Check for an existing instance method with the given selector name.
4001   if (!CfToNs && IMId) {
4002     Selector Sel = Context.Selectors.getNullarySelector(IMId);
4003     InstanceMethod = RelatedClass->lookupMethod(Sel, true);
4004     if (!InstanceMethod) {
4005       if (Diagnose) {
4006         Diag(Loc, diag::err_objc_bridged_related_known_method)
4007               << SrcType << DestType << Sel << true;
4008         Diag(TDNDecl->getLocStart(), diag::note_declared_at);
4009       }
4010       return false;
4011     }
4012   }
4013   return true;
4014 }
4015
4016 bool
4017 Sema::CheckObjCBridgeRelatedConversions(SourceLocation Loc,
4018                                         QualType DestType, QualType SrcType,
4019                                         Expr *&SrcExpr, bool Diagnose) {
4020   ARCConversionTypeClass rhsExprACTC = classifyTypeForARCConversion(SrcType);
4021   ARCConversionTypeClass lhsExprACTC = classifyTypeForARCConversion(DestType);
4022   bool CfToNs = (rhsExprACTC == ACTC_coreFoundation && lhsExprACTC == ACTC_retainable);
4023   bool NsToCf = (rhsExprACTC == ACTC_retainable && lhsExprACTC == ACTC_coreFoundation);
4024   if (!CfToNs && !NsToCf)
4025     return false;
4026
4027   ObjCInterfaceDecl *RelatedClass;
4028   ObjCMethodDecl *ClassMethod = nullptr;
4029   ObjCMethodDecl *InstanceMethod = nullptr;
4030   TypedefNameDecl *TDNDecl = nullptr;
4031   if (!checkObjCBridgeRelatedComponents(Loc, DestType, SrcType, RelatedClass,
4032                                         ClassMethod, InstanceMethod, TDNDecl,
4033                                         CfToNs, Diagnose))
4034     return false;
4035
4036   if (CfToNs) {
4037     // Implicit conversion from CF to ObjC object is needed.
4038     if (ClassMethod) {
4039       if (Diagnose) {
4040         std::string ExpressionString = "[";
4041         ExpressionString += RelatedClass->getNameAsString();
4042         ExpressionString += " ";
4043         ExpressionString += ClassMethod->getSelector().getAsString();
4044         SourceLocation SrcExprEndLoc = getLocForEndOfToken(SrcExpr->getLocEnd());
4045         // Provide a fixit: [RelatedClass ClassMethod SrcExpr]
4046         Diag(Loc, diag::err_objc_bridged_related_known_method)
4047           << SrcType << DestType << ClassMethod->getSelector() << false
4048           << FixItHint::CreateInsertion(SrcExpr->getLocStart(), ExpressionString)
4049           << FixItHint::CreateInsertion(SrcExprEndLoc, "]");
4050         Diag(RelatedClass->getLocStart(), diag::note_declared_at);
4051         Diag(TDNDecl->getLocStart(), diag::note_declared_at);
4052
4053         QualType receiverType = Context.getObjCInterfaceType(RelatedClass);
4054         // Argument.
4055         Expr *args[] = { SrcExpr };
4056         ExprResult msg = BuildClassMessageImplicit(receiverType, false,
4057                                       ClassMethod->getLocation(),
4058                                       ClassMethod->getSelector(), ClassMethod,
4059                                       MultiExprArg(args, 1));
4060         SrcExpr = msg.get();
4061       }
4062       return true;
4063     }
4064   }
4065   else {
4066     // Implicit conversion from ObjC type to CF object is needed.
4067     if (InstanceMethod) {
4068       if (Diagnose) {
4069         std::string ExpressionString;
4070         SourceLocation SrcExprEndLoc =
4071             getLocForEndOfToken(SrcExpr->getLocEnd());
4072         if (InstanceMethod->isPropertyAccessor())
4073           if (const ObjCPropertyDecl *PDecl =
4074                   InstanceMethod->findPropertyDecl()) {
4075             // fixit: ObjectExpr.propertyname when it is  aproperty accessor.
4076             ExpressionString = ".";
4077             ExpressionString += PDecl->getNameAsString();
4078             Diag(Loc, diag::err_objc_bridged_related_known_method)
4079                 << SrcType << DestType << InstanceMethod->getSelector() << true
4080                 << FixItHint::CreateInsertion(SrcExprEndLoc, ExpressionString);
4081           }
4082         if (ExpressionString.empty()) {
4083           // Provide a fixit: [ObjectExpr InstanceMethod]
4084           ExpressionString = " ";
4085           ExpressionString += InstanceMethod->getSelector().getAsString();
4086           ExpressionString += "]";
4087
4088           Diag(Loc, diag::err_objc_bridged_related_known_method)
4089               << SrcType << DestType << InstanceMethod->getSelector() << true
4090               << FixItHint::CreateInsertion(SrcExpr->getLocStart(), "[")
4091               << FixItHint::CreateInsertion(SrcExprEndLoc, ExpressionString);
4092         }
4093         Diag(RelatedClass->getLocStart(), diag::note_declared_at);
4094         Diag(TDNDecl->getLocStart(), diag::note_declared_at);
4095
4096         ExprResult msg =
4097           BuildInstanceMessageImplicit(SrcExpr, SrcType,
4098                                        InstanceMethod->getLocation(),
4099                                        InstanceMethod->getSelector(),
4100                                        InstanceMethod, None);
4101         SrcExpr = msg.get();
4102       }
4103       return true;
4104     }
4105   }
4106   return false;
4107 }
4108
4109 Sema::ARCConversionResult
4110 Sema::CheckObjCConversion(SourceRange castRange, QualType castType,
4111                           Expr *&castExpr, CheckedConversionKind CCK,
4112                           bool Diagnose, bool DiagnoseCFAudited,
4113                           BinaryOperatorKind Opc) {
4114   QualType castExprType = castExpr->getType();
4115
4116   // For the purposes of the classification, we assume reference types
4117   // will bind to temporaries.
4118   QualType effCastType = castType;
4119   if (const ReferenceType *ref = castType->getAs<ReferenceType>())
4120     effCastType = ref->getPointeeType();
4121
4122   ARCConversionTypeClass exprACTC = classifyTypeForARCConversion(castExprType);
4123   ARCConversionTypeClass castACTC = classifyTypeForARCConversion(effCastType);
4124   if (exprACTC == castACTC) {
4125     // Check for viability and report error if casting an rvalue to a
4126     // life-time qualifier.
4127     if (castACTC == ACTC_retainable &&
4128         (CCK == CCK_CStyleCast || CCK == CCK_OtherCast) &&
4129         castType != castExprType) {
4130       const Type *DT = castType.getTypePtr();
4131       QualType QDT = castType;
4132       // We desugar some types but not others. We ignore those
4133       // that cannot happen in a cast; i.e. auto, and those which
4134       // should not be de-sugared; i.e typedef.
4135       if (const ParenType *PT = dyn_cast<ParenType>(DT))
4136         QDT = PT->desugar();
4137       else if (const TypeOfType *TP = dyn_cast<TypeOfType>(DT))
4138         QDT = TP->desugar();
4139       else if (const AttributedType *AT = dyn_cast<AttributedType>(DT))
4140         QDT = AT->desugar();
4141       if (QDT != castType &&
4142           QDT.getObjCLifetime() !=  Qualifiers::OCL_None) {
4143         if (Diagnose) {
4144           SourceLocation loc = (castRange.isValid() ? castRange.getBegin()
4145                                                     : castExpr->getExprLoc());
4146           Diag(loc, diag::err_arc_nolifetime_behavior);
4147         }
4148         return ACR_error;
4149       }
4150     }
4151     return ACR_okay;
4152   }
4153
4154   // The life-time qualifier cast check above is all we need for ObjCWeak.
4155   // ObjCAutoRefCount has more restrictions on what is legal.
4156   if (!getLangOpts().ObjCAutoRefCount)
4157     return ACR_okay;
4158
4159   if (isAnyCLike(exprACTC) && isAnyCLike(castACTC)) return ACR_okay;
4160
4161   // Allow all of these types to be cast to integer types (but not
4162   // vice-versa).
4163   if (castACTC == ACTC_none && castType->isIntegralType(Context))
4164     return ACR_okay;
4165
4166   // Allow casts between pointers to lifetime types (e.g., __strong id*)
4167   // and pointers to void (e.g., cv void *). Casting from void* to lifetime*
4168   // must be explicit.
4169   if (exprACTC == ACTC_indirectRetainable && castACTC == ACTC_voidPtr)
4170     return ACR_okay;
4171   if (castACTC == ACTC_indirectRetainable && exprACTC == ACTC_voidPtr &&
4172       CCK != CCK_ImplicitConversion)
4173     return ACR_okay;
4174
4175   switch (ARCCastChecker(Context, exprACTC, castACTC, false).Visit(castExpr)) {
4176   // For invalid casts, fall through.
4177   case ACC_invalid:
4178     break;
4179
4180   // Do nothing for both bottom and +0.
4181   case ACC_bottom:
4182   case ACC_plusZero:
4183     return ACR_okay;
4184
4185   // If the result is +1, consume it here.
4186   case ACC_plusOne:
4187     castExpr = ImplicitCastExpr::Create(Context, castExpr->getType(),
4188                                         CK_ARCConsumeObject, castExpr,
4189                                         nullptr, VK_RValue);
4190     Cleanup.setExprNeedsCleanups(true);
4191     return ACR_okay;
4192   }
4193
4194   // If this is a non-implicit cast from id or block type to a
4195   // CoreFoundation type, delay complaining in case the cast is used
4196   // in an acceptable context.
4197   if (exprACTC == ACTC_retainable && isAnyRetainable(castACTC) &&
4198       CCK != CCK_ImplicitConversion)
4199     return ACR_unbridged;
4200
4201   // Issue a diagnostic about a missing @-sign when implicit casting a cstring
4202   // to 'NSString *', instead of falling through to report a "bridge cast"
4203   // diagnostic.
4204   if (castACTC == ACTC_retainable && exprACTC == ACTC_none &&
4205       ConversionToObjCStringLiteralCheck(castType, castExpr, Diagnose))
4206     return ACR_error;
4207
4208   // Do not issue "bridge cast" diagnostic when implicit casting
4209   // a retainable object to a CF type parameter belonging to an audited
4210   // CF API function. Let caller issue a normal type mismatched diagnostic
4211   // instead.
4212   if ((!DiagnoseCFAudited || exprACTC != ACTC_retainable ||
4213        castACTC != ACTC_coreFoundation) &&
4214       !(exprACTC == ACTC_voidPtr && castACTC == ACTC_retainable &&
4215         (Opc == BO_NE || Opc == BO_EQ))) {
4216     if (Diagnose)
4217       diagnoseObjCARCConversion(*this, castRange, castType, castACTC, castExpr,
4218                                 castExpr, exprACTC, CCK);
4219     return ACR_error;
4220   }
4221   return ACR_okay;
4222 }
4223
4224 /// Given that we saw an expression with the ARCUnbridgedCastTy
4225 /// placeholder type, complain bitterly.
4226 void Sema::diagnoseARCUnbridgedCast(Expr *e) {
4227   // We expect the spurious ImplicitCastExpr to already have been stripped.
4228   assert(!e->hasPlaceholderType(BuiltinType::ARCUnbridgedCast));
4229   CastExpr *realCast = cast<CastExpr>(e->IgnoreParens());
4230
4231   SourceRange castRange;
4232   QualType castType;
4233   CheckedConversionKind CCK;
4234
4235   if (CStyleCastExpr *cast = dyn_cast<CStyleCastExpr>(realCast)) {
4236     castRange = SourceRange(cast->getLParenLoc(), cast->getRParenLoc());
4237     castType = cast->getTypeAsWritten();
4238     CCK = CCK_CStyleCast;
4239   } else if (ExplicitCastExpr *cast = dyn_cast<ExplicitCastExpr>(realCast)) {
4240     castRange = cast->getTypeInfoAsWritten()->getTypeLoc().getSourceRange();
4241     castType = cast->getTypeAsWritten();
4242     CCK = CCK_OtherCast;
4243   } else {
4244     llvm_unreachable("Unexpected ImplicitCastExpr");
4245   }
4246
4247   ARCConversionTypeClass castACTC =
4248     classifyTypeForARCConversion(castType.getNonReferenceType());
4249
4250   Expr *castExpr = realCast->getSubExpr();
4251   assert(classifyTypeForARCConversion(castExpr->getType()) == ACTC_retainable);
4252
4253   diagnoseObjCARCConversion(*this, castRange, castType, castACTC,
4254                             castExpr, realCast, ACTC_retainable, CCK);
4255 }
4256
4257 /// stripARCUnbridgedCast - Given an expression of ARCUnbridgedCast
4258 /// type, remove the placeholder cast.
4259 Expr *Sema::stripARCUnbridgedCast(Expr *e) {
4260   assert(e->hasPlaceholderType(BuiltinType::ARCUnbridgedCast));
4261
4262   if (ParenExpr *pe = dyn_cast<ParenExpr>(e)) {
4263     Expr *sub = stripARCUnbridgedCast(pe->getSubExpr());
4264     return new (Context) ParenExpr(pe->getLParen(), pe->getRParen(), sub);
4265   } else if (UnaryOperator *uo = dyn_cast<UnaryOperator>(e)) {
4266     assert(uo->getOpcode() == UO_Extension);
4267     Expr *sub = stripARCUnbridgedCast(uo->getSubExpr());
4268     return new (Context) UnaryOperator(sub, UO_Extension, sub->getType(),
4269                                    sub->getValueKind(), sub->getObjectKind(),
4270                                        uo->getOperatorLoc());
4271   } else if (GenericSelectionExpr *gse = dyn_cast<GenericSelectionExpr>(e)) {
4272     assert(!gse->isResultDependent());
4273
4274     unsigned n = gse->getNumAssocs();
4275     SmallVector<Expr*, 4> subExprs(n);
4276     SmallVector<TypeSourceInfo*, 4> subTypes(n);
4277     for (unsigned i = 0; i != n; ++i) {
4278       subTypes[i] = gse->getAssocTypeSourceInfo(i);
4279       Expr *sub = gse->getAssocExpr(i);
4280       if (i == gse->getResultIndex())
4281         sub = stripARCUnbridgedCast(sub);
4282       subExprs[i] = sub;
4283     }
4284
4285     return new (Context) GenericSelectionExpr(Context, gse->getGenericLoc(),
4286                                               gse->getControllingExpr(),
4287                                               subTypes, subExprs,
4288                                               gse->getDefaultLoc(),
4289                                               gse->getRParenLoc(),
4290                                        gse->containsUnexpandedParameterPack(),
4291                                               gse->getResultIndex());
4292   } else {
4293     assert(isa<ImplicitCastExpr>(e) && "bad form of unbridged cast!");
4294     return cast<ImplicitCastExpr>(e)->getSubExpr();
4295   }
4296 }
4297
4298 bool Sema::CheckObjCARCUnavailableWeakConversion(QualType castType,
4299                                                  QualType exprType) {
4300   QualType canCastType =
4301     Context.getCanonicalType(castType).getUnqualifiedType();
4302   QualType canExprType =
4303     Context.getCanonicalType(exprType).getUnqualifiedType();
4304   if (isa<ObjCObjectPointerType>(canCastType) &&
4305       castType.getObjCLifetime() == Qualifiers::OCL_Weak &&
4306       canExprType->isObjCObjectPointerType()) {
4307     if (const ObjCObjectPointerType *ObjT =
4308         canExprType->getAs<ObjCObjectPointerType>())
4309       if (const ObjCInterfaceDecl *ObjI = ObjT->getInterfaceDecl())
4310         return !ObjI->isArcWeakrefUnavailable();
4311   }
4312   return true;
4313 }
4314
4315 /// Look for an ObjCReclaimReturnedObject cast and destroy it.
4316 static Expr *maybeUndoReclaimObject(Expr *e) {
4317   // For now, we just undo operands that are *immediately* reclaim
4318   // expressions, which prevents the vast majority of potential
4319   // problems here.  To catch them all, we'd need to rebuild arbitrary
4320   // value-propagating subexpressions --- we can't reliably rebuild
4321   // in-place because of expression sharing.
4322   if (ImplicitCastExpr *ice = dyn_cast<ImplicitCastExpr>(e))
4323     if (ice->getCastKind() == CK_ARCReclaimReturnedObject)
4324       return ice->getSubExpr();
4325
4326   return e;
4327 }
4328
4329 ExprResult Sema::BuildObjCBridgedCast(SourceLocation LParenLoc,
4330                                       ObjCBridgeCastKind Kind,
4331                                       SourceLocation BridgeKeywordLoc,
4332                                       TypeSourceInfo *TSInfo,
4333                                       Expr *SubExpr) {
4334   ExprResult SubResult = UsualUnaryConversions(SubExpr);
4335   if (SubResult.isInvalid()) return ExprError();
4336   SubExpr = SubResult.get();
4337
4338   QualType T = TSInfo->getType();
4339   QualType FromType = SubExpr->getType();
4340
4341   CastKind CK;
4342
4343   bool MustConsume = false;
4344   if (T->isDependentType() || SubExpr->isTypeDependent()) {
4345     // Okay: we'll build a dependent expression type.
4346     CK = CK_Dependent;
4347   } else if (T->isObjCARCBridgableType() && FromType->isCARCBridgableType()) {
4348     // Casting CF -> id
4349     CK = (T->isBlockPointerType() ? CK_AnyPointerToBlockPointerCast
4350                                   : CK_CPointerToObjCPointerCast);
4351     switch (Kind) {
4352     case OBC_Bridge:
4353       break;
4354
4355     case OBC_BridgeRetained: {
4356       bool br = isKnownName("CFBridgingRelease");
4357       Diag(BridgeKeywordLoc, diag::err_arc_bridge_cast_wrong_kind)
4358         << 2
4359         << FromType
4360         << (T->isBlockPointerType()? 1 : 0)
4361         << T
4362         << SubExpr->getSourceRange()
4363         << Kind;
4364       Diag(BridgeKeywordLoc, diag::note_arc_bridge)
4365         << FixItHint::CreateReplacement(BridgeKeywordLoc, "__bridge");
4366       Diag(BridgeKeywordLoc, diag::note_arc_bridge_transfer)
4367         << FromType << br
4368         << FixItHint::CreateReplacement(BridgeKeywordLoc,
4369                                         br ? "CFBridgingRelease "
4370                                            : "__bridge_transfer ");
4371
4372       Kind = OBC_Bridge;
4373       break;
4374     }
4375
4376     case OBC_BridgeTransfer:
4377       // We must consume the Objective-C object produced by the cast.
4378       MustConsume = true;
4379       break;
4380     }
4381   } else if (T->isCARCBridgableType() && FromType->isObjCARCBridgableType()) {
4382     // Okay: id -> CF
4383     CK = CK_BitCast;
4384     switch (Kind) {
4385     case OBC_Bridge:
4386       // Reclaiming a value that's going to be __bridge-casted to CF
4387       // is very dangerous, so we don't do it.
4388       SubExpr = maybeUndoReclaimObject(SubExpr);
4389       break;
4390
4391     case OBC_BridgeRetained:
4392       // Produce the object before casting it.
4393       SubExpr = ImplicitCastExpr::Create(Context, FromType,
4394                                          CK_ARCProduceObject,
4395                                          SubExpr, nullptr, VK_RValue);
4396       break;
4397
4398     case OBC_BridgeTransfer: {
4399       bool br = isKnownName("CFBridgingRetain");
4400       Diag(BridgeKeywordLoc, diag::err_arc_bridge_cast_wrong_kind)
4401         << (FromType->isBlockPointerType()? 1 : 0)
4402         << FromType
4403         << 2
4404         << T
4405         << SubExpr->getSourceRange()
4406         << Kind;
4407
4408       Diag(BridgeKeywordLoc, diag::note_arc_bridge)
4409         << FixItHint::CreateReplacement(BridgeKeywordLoc, "__bridge ");
4410       Diag(BridgeKeywordLoc, diag::note_arc_bridge_retained)
4411         << T << br
4412         << FixItHint::CreateReplacement(BridgeKeywordLoc,
4413                           br ? "CFBridgingRetain " : "__bridge_retained");
4414
4415       Kind = OBC_Bridge;
4416       break;
4417     }
4418     }
4419   } else {
4420     Diag(LParenLoc, diag::err_arc_bridge_cast_incompatible)
4421       << FromType << T << Kind
4422       << SubExpr->getSourceRange()
4423       << TSInfo->getTypeLoc().getSourceRange();
4424     return ExprError();
4425   }
4426
4427   Expr *Result = new (Context) ObjCBridgedCastExpr(LParenLoc, Kind, CK,
4428                                                    BridgeKeywordLoc,
4429                                                    TSInfo, SubExpr);
4430
4431   if (MustConsume) {
4432     Cleanup.setExprNeedsCleanups(true);
4433     Result = ImplicitCastExpr::Create(Context, T, CK_ARCConsumeObject, Result,
4434                                       nullptr, VK_RValue);
4435   }
4436
4437   return Result;
4438 }
4439
4440 ExprResult Sema::ActOnObjCBridgedCast(Scope *S,
4441                                       SourceLocation LParenLoc,
4442                                       ObjCBridgeCastKind Kind,
4443                                       SourceLocation BridgeKeywordLoc,
4444                                       ParsedType Type,
4445                                       SourceLocation RParenLoc,
4446                                       Expr *SubExpr) {
4447   TypeSourceInfo *TSInfo = nullptr;
4448   QualType T = GetTypeFromParser(Type, &TSInfo);
4449   if (Kind == OBC_Bridge)
4450     CheckTollFreeBridgeCast(T, SubExpr);
4451   if (!TSInfo)
4452     TSInfo = Context.getTrivialTypeSourceInfo(T, LParenLoc);
4453   return BuildObjCBridgedCast(LParenLoc, Kind, BridgeKeywordLoc, TSInfo,
4454                               SubExpr);
4455 }