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       // Transfer the nullability from method's return type.
 568       Optional<NullabilityKind> Nullability =
 569           BoxingMethod->getReturnType()->getNullability(Context);
 570       if (Nullability)
 571         BoxedType = Context.getAttributedType(
 572             AttributedType::getNullabilityAttrKind(*Nullability), BoxedType,
 573             BoxedType);
 574     }
 575   } else if (ValueType->isBuiltinType()) {
 576     // The other types we support are numeric, char and BOOL/bool. We could also
 577     // provide limited support for structure types, such as NSRange, NSRect, and
 578     // NSSize. See NSValue (NSValueGeometryExtensions) in <Foundation/NSGeometry.h>
 579     // for more details.
 580
 581     // Check for a top-level character literal.
 582     if (const CharacterLiteral *Char =
 583         dyn_cast<CharacterLiteral>(ValueExpr->IgnoreParens())) {
 584       // In C, character literals have type 'int'. That's not the type we want
 585       // to use to determine the Objective-c literal kind.
 586       switch (Char->getKind()) {
 587       case CharacterLiteral::Ascii:
 588       case CharacterLiteral::UTF8:
 589         ValueType = Context.CharTy;
 590         break;
 591
 592       case CharacterLiteral::Wide:
 593         ValueType = Context.getWideCharType();
 594         break;
 595
 596       case CharacterLiteral::UTF16:
 597         ValueType = Context.Char16Ty;
 598         break;
 599
 600       case CharacterLiteral::UTF32:
 601         ValueType = Context.Char32Ty;
 602         break;
 603       }
 604     }
 605     // FIXME:  Do I need to do anything special with BoolTy expressions?
 606
 607     // Look for the appropriate method within NSNumber.
 608     BoxingMethod = getNSNumberFactoryMethod(*this, Loc, ValueType);
 609     BoxedType = NSNumberPointer;
 610   } else if (const EnumType *ET = ValueType->getAs<EnumType>()) {
 611     if (!ET->getDecl()->isComplete()) {
 612       Diag(Loc, diag::err_objc_incomplete_boxed_expression_type)
 613         << ValueType << ValueExpr->getSourceRange();
 614       return ExprError();
 615     }
 616
 617     BoxingMethod = getNSNumberFactoryMethod(*this, Loc,
 618                                             ET->getDecl()->getIntegerType());
 619     BoxedType = NSNumberPointer;
 620   } else if (ValueType->isObjCBoxableRecordType()) {
 621     // Support for structure types, that marked as objc_boxable
 622     // struct __attribute__((objc_boxable)) s { ... };
 623
 624     // Look up the NSValue class, if we haven't done so already. It's cached
 625     // in the Sema instance.
 626     if (!NSValueDecl) {
 627       NSValueDecl = LookupObjCInterfaceDeclForLiteral(*this, Loc,
 628                                                       Sema::LK_Boxed);
 629       if (!NSValueDecl) {
 630         return ExprError();
 631       }
 632
 633       // generate the pointer to NSValue type.
 634       QualType NSValueObject = Context.getObjCInterfaceType(NSValueDecl);
 635       NSValuePointer = Context.getObjCObjectPointerType(NSValueObject);
 636     }
 637
 638     if (!ValueWithBytesObjCTypeMethod) {
 639       IdentifierInfo *II[] = {
 640         &Context.Idents.get("valueWithBytes"),
 641         &Context.Idents.get("objCType")
 642       };
 643       Selector ValueWithBytesObjCType = Context.Selectors.getSelector(2, II);
 644
 645       // Look for the appropriate method within NSValue.
 646       BoxingMethod = NSValueDecl->lookupClassMethod(ValueWithBytesObjCType);
 647       if (!BoxingMethod && getLangOpts().DebuggerObjCLiteral) {
 648         // Debugger needs to work even if NSValue hasn't been defined.
 649         TypeSourceInfo *ReturnTInfo = nullptr;
 650         ObjCMethodDecl *M = ObjCMethodDecl::Create(
 651                                                Context,
 652                                                SourceLocation(),
 653                                                SourceLocation(),
 654                                                ValueWithBytesObjCType,
 655                                                NSValuePointer,
 656                                                ReturnTInfo,
 657                                                NSValueDecl,
 658                                                /*isInstance=*/false,
 659                                                /*isVariadic=*/false,
 660                                                /*isPropertyAccessor=*/false,
 661                                                /*isImplicitlyDeclared=*/true,
 662                                                /*isDefined=*/false,
 663                                                ObjCMethodDecl::Required,
 664                                                /*HasRelatedResultType=*/false);
 665
 666         SmallVector<ParmVarDecl *, 2> Params;
 667
 668         ParmVarDecl *bytes =
 669         ParmVarDecl::Create(Context, M,
 670                             SourceLocation(), SourceLocation(),
 671                             &Context.Idents.get("bytes"),
 672                             Context.VoidPtrTy.withConst(),
 673                             /*TInfo=*/nullptr,
 674                             SC_None, nullptr);
 675         Params.push_back(bytes);
 676
 677         QualType ConstCharType = Context.CharTy.withConst();
 678         ParmVarDecl *type =
 679         ParmVarDecl::Create(Context, M,
 680                             SourceLocation(), SourceLocation(),
 681                             &Context.Idents.get("type"),
 682                             Context.getPointerType(ConstCharType),
 683                             /*TInfo=*/nullptr,
 684                             SC_None, nullptr);
 685         Params.push_back(type);
 686
 687         M->setMethodParams(Context, Params, None);
 688         BoxingMethod = M;
 689       }
 690
 691       if (!validateBoxingMethod(*this, Loc, NSValueDecl,
 692                                 ValueWithBytesObjCType, BoxingMethod))
 693         return ExprError();
 694
 695       ValueWithBytesObjCTypeMethod = BoxingMethod;
 696     }
 697
 698     if (!ValueType.isTriviallyCopyableType(Context)) {
 699       Diag(Loc, diag::err_objc_non_trivially_copyable_boxed_expression_type)
 700         << ValueType << ValueExpr->getSourceRange();
 701       return ExprError();
 702     }
 703
 704     BoxingMethod = ValueWithBytesObjCTypeMethod;
 705     BoxedType = NSValuePointer;
 706   }
 707
 708   if (!BoxingMethod) {
 709     Diag(Loc, diag::err_objc_illegal_boxed_expression_type)
 710       << ValueType << ValueExpr->getSourceRange();
 711     return ExprError();
 712   }
 713
 714   DiagnoseUseOfDecl(BoxingMethod, Loc);
 715
 716   ExprResult ConvertedValueExpr;
 717   if (ValueType->isObjCBoxableRecordType()) {
 718     InitializedEntity IE = InitializedEntity::InitializeTemporary(ValueType);
 719     ConvertedValueExpr = PerformCopyInitialization(IE, ValueExpr->getExprLoc(),
 720                                                    ValueExpr);
 721   } else {
 722     // Convert the expression to the type that the parameter requires.
 723     ParmVarDecl *ParamDecl = BoxingMethod->parameters()[0];
 724     InitializedEntity IE = InitializedEntity::InitializeParameter(Context,
 725                                                                   ParamDecl);
 726     ConvertedValueExpr = PerformCopyInitialization(IE, SourceLocation(),
 727                                                    ValueExpr);
 728   }
 729
 730   if (ConvertedValueExpr.isInvalid())
 731     return ExprError();
 732   ValueExpr = ConvertedValueExpr.get();
 733
 734   ObjCBoxedExpr *BoxedExpr =
 735     new (Context) ObjCBoxedExpr(ValueExpr, BoxedType,
 736                                       BoxingMethod, SR);
 737   return MaybeBindToTemporary(BoxedExpr);
 738 }
 739
 740 /// Build an ObjC subscript pseudo-object expression, given that
 741 /// that's supported by the runtime.
 742 ExprResult Sema::BuildObjCSubscriptExpression(SourceLocation RB, Expr *BaseExpr,
 743                                         Expr *IndexExpr,
 744                                         ObjCMethodDecl *getterMethod,
 745                                         ObjCMethodDecl *setterMethod) {
 746   assert(!LangOpts.isSubscriptPointerArithmetic());
 747
 748   // We can't get dependent types here; our callers should have
 749   // filtered them out.
 750   assert((!BaseExpr->isTypeDependent() && !IndexExpr->isTypeDependent()) &&
 751          "base or index cannot have dependent type here");
 752
 753   // Filter out placeholders in the index.  In theory, overloads could
 754   // be preserved here, although that might not actually work correctly.
 755   ExprResult Result = CheckPlaceholderExpr(IndexExpr);
 756   if (Result.isInvalid())
 757     return ExprError();
 758   IndexExpr = Result.get();
 759
 760   // Perform lvalue-to-rvalue conversion on the base.
 761   Result = DefaultLvalueConversion(BaseExpr);
 762   if (Result.isInvalid())
 763     return ExprError();
 764   BaseExpr = Result.get();
 765
 766   // Build the pseudo-object expression.
 767   return new (Context) ObjCSubscriptRefExpr(
 768       BaseExpr, IndexExpr, Context.PseudoObjectTy, VK_LValue, OK_ObjCSubscript,
 769       getterMethod, setterMethod, RB);
 770 }
 771
 772 ExprResult Sema::BuildObjCArrayLiteral(SourceRange SR, MultiExprArg Elements) {
 773   SourceLocation Loc = SR.getBegin();
 774
 775   if (!NSArrayDecl) {
 776     NSArrayDecl = LookupObjCInterfaceDeclForLiteral(*this, Loc,
 777                                                     Sema::LK_Array);
 778     if (!NSArrayDecl) {
 779       return ExprError();
 780     }
 781   }
 782
 783   // Find the arrayWithObjects:count: method, if we haven't done so already.
 784   QualType IdT = Context.getObjCIdType();
 785   if (!ArrayWithObjectsMethod) {
 786     Selector
 787       Sel = NSAPIObj->getNSArraySelector(NSAPI::NSArr_arrayWithObjectsCount);
 788     ObjCMethodDecl *Method = NSArrayDecl->lookupClassMethod(Sel);
 789     if (!Method && getLangOpts().DebuggerObjCLiteral) {
 790       TypeSourceInfo *ReturnTInfo = nullptr;
 791       Method = ObjCMethodDecl::Create(
 792           Context, SourceLocation(), SourceLocation(), Sel, IdT, ReturnTInfo,
 793           Context.getTranslationUnitDecl(), false /*Instance*/,
 794           false /*isVariadic*/,
 795           /*isPropertyAccessor=*/false,
 796           /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
 797           ObjCMethodDecl::Required, false);
 798       SmallVector<ParmVarDecl *, 2> Params;
 799       ParmVarDecl *objects = ParmVarDecl::Create(Context, Method,
 800                                                  SourceLocation(),
 801                                                  SourceLocation(),
 802                                                  &Context.Idents.get("objects"),
 803                                                  Context.getPointerType(IdT),
 804                                                  /*TInfo=*/nullptr,
 805                                                  SC_None, nullptr);
 806       Params.push_back(objects);
 807       ParmVarDecl *cnt = ParmVarDecl::Create(Context, Method,
 808                                              SourceLocation(),
 809                                              SourceLocation(),
 810                                              &Context.Idents.get("cnt"),
 811                                              Context.UnsignedLongTy,
 812                                              /*TInfo=*/nullptr, SC_None,
 813                                              nullptr);
 814       Params.push_back(cnt);
 815       Method->setMethodParams(Context, Params, None);
 816     }
 817
 818     if (!validateBoxingMethod(*this, Loc, NSArrayDecl, Sel, Method))
 819       return ExprError();
 820
 821     // Dig out the type that all elements should be converted to.
 822     QualType T = Method->parameters()[0]->getType();
 823     const PointerType *PtrT = T->getAs<PointerType>();
 824     if (!PtrT ||
 825         !Context.hasSameUnqualifiedType(PtrT->getPointeeType(), IdT)) {
 826       Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
 827         << Sel;
 828       Diag(Method->parameters()[0]->getLocation(),
 829            diag::note_objc_literal_method_param)
 830         << 0 << T
 831         << Context.getPointerType(IdT.withConst());
 832       return ExprError();
 833     }
 834
 835     // Check that the 'count' parameter is integral.
 836     if (!Method->parameters()[1]->getType()->isIntegerType()) {
 837       Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
 838         << Sel;
 839       Diag(Method->parameters()[1]->getLocation(),
 840            diag::note_objc_literal_method_param)
 841         << 1
 842         << Method->parameters()[1]->getType()
 843         << "integral";
 844       return ExprError();
 845     }
 846
 847     // We've found a good +arrayWithObjects:count: method. Save it!
 848     ArrayWithObjectsMethod = Method;
 849   }
 850
 851   QualType ObjectsType = ArrayWithObjectsMethod->parameters()[0]->getType();
 852   QualType RequiredType = ObjectsType->castAs<PointerType>()->getPointeeType();
 853
 854   // Check that each of the elements provided is valid in a collection literal,
 855   // performing conversions as necessary.
 856   Expr **ElementsBuffer = Elements.data();
 857   for (unsigned I = 0, N = Elements.size(); I != N; ++I) {
 858     ExprResult Converted = CheckObjCCollectionLiteralElement(*this,
 859                                                              ElementsBuffer[I],
 860                                                              RequiredType, true);
 861     if (Converted.isInvalid())
 862       return ExprError();
 863
 864     ElementsBuffer[I] = Converted.get();
 865   }
 866
 867   QualType Ty
 868     = Context.getObjCObjectPointerType(
 869                                     Context.getObjCInterfaceType(NSArrayDecl));
 870
 871   return MaybeBindToTemporary(
 872            ObjCArrayLiteral::Create(Context, Elements, Ty,
 873                                     ArrayWithObjectsMethod, SR));
 874 }
 875
 876 ExprResult Sema::BuildObjCDictionaryLiteral(SourceRange SR,
 877                               MutableArrayRef<ObjCDictionaryElement> Elements) {
 878   SourceLocation Loc = SR.getBegin();
 879
 880   if (!NSDictionaryDecl) {
 881     NSDictionaryDecl = LookupObjCInterfaceDeclForLiteral(*this, Loc,
 882                                                          Sema::LK_Dictionary);
 883     if (!NSDictionaryDecl) {
 884       return ExprError();
 885     }
 886   }
 887
 888   // Find the dictionaryWithObjects:forKeys:count: method, if we haven't done
 889   // so already.
 890   QualType IdT = Context.getObjCIdType();
 891   if (!DictionaryWithObjectsMethod) {
 892     Selector Sel = NSAPIObj->getNSDictionarySelector(
 893                                NSAPI::NSDict_dictionaryWithObjectsForKeysCount);
 894     ObjCMethodDecl *Method = NSDictionaryDecl->lookupClassMethod(Sel);
 895     if (!Method && getLangOpts().DebuggerObjCLiteral) {
 896       Method = ObjCMethodDecl::Create(Context,
 897                            SourceLocation(), SourceLocation(), Sel,
 898                            IdT,
 899                            nullptr /*TypeSourceInfo */,
 900                            Context.getTranslationUnitDecl(),
 901                            false /*Instance*/, false/*isVariadic*/,
 902                            /*isPropertyAccessor=*/false,
 903                            /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
 904                            ObjCMethodDecl::Required,
 905                            false);
 906       SmallVector<ParmVarDecl *, 3> Params;
 907       ParmVarDecl *objects = ParmVarDecl::Create(Context, Method,
 908                                                  SourceLocation(),
 909                                                  SourceLocation(),
 910                                                  &Context.Idents.get("objects"),
 911                                                  Context.getPointerType(IdT),
 912                                                  /*TInfo=*/nullptr, SC_None,
 913                                                  nullptr);
 914       Params.push_back(objects);
 915       ParmVarDecl *keys = ParmVarDecl::Create(Context, Method,
 916                                               SourceLocation(),
 917                                               SourceLocation(),
 918                                               &Context.Idents.get("keys"),
 919                                               Context.getPointerType(IdT),
 920                                               /*TInfo=*/nullptr, SC_None,
 921                                               nullptr);
 922       Params.push_back(keys);
 923       ParmVarDecl *cnt = ParmVarDecl::Create(Context, Method,
 924                                              SourceLocation(),
 925                                              SourceLocation(),
 926                                              &Context.Idents.get("cnt"),
 927                                              Context.UnsignedLongTy,
 928                                              /*TInfo=*/nullptr, SC_None,
 929                                              nullptr);
 930       Params.push_back(cnt);
 931       Method->setMethodParams(Context, Params, None);
 932     }
 933
 934     if (!validateBoxingMethod(*this, SR.getBegin(), NSDictionaryDecl, Sel,
 935                               Method))
 936        return ExprError();
 937
 938     // Dig out the type that all values should be converted to.
 939     QualType ValueT = Method->parameters()[0]->getType();
 940     const PointerType *PtrValue = ValueT->getAs<PointerType>();
 941     if (!PtrValue ||
 942         !Context.hasSameUnqualifiedType(PtrValue->getPointeeType(), IdT)) {
 943       Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
 944         << Sel;
 945       Diag(Method->parameters()[0]->getLocation(),
 946            diag::note_objc_literal_method_param)
 947         << 0 << ValueT
 948         << Context.getPointerType(IdT.withConst());
 949       return ExprError();
 950     }
 951
 952     // Dig out the type that all keys should be converted to.
 953     QualType KeyT = Method->parameters()[1]->getType();
 954     const PointerType *PtrKey = KeyT->getAs<PointerType>();
 955     if (!PtrKey ||
 956         !Context.hasSameUnqualifiedType(PtrKey->getPointeeType(),
 957                                         IdT)) {
 958       bool err = true;
 959       if (PtrKey) {
 960         if (QIDNSCopying.isNull()) {
 961           // key argument of selector is id<NSCopying>?
 962           if (ObjCProtocolDecl *NSCopyingPDecl =
 963               LookupProtocol(&Context.Idents.get("NSCopying"), SR.getBegin())) {
 964             ObjCProtocolDecl *PQ[] = {NSCopyingPDecl};
 965             QIDNSCopying =
 966               Context.getObjCObjectType(Context.ObjCBuiltinIdTy, { },
 967                                         llvm::makeArrayRef(
 968                                           (ObjCProtocolDecl**) PQ,
 969                                           1),
 970                                         false);
 971             QIDNSCopying = Context.getObjCObjectPointerType(QIDNSCopying);
 972           }
 973         }
 974         if (!QIDNSCopying.isNull())
 975           err = !Context.hasSameUnqualifiedType(PtrKey->getPointeeType(),
 976                                                 QIDNSCopying);
 977       }
 978
 979       if (err) {
 980         Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
 981           << Sel;
 982         Diag(Method->parameters()[1]->getLocation(),
 983              diag::note_objc_literal_method_param)
 984           << 1 << KeyT
 985           << Context.getPointerType(IdT.withConst());
 986         return ExprError();
 987       }
 988     }
 989
 990     // Check that the 'count' parameter is integral.
 991     QualType CountType = Method->parameters()[2]->getType();
 992     if (!CountType->isIntegerType()) {
 993       Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
 994         << Sel;
 995       Diag(Method->parameters()[2]->getLocation(),
 996            diag::note_objc_literal_method_param)
 997         << 2 << CountType
 998         << "integral";
 999       return ExprError();
1000     }
1001
1002     // We've found a good +dictionaryWithObjects:keys:count: method; save it!
1003     DictionaryWithObjectsMethod = Method;
1004   }
1005
1006   QualType ValuesT = DictionaryWithObjectsMethod->parameters()[0]->getType();
1007   QualType ValueT = ValuesT->castAs<PointerType>()->getPointeeType();
1008   QualType KeysT = DictionaryWithObjectsMethod->parameters()[1]->getType();
1009   QualType KeyT = KeysT->castAs<PointerType>()->getPointeeType();
1010
1011   // Check that each of the keys and values provided is valid in a collection
1012   // literal, performing conversions as necessary.
1013   bool HasPackExpansions = false;
1014   for (ObjCDictionaryElement &Element : Elements) {
1015     // Check the key.
1016     ExprResult Key = CheckObjCCollectionLiteralElement(*this, Element.Key,
1017                                                        KeyT);
1018     if (Key.isInvalid())
1019       return ExprError();
1020
1021     // Check the value.
1022     ExprResult Value
1023       = CheckObjCCollectionLiteralElement(*this, Element.Value, ValueT);
1024     if (Value.isInvalid())
1025       return ExprError();
1026
1027     Element.Key = Key.get();
1028     Element.Value = Value.get();
1029
1030     if (Element.EllipsisLoc.isInvalid())
1031       continue;
1032
1033     if (!Element.Key->containsUnexpandedParameterPack() &&
1034         !Element.Value->containsUnexpandedParameterPack()) {
1035       Diag(Element.EllipsisLoc,
1036            diag::err_pack_expansion_without_parameter_packs)
1037         << SourceRange(Element.Key->getLocStart(),
1038                        Element.Value->getLocEnd());
1039       return ExprError();
1040     }
1041
1042     HasPackExpansions = true;
1043   }
1044
1045   QualType Ty
1046     = Context.getObjCObjectPointerType(
1047                                 Context.getObjCInterfaceType(NSDictionaryDecl));
1048   return MaybeBindToTemporary(ObjCDictionaryLiteral::Create(
1049       Context, Elements, HasPackExpansions, Ty,
1050       DictionaryWithObjectsMethod, SR));
1051 }
1052
1053 ExprResult Sema::BuildObjCEncodeExpression(SourceLocation AtLoc,
1054                                       TypeSourceInfo *EncodedTypeInfo,
1055                                       SourceLocation RParenLoc) {
1056   QualType EncodedType = EncodedTypeInfo->getType();
1057   QualType StrTy;
1058   if (EncodedType->isDependentType())
1059     StrTy = Context.DependentTy;
1060   else {
1061     if (!EncodedType->getAsArrayTypeUnsafe() && //// Incomplete array is handled.
1062         !EncodedType->isVoidType()) // void is handled too.
1063       if (RequireCompleteType(AtLoc, EncodedType,
1064                               diag::err_incomplete_type_objc_at_encode,
1065                               EncodedTypeInfo->getTypeLoc()))
1066         return ExprError();
1067
1068     std::string Str;
1069     QualType NotEncodedT;
1070     Context.getObjCEncodingForType(EncodedType, Str, nullptr, &NotEncodedT);
1071     if (!NotEncodedT.isNull())
1072       Diag(AtLoc, diag::warn_incomplete_encoded_type)
1073         << EncodedType << NotEncodedT;
1074
1075     // The type of @encode is the same as the type of the corresponding string,
1076     // which is an array type.
1077     StrTy = Context.CharTy;
1078     // A C++ string literal has a const-qualified element type (C++ 2.13.4p1).
1079     if (getLangOpts().CPlusPlus || getLangOpts().ConstStrings)
1080       StrTy.addConst();
1081     StrTy = Context.getConstantArrayType(StrTy, llvm::APInt(32, Str.size()+1),
1082                                          ArrayType::Normal, 0);
1083   }
1084
1085   return new (Context) ObjCEncodeExpr(StrTy, EncodedTypeInfo, AtLoc, RParenLoc);
1086 }
1087
1088 ExprResult Sema::ParseObjCEncodeExpression(SourceLocation AtLoc,
1089                                            SourceLocation EncodeLoc,
1090                                            SourceLocation LParenLoc,
1091                                            ParsedType ty,
1092                                            SourceLocation RParenLoc) {
1093   // FIXME: Preserve type source info ?
1094   TypeSourceInfo *TInfo;
1095   QualType EncodedType = GetTypeFromParser(ty, &TInfo);
1096   if (!TInfo)
1097     TInfo = Context.getTrivialTypeSourceInfo(EncodedType,
1098                                              getLocForEndOfToken(LParenLoc));
1099
1100   return BuildObjCEncodeExpression(AtLoc, TInfo, RParenLoc);
1101 }
1102
1103 static bool HelperToDiagnoseMismatchedMethodsInGlobalPool(Sema &S,
1104                                                SourceLocation AtLoc,
1105                                                SourceLocation LParenLoc,
1106                                                SourceLocation RParenLoc,
1107                                                ObjCMethodDecl *Method,
1108                                                ObjCMethodList &MethList) {
1109   ObjCMethodList *M = &MethList;
1110   bool Warned = false;
1111   for (M = M->getNext(); M; M=M->getNext()) {
1112     ObjCMethodDecl *MatchingMethodDecl = M->getMethod();
1113     if (MatchingMethodDecl == Method ||
1114         isa<ObjCImplDecl>(MatchingMethodDecl->getDeclContext()) ||
1115         MatchingMethodDecl->getSelector() != Method->getSelector())
1116       continue;
1117     if (!S.MatchTwoMethodDeclarations(Method,
1118                                       MatchingMethodDecl, Sema::MMS_loose)) {
1119       if (!Warned) {
1120         Warned = true;
1121         S.Diag(AtLoc, diag::warn_multiple_selectors)
1122           << Method->getSelector() << FixItHint::CreateInsertion(LParenLoc, "(")
1123           << FixItHint::CreateInsertion(RParenLoc, ")");
1124         S.Diag(Method->getLocation(), diag::note_method_declared_at)
1125           << Method->getDeclName();
1126       }
1127       S.Diag(MatchingMethodDecl->getLocation(), diag::note_method_declared_at)
1128         << MatchingMethodDecl->getDeclName();
1129     }
1130   }
1131   return Warned;
1132 }
1133
1134 static void DiagnoseMismatchedSelectors(Sema &S, SourceLocation AtLoc,
1135                                         ObjCMethodDecl *Method,
1136                                         SourceLocation LParenLoc,
1137                                         SourceLocation RParenLoc,
1138                                         bool WarnMultipleSelectors) {
1139   if (!WarnMultipleSelectors ||
1140       S.Diags.isIgnored(diag::warn_multiple_selectors, SourceLocation()))
1141     return;
1142   bool Warned = false;
1143   for (Sema::GlobalMethodPool::iterator b = S.MethodPool.begin(),
1144        e = S.MethodPool.end(); b != e; b++) {
1145     // first, instance methods
1146     ObjCMethodList &InstMethList = b->second.first;
1147     if (HelperToDiagnoseMismatchedMethodsInGlobalPool(S, AtLoc, LParenLoc, RParenLoc,
1148                                                       Method, InstMethList))
1149       Warned = true;
1150
1151     // second, class methods
1152     ObjCMethodList &ClsMethList = b->second.second;
1153     if (HelperToDiagnoseMismatchedMethodsInGlobalPool(S, AtLoc, LParenLoc, RParenLoc,
1154                                                       Method, ClsMethList) || Warned)
1155       return;
1156   }
1157 }
1158
1159 ExprResult Sema::ParseObjCSelectorExpression(Selector Sel,
1160                                              SourceLocation AtLoc,
1161                                              SourceLocation SelLoc,
1162                                              SourceLocation LParenLoc,
1163                                              SourceLocation RParenLoc,
1164                                              bool WarnMultipleSelectors) {
1165   ObjCMethodDecl *Method = LookupInstanceMethodInGlobalPool(Sel,
1166                              SourceRange(LParenLoc, RParenLoc));
1167   if (!Method)
1168     Method = LookupFactoryMethodInGlobalPool(Sel,
1169                                           SourceRange(LParenLoc, RParenLoc));
1170   if (!Method) {
1171     if (const ObjCMethodDecl *OM = SelectorsForTypoCorrection(Sel)) {
1172       Selector MatchedSel = OM->getSelector();
1173       SourceRange SelectorRange(LParenLoc.getLocWithOffset(1),
1174                                 RParenLoc.getLocWithOffset(-1));
1175       Diag(SelLoc, diag::warn_undeclared_selector_with_typo)
1176         << Sel << MatchedSel
1177         << FixItHint::CreateReplacement(SelectorRange, MatchedSel.getAsString());
1178
1179     } else
1180         Diag(SelLoc, diag::warn_undeclared_selector) << Sel;
1181   } else
1182     DiagnoseMismatchedSelectors(*this, AtLoc, Method, LParenLoc, RParenLoc,
1183                                 WarnMultipleSelectors);
1184
1185   if (Method &&
1186       Method->getImplementationControl() != ObjCMethodDecl::Optional &&
1187       !getSourceManager().isInSystemHeader(Method->getLocation()))
1188     ReferencedSelectors.insert(std::make_pair(Sel, AtLoc));
1189
1190   // In ARC, forbid the user from using @selector for
1191   // retain/release/autorelease/dealloc/retainCount.
1192   if (getLangOpts().ObjCAutoRefCount) {
1193     switch (Sel.getMethodFamily()) {
1194     case OMF_retain:
1195     case OMF_release:
1196     case OMF_autorelease:
1197     case OMF_retainCount:
1198     case OMF_dealloc:
1199       Diag(AtLoc, diag::err_arc_illegal_selector) <<
1200         Sel << SourceRange(LParenLoc, RParenLoc);
1201       break;
1202
1203     case OMF_None:
1204     case OMF_alloc:
1205     case OMF_copy:
1206     case OMF_finalize:
1207     case OMF_init:
1208     case OMF_mutableCopy:
1209     case OMF_new:
1210     case OMF_self:
1211     case OMF_initialize:
1212     case OMF_performSelector:
1213       break;
1214     }
1215   }
1216   QualType Ty = Context.getObjCSelType();
1217   return new (Context) ObjCSelectorExpr(Ty, Sel, AtLoc, RParenLoc);
1218 }
1219
1220 ExprResult Sema::ParseObjCProtocolExpression(IdentifierInfo *ProtocolId,
1221                                              SourceLocation AtLoc,
1222                                              SourceLocation ProtoLoc,
1223                                              SourceLocation LParenLoc,
1224                                              SourceLocation ProtoIdLoc,
1225                                              SourceLocation RParenLoc) {
1226   ObjCProtocolDecl* PDecl = LookupProtocol(ProtocolId, ProtoIdLoc);
1227   if (!PDecl) {
1228     Diag(ProtoLoc, diag::err_undeclared_protocol) << ProtocolId;
1229     return true;
1230   }
1231   if (PDecl->hasDefinition())
1232     PDecl = PDecl->getDefinition();
1233
1234   QualType Ty = Context.getObjCProtoType();
1235   if (Ty.isNull())
1236     return true;
1237   Ty = Context.getObjCObjectPointerType(Ty);
1238   return new (Context) ObjCProtocolExpr(Ty, PDecl, AtLoc, ProtoIdLoc, RParenLoc);
1239 }
1240
1241 /// Try to capture an implicit reference to 'self'.
1242 ObjCMethodDecl *Sema::tryCaptureObjCSelf(SourceLocation Loc) {
1243   DeclContext *DC = getFunctionLevelDeclContext();
1244
1245   // If we're not in an ObjC method, error out.  Note that, unlike the
1246   // C++ case, we don't require an instance method --- class methods
1247   // still have a 'self', and we really do still need to capture it!
1248   ObjCMethodDecl *method = dyn_cast<ObjCMethodDecl>(DC);
1249   if (!method)
1250     return nullptr;
1251
1252   tryCaptureVariable(method->getSelfDecl(), Loc);
1253
1254   return method;
1255 }
1256
1257 static QualType stripObjCInstanceType(ASTContext &Context, QualType T) {
1258   QualType origType = T;
1259   if (auto nullability = AttributedType::stripOuterNullability(T)) {
1260     if (T == Context.getObjCInstanceType()) {
1261       return Context.getAttributedType(
1262                AttributedType::getNullabilityAttrKind(*nullability),
1263                Context.getObjCIdType(),
1264                Context.getObjCIdType());
1265     }
1266
1267     return origType;
1268   }
1269
1270   if (T == Context.getObjCInstanceType())
1271     return Context.getObjCIdType();
1272
1273   return origType;
1274 }
1275
1276 /// Determine the result type of a message send based on the receiver type,
1277 /// method, and the kind of message send.
1278 ///
1279 /// This is the "base" result type, which will still need to be adjusted
1280 /// to account for nullability.
1281 static QualType getBaseMessageSendResultType(Sema &S,
1282                                              QualType ReceiverType,
1283                                              ObjCMethodDecl *Method,
1284                                              bool isClassMessage,
1285                                              bool isSuperMessage) {
1286   assert(Method && "Must have a method");
1287   if (!Method->hasRelatedResultType())
1288     return Method->getSendResultType(ReceiverType);
1289
1290   ASTContext &Context = S.Context;
1291
1292   // Local function that transfers the nullability of the method's
1293   // result type to the returned result.
1294   auto transferNullability = [&](QualType type) -> QualType {
1295     // If the method's result type has nullability, extract it.
1296     if (auto nullability = Method->getSendResultType(ReceiverType)
1297                              ->getNullability(Context)){
1298       // Strip off any outer nullability sugar from the provided type.
1299       (void)AttributedType::stripOuterNullability(type);
1300
1301       // Form a new attributed type using the method result type's nullability.
1302       return Context.getAttributedType(
1303                AttributedType::getNullabilityAttrKind(*nullability),
1304                type,
1305                type);
1306     }
1307
1308     return type;
1309   };
1310
1311   // If a method has a related return type:
1312   //   - if the method found is an instance method, but the message send
1313   //     was a class message send, T is the declared return type of the method
1314   //     found
1315   if (Method->isInstanceMethod() && isClassMessage)
1316     return stripObjCInstanceType(Context,
1317                                  Method->getSendResultType(ReceiverType));
1318
1319   //   - if the receiver is super, T is a pointer to the class of the
1320   //     enclosing method definition
1321   if (isSuperMessage) {
1322     if (ObjCMethodDecl *CurMethod = S.getCurMethodDecl())
1323       if (ObjCInterfaceDecl *Class = CurMethod->getClassInterface()) {
1324         return transferNullability(
1325                  Context.getObjCObjectPointerType(
1326                    Context.getObjCInterfaceType(Class)));
1327       }
1328   }
1329
1330   //   - if the receiver is the name of a class U, T is a pointer to U
1331   if (ReceiverType->getAsObjCInterfaceType())
1332     return transferNullability(Context.getObjCObjectPointerType(ReceiverType));
1333   //   - if the receiver is of type Class or qualified Class type,
1334   //     T is the declared return type of the method.
1335   if (ReceiverType->isObjCClassType() ||
1336       ReceiverType->isObjCQualifiedClassType())
1337     return stripObjCInstanceType(Context,
1338                                  Method->getSendResultType(ReceiverType));
1339
1340   //   - if the receiver is id, qualified id, Class, or qualified Class, T
1341   //     is the receiver type, otherwise
1342   //   - T is the type of the receiver expression.
1343   return transferNullability(ReceiverType);
1344 }
1345
1346 QualType Sema::getMessageSendResultType(QualType ReceiverType,
1347                                         ObjCMethodDecl *Method,
1348                                         bool isClassMessage,
1349                                         bool isSuperMessage) {
1350   // Produce the result type.
1351   QualType resultType = getBaseMessageSendResultType(*this, ReceiverType,
1352                                                      Method,
1353                                                      isClassMessage,
1354                                                      isSuperMessage);
1355
1356   // If this is a class message, ignore the nullability of the receiver.
1357   if (isClassMessage)
1358     return resultType;
1359
1360   // Map the nullability of the result into a table index.
1361   unsigned receiverNullabilityIdx = 0;
1362   if (auto nullability = ReceiverType->getNullability(Context))
1363     receiverNullabilityIdx = 1 + static_cast<unsigned>(*nullability);
1364
1365   unsigned resultNullabilityIdx = 0;
1366   if (auto nullability = resultType->getNullability(Context))
1367     resultNullabilityIdx = 1 + static_cast<unsigned>(*nullability);
1368
1369   // The table of nullability mappings, indexed by the receiver's nullability
1370   // and then the result type's nullability.
1371   static const uint8_t None = 0;
1372   static const uint8_t NonNull = 1;
1373   static const uint8_t Nullable = 2;
1374   static const uint8_t Unspecified = 3;
1375   static const uint8_t nullabilityMap[4][4] = {
1376     //                  None        NonNull       Nullable    Unspecified
1377     /* None */        { None,       None,         Nullable,   None },
1378     /* NonNull */     { None,       NonNull,      Nullable,   Unspecified },
1379     /* Nullable */    { Nullable,   Nullable,     Nullable,   Nullable },
1380     /* Unspecified */ { None,       Unspecified,  Nullable,   Unspecified }
1381   };
1382
1383   unsigned newResultNullabilityIdx
1384     = nullabilityMap[receiverNullabilityIdx][resultNullabilityIdx];
1385   if (newResultNullabilityIdx == resultNullabilityIdx)
1386     return resultType;
1387
1388   // Strip off the existing nullability. This removes as little type sugar as
1389   // possible.
1390   do {
1391     if (auto attributed = dyn_cast<AttributedType>(resultType.getTypePtr())) {
1392       resultType = attributed->getModifiedType();
1393     } else {
1394       resultType = resultType.getDesugaredType(Context);
1395     }
1396   } while (resultType->getNullability(Context));
1397
1398   // Add nullability back if needed.
1399   if (newResultNullabilityIdx > 0) {
1400     auto newNullability
1401       = static_cast<NullabilityKind>(newResultNullabilityIdx-1);
1402     return Context.getAttributedType(
1403              AttributedType::getNullabilityAttrKind(newNullability),
1404              resultType, resultType);
1405   }
1406
1407   return resultType;
1408 }
1409
1410 /// Look for an ObjC method whose result type exactly matches the given type.
1411 static const ObjCMethodDecl *
1412 findExplicitInstancetypeDeclarer(const ObjCMethodDecl *MD,
1413                                  QualType instancetype) {
1414   if (MD->getReturnType() == instancetype)
1415     return MD;
1416
1417   // For these purposes, a method in an @implementation overrides a
1418   // declaration in the @interface.
1419   if (const ObjCImplDecl *impl =
1420         dyn_cast<ObjCImplDecl>(MD->getDeclContext())) {
1421     const ObjCContainerDecl *iface;
1422     if (const ObjCCategoryImplDecl *catImpl =
1423           dyn_cast<ObjCCategoryImplDecl>(impl)) {
1424       iface = catImpl->getCategoryDecl();
1425     } else {
1426       iface = impl->getClassInterface();
1427     }
1428
1429     const ObjCMethodDecl *ifaceMD =
1430       iface->getMethod(MD->getSelector(), MD->isInstanceMethod());
1431     if (ifaceMD) return findExplicitInstancetypeDeclarer(ifaceMD, instancetype);
1432   }
1433
1434   SmallVector<const ObjCMethodDecl *, 4> overrides;
1435   MD->getOverriddenMethods(overrides);
1436   for (unsigned i = 0, e = overrides.size(); i != e; ++i) {
1437     if (const ObjCMethodDecl *result =
1438           findExplicitInstancetypeDeclarer(overrides[i], instancetype))
1439       return result;
1440   }
1441
1442   return nullptr;
1443 }
1444
1445 void Sema::EmitRelatedResultTypeNoteForReturn(QualType destType) {
1446   // Only complain if we're in an ObjC method and the required return
1447   // type doesn't match the method's declared return type.
1448   ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(CurContext);
1449   if (!MD || !MD->hasRelatedResultType() ||
1450       Context.hasSameUnqualifiedType(destType, MD->getReturnType()))
1451     return;
1452
1453   // Look for a method overridden by this method which explicitly uses
1454   // 'instancetype'.
1455   if (const ObjCMethodDecl *overridden =
1456         findExplicitInstancetypeDeclarer(MD, Context.getObjCInstanceType())) {
1457     SourceRange range = overridden->getReturnTypeSourceRange();
1458     SourceLocation loc = range.getBegin();
1459     if (loc.isInvalid())
1460       loc = overridden->getLocation();
1461     Diag(loc, diag::note_related_result_type_explicit)
1462       << /*current method*/ 1 << range;
1463     return;
1464   }
1465
1466   // Otherwise, if we have an interesting method family, note that.
1467   // This should always trigger if the above didn't.
1468   if (ObjCMethodFamily family = MD->getMethodFamily())
1469     Diag(MD->getLocation(), diag::note_related_result_type_family)
1470       << /*current method*/ 1
1471       << family;
1472 }
1473
1474 void Sema::EmitRelatedResultTypeNote(const Expr *E) {
1475   E = E->IgnoreParenImpCasts();
1476   const ObjCMessageExpr *MsgSend = dyn_cast<ObjCMessageExpr>(E);
1477   if (!MsgSend)
1478     return;
1479
1480   const ObjCMethodDecl *Method = MsgSend->getMethodDecl();
1481   if (!Method)
1482     return;
1483
1484   if (!Method->hasRelatedResultType())
1485     return;
1486
1487   if (Context.hasSameUnqualifiedType(
1488           Method->getReturnType().getNonReferenceType(), MsgSend->getType()))
1489     return;
1490
1491   if (!Context.hasSameUnqualifiedType(Method->getReturnType(),
1492                                       Context.getObjCInstanceType()))
1493     return;
1494
1495   Diag(Method->getLocation(), diag::note_related_result_type_inferred)
1496     << Method->isInstanceMethod() << Method->getSelector()
1497     << MsgSend->getType();
1498 }
1499
1500 bool Sema::CheckMessageArgumentTypes(QualType ReceiverType,
1501                                      MultiExprArg Args,
1502                                      Selector Sel,
1503                                      ArrayRef<SourceLocation> SelectorLocs,
1504                                      ObjCMethodDecl *Method,
1505                                      bool isClassMessage, bool isSuperMessage,
1506                                      SourceLocation lbrac, SourceLocation rbrac,
1507                                      SourceRange RecRange,
1508                                      QualType &ReturnType, ExprValueKind &VK) {
1509   SourceLocation SelLoc;
1510   if (!SelectorLocs.empty() && SelectorLocs.front().isValid())
1511     SelLoc = SelectorLocs.front();
1512   else
1513     SelLoc = lbrac;
1514
1515   if (!Method) {
1516     // Apply default argument promotion as for (C99 6.5.2.2p6).
1517     for (unsigned i = 0, e = Args.size(); i != e; i++) {
1518       if (Args[i]->isTypeDependent())
1519         continue;
1520
1521       ExprResult result;
1522       if (getLangOpts().DebuggerSupport) {
1523         QualType paramTy; // ignored
1524         result = checkUnknownAnyArg(SelLoc, Args[i], paramTy);
1525       } else {
1526         result = DefaultArgumentPromotion(Args[i]);
1527       }
1528       if (result.isInvalid())
1529         return true;
1530       Args[i] = result.get();
1531     }
1532
1533     unsigned DiagID;
1534     if (getLangOpts().ObjCAutoRefCount)
1535       DiagID = diag::err_arc_method_not_found;
1536     else
1537       DiagID = isClassMessage ? diag::warn_class_method_not_found
1538                               : diag::warn_inst_method_not_found;
1539     if (!getLangOpts().DebuggerSupport) {
1540       const ObjCMethodDecl *OMD = SelectorsForTypoCorrection(Sel, ReceiverType);
1541       if (OMD && !OMD->isInvalidDecl()) {
1542         if (getLangOpts().ObjCAutoRefCount)
1543           DiagID = diag::err_method_not_found_with_typo;
1544         else
1545           DiagID = isClassMessage ? diag::warn_class_method_not_found_with_typo
1546                                   : diag::warn_instance_method_not_found_with_typo;
1547         Selector MatchedSel = OMD->getSelector();
1548         SourceRange SelectorRange(SelectorLocs.front(), SelectorLocs.back());
1549         if (MatchedSel.isUnarySelector())
1550           Diag(SelLoc, DiagID)
1551             << Sel<< isClassMessage << MatchedSel
1552             << FixItHint::CreateReplacement(SelectorRange, MatchedSel.getAsString());
1553         else
1554           Diag(SelLoc, DiagID) << Sel<< isClassMessage << MatchedSel;
1555       }
1556       else
1557         Diag(SelLoc, DiagID)
1558           << Sel << isClassMessage << SourceRange(SelectorLocs.front(),
1559                                                 SelectorLocs.back());
1560       // Find the class to which we are sending this message.
1561       if (ReceiverType->isObjCObjectPointerType()) {
1562         if (ObjCInterfaceDecl *ThisClass =
1563             ReceiverType->getAs<ObjCObjectPointerType>()->getInterfaceDecl()) {
1564           Diag(ThisClass->getLocation(), diag::note_receiver_class_declared);
1565           if (!RecRange.isInvalid())
1566             if (ThisClass->lookupClassMethod(Sel))
1567               Diag(RecRange.getBegin(),diag::note_receiver_expr_here)
1568                 << FixItHint::CreateReplacement(RecRange,
1569                                                 ThisClass->getNameAsString());
1570         }
1571       }
1572     }
1573
1574     // In debuggers, we want to use __unknown_anytype for these
1575     // results so that clients can cast them.
1576     if (getLangOpts().DebuggerSupport) {
1577       ReturnType = Context.UnknownAnyTy;
1578     } else {
1579       ReturnType = Context.getObjCIdType();
1580     }
1581     VK = VK_RValue;
1582     return false;
1583   }
1584
1585   ReturnType = getMessageSendResultType(ReceiverType, Method, isClassMessage,
1586                                         isSuperMessage);
1587   VK = Expr::getValueKindForType(Method->getReturnType());
1588
1589   unsigned NumNamedArgs = Sel.getNumArgs();
1590   // Method might have more arguments than selector indicates. This is due
1591   // to addition of c-style arguments in method.
1592   if (Method->param_size() > Sel.getNumArgs())
1593     NumNamedArgs = Method->param_size();
1594   // FIXME. This need be cleaned up.
1595   if (Args.size() < NumNamedArgs) {
1596     Diag(SelLoc, diag::err_typecheck_call_too_few_args)
1597       << 2 << NumNamedArgs << static_cast<unsigned>(Args.size());
1598     return false;
1599   }
1600
1601   // Compute the set of type arguments to be substituted into each parameter
1602   // type.
1603   Optional<ArrayRef<QualType>> typeArgs
1604     = ReceiverType->getObjCSubstitutions(Method->getDeclContext());
1605   bool IsError = false;
1606   for (unsigned i = 0; i < NumNamedArgs; i++) {
1607     // We can't do any type-checking on a type-dependent argument.
1608     if (Args[i]->isTypeDependent())
1609       continue;
1610
1611     Expr *argExpr = Args[i];
1612
1613     ParmVarDecl *param = Method->parameters()[i];
1614     assert(argExpr && "CheckMessageArgumentTypes(): missing expression");
1615
1616     // Strip the unbridged-cast placeholder expression off unless it's
1617     // a consumed argument.
1618     if (argExpr->hasPlaceholderType(BuiltinType::ARCUnbridgedCast) &&
1619         !param->hasAttr<CFConsumedAttr>())
1620       argExpr = stripARCUnbridgedCast(argExpr);
1621
1622     // If the parameter is __unknown_anytype, infer its type
1623     // from the argument.
1624     if (param->getType() == Context.UnknownAnyTy) {
1625       QualType paramType;
1626       ExprResult argE = checkUnknownAnyArg(SelLoc, argExpr, paramType);
1627       if (argE.isInvalid()) {
1628         IsError = true;
1629       } else {
1630         Args[i] = argE.get();
1631
1632         // Update the parameter type in-place.
1633         param->setType(paramType);
1634       }
1635       continue;
1636     }
1637
1638     QualType origParamType = param->getType();
1639     QualType paramType = param->getType();
1640     if (typeArgs)
1641       paramType = paramType.substObjCTypeArgs(
1642                     Context,
1643                     *typeArgs,
1644                     ObjCSubstitutionContext::Parameter);
1645
1646     if (RequireCompleteType(argExpr->getSourceRange().getBegin(),
1647                             paramType,
1648                             diag::err_call_incomplete_argument, argExpr))
1649       return true;
1650
1651     InitializedEntity Entity
1652       = InitializedEntity::InitializeParameter(Context, param, paramType);
1653     ExprResult ArgE = PerformCopyInitialization(Entity, SourceLocation(), argExpr);
1654     if (ArgE.isInvalid())
1655       IsError = true;
1656     else {
1657       Args[i] = ArgE.getAs<Expr>();
1658
1659       // If we are type-erasing a block to a block-compatible
1660       // Objective-C pointer type, we may need to extend the lifetime
1661       // of the block object.
1662       if (typeArgs && Args[i]->isRValue() && paramType->isBlockPointerType() &&
1663           Args[i]->getType()->isBlockPointerType() &&
1664           origParamType->isObjCObjectPointerType()) {
1665         ExprResult arg = Args[i];
1666         maybeExtendBlockObject(arg);
1667         Args[i] = arg.get();
1668       }
1669     }
1670   }
1671
1672   // Promote additional arguments to variadic methods.
1673   if (Method->isVariadic()) {
1674     for (unsigned i = NumNamedArgs, e = Args.size(); i < e; ++i) {
1675       if (Args[i]->isTypeDependent())
1676         continue;
1677
1678       ExprResult Arg = DefaultVariadicArgumentPromotion(Args[i], VariadicMethod,
1679                                                         nullptr);
1680       IsError |= Arg.isInvalid();
1681       Args[i] = Arg.get();
1682     }
1683   } else {
1684     // Check for extra arguments to non-variadic methods.
1685     if (Args.size() != NumNamedArgs) {
1686       Diag(Args[NumNamedArgs]->getLocStart(),
1687            diag::err_typecheck_call_too_many_args)
1688         << 2 /*method*/ << NumNamedArgs << static_cast<unsigned>(Args.size())
1689         << Method->getSourceRange()
1690         << SourceRange(Args[NumNamedArgs]->getLocStart(),
1691                        Args.back()->getLocEnd());
1692     }
1693   }
1694
1695   DiagnoseSentinelCalls(Method, SelLoc, Args);
1696
1697   // Do additional checkings on method.
1698   IsError |= CheckObjCMethodCall(
1699       Method, SelLoc, makeArrayRef(Args.data(), Args.size()));
1700
1701   return IsError;
1702 }
1703
1704 bool Sema::isSelfExpr(Expr *RExpr) {
1705   // 'self' is objc 'self' in an objc method only.
1706   ObjCMethodDecl *Method =
1707       dyn_cast_or_null<ObjCMethodDecl>(CurContext->getNonClosureAncestor());
1708   return isSelfExpr(RExpr, Method);
1709 }
1710
1711 bool Sema::isSelfExpr(Expr *receiver, const ObjCMethodDecl *method) {
1712   if (!method) return false;
1713
1714   receiver = receiver->IgnoreParenLValueCasts();
1715   if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(receiver))
1716     if (DRE->getDecl() == method->getSelfDecl())
1717       return true;
1718   return false;
1719 }
1720
1721 /// LookupMethodInType - Look up a method in an ObjCObjectType.
1722 ObjCMethodDecl *Sema::LookupMethodInObjectType(Selector sel, QualType type,
1723                                                bool isInstance) {
1724   const ObjCObjectType *objType = type->castAs<ObjCObjectType>();
1725   if (ObjCInterfaceDecl *iface = objType->getInterface()) {
1726     // Look it up in the main interface (and categories, etc.)
1727     if (ObjCMethodDecl *method = iface->lookupMethod(sel, isInstance))
1728       return method;
1729
1730     // Okay, look for "private" methods declared in any
1731     // @implementations we've seen.
1732     if (ObjCMethodDecl *method = iface->lookupPrivateMethod(sel, isInstance))
1733       return method;
1734   }
1735
1736   // Check qualifiers.
1737   for (const auto *I : objType->quals())
1738     if (ObjCMethodDecl *method = I->lookupMethod(sel, isInstance))
1739       return method;
1740
1741   return nullptr;
1742 }
1743
1744 /// LookupMethodInQualifiedType - Lookups up a method in protocol qualifier
1745 /// list of a qualified objective pointer type.
1746 ObjCMethodDecl *Sema::LookupMethodInQualifiedType(Selector Sel,
1747                                               const ObjCObjectPointerType *OPT,
1748                                               bool Instance)
1749 {
1750   ObjCMethodDecl *MD = nullptr;
1751   for (const auto *PROTO : OPT->quals()) {
1752     if ((MD = PROTO->lookupMethod(Sel, Instance))) {
1753       return MD;
1754     }
1755   }
1756   return nullptr;
1757 }
1758
1759 /// HandleExprPropertyRefExpr - Handle foo.bar where foo is a pointer to an
1760 /// objective C interface.  This is a property reference expression.
1761 ExprResult Sema::
1762 HandleExprPropertyRefExpr(const ObjCObjectPointerType *OPT,
1763                           Expr *BaseExpr, SourceLocation OpLoc,
1764                           DeclarationName MemberName,
1765                           SourceLocation MemberLoc,
1766                           SourceLocation SuperLoc, QualType SuperType,
1767                           bool Super) {
1768   const ObjCInterfaceType *IFaceT = OPT->getInterfaceType();
1769   ObjCInterfaceDecl *IFace = IFaceT->getDecl();
1770
1771   if (!MemberName.isIdentifier()) {
1772     Diag(MemberLoc, diag::err_invalid_property_name)
1773       << MemberName << QualType(OPT, 0);
1774     return ExprError();
1775   }
1776
1777   IdentifierInfo *Member = MemberName.getAsIdentifierInfo();
1778
1779   SourceRange BaseRange = Super? SourceRange(SuperLoc)
1780                                : BaseExpr->getSourceRange();
1781   if (RequireCompleteType(MemberLoc, OPT->getPointeeType(),
1782                           diag::err_property_not_found_forward_class,
1783                           MemberName, BaseRange))
1784     return ExprError();
1785
1786   if (ObjCPropertyDecl *PD = IFace->FindPropertyDeclaration(
1787           Member, ObjCPropertyQueryKind::OBJC_PR_query_instance)) {
1788     // Check whether we can reference this property.
1789     if (DiagnoseUseOfDecl(PD, MemberLoc))
1790       return ExprError();
1791     if (Super)
1792       return new (Context)
1793           ObjCPropertyRefExpr(PD, Context.PseudoObjectTy, VK_LValue,
1794                               OK_ObjCProperty, MemberLoc, SuperLoc, SuperType);
1795     else
1796       return new (Context)
1797           ObjCPropertyRefExpr(PD, Context.PseudoObjectTy, VK_LValue,
1798                               OK_ObjCProperty, MemberLoc, BaseExpr);
1799   }
1800   // Check protocols on qualified interfaces.
1801   for (const auto *I : OPT->quals())
1802     if (ObjCPropertyDecl *PD = I->FindPropertyDeclaration(
1803             Member, ObjCPropertyQueryKind::OBJC_PR_query_instance)) {
1804       // Check whether we can reference this property.
1805       if (DiagnoseUseOfDecl(PD, MemberLoc))
1806         return ExprError();
1807
1808       if (Super)
1809         return new (Context) ObjCPropertyRefExpr(
1810             PD, Context.PseudoObjectTy, VK_LValue, OK_ObjCProperty, MemberLoc,
1811             SuperLoc, SuperType);
1812       else
1813         return new (Context)
1814             ObjCPropertyRefExpr(PD, Context.PseudoObjectTy, VK_LValue,
1815                                 OK_ObjCProperty, MemberLoc, BaseExpr);
1816     }
1817   // If that failed, look for an "implicit" property by seeing if the nullary
1818   // selector is implemented.
1819
1820   // FIXME: The logic for looking up nullary and unary selectors should be
1821   // shared with the code in ActOnInstanceMessage.
1822
1823   Selector Sel = PP.getSelectorTable().getNullarySelector(Member);
1824   ObjCMethodDecl *Getter = IFace->lookupInstanceMethod(Sel);
1825
1826   // May be found in property's qualified list.
1827   if (!Getter)
1828     Getter = LookupMethodInQualifiedType(Sel, OPT, true);
1829
1830   // If this reference is in an @implementation, check for 'private' methods.
1831   if (!Getter)
1832     Getter = IFace->lookupPrivateMethod(Sel);
1833
1834   if (Getter) {
1835     // Check if we can reference this property.
1836     if (DiagnoseUseOfDecl(Getter, MemberLoc))
1837       return ExprError();
1838   }
1839   // If we found a getter then this may be a valid dot-reference, we
1840   // will look for the matching setter, in case it is needed.
1841   Selector SetterSel =
1842     SelectorTable::constructSetterSelector(PP.getIdentifierTable(),
1843                                            PP.getSelectorTable(), Member);
1844   ObjCMethodDecl *Setter = IFace->lookupInstanceMethod(SetterSel);
1845
1846   // May be found in property's qualified list.
1847   if (!Setter)
1848     Setter = LookupMethodInQualifiedType(SetterSel, OPT, true);
1849
1850   if (!Setter) {
1851     // If this reference is in an @implementation, also check for 'private'
1852     // methods.
1853     Setter = IFace->lookupPrivateMethod(SetterSel);
1854   }
1855
1856   if (Setter && DiagnoseUseOfDecl(Setter, MemberLoc))
1857     return ExprError();
1858
1859   // Special warning if member name used in a property-dot for a setter accessor
1860   // does not use a property with same name; e.g. obj.X = ... for a property with
1861   // name 'x'.
1862   if (Setter && Setter->isImplicit() && Setter->isPropertyAccessor() &&
1863       !IFace->FindPropertyDeclaration(
1864           Member, ObjCPropertyQueryKind::OBJC_PR_query_instance)) {
1865       if (const ObjCPropertyDecl *PDecl = Setter->findPropertyDecl()) {
1866         // Do not warn if user is using property-dot syntax to make call to
1867         // user named setter.
1868         if (!(PDecl->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_setter))
1869           Diag(MemberLoc,
1870                diag::warn_property_access_suggest)
1871           << MemberName << QualType(OPT, 0) << PDecl->getName()
1872           << FixItHint::CreateReplacement(MemberLoc, PDecl->getName());
1873       }
1874   }
1875
1876   if (Getter || Setter) {
1877     if (Super)
1878       return new (Context)
1879           ObjCPropertyRefExpr(Getter, Setter, Context.PseudoObjectTy, VK_LValue,
1880                               OK_ObjCProperty, MemberLoc, SuperLoc, SuperType);
1881     else
1882       return new (Context)
1883           ObjCPropertyRefExpr(Getter, Setter, Context.PseudoObjectTy, VK_LValue,
1884                               OK_ObjCProperty, MemberLoc, BaseExpr);
1885
1886   }
1887
1888   // Attempt to correct for typos in property names.
1889   if (TypoCorrection Corrected =
1890           CorrectTypo(DeclarationNameInfo(MemberName, MemberLoc),
1891                       LookupOrdinaryName, nullptr, nullptr,
1892                       llvm::make_unique<DeclFilterCCC<ObjCPropertyDecl>>(),
1893                       CTK_ErrorRecovery, IFace, false, OPT)) {
1894     DeclarationName TypoResult = Corrected.getCorrection();
1895     if (TypoResult.isIdentifier() &&
1896         TypoResult.getAsIdentifierInfo() == Member) {
1897       // There is no need to try the correction if it is the same.
1898       NamedDecl *ChosenDecl =
1899         Corrected.isKeyword() ? nullptr : Corrected.getFoundDecl();
1900       if (ChosenDecl && isa<ObjCPropertyDecl>(ChosenDecl))
1901         if (cast<ObjCPropertyDecl>(ChosenDecl)->isClassProperty()) {
1902           // This is a class property, we should not use the instance to
1903           // access it.
1904           Diag(MemberLoc, diag::err_class_property_found) << MemberName
1905           << OPT->getInterfaceDecl()->getName()
1906           << FixItHint::CreateReplacement(BaseExpr->getSourceRange(),
1907                                           OPT->getInterfaceDecl()->getName());
1908           return ExprError();
1909         }
1910     } else {
1911       diagnoseTypo(Corrected, PDiag(diag::err_property_not_found_suggest)
1912                                 << MemberName << QualType(OPT, 0));
1913       return HandleExprPropertyRefExpr(OPT, BaseExpr, OpLoc,
1914                                        TypoResult, MemberLoc,
1915                                        SuperLoc, SuperType, Super);
1916     }
1917   }
1918   ObjCInterfaceDecl *ClassDeclared;
1919   if (ObjCIvarDecl *Ivar =
1920       IFace->lookupInstanceVariable(Member, ClassDeclared)) {
1921     QualType T = Ivar->getType();
1922     if (const ObjCObjectPointerType * OBJPT =
1923         T->getAsObjCInterfacePointerType()) {
1924       if (RequireCompleteType(MemberLoc, OBJPT->getPointeeType(),
1925                               diag::err_property_not_as_forward_class,
1926                               MemberName, BaseExpr))
1927         return ExprError();
1928     }
1929     Diag(MemberLoc,
1930          diag::err_ivar_access_using_property_syntax_suggest)
1931     << MemberName << QualType(OPT, 0) << Ivar->getDeclName()
1932     << FixItHint::CreateReplacement(OpLoc, "->");
1933     return ExprError();
1934   }
1935
1936   Diag(MemberLoc, diag::err_property_not_found)
1937     << MemberName << QualType(OPT, 0);
1938   if (Setter)
1939     Diag(Setter->getLocation(), diag::note_getter_unavailable)
1940           << MemberName << BaseExpr->getSourceRange();
1941   return ExprError();
1942 }
1943
1944 ExprResult Sema::
1945 ActOnClassPropertyRefExpr(IdentifierInfo &receiverName,
1946                           IdentifierInfo &propertyName,
1947                           SourceLocation receiverNameLoc,
1948                           SourceLocation propertyNameLoc) {
1949
1950   IdentifierInfo *receiverNamePtr = &receiverName;
1951   ObjCInterfaceDecl *IFace = getObjCInterfaceDecl(receiverNamePtr,
1952                                                   receiverNameLoc);
1953
1954   QualType SuperType;
1955   if (!IFace) {
1956     // If the "receiver" is 'super' in a method, handle it as an expression-like
1957     // property reference.
1958     if (receiverNamePtr->isStr("super")) {
1959       if (ObjCMethodDecl *CurMethod = tryCaptureObjCSelf(receiverNameLoc)) {
1960         if (auto classDecl = CurMethod->getClassInterface()) {
1961           SuperType = QualType(classDecl->getSuperClassType(), 0);
1962           if (CurMethod->isInstanceMethod()) {
1963             if (SuperType.isNull()) {
1964               // The current class does not have a superclass.
1965               Diag(receiverNameLoc, diag::err_root_class_cannot_use_super)
1966                 << CurMethod->getClassInterface()->getIdentifier();
1967               return ExprError();
1968             }
1969             QualType T = Context.getObjCObjectPointerType(SuperType);
1970
1971             return HandleExprPropertyRefExpr(T->castAs<ObjCObjectPointerType>(),
1972                                              /*BaseExpr*/nullptr,
1973                                              SourceLocation()/*OpLoc*/,
1974                                              &propertyName,
1975                                              propertyNameLoc,
1976                                              receiverNameLoc, T, true);
1977           }
1978
1979           // Otherwise, if this is a class method, try dispatching to our
1980           // superclass.
1981           IFace = CurMethod->getClassInterface()->getSuperClass();
1982         }
1983       }
1984     }
1985
1986     if (!IFace) {
1987       Diag(receiverNameLoc, diag::err_expected_either) << tok::identifier
1988                                                        << tok::l_paren;
1989       return ExprError();
1990     }
1991   }
1992
1993   Selector GetterSel;
1994   Selector SetterSel;
1995   if (auto PD = IFace->FindPropertyDeclaration(
1996           &propertyName, ObjCPropertyQueryKind::OBJC_PR_query_class)) {
1997     GetterSel = PD->getGetterName();
1998     SetterSel = PD->getSetterName();
1999   } else {
2000     GetterSel = PP.getSelectorTable().getNullarySelector(&propertyName);
2001     SetterSel = SelectorTable::constructSetterSelector(
2002         PP.getIdentifierTable(), PP.getSelectorTable(), &propertyName);
2003   }
2004
2005   // Search for a declared property first.
2006   ObjCMethodDecl *Getter = IFace->lookupClassMethod(GetterSel);
2007
2008   // If this reference is in an @implementation, check for 'private' methods.
2009   if (!Getter)
2010     Getter = IFace->lookupPrivateClassMethod(GetterSel);
2011
2012   if (Getter) {
2013     // FIXME: refactor/share with ActOnMemberReference().
2014     // Check if we can reference this property.
2015     if (DiagnoseUseOfDecl(Getter, propertyNameLoc))
2016       return ExprError();
2017   }
2018
2019   // Look for the matching setter, in case it is needed.
2020   ObjCMethodDecl *Setter = IFace->lookupClassMethod(SetterSel);
2021   if (!Setter) {
2022     // If this reference is in an @implementation, also check for 'private'
2023     // methods.
2024     Setter = IFace->lookupPrivateClassMethod(SetterSel);
2025   }
2026   // Look through local category implementations associated with the class.
2027   if (!Setter)
2028     Setter = IFace->getCategoryClassMethod(SetterSel);
2029
2030   if (Setter && DiagnoseUseOfDecl(Setter, propertyNameLoc))
2031     return ExprError();
2032
2033   if (Getter || Setter) {
2034     if (!SuperType.isNull())
2035       return new (Context)
2036           ObjCPropertyRefExpr(Getter, Setter, Context.PseudoObjectTy, VK_LValue,
2037                               OK_ObjCProperty, propertyNameLoc, receiverNameLoc,
2038                               SuperType);
2039
2040     return new (Context) ObjCPropertyRefExpr(
2041         Getter, Setter, Context.PseudoObjectTy, VK_LValue, OK_ObjCProperty,
2042         propertyNameLoc, receiverNameLoc, IFace);
2043   }
2044   return ExprError(Diag(propertyNameLoc, diag::err_property_not_found)
2045                      << &propertyName << Context.getObjCInterfaceType(IFace));
2046 }
2047
2048 namespace {
2049
2050 class ObjCInterfaceOrSuperCCC : public CorrectionCandidateCallback {
2051  public:
2052   ObjCInterfaceOrSuperCCC(ObjCMethodDecl *Method) {
2053     // Determine whether "super" is acceptable in the current context.
2054     if (Method && Method->getClassInterface())
2055       WantObjCSuper = Method->getClassInterface()->getSuperClass();
2056   }
2057
2058   bool ValidateCandidate(const TypoCorrection &candidate) override {
2059     return candidate.getCorrectionDeclAs<ObjCInterfaceDecl>() ||
2060         candidate.isKeyword("super");
2061   }
2062 };
2063
2064 } // end anonymous namespace
2065
2066 Sema::ObjCMessageKind Sema::getObjCMessageKind(Scope *S,
2067                                                IdentifierInfo *Name,
2068                                                SourceLocation NameLoc,
2069                                                bool IsSuper,
2070                                                bool HasTrailingDot,
2071                                                ParsedType &ReceiverType) {
2072   ReceiverType = nullptr;
2073
2074   // If the identifier is "super" and there is no trailing dot, we're
2075   // messaging super. If the identifier is "super" and there is a
2076   // trailing dot, it's an instance message.
2077   if (IsSuper && S->isInObjcMethodScope())
2078     return HasTrailingDot? ObjCInstanceMessage : ObjCSuperMessage;
2079
2080   LookupResult Result(*this, Name, NameLoc, LookupOrdinaryName);
2081   LookupName(Result, S);
2082
2083   switch (Result.getResultKind()) {
2084   case LookupResult::NotFound:
2085     // Normal name lookup didn't find anything. If we're in an
2086     // Objective-C method, look for ivars. If we find one, we're done!
2087     // FIXME: This is a hack. Ivar lookup should be part of normal
2088     // lookup.
2089     if (ObjCMethodDecl *Method = getCurMethodDecl()) {
2090       if (!Method->getClassInterface()) {
2091         // Fall back: let the parser try to parse it as an instance message.
2092         return ObjCInstanceMessage;
2093       }
2094
2095       ObjCInterfaceDecl *ClassDeclared;
2096       if (Method->getClassInterface()->lookupInstanceVariable(Name,
2097                                                               ClassDeclared))
2098         return ObjCInstanceMessage;
2099     }
2100
2101     // Break out; we'll perform typo correction below.
2102     break;
2103
2104   case LookupResult::NotFoundInCurrentInstantiation:
2105   case LookupResult::FoundOverloaded:
2106   case LookupResult::FoundUnresolvedValue:
2107   case LookupResult::Ambiguous:
2108     Result.suppressDiagnostics();
2109     return ObjCInstanceMessage;
2110
2111   case LookupResult::Found: {
2112     // If the identifier is a class or not, and there is a trailing dot,
2113     // it's an instance message.
2114     if (HasTrailingDot)
2115       return ObjCInstanceMessage;
2116     // We found something. If it's a type, then we have a class
2117     // message. Otherwise, it's an instance message.
2118     NamedDecl *ND = Result.getFoundDecl();
2119     QualType T;
2120     if (ObjCInterfaceDecl *Class = dyn_cast<ObjCInterfaceDecl>(ND))
2121       T = Context.getObjCInterfaceType(Class);
2122     else if (TypeDecl *Type = dyn_cast<TypeDecl>(ND)) {
2123       T = Context.getTypeDeclType(Type);
2124       DiagnoseUseOfDecl(Type, NameLoc);
2125     }
2126     else
2127       return ObjCInstanceMessage;
2128
2129     //  We have a class message, and T is the type we're
2130     //  messaging. Build source-location information for it.
2131     TypeSourceInfo *TSInfo = Context.getTrivialTypeSourceInfo(T, NameLoc);
2132     ReceiverType = CreateParsedType(T, TSInfo);
2133     return ObjCClassMessage;
2134   }
2135   }
2136
2137   if (TypoCorrection Corrected = CorrectTypo(
2138           Result.getLookupNameInfo(), Result.getLookupKind(), S, nullptr,
2139           llvm::make_unique<ObjCInterfaceOrSuperCCC>(getCurMethodDecl()),
2140           CTK_ErrorRecovery, nullptr, false, nullptr, false)) {
2141     if (Corrected.isKeyword()) {
2142       // If we've found the keyword "super" (the only keyword that would be
2143       // returned by CorrectTypo), this is a send to super.
2144       diagnoseTypo(Corrected,
2145                    PDiag(diag::err_unknown_receiver_suggest) << Name);
2146       return ObjCSuperMessage;
2147     } else if (ObjCInterfaceDecl *Class =
2148                    Corrected.getCorrectionDeclAs<ObjCInterfaceDecl>()) {
2149       // If we found a declaration, correct when it refers to an Objective-C
2150       // class.
2151       diagnoseTypo(Corrected,
2152                    PDiag(diag::err_unknown_receiver_suggest) << Name);
2153       QualType T = Context.getObjCInterfaceType(Class);
2154       TypeSourceInfo *TSInfo = Context.getTrivialTypeSourceInfo(T, NameLoc);
2155       ReceiverType = CreateParsedType(T, TSInfo);
2156       return ObjCClassMessage;
2157     }
2158   }
2159
2160   // Fall back: let the parser try to parse it as an instance message.
2161   return ObjCInstanceMessage;
2162 }
2163
2164 ExprResult Sema::ActOnSuperMessage(Scope *S,
2165                                    SourceLocation SuperLoc,
2166                                    Selector Sel,
2167                                    SourceLocation LBracLoc,
2168                                    ArrayRef<SourceLocation> SelectorLocs,
2169                                    SourceLocation RBracLoc,
2170                                    MultiExprArg Args) {
2171   // Determine whether we are inside a method or not.
2172   ObjCMethodDecl *Method = tryCaptureObjCSelf(SuperLoc);
2173   if (!Method) {
2174     Diag(SuperLoc, diag::err_invalid_receiver_to_message_super);
2175     return ExprError();
2176   }
2177
2178   ObjCInterfaceDecl *Class = Method->getClassInterface();
2179   if (!Class) {
2180     Diag(SuperLoc, diag::err_no_super_class_message)
2181       << Method->getDeclName();
2182     return ExprError();
2183   }
2184
2185   QualType SuperTy(Class->getSuperClassType(), 0);
2186   if (SuperTy.isNull()) {
2187     // The current class does not have a superclass.
2188     Diag(SuperLoc, diag::err_root_class_cannot_use_super)
2189       << Class->getIdentifier();
2190     return ExprError();
2191   }
2192
2193   // We are in a method whose class has a superclass, so 'super'
2194   // is acting as a keyword.
2195   if (Method->getSelector() == Sel)
2196     getCurFunction()->ObjCShouldCallSuper = false;
2197
2198   if (Method->isInstanceMethod()) {
2199     // Since we are in an instance method, this is an instance
2200     // message to the superclass instance.
2201     SuperTy = Context.getObjCObjectPointerType(SuperTy);
2202     return BuildInstanceMessage(nullptr, SuperTy, SuperLoc,
2203                                 Sel, /*Method=*/nullptr,
2204                                 LBracLoc, SelectorLocs, RBracLoc, Args);
2205   }
2206
2207   // Since we are in a class method, this is a class message to
2208   // the superclass.
2209   return BuildClassMessage(/*ReceiverTypeInfo=*/nullptr,
2210                            SuperTy,
2211                            SuperLoc, Sel, /*Method=*/nullptr,
2212                            LBracLoc, SelectorLocs, RBracLoc, Args);
2213 }
2214
2215 ExprResult Sema::BuildClassMessageImplicit(QualType ReceiverType,
2216                                            bool isSuperReceiver,
2217                                            SourceLocation Loc,
2218                                            Selector Sel,
2219                                            ObjCMethodDecl *Method,
2220                                            MultiExprArg Args) {
2221   TypeSourceInfo *receiverTypeInfo = nullptr;
2222   if (!ReceiverType.isNull())
2223     receiverTypeInfo = Context.getTrivialTypeSourceInfo(ReceiverType);
2224
2225   return BuildClassMessage(receiverTypeInfo, ReceiverType,
2226                           /*SuperLoc=*/isSuperReceiver ? Loc : SourceLocation(),
2227                            Sel, Method, Loc, Loc, Loc, Args,
2228                            /*isImplicit=*/true);
2229 }
2230
2231 static void applyCocoaAPICheck(Sema &S, const ObjCMessageExpr *Msg,
2232                                unsigned DiagID,
2233                                bool (*refactor)(const ObjCMessageExpr *,
2234                                               const NSAPI &, edit::Commit &)) {
2235   SourceLocation MsgLoc = Msg->getExprLoc();
2236   if (S.Diags.isIgnored(DiagID, MsgLoc))
2237     return;
2238
2239   SourceManager &SM = S.SourceMgr;
2240   edit::Commit ECommit(SM, S.LangOpts);
2241   if (refactor(Msg,*S.NSAPIObj, ECommit)) {
2242     DiagnosticBuilder Builder = S.Diag(MsgLoc, DiagID)
2243                         << Msg->getSelector() << Msg->getSourceRange();
2244     // FIXME: Don't emit diagnostic at all if fixits are non-commitable.
2245     if (!ECommit.isCommitable())
2246       return;
2247     for (edit::Commit::edit_iterator
2248            I = ECommit.edit_begin(), E = ECommit.edit_end(); I != E; ++I) {
2249       const edit::Commit::Edit &Edit = *I;
2250       switch (Edit.Kind) {
2251       case edit::Commit::Act_Insert:
2252         Builder.AddFixItHint(FixItHint::CreateInsertion(Edit.OrigLoc,
2253                                                         Edit.Text,
2254                                                         Edit.BeforePrev));
2255         break;
2256       case edit::Commit::Act_InsertFromRange:
2257         Builder.AddFixItHint(
2258             FixItHint::CreateInsertionFromRange(Edit.OrigLoc,
2259                                                 Edit.getInsertFromRange(SM),
2260                                                 Edit.BeforePrev));
2261         break;
2262       case edit::Commit::Act_Remove:
2263         Builder.AddFixItHint(FixItHint::CreateRemoval(Edit.getFileRange(SM)));
2264         break;
2265       }
2266     }
2267   }
2268 }
2269
2270 static void checkCocoaAPI(Sema &S, const ObjCMessageExpr *Msg) {
2271   applyCocoaAPICheck(S, Msg, diag::warn_objc_redundant_literal_use,
2272                      edit::rewriteObjCRedundantCallWithLiteral);
2273 }
2274
2275 static void checkFoundationAPI(Sema &S, SourceLocation Loc,
2276                                const ObjCMethodDecl *Method,
2277                                ArrayRef<Expr *> Args, QualType ReceiverType,
2278                                bool IsClassObjectCall) {
2279   // Check if this is a performSelector method that uses a selector that returns
2280   // a record or a vector type.
2281   if (Method->getSelector().getMethodFamily() != OMF_performSelector ||
2282       Args.empty())
2283     return;
2284   const auto *SE = dyn_cast<ObjCSelectorExpr>(Args[0]->IgnoreParens());
2285   if (!SE)
2286     return;
2287   ObjCMethodDecl *ImpliedMethod;
2288   if (!IsClassObjectCall) {
2289     const auto *OPT = ReceiverType->getAs<ObjCObjectPointerType>();
2290     if (!OPT || !OPT->getInterfaceDecl())
2291       return;
2292     ImpliedMethod =
2293         OPT->getInterfaceDecl()->lookupInstanceMethod(SE->getSelector());
2294     if (!ImpliedMethod)
2295       ImpliedMethod =
2296           OPT->getInterfaceDecl()->lookupPrivateMethod(SE->getSelector());
2297   } else {
2298     const auto *IT = ReceiverType->getAs<ObjCInterfaceType>();
2299     if (!IT)
2300       return;
2301     ImpliedMethod = IT->getDecl()->lookupClassMethod(SE->getSelector());
2302     if (!ImpliedMethod)
2303       ImpliedMethod =
2304           IT->getDecl()->lookupPrivateClassMethod(SE->getSelector());
2305   }
2306   if (!ImpliedMethod)
2307     return;
2308   QualType Ret = ImpliedMethod->getReturnType();
2309   if (Ret->isRecordType() || Ret->isVectorType() || Ret->isExtVectorType()) {
2310     QualType Ret = ImpliedMethod->getReturnType();
2311     S.Diag(Loc, diag::warn_objc_unsafe_perform_selector)
2312         << Method->getSelector()
2313         << (!Ret->isRecordType()
2314                 ? /*Vector*/ 2
2315                 : Ret->isUnionType() ? /*Union*/ 1 : /*Struct*/ 0);
2316     S.Diag(ImpliedMethod->getLocStart(),
2317            diag::note_objc_unsafe_perform_selector_method_declared_here)
2318         << ImpliedMethod->getSelector() << Ret;
2319   }
2320 }
2321
2322 /// \brief Diagnose use of %s directive in an NSString which is being passed
2323 /// as formatting string to formatting method.
2324 static void
2325 DiagnoseCStringFormatDirectiveInObjCAPI(Sema &S,
2326                                         ObjCMethodDecl *Method,
2327                                         Selector Sel,
2328                                         Expr **Args, unsigned NumArgs) {
2329   unsigned Idx = 0;
2330   bool Format = false;
2331   ObjCStringFormatFamily SFFamily = Sel.getStringFormatFamily();
2332   if (SFFamily == ObjCStringFormatFamily::SFF_NSString) {
2333     Idx = 0;
2334     Format = true;
2335   }
2336   else if (Method) {
2337     for (const auto *I : Method->specific_attrs<FormatAttr>()) {
2338       if (S.GetFormatNSStringIdx(I, Idx)) {
2339         Format = true;
2340         break;
2341       }
2342     }
2343   }
2344   if (!Format || NumArgs <= Idx)
2345     return;
2346
2347   Expr *FormatExpr = Args[Idx];
2348   if (ObjCStringLiteral *OSL =
2349       dyn_cast<ObjCStringLiteral>(FormatExpr->IgnoreParenImpCasts())) {
2350     StringLiteral *FormatString = OSL->getString();
2351     if (S.FormatStringHasSArg(FormatString)) {
2352       S.Diag(FormatExpr->getExprLoc(), diag::warn_objc_cdirective_format_string)
2353         << "%s" << 0 << 0;
2354       if (Method)
2355         S.Diag(Method->getLocation(), diag::note_method_declared_at)
2356           << Method->getDeclName();
2357     }
2358   }
2359 }
2360
2361 /// \brief Build an Objective-C class message expression.
2362 ///
2363 /// This routine takes care of both normal class messages and
2364 /// class messages to the superclass.
2365 ///
2366 /// \param ReceiverTypeInfo Type source information that describes the
2367 /// receiver of this message. This may be NULL, in which case we are
2368 /// sending to the superclass and \p SuperLoc must be a valid source
2369 /// location.
2370
2371 /// \param ReceiverType The type of the object receiving the
2372 /// message. When \p ReceiverTypeInfo is non-NULL, this is the same
2373 /// type as that refers to. For a superclass send, this is the type of
2374 /// the superclass.
2375 ///
2376 /// \param SuperLoc The location of the "super" keyword in a
2377 /// superclass message.
2378 ///
2379 /// \param Sel The selector to which the message is being sent.
2380 ///
2381 /// \param Method The method that this class message is invoking, if
2382 /// already known.
2383 ///
2384 /// \param LBracLoc The location of the opening square bracket ']'.
2385 ///
2386 /// \param RBracLoc The location of the closing square bracket ']'.
2387 ///
2388 /// \param ArgsIn The message arguments.
2389 ExprResult Sema::BuildClassMessage(TypeSourceInfo *ReceiverTypeInfo,
2390                                    QualType ReceiverType,
2391                                    SourceLocation SuperLoc,
2392                                    Selector Sel,
2393                                    ObjCMethodDecl *Method,
2394                                    SourceLocation LBracLoc,
2395                                    ArrayRef<SourceLocation> SelectorLocs,
2396                                    SourceLocation RBracLoc,
2397                                    MultiExprArg ArgsIn,
2398                                    bool isImplicit) {
2399   SourceLocation Loc = SuperLoc.isValid()? SuperLoc
2400     : ReceiverTypeInfo->getTypeLoc().getSourceRange().getBegin();
2401   if (LBracLoc.isInvalid()) {
2402     Diag(Loc, diag::err_missing_open_square_message_send)
2403       << FixItHint::CreateInsertion(Loc, "[");
2404     LBracLoc = Loc;
2405   }
2406   SourceLocation SelLoc;
2407   if (!SelectorLocs.empty() && SelectorLocs.front().isValid())
2408     SelLoc = SelectorLocs.front();
2409   else
2410     SelLoc = Loc;
2411
2412   if (ReceiverType->isDependentType()) {
2413     // If the receiver type is dependent, we can't type-check anything
2414     // at this point. Build a dependent expression.
2415     unsigned NumArgs = ArgsIn.size();
2416     Expr **Args = ArgsIn.data();
2417     assert(SuperLoc.isInvalid() && "Message to super with dependent type");
2418     return ObjCMessageExpr::Create(
2419         Context, ReceiverType, VK_RValue, LBracLoc, ReceiverTypeInfo, Sel,
2420         SelectorLocs, /*Method=*/nullptr, makeArrayRef(Args, NumArgs), RBracLoc,
2421         isImplicit);
2422   }
2423
2424   // Find the class to which we are sending this message.
2425   ObjCInterfaceDecl *Class = nullptr;
2426   const ObjCObjectType *ClassType = ReceiverType->getAs<ObjCObjectType>();
2427   if (!ClassType || !(Class = ClassType->getInterface())) {
2428     Diag(Loc, diag::err_invalid_receiver_class_message)
2429       << ReceiverType;
2430     return ExprError();
2431   }
2432   assert(Class && "We don't know which class we're messaging?");
2433   // objc++ diagnoses during typename annotation.
2434   if (!getLangOpts().CPlusPlus)
2435     (void)DiagnoseUseOfDecl(Class, SelLoc);
2436   // Find the method we are messaging.
2437   if (!Method) {
2438     SourceRange TypeRange
2439       = SuperLoc.isValid()? SourceRange(SuperLoc)
2440                           : ReceiverTypeInfo->getTypeLoc().getSourceRange();
2441     if (RequireCompleteType(Loc, Context.getObjCInterfaceType(Class),
2442                             (getLangOpts().ObjCAutoRefCount
2443                                ? diag::err_arc_receiver_forward_class
2444                                : diag::warn_receiver_forward_class),
2445                             TypeRange)) {
2446       // A forward class used in messaging is treated as a 'Class'
2447       Method = LookupFactoryMethodInGlobalPool(Sel,
2448                                                SourceRange(LBracLoc, RBracLoc));
2449       if (Method && !getLangOpts().ObjCAutoRefCount)
2450         Diag(Method->getLocation(), diag::note_method_sent_forward_class)
2451           << Method->getDeclName();
2452     }
2453     if (!Method)
2454       Method = Class->lookupClassMethod(Sel);
2455
2456     // If we have an implementation in scope, check "private" methods.
2457     if (!Method)
2458       Method = Class->lookupPrivateClassMethod(Sel);
2459
2460     if (Method && DiagnoseUseOfDecl(Method, SelLoc))
2461       return ExprError();
2462   }
2463
2464   // Check the argument types and determine the result type.
2465   QualType ReturnType;
2466   ExprValueKind VK = VK_RValue;
2467
2468   unsigned NumArgs = ArgsIn.size();
2469   Expr **Args = ArgsIn.data();
2470   if (CheckMessageArgumentTypes(ReceiverType, MultiExprArg(Args, NumArgs),
2471                                 Sel, SelectorLocs,
2472                                 Method, true,
2473                                 SuperLoc.isValid(), LBracLoc, RBracLoc,
2474                                 SourceRange(),
2475                                 ReturnType, VK))
2476     return ExprError();
2477
2478   if (Method && !Method->getReturnType()->isVoidType() &&
2479       RequireCompleteType(LBracLoc, Method->getReturnType(),
2480                           diag::err_illegal_message_expr_incomplete_type))
2481     return ExprError();
2482
2483   // Warn about explicit call of +initialize on its own class. But not on 'super'.
2484   if (Method && Method->getMethodFamily() == OMF_initialize) {
2485     if (!SuperLoc.isValid()) {
2486       const ObjCInterfaceDecl *ID =
2487         dyn_cast<ObjCInterfaceDecl>(Method->getDeclContext());
2488       if (ID == Class) {
2489         Diag(Loc, diag::warn_direct_initialize_call);
2490         Diag(Method->getLocation(), diag::note_method_declared_at)
2491           << Method->getDeclName();
2492       }
2493     }
2494     else if (ObjCMethodDecl *CurMeth = getCurMethodDecl()) {
2495       // [super initialize] is allowed only within an +initialize implementation
2496       if (CurMeth->getMethodFamily() != OMF_initialize) {
2497         Diag(Loc, diag::warn_direct_super_initialize_call);
2498         Diag(Method->getLocation(), diag::note_method_declared_at)
2499           << Method->getDeclName();
2500         Diag(CurMeth->getLocation(), diag::note_method_declared_at)
2501         << CurMeth->getDeclName();
2502       }
2503     }
2504   }
2505
2506   DiagnoseCStringFormatDirectiveInObjCAPI(*this, Method, Sel, Args, NumArgs);
2507
2508   // Construct the appropriate ObjCMessageExpr.
2509   ObjCMessageExpr *Result;
2510   if (SuperLoc.isValid())
2511     Result = ObjCMessageExpr::Create(Context, ReturnType, VK, LBracLoc,
2512                                      SuperLoc, /*IsInstanceSuper=*/false,
2513                                      ReceiverType, Sel, SelectorLocs,
2514                                      Method, makeArrayRef(Args, NumArgs),
2515                                      RBracLoc, isImplicit);
2516   else {
2517     Result = ObjCMessageExpr::Create(Context, ReturnType, VK, LBracLoc,
2518                                      ReceiverTypeInfo, Sel, SelectorLocs,
2519                                      Method, makeArrayRef(Args, NumArgs),
2520                                      RBracLoc, isImplicit);
2521     if (!isImplicit)
2522       checkCocoaAPI(*this, Result);
2523   }
2524   if (Method)
2525     checkFoundationAPI(*this, SelLoc, Method, makeArrayRef(Args, NumArgs),
2526                        ReceiverType, /*IsClassObjectCall=*/true);
2527   return MaybeBindToTemporary(Result);
2528 }
2529
2530 // ActOnClassMessage - used for both unary and keyword messages.
2531 // ArgExprs is optional - if it is present, the number of expressions
2532 // is obtained from Sel.getNumArgs().
2533 ExprResult Sema::ActOnClassMessage(Scope *S,
2534                                    ParsedType Receiver,
2535                                    Selector Sel,
2536                                    SourceLocation LBracLoc,
2537                                    ArrayRef<SourceLocation> SelectorLocs,
2538                                    SourceLocation RBracLoc,
2539                                    MultiExprArg Args) {
2540   TypeSourceInfo *ReceiverTypeInfo;
2541   QualType ReceiverType = GetTypeFromParser(Receiver, &ReceiverTypeInfo);
2542   if (ReceiverType.isNull())
2543     return ExprError();
2544
2545   if (!ReceiverTypeInfo)
2546     ReceiverTypeInfo = Context.getTrivialTypeSourceInfo(ReceiverType, LBracLoc);
2547
2548   return BuildClassMessage(ReceiverTypeInfo, ReceiverType,
2549                            /*SuperLoc=*/SourceLocation(), Sel,
2550                            /*Method=*/nullptr, LBracLoc, SelectorLocs, RBracLoc,
2551                            Args);
2552 }
2553
2554 ExprResult Sema::BuildInstanceMessageImplicit(Expr *Receiver,
2555                                               QualType ReceiverType,
2556                                               SourceLocation Loc,
2557                                               Selector Sel,
2558                                               ObjCMethodDecl *Method,
2559                                               MultiExprArg Args) {
2560   return BuildInstanceMessage(Receiver, ReceiverType,
2561                               /*SuperLoc=*/!Receiver ? Loc : SourceLocation(),
2562                               Sel, Method, Loc, Loc, Loc, Args,
2563                               /*isImplicit=*/true);
2564 }
2565
2566 static bool isMethodDeclaredInRootProtocol(Sema &S, const ObjCMethodDecl *M) {
2567   if (!S.NSAPIObj)
2568     return false;
2569   const auto *Protocol = dyn_cast<ObjCProtocolDecl>(M->getDeclContext());
2570   if (!Protocol)
2571     return false;
2572   const IdentifierInfo *II = S.NSAPIObj->getNSClassId(NSAPI::ClassId_NSObject);
2573   if (const auto *RootClass = dyn_cast_or_null<ObjCInterfaceDecl>(
2574           S.LookupSingleName(S.TUScope, II, Protocol->getLocStart(),
2575                              Sema::LookupOrdinaryName))) {
2576     for (const ObjCProtocolDecl *P : RootClass->all_referenced_protocols()) {
2577       if (P->getCanonicalDecl() == Protocol->getCanonicalDecl())
2578         return true;
2579     }
2580   }
2581   return false;
2582 }
2583
2584 /// \brief Build an Objective-C instance message expression.
2585 ///
2586 /// This routine takes care of both normal instance messages and
2587 /// instance messages to the superclass instance.
2588 ///
2589 /// \param Receiver The expression that computes the object that will
2590 /// receive this message. This may be empty, in which case we are
2591 /// sending to the superclass instance and \p SuperLoc must be a valid
2592 /// source location.
2593 ///
2594 /// \param ReceiverType The (static) type of the object receiving the
2595 /// message. When a \p Receiver expression is provided, this is the
2596 /// same type as that expression. For a superclass instance send, this
2597 /// is a pointer to the type of the superclass.
2598 ///
2599 /// \param SuperLoc The location of the "super" keyword in a
2600 /// superclass instance message.
2601 ///
2602 /// \param Sel The selector to which the message is being sent.
2603 ///
2604 /// \param Method The method that this instance message is invoking, if
2605 /// already known.
2606 ///
2607 /// \param LBracLoc The location of the opening square bracket ']'.
2608 ///
2609 /// \param RBracLoc The location of the closing square bracket ']'.
2610 ///
2611 /// \param ArgsIn The message arguments.
2612 ExprResult Sema::BuildInstanceMessage(Expr *Receiver,
2613                                       QualType ReceiverType,
2614                                       SourceLocation SuperLoc,
2615                                       Selector Sel,
2616                                       ObjCMethodDecl *Method,
2617                                       SourceLocation LBracLoc,
2618                                       ArrayRef<SourceLocation> SelectorLocs,
2619                                       SourceLocation RBracLoc,
2620                                       MultiExprArg ArgsIn,
2621                                       bool isImplicit) {
2622   assert((Receiver || SuperLoc.isValid()) && "If the Receiver is null, the "
2623                                              "SuperLoc must be valid so we can "
2624                                              "use it instead.");
2625
2626   // The location of the receiver.
2627   SourceLocation Loc = SuperLoc.isValid()? SuperLoc : Receiver->getLocStart();
2628   SourceRange RecRange =
2629       SuperLoc.isValid()? SuperLoc : Receiver->getSourceRange();
2630   SourceLocation SelLoc;
2631   if (!SelectorLocs.empty() && SelectorLocs.front().isValid())
2632     SelLoc = SelectorLocs.front();
2633   else
2634     SelLoc = Loc;
2635
2636   if (LBracLoc.isInvalid()) {
2637     Diag(Loc, diag::err_missing_open_square_message_send)
2638       << FixItHint::CreateInsertion(Loc, "[");
2639     LBracLoc = Loc;
2640   }
2641
2642   // If we have a receiver expression, perform appropriate promotions
2643   // and determine receiver type.
2644   if (Receiver) {
2645     if (Receiver->hasPlaceholderType()) {
2646       ExprResult Result;
2647       if (Receiver->getType() == Context.UnknownAnyTy)
2648         Result = forceUnknownAnyToType(Receiver, Context.getObjCIdType());
2649       else
2650         Result = CheckPlaceholderExpr(Receiver);
2651       if (Result.isInvalid()) return ExprError();
2652       Receiver = Result.get();
2653     }
2654
2655     if (Receiver->isTypeDependent()) {
2656       // If the receiver is type-dependent, we can't type-check anything
2657       // at this point. Build a dependent expression.
2658       unsigned NumArgs = ArgsIn.size();
2659       Expr **Args = ArgsIn.data();
2660       assert(SuperLoc.isInvalid() && "Message to super with dependent type");
2661       return ObjCMessageExpr::Create(
2662           Context, Context.DependentTy, VK_RValue, LBracLoc, Receiver, Sel,
2663           SelectorLocs, /*Method=*/nullptr, makeArrayRef(Args, NumArgs),
2664           RBracLoc, isImplicit);
2665     }
2666
2667     // If necessary, apply function/array conversion to the receiver.
2668     // C99 6.7.5.3p[7,8].
2669     ExprResult Result = DefaultFunctionArrayLvalueConversion(Receiver);
2670     if (Result.isInvalid())
2671       return ExprError();
2672     Receiver = Result.get();
2673     ReceiverType = Receiver->getType();
2674
2675     // If the receiver is an ObjC pointer, a block pointer, or an
2676     // __attribute__((NSObject)) pointer, we don't need to do any
2677     // special conversion in order to look up a receiver.
2678     if (ReceiverType->isObjCRetainableType()) {
2679       // do nothing
2680     } else if (!getLangOpts().ObjCAutoRefCount &&
2681                !Context.getObjCIdType().isNull() &&
2682                (ReceiverType->isPointerType() ||
2683                 ReceiverType->isIntegerType())) {
2684       // Implicitly convert integers and pointers to 'id' but emit a warning.
2685       // But not in ARC.
2686       Diag(Loc, diag::warn_bad_receiver_type)
2687         << ReceiverType
2688         << Receiver->getSourceRange();
2689       if (ReceiverType->isPointerType()) {
2690         Receiver = ImpCastExprToType(Receiver, Context.getObjCIdType(),
2691                                      CK_CPointerToObjCPointerCast).get();
2692       } else {
2693         // TODO: specialized warning on null receivers?
2694         bool IsNull = Receiver->isNullPointerConstant(Context,
2695                                               Expr::NPC_ValueDependentIsNull);
2696         CastKind Kind = IsNull ? CK_NullToPointer : CK_IntegralToPointer;
2697         Receiver = ImpCastExprToType(Receiver, Context.getObjCIdType(),
2698                                      Kind).get();
2699       }
2700       ReceiverType = Receiver->getType();
2701     } else if (getLangOpts().CPlusPlus) {
2702       // The receiver must be a complete type.
2703       if (RequireCompleteType(Loc, Receiver->getType(),
2704                               diag::err_incomplete_receiver_type))
2705         return ExprError();
2706
2707       ExprResult result = PerformContextuallyConvertToObjCPointer(Receiver);
2708       if (result.isUsable()) {
2709         Receiver = result.get();
2710         ReceiverType = Receiver->getType();
2711       }
2712     }
2713   }
2714
2715   if (ReceiverType->isObjCIdType() && !isImplicit)
2716     Diag(Receiver->getExprLoc(), diag::warn_messaging_unqualified_id);
2717
2718   // There's a somewhat weird interaction here where we assume that we
2719   // won't actually have a method unless we also don't need to do some
2720   // of the more detailed type-checking on the receiver.
2721
2722   if (!Method) {
2723     // Handle messages to id and __kindof types (where we use the
2724     // global method pool).
2725     const ObjCObjectType *typeBound = nullptr;
2726     bool receiverIsIdLike = ReceiverType->isObjCIdOrObjectKindOfType(Context,
2727                                                                      typeBound);
2728     if (receiverIsIdLike || ReceiverType->isBlockPointerType() ||
2729         (Receiver && Context.isObjCNSObjectType(Receiver->getType()))) {
2730       SmallVector<ObjCMethodDecl*, 4> Methods;
2731       // If we have a type bound, further filter the methods.
2732       CollectMultipleMethodsInGlobalPool(Sel, Methods, true/*InstanceFirst*/,
2733                                          true/*CheckTheOther*/, typeBound);
2734       if (!Methods.empty()) {
2735         // We choose the first method as the initial candidate, then try to
2736         // select a better one.
2737         Method = Methods[0];
2738
2739         if (ObjCMethodDecl *BestMethod =
2740             SelectBestMethod(Sel, ArgsIn, Method->isInstanceMethod(), Methods))
2741           Method = BestMethod;
2742
2743         if (!AreMultipleMethodsInGlobalPool(Sel, Method,
2744                                             SourceRange(LBracLoc, RBracLoc),
2745                                             receiverIsIdLike, Methods))
2746            DiagnoseUseOfDecl(Method, SelLoc);
2747       }
2748     } else if (ReceiverType->isObjCClassOrClassKindOfType() ||
2749                ReceiverType->isObjCQualifiedClassType()) {
2750       // Handle messages to Class.
2751       // We allow sending a message to a qualified Class ("Class<foo>"), which
2752       // is ok as long as one of the protocols implements the selector (if not,
2753       // warn).
2754       if (!ReceiverType->isObjCClassOrClassKindOfType()) {
2755         const ObjCObjectPointerType *QClassTy
2756           = ReceiverType->getAsObjCQualifiedClassType();
2757         // Search protocols for class methods.
2758         Method = LookupMethodInQualifiedType(Sel, QClassTy, false);
2759         if (!Method) {
2760           Method = LookupMethodInQualifiedType(Sel, QClassTy, true);
2761           // warn if instance method found for a Class message.
2762           if (Method && !isMethodDeclaredInRootProtocol(*this, Method)) {
2763             Diag(SelLoc, diag::warn_instance_method_on_class_found)
2764               << Method->getSelector() << Sel;
2765             Diag(Method->getLocation(), diag::note_method_declared_at)
2766               << Method->getDeclName();
2767           }
2768         }
2769       } else {
2770         if (ObjCMethodDecl *CurMeth = getCurMethodDecl()) {
2771           if (ObjCInterfaceDecl *ClassDecl = CurMeth->getClassInterface()) {
2772             // First check the public methods in the class interface.
2773             Method = ClassDecl->lookupClassMethod(Sel);
2774
2775             if (!Method)
2776               Method = ClassDecl->lookupPrivateClassMethod(Sel);
2777           }
2778           if (Method && DiagnoseUseOfDecl(Method, SelLoc))
2779             return ExprError();
2780         }
2781         if (!Method) {
2782           // If not messaging 'self', look for any factory method named 'Sel'.
2783           if (!Receiver || !isSelfExpr(Receiver)) {
2784             // If no class (factory) method was found, check if an _instance_
2785             // method of the same name exists in the root class only.
2786             SmallVector<ObjCMethodDecl*, 4> Methods;
2787             CollectMultipleMethodsInGlobalPool(Sel, Methods,
2788                                                false/*InstanceFirst*/,
2789                                                true/*CheckTheOther*/);
2790             if (!Methods.empty()) {
2791               // We choose the first method as the initial candidate, then try
2792               // to select a better one.
2793               Method = Methods[0];
2794
2795               // If we find an instance method, emit waring.
2796               if (Method->isInstanceMethod()) {
2797                 if (const ObjCInterfaceDecl *ID =
2798                     dyn_cast<ObjCInterfaceDecl>(Method->getDeclContext())) {
2799                   if (ID->getSuperClass())
2800                     Diag(SelLoc, diag::warn_root_inst_method_not_found)
2801                         << Sel << SourceRange(LBracLoc, RBracLoc);
2802                 }
2803               }
2804
2805              if (ObjCMethodDecl *BestMethod =
2806                  SelectBestMethod(Sel, ArgsIn, Method->isInstanceMethod(),
2807                                   Methods))
2808                Method = BestMethod;
2809             }
2810           }
2811         }
2812       }
2813     } else {
2814       ObjCInterfaceDecl *ClassDecl = nullptr;
2815
2816       // We allow sending a message to a qualified ID ("id<foo>"), which is ok as
2817       // long as one of the protocols implements the selector (if not, warn).
2818       // And as long as message is not deprecated/unavailable (warn if it is).
2819       if (const ObjCObjectPointerType *QIdTy
2820                                    = ReceiverType->getAsObjCQualifiedIdType()) {
2821         // Search protocols for instance methods.
2822         Method = LookupMethodInQualifiedType(Sel, QIdTy, true);
2823         if (!Method)
2824           Method = LookupMethodInQualifiedType(Sel, QIdTy, false);
2825         if (Method && DiagnoseUseOfDecl(Method, SelLoc))
2826           return ExprError();
2827       } else if (const ObjCObjectPointerType *OCIType
2828                    = ReceiverType->getAsObjCInterfacePointerType()) {
2829         // We allow sending a message to a pointer to an interface (an object).
2830         ClassDecl = OCIType->getInterfaceDecl();
2831
2832         // Try to complete the type. Under ARC, this is a hard error from which
2833         // we don't try to recover.
2834         // FIXME: In the non-ARC case, this will still be a hard error if the
2835         // definition is found in a module that's not visible.
2836         const ObjCInterfaceDecl *forwardClass = nullptr;
2837         if (RequireCompleteType(Loc, OCIType->getPointeeType(),
2838               getLangOpts().ObjCAutoRefCount
2839                 ? diag::err_arc_receiver_forward_instance
2840                 : diag::warn_receiver_forward_instance,
2841                                 Receiver? Receiver->getSourceRange()
2842                                         : SourceRange(SuperLoc))) {
2843           if (getLangOpts().ObjCAutoRefCount)
2844             return ExprError();
2845
2846           forwardClass = OCIType->getInterfaceDecl();
2847           Diag(Receiver ? Receiver->getLocStart()
2848                         : SuperLoc, diag::note_receiver_is_id);
2849           Method = nullptr;
2850         } else {
2851           Method = ClassDecl->lookupInstanceMethod(Sel);
2852         }
2853
2854         if (!Method)
2855           // Search protocol qualifiers.
2856           Method = LookupMethodInQualifiedType(Sel, OCIType, true);
2857
2858         if (!Method) {
2859           // If we have implementations in scope, check "private" methods.
2860           Method = ClassDecl->lookupPrivateMethod(Sel);
2861
2862           if (!Method && getLangOpts().ObjCAutoRefCount) {
2863             Diag(SelLoc, diag::err_arc_may_not_respond)
2864               << OCIType->getPointeeType() << Sel << RecRange
2865               << SourceRange(SelectorLocs.front(), SelectorLocs.back());
2866             return ExprError();
2867           }
2868
2869           if (!Method && (!Receiver || !isSelfExpr(Receiver))) {
2870             // If we still haven't found a method, look in the global pool. This
2871             // behavior isn't very desirable, however we need it for GCC
2872             // compatibility. FIXME: should we deviate??
2873             if (OCIType->qual_empty()) {
2874               SmallVector<ObjCMethodDecl*, 4> Methods;
2875               CollectMultipleMethodsInGlobalPool(Sel, Methods,
2876                                                  true/*InstanceFirst*/,
2877                                                  false/*CheckTheOther*/);
2878               if (!Methods.empty()) {
2879                 // We choose the first method as the initial candidate, then try
2880                 // to select a better one.
2881                 Method = Methods[0];
2882
2883                 if (ObjCMethodDecl *BestMethod =
2884                     SelectBestMethod(Sel, ArgsIn, Method->isInstanceMethod(),
2885                                      Methods))
2886                   Method = BestMethod;
2887
2888                 AreMultipleMethodsInGlobalPool(Sel, Method,
2889                                                SourceRange(LBracLoc, RBracLoc),
2890                                                true/*receiverIdOrClass*/,
2891                                                Methods);
2892               }
2893               if (Method && !forwardClass)
2894                 Diag(SelLoc, diag::warn_maynot_respond)
2895                   << OCIType->getInterfaceDecl()->getIdentifier()
2896                   << Sel << RecRange;
2897             }
2898           }
2899         }
2900         if (Method && DiagnoseUseOfDecl(Method, SelLoc, forwardClass))
2901           return ExprError();
2902       } else {
2903         // Reject other random receiver types (e.g. structs).
2904         Diag(Loc, diag::err_bad_receiver_type)
2905           << ReceiverType << Receiver->getSourceRange();
2906         return ExprError();
2907       }
2908     }
2909   }
2910
2911   FunctionScopeInfo *DIFunctionScopeInfo =
2912     (Method && Method->getMethodFamily() == OMF_init)
2913       ? getEnclosingFunction() : nullptr;
2914
2915   if (DIFunctionScopeInfo &&
2916       DIFunctionScopeInfo->ObjCIsDesignatedInit &&
2917       (SuperLoc.isValid() || isSelfExpr(Receiver))) {
2918     bool isDesignatedInitChain = false;
2919     if (SuperLoc.isValid()) {
2920       if (const ObjCObjectPointerType *
2921             OCIType = ReceiverType->getAsObjCInterfacePointerType()) {
2922         if (const ObjCInterfaceDecl *ID = OCIType->getInterfaceDecl()) {
2923           // Either we know this is a designated initializer or we
2924           // conservatively assume it because we don't know for sure.
2925           if (!ID->declaresOrInheritsDesignatedInitializers() ||
2926               ID->isDesignatedInitializer(Sel)) {
2927             isDesignatedInitChain = true;
2928             DIFunctionScopeInfo->ObjCWarnForNoDesignatedInitChain = false;
2929           }
2930         }
2931       }
2932     }
2933     if (!isDesignatedInitChain) {
2934       const ObjCMethodDecl *InitMethod = nullptr;
2935       bool isDesignated =
2936         getCurMethodDecl()->isDesignatedInitializerForTheInterface(&InitMethod);
2937       assert(isDesignated && InitMethod);
2938       (void)isDesignated;
2939       Diag(SelLoc, SuperLoc.isValid() ?
2940              diag::warn_objc_designated_init_non_designated_init_call :
2941              diag::warn_objc_designated_init_non_super_designated_init_call);
2942       Diag(InitMethod->getLocation(),
2943            diag::note_objc_designated_init_marked_here);
2944     }
2945   }
2946
2947   if (DIFunctionScopeInfo &&
2948       DIFunctionScopeInfo->ObjCIsSecondaryInit &&
2949       (SuperLoc.isValid() || isSelfExpr(Receiver))) {
2950     if (SuperLoc.isValid()) {
2951       Diag(SelLoc, diag::warn_objc_secondary_init_super_init_call);
2952     } else {
2953       DIFunctionScopeInfo->ObjCWarnForNoInitDelegation = false;
2954     }
2955   }
2956
2957   // Check the message arguments.
2958   unsigned NumArgs = ArgsIn.size();
2959   Expr **Args = ArgsIn.data();
2960   QualType ReturnType;
2961   ExprValueKind VK = VK_RValue;
2962   bool ClassMessage = (ReceiverType->isObjCClassType() ||
2963                        ReceiverType->isObjCQualifiedClassType());
2964   if (CheckMessageArgumentTypes(ReceiverType, MultiExprArg(Args, NumArgs),
2965                                 Sel, SelectorLocs, Method,
2966                                 ClassMessage, SuperLoc.isValid(),
2967                                 LBracLoc, RBracLoc, RecRange, ReturnType, VK))
2968     return ExprError();
2969
2970   if (Method && !Method->getReturnType()->isVoidType() &&
2971       RequireCompleteType(LBracLoc, Method->getReturnType(),
2972                           diag::err_illegal_message_expr_incomplete_type))
2973     return ExprError();
2974
2975   // In ARC, forbid the user from sending messages to
2976   // retain/release/autorelease/dealloc/retainCount explicitly.
2977   if (getLangOpts().ObjCAutoRefCount) {
2978     ObjCMethodFamily family =
2979       (Method ? Method->getMethodFamily() : Sel.getMethodFamily());
2980     switch (family) {
2981     case OMF_init:
2982       if (Method)
2983         checkInitMethod(Method, ReceiverType);
2984       break;
2985
2986     case OMF_None:
2987     case OMF_alloc:
2988     case OMF_copy:
2989     case OMF_finalize:
2990     case OMF_mutableCopy:
2991     case OMF_new:
2992     case OMF_self:
2993     case OMF_initialize:
2994       break;
2995
2996     case OMF_dealloc:
2997     case OMF_retain:
2998     case OMF_release:
2999     case OMF_autorelease:
3000     case OMF_retainCount:
3001       Diag(SelLoc, diag::err_arc_illegal_explicit_message)
3002         << Sel << RecRange;
3003       break;
3004
3005     case OMF_performSelector:
3006       if (Method && NumArgs >= 1) {
3007         if (const auto *SelExp =
3008                 dyn_cast<ObjCSelectorExpr>(Args[0]->IgnoreParens())) {
3009           Selector ArgSel = SelExp->getSelector();
3010           ObjCMethodDecl *SelMethod =
3011             LookupInstanceMethodInGlobalPool(ArgSel,
3012                                              SelExp->getSourceRange());
3013           if (!SelMethod)
3014             SelMethod =
3015               LookupFactoryMethodInGlobalPool(ArgSel,
3016                                               SelExp->getSourceRange());
3017           if (SelMethod) {
3018             ObjCMethodFamily SelFamily = SelMethod->getMethodFamily();
3019             switch (SelFamily) {
3020               case OMF_alloc:
3021               case OMF_copy:
3022               case OMF_mutableCopy:
3023               case OMF_new:
3024               case OMF_init:
3025                 // Issue error, unless ns_returns_not_retained.
3026                 if (!SelMethod->hasAttr<NSReturnsNotRetainedAttr>()) {
3027                   // selector names a +1 method
3028                   Diag(SelLoc,
3029                        diag::err_arc_perform_selector_retains);
3030                   Diag(SelMethod->getLocation(), diag::note_method_declared_at)
3031                     << SelMethod->getDeclName();
3032                 }
3033                 break;
3034               default:
3035                 // +0 call. OK. unless ns_returns_retained.
3036                 if (SelMethod->hasAttr<NSReturnsRetainedAttr>()) {
3037                   // selector names a +1 method
3038                   Diag(SelLoc,
3039                        diag::err_arc_perform_selector_retains);
3040                   Diag(SelMethod->getLocation(), diag::note_method_declared_at)
3041                     << SelMethod->getDeclName();
3042                 }
3043                 break;
3044             }
3045           }
3046         } else {
3047           // error (may leak).
3048           Diag(SelLoc, diag::warn_arc_perform_selector_leaks);
3049           Diag(Args[0]->getExprLoc(), diag::note_used_here);
3050         }
3051       }
3052       break;
3053     }
3054   }
3055
3056   DiagnoseCStringFormatDirectiveInObjCAPI(*this, Method, Sel, Args, NumArgs);
3057
3058   // Construct the appropriate ObjCMessageExpr instance.
3059   ObjCMessageExpr *Result;
3060   if (SuperLoc.isValid())
3061     Result = ObjCMessageExpr::Create(Context, ReturnType, VK, LBracLoc,
3062                                      SuperLoc,  /*IsInstanceSuper=*/true,
3063                                      ReceiverType, Sel, SelectorLocs, Method,
3064                                      makeArrayRef(Args, NumArgs), RBracLoc,
3065                                      isImplicit);
3066   else {
3067     Result = ObjCMessageExpr::Create(Context, ReturnType, VK, LBracLoc,
3068                                      Receiver, Sel, SelectorLocs, Method,
3069                                      makeArrayRef(Args, NumArgs), RBracLoc,
3070                                      isImplicit);
3071     if (!isImplicit)
3072       checkCocoaAPI(*this, Result);
3073   }
3074   if (Method) {
3075     bool IsClassObjectCall = ClassMessage;
3076     // 'self' message receivers in class methods should be treated as message
3077     // sends to the class object in order for the semantic checks to be
3078     // performed correctly. Messages to 'super' already count as class messages,
3079     // so they don't need to be handled here.
3080     if (Receiver && isSelfExpr(Receiver)) {
3081       if (const auto *OPT = ReceiverType->getAs<ObjCObjectPointerType>()) {
3082         if (OPT->getObjectType()->isObjCClass()) {
3083           if (const auto *CurMeth = getCurMethodDecl()) {
3084             IsClassObjectCall = true;
3085             ReceiverType =
3086                 Context.getObjCInterfaceType(CurMeth->getClassInterface());
3087           }
3088         }
3089       }
3090     }
3091     checkFoundationAPI(*this, SelLoc, Method, makeArrayRef(Args, NumArgs),
3092                        ReceiverType, IsClassObjectCall);
3093   }
3094
3095   if (getLangOpts().ObjCAutoRefCount) {
3096     // In ARC, annotate delegate init calls.
3097     if (Result->getMethodFamily() == OMF_init &&
3098         (SuperLoc.isValid() || isSelfExpr(Receiver))) {
3099       // Only consider init calls *directly* in init implementations,
3100       // not within blocks.
3101       ObjCMethodDecl *method = dyn_cast<ObjCMethodDecl>(CurContext);
3102       if (method && method->getMethodFamily() == OMF_init) {
3103         // The implicit assignment to self means we also don't want to
3104         // consume the result.
3105         Result->setDelegateInitCall(true);
3106         return Result;
3107       }
3108     }
3109
3110     // In ARC, check for message sends which are likely to introduce
3111     // retain cycles.
3112     checkRetainCycles(Result);
3113   }
3114
3115   if (getLangOpts().ObjCWeak) {
3116     if (!isImplicit && Method) {
3117       if (const ObjCPropertyDecl *Prop = Method->findPropertyDecl()) {
3118         bool IsWeak =
3119           Prop->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_weak;
3120         if (!IsWeak && Sel.isUnarySelector())
3121           IsWeak = ReturnType.getObjCLifetime() & Qualifiers::OCL_Weak;
3122         if (IsWeak &&
3123             !Diags.isIgnored(diag::warn_arc_repeated_use_of_weak, LBracLoc))
3124           getCurFunction()->recordUseOfWeak(Result, Prop);
3125       }
3126     }
3127   }
3128
3129   CheckObjCCircularContainer(Result);
3130
3131   return MaybeBindToTemporary(Result);
3132 }
3133
3134 static void RemoveSelectorFromWarningCache(Sema &S, Expr* Arg) {
3135   if (ObjCSelectorExpr *OSE =
3136       dyn_cast<ObjCSelectorExpr>(Arg->IgnoreParenCasts())) {
3137     Selector Sel = OSE->getSelector();
3138     SourceLocation Loc = OSE->getAtLoc();
3139     auto Pos = S.ReferencedSelectors.find(Sel);
3140     if (Pos != S.ReferencedSelectors.end() && Pos->second == Loc)
3141       S.ReferencedSelectors.erase(Pos);
3142   }
3143 }
3144
3145 // ActOnInstanceMessage - used for both unary and keyword messages.
3146 // ArgExprs is optional - if it is present, the number of expressions
3147 // is obtained from Sel.getNumArgs().
3148 ExprResult Sema::ActOnInstanceMessage(Scope *S,
3149                                       Expr *Receiver,
3150                                       Selector Sel,
3151                                       SourceLocation LBracLoc,
3152                                       ArrayRef<SourceLocation> SelectorLocs,
3153                                       SourceLocation RBracLoc,
3154                                       MultiExprArg Args) {
3155   if (!Receiver)
3156     return ExprError();
3157
3158   // A ParenListExpr can show up while doing error recovery with invalid code.
3159   if (isa<ParenListExpr>(Receiver)) {
3160     ExprResult Result = MaybeConvertParenListExprToParenExpr(S, Receiver);
3161     if (Result.isInvalid()) return ExprError();
3162     Receiver = Result.get();
3163   }
3164
3165   if (RespondsToSelectorSel.isNull()) {
3166     IdentifierInfo *SelectorId = &Context.Idents.get("respondsToSelector");
3167     RespondsToSelectorSel = Context.Selectors.getUnarySelector(SelectorId);
3168   }
3169   if (Sel == RespondsToSelectorSel)
3170     RemoveSelectorFromWarningCache(*this, Args[0]);
3171
3172   return BuildInstanceMessage(Receiver, Receiver->getType(),
3173                               /*SuperLoc=*/SourceLocation(), Sel,
3174                               /*Method=*/nullptr, LBracLoc, SelectorLocs,
3175                               RBracLoc, Args);
3176 }
3177
3178 enum ARCConversionTypeClass {
3179   /// int, void, struct A
3180   ACTC_none,
3181
3182   /// id, void (^)()
3183   ACTC_retainable,
3184
3185   /// id*, id***, void (^*)(),
3186   ACTC_indirectRetainable,
3187
3188   /// void* might be a normal C type, or it might a CF type.
3189   ACTC_voidPtr,
3190
3191   /// struct A*
3192   ACTC_coreFoundation
3193 };
3194
3195 static bool isAnyRetainable(ARCConversionTypeClass ACTC) {
3196   return (ACTC == ACTC_retainable ||
3197           ACTC == ACTC_coreFoundation ||
3198           ACTC == ACTC_voidPtr);
3199 }
3200
3201 static bool isAnyCLike(ARCConversionTypeClass ACTC) {
3202   return ACTC == ACTC_none ||
3203          ACTC == ACTC_voidPtr ||
3204          ACTC == ACTC_coreFoundation;
3205 }
3206
3207 static ARCConversionTypeClass classifyTypeForARCConversion(QualType type) {
3208   bool isIndirect = false;
3209
3210   // Ignore an outermost reference type.
3211   if (const ReferenceType *ref = type->getAs<ReferenceType>()) {
3212     type = ref->getPointeeType();
3213     isIndirect = true;
3214   }
3215
3216   // Drill through pointers and arrays recursively.
3217   while (true) {
3218     if (const PointerType *ptr = type->getAs<PointerType>()) {
3219       type = ptr->getPointeeType();
3220
3221       // The first level of pointer may be the innermost pointer on a CF type.
3222       if (!isIndirect) {
3223         if (type->isVoidType()) return ACTC_voidPtr;
3224         if (type->isRecordType()) return ACTC_coreFoundation;
3225       }
3226     } else if (const ArrayType *array = type->getAsArrayTypeUnsafe()) {
3227       type = QualType(array->getElementType()->getBaseElementTypeUnsafe(), 0);
3228     } else {
3229       break;
3230     }
3231     isIndirect = true;
3232   }
3233
3234   if (isIndirect) {
3235     if (type->isObjCARCBridgableType())
3236       return ACTC_indirectRetainable;
3237     return ACTC_none;
3238   }
3239
3240   if (type->isObjCARCBridgableType())
3241     return ACTC_retainable;
3242
3243   return ACTC_none;
3244 }
3245
3246 namespace {
3247   /// A result from the cast checker.
3248   enum ACCResult {
3249     /// Cannot be casted.
3250     ACC_invalid,
3251
3252     /// Can be safely retained or not retained.
3253     ACC_bottom,
3254
3255     /// Can be casted at +0.
3256     ACC_plusZero,
3257
3258     /// Can be casted at +1.
3259     ACC_plusOne
3260   };
3261   ACCResult merge(ACCResult left, ACCResult right) {
3262     if (left == right) return left;
3263     if (left == ACC_bottom) return right;
3264     if (right == ACC_bottom) return left;
3265     return ACC_invalid;
3266   }
3267
3268   /// A checker which white-lists certain expressions whose conversion
3269   /// to or from retainable type would otherwise be forbidden in ARC.
3270   class ARCCastChecker : public StmtVisitor<ARCCastChecker, ACCResult> {
3271     typedef StmtVisitor<ARCCastChecker, ACCResult> super;
3272
3273     ASTContext &Context;
3274     ARCConversionTypeClass SourceClass;
3275     ARCConversionTypeClass TargetClass;
3276     bool Diagnose;
3277
3278     static bool isCFType(QualType type) {
3279       // Someday this can use ns_bridged.  For now, it has to do this.
3280       return type->isCARCBridgableType();
3281     }
3282
3283   public:
3284     ARCCastChecker(ASTContext &Context, ARCConversionTypeClass source,
3285                    ARCConversionTypeClass target, bool diagnose)
3286       : Context(Context), SourceClass(source), TargetClass(target),
3287         Diagnose(diagnose) {}
3288
3289     using super::Visit;
3290     ACCResult Visit(Expr *e) {
3291       return super::Visit(e->IgnoreParens());
3292     }
3293
3294     ACCResult VisitStmt(Stmt *s) {
3295       return ACC_invalid;
3296     }
3297
3298     /// Null pointer constants can be casted however you please.
3299     ACCResult VisitExpr(Expr *e) {
3300       if (e->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNotNull))
3301         return ACC_bottom;
3302       return ACC_invalid;
3303     }
3304
3305     /// Objective-C string literals can be safely casted.
3306     ACCResult VisitObjCStringLiteral(ObjCStringLiteral *e) {
3307       // If we're casting to any retainable type, go ahead.  Global
3308       // strings are immune to retains, so this is bottom.
3309       if (isAnyRetainable(TargetClass)) return ACC_bottom;
3310
3311       return ACC_invalid;
3312     }
3313
3314     /// Look through certain implicit and explicit casts.
3315     ACCResult VisitCastExpr(CastExpr *e) {
3316       switch (e->getCastKind()) {
3317         case CK_NullToPointer:
3318           return ACC_bottom;
3319
3320         case CK_NoOp:
3321         case CK_LValueToRValue:
3322         case CK_BitCast:
3323         case CK_CPointerToObjCPointerCast:
3324         case CK_BlockPointerToObjCPointerCast:
3325         case CK_AnyPointerToBlockPointerCast:
3326           return Visit(e->getSubExpr());
3327
3328         default:
3329           return ACC_invalid;
3330       }
3331     }
3332
3333     /// Look through unary extension.
3334     ACCResult VisitUnaryExtension(UnaryOperator *e) {
3335       return Visit(e->getSubExpr());
3336     }
3337
3338     /// Ignore the LHS of a comma operator.
3339     ACCResult VisitBinComma(BinaryOperator *e) {
3340       return Visit(e->getRHS());
3341     }
3342
3343     /// Conditional operators are okay if both sides are okay.
3344     ACCResult VisitConditionalOperator(ConditionalOperator *e) {
3345       ACCResult left = Visit(e->getTrueExpr());
3346       if (left == ACC_invalid) return ACC_invalid;
3347       return merge(left, Visit(e->getFalseExpr()));
3348     }
3349
3350     /// Look through pseudo-objects.
3351     ACCResult VisitPseudoObjectExpr(PseudoObjectExpr *e) {
3352       // If we're getting here, we should always have a result.
3353       return Visit(e->getResultExpr());
3354     }
3355
3356     /// Statement expressions are okay if their result expression is okay.
3357     ACCResult VisitStmtExpr(StmtExpr *e) {
3358       return Visit(e->getSubStmt()->body_back());
3359     }
3360
3361     /// Some declaration references are okay.
3362     ACCResult VisitDeclRefExpr(DeclRefExpr *e) {
3363       VarDecl *var = dyn_cast<VarDecl>(e->getDecl());
3364       // References to global constants are okay.
3365       if (isAnyRetainable(TargetClass) &&
3366           isAnyRetainable(SourceClass) &&
3367           var &&
3368           !var->hasDefinition(Context) &&
3369           var->getType().isConstQualified()) {
3370
3371         // In system headers, they can also be assumed to be immune to retains.
3372         // These are things like 'kCFStringTransformToLatin'.
3373         if (Context.getSourceManager().isInSystemHeader(var->getLocation()))
3374           return ACC_bottom;
3375
3376         return ACC_plusZero;
3377       }
3378
3379       // Nothing else.
3380       return ACC_invalid;
3381     }
3382
3383     /// Some calls are okay.
3384     ACCResult VisitCallExpr(CallExpr *e) {
3385       if (FunctionDecl *fn = e->getDirectCallee())
3386         if (ACCResult result = checkCallToFunction(fn))
3387           return result;
3388
3389       return super::VisitCallExpr(e);
3390     }
3391
3392     ACCResult checkCallToFunction(FunctionDecl *fn) {
3393       // Require a CF*Ref return type.
3394       if (!isCFType(fn->getReturnType()))
3395         return ACC_invalid;
3396
3397       if (!isAnyRetainable(TargetClass))
3398         return ACC_invalid;
3399
3400       // Honor an explicit 'not retained' attribute.
3401       if (fn->hasAttr<CFReturnsNotRetainedAttr>())
3402         return ACC_plusZero;
3403
3404       // Honor an explicit 'retained' attribute, except that for
3405       // now we're not going to permit implicit handling of +1 results,
3406       // because it's a bit frightening.
3407       if (fn->hasAttr<CFReturnsRetainedAttr>())
3408         return Diagnose ? ACC_plusOne
3409                         : ACC_invalid; // ACC_plusOne if we start accepting this
3410
3411       // Recognize this specific builtin function, which is used by CFSTR.
3412       unsigned builtinID = fn->getBuiltinID();
3413       if (builtinID == Builtin::BI__builtin___CFStringMakeConstantString)
3414         return ACC_bottom;
3415
3416       // Otherwise, don't do anything implicit with an unaudited function.
3417       if (!fn->hasAttr<CFAuditedTransferAttr>())
3418         return ACC_invalid;
3419
3420       // Otherwise, it's +0 unless it follows the create convention.
3421       if (ento::coreFoundation::followsCreateRule(fn))
3422         return Diagnose ? ACC_plusOne
3423                         : ACC_invalid; // ACC_plusOne if we start accepting this
3424
3425       return ACC_plusZero;
3426     }
3427
3428     ACCResult VisitObjCMessageExpr(ObjCMessageExpr *e) {
3429       return checkCallToMethod(e->getMethodDecl());
3430     }
3431
3432     ACCResult VisitObjCPropertyRefExpr(ObjCPropertyRefExpr *e) {
3433       ObjCMethodDecl *method;
3434       if (e->isExplicitProperty())
3435         method = e->getExplicitProperty()->getGetterMethodDecl();
3436       else
3437         method = e->getImplicitPropertyGetter();
3438       return checkCallToMethod(method);
3439     }
3440
3441     ACCResult checkCallToMethod(ObjCMethodDecl *method) {
3442       if (!method) return ACC_invalid;
3443
3444       // Check for message sends to functions returning CF types.  We
3445       // just obey the Cocoa conventions with these, even though the
3446       // return type is CF.
3447       if (!isAnyRetainable(TargetClass) || !isCFType(method->getReturnType()))
3448         return ACC_invalid;
3449
3450       // If the method is explicitly marked not-retained, it's +0.
3451       if (method->hasAttr<CFReturnsNotRetainedAttr>())
3452         return ACC_plusZero;
3453
3454       // If the method is explicitly marked as returning retained, or its
3455       // selector follows a +1 Cocoa convention, treat it as +1.
3456       if (method->hasAttr<CFReturnsRetainedAttr>())
3457         return ACC_plusOne;
3458
3459       switch (method->getSelector().getMethodFamily()) {
3460       case OMF_alloc:
3461       case OMF_copy:
3462       case OMF_mutableCopy:
3463       case OMF_new:
3464         return ACC_plusOne;
3465
3466       default:
3467         // Otherwise, treat it as +0.
3468         return ACC_plusZero;
3469       }
3470     }
3471   };
3472 } // end anonymous namespace
3473
3474 bool Sema::isKnownName(StringRef name) {
3475   if (name.empty())
3476     return false;
3477   LookupResult R(*this, &Context.Idents.get(name), SourceLocation(),
3478                  Sema::LookupOrdinaryName);
3479   return LookupName(R, TUScope, false);
3480 }
3481
3482 static void addFixitForObjCARCConversion(Sema &S,
3483                                          DiagnosticBuilder &DiagB,
3484                                          Sema::CheckedConversionKind CCK,
3485                                          SourceLocation afterLParen,
3486                                          QualType castType,
3487                                          Expr *castExpr,
3488                                          Expr *realCast,
3489                                          const char *bridgeKeyword,
3490                                          const char *CFBridgeName) {
3491   // We handle C-style and implicit casts here.
3492   switch (CCK) {
3493   case Sema::CCK_ImplicitConversion:
3494   case Sema::CCK_CStyleCast:
3495   case Sema::CCK_OtherCast:
3496     break;
3497   case Sema::CCK_FunctionalCast:
3498     return;
3499   }
3500
3501   if (CFBridgeName) {
3502     if (CCK == Sema::CCK_OtherCast) {
3503       if (const CXXNamedCastExpr *NCE = dyn_cast<CXXNamedCastExpr>(realCast)) {
3504         SourceRange range(NCE->getOperatorLoc(),
3505                           NCE->getAngleBrackets().getEnd());
3506         SmallString<32> BridgeCall;
3507
3508         SourceManager &SM = S.getSourceManager();
3509         char PrevChar = *SM.getCharacterData(range.getBegin().getLocWithOffset(-1));
3510         if (Lexer::isIdentifierBodyChar(PrevChar, S.getLangOpts()))
3511           BridgeCall += ' ';
3512
3513         BridgeCall += CFBridgeName;
3514         DiagB.AddFixItHint(FixItHint::CreateReplacement(range, BridgeCall));
3515       }
3516       return;
3517     }
3518     Expr *castedE = castExpr;
3519     if (CStyleCastExpr *CCE = dyn_cast<CStyleCastExpr>(castedE))
3520       castedE = CCE->getSubExpr();
3521     castedE = castedE->IgnoreImpCasts();
3522     SourceRange range = castedE->getSourceRange();
3523
3524     SmallString<32> BridgeCall;
3525
3526     SourceManager &SM = S.getSourceManager();
3527     char PrevChar = *SM.getCharacterData(range.getBegin().getLocWithOffset(-1));
3528     if (Lexer::isIdentifierBodyChar(PrevChar, S.getLangOpts()))
3529       BridgeCall += ' ';
3530
3531     BridgeCall += CFBridgeName;
3532
3533     if (isa<ParenExpr>(castedE)) {
3534       DiagB.AddFixItHint(FixItHint::CreateInsertion(range.getBegin(),
3535                          BridgeCall));
3536     } else {
3537       BridgeCall += '(';
3538       DiagB.AddFixItHint(FixItHint::CreateInsertion(range.getBegin(),
3539                                                     BridgeCall));
3540       DiagB.AddFixItHint(FixItHint::CreateInsertion(
3541                                        S.getLocForEndOfToken(range.getEnd()),
3542                                        ")"));
3543     }
3544     return;
3545   }
3546
3547   if (CCK == Sema::CCK_CStyleCast) {
3548     DiagB.AddFixItHint(FixItHint::CreateInsertion(afterLParen, bridgeKeyword));
3549   } else if (CCK == Sema::CCK_OtherCast) {
3550     if (const CXXNamedCastExpr *NCE = dyn_cast<CXXNamedCastExpr>(realCast)) {
3551       std::string castCode = "(";
3552       castCode += bridgeKeyword;
3553       castCode += castType.getAsString();
3554       castCode += ")";
3555       SourceRange Range(NCE->getOperatorLoc(),
3556                         NCE->getAngleBrackets().getEnd());
3557       DiagB.AddFixItHint(FixItHint::CreateReplacement(Range, castCode));
3558     }
3559   } else {
3560     std::string castCode = "(";
3561     castCode += bridgeKeyword;
3562     castCode += castType.getAsString();
3563     castCode += ")";
3564     Expr *castedE = castExpr->IgnoreImpCasts();
3565     SourceRange range = castedE->getSourceRange();
3566     if (isa<ParenExpr>(castedE)) {
3567       DiagB.AddFixItHint(FixItHint::CreateInsertion(range.getBegin(),
3568                          castCode));
3569     } else {
3570       castCode += "(";
3571       DiagB.AddFixItHint(FixItHint::CreateInsertion(range.getBegin(),
3572                                                     castCode));
3573       DiagB.AddFixItHint(FixItHint::CreateInsertion(
3574                                        S.getLocForEndOfToken(range.getEnd()),
3575                                        ")"));
3576     }
3577   }
3578 }
3579
3580 template <typename T>
3581 static inline T *getObjCBridgeAttr(const TypedefType *TD) {
3582   TypedefNameDecl *TDNDecl = TD->getDecl();
3583   QualType QT = TDNDecl->getUnderlyingType();
3584   if (QT->isPointerType()) {
3585     QT = QT->getPointeeType();
3586     if (const RecordType *RT = QT->getAs<RecordType>())
3587       if (RecordDecl *RD = RT->getDecl()->getMostRecentDecl())
3588         return RD->getAttr<T>();
3589   }
3590   return nullptr;
3591 }
3592
3593 static ObjCBridgeRelatedAttr *ObjCBridgeRelatedAttrFromType(QualType T,
3594                                                             TypedefNameDecl *&TDNDecl) {
3595   while (const TypedefType *TD = dyn_cast<TypedefType>(T.getTypePtr())) {
3596     TDNDecl = TD->getDecl();
3597     if (ObjCBridgeRelatedAttr *ObjCBAttr =
3598         getObjCBridgeAttr<ObjCBridgeRelatedAttr>(TD))
3599       return ObjCBAttr;
3600     T = TDNDecl->getUnderlyingType();
3601   }
3602   return nullptr;
3603 }
3604
3605 static void
3606 diagnoseObjCARCConversion(Sema &S, SourceRange castRange,
3607                           QualType castType, ARCConversionTypeClass castACTC,
3608                           Expr *castExpr, Expr *realCast,
3609                           ARCConversionTypeClass exprACTC,
3610                           Sema::CheckedConversionKind CCK) {
3611   SourceLocation loc =
3612     (castRange.isValid() ? castRange.getBegin() : castExpr->getExprLoc());
3613
3614   if (S.makeUnavailableInSystemHeader(loc,
3615                                  UnavailableAttr::IR_ARCForbiddenConversion))
3616     return;
3617
3618   QualType castExprType = castExpr->getType();
3619   // Defer emitting a diagnostic for bridge-related casts; that will be
3620   // handled by CheckObjCBridgeRelatedConversions.
3621   TypedefNameDecl *TDNDecl = nullptr;
3622   if ((castACTC == ACTC_coreFoundation &&  exprACTC == ACTC_retainable &&
3623        ObjCBridgeRelatedAttrFromType(castType, TDNDecl)) ||
3624       (exprACTC == ACTC_coreFoundation && castACTC == ACTC_retainable &&
3625        ObjCBridgeRelatedAttrFromType(castExprType, TDNDecl)))
3626     return;
3627
3628   unsigned srcKind = 0;
3629   switch (exprACTC) {
3630   case ACTC_none:
3631   case ACTC_coreFoundation:
3632   case ACTC_voidPtr:
3633     srcKind = (castExprType->isPointerType() ? 1 : 0);
3634     break;
3635   case ACTC_retainable:
3636     srcKind = (castExprType->isBlockPointerType() ? 2 : 3);
3637     break;
3638   case ACTC_indirectRetainable:
3639     srcKind = 4;
3640     break;
3641   }
3642
3643   // Check whether this could be fixed with a bridge cast.
3644   SourceLocation afterLParen = S.getLocForEndOfToken(castRange.getBegin());
3645   SourceLocation noteLoc = afterLParen.isValid() ? afterLParen : loc;
3646
3647   // Bridge from an ARC type to a CF type.
3648   if (castACTC == ACTC_retainable && isAnyRetainable(exprACTC)) {
3649
3650     S.Diag(loc, diag::err_arc_cast_requires_bridge)
3651       << unsigned(CCK == Sema::CCK_ImplicitConversion) // cast|implicit
3652       << 2 // of C pointer type
3653       << castExprType
3654       << unsigned(castType->isBlockPointerType()) // to ObjC|block type
3655       << castType
3656       << castRange
3657       << castExpr->getSourceRange();
3658     bool br = S.isKnownName("CFBridgingRelease");
3659     ACCResult CreateRule =
3660       ARCCastChecker(S.Context, exprACTC, castACTC, true).Visit(castExpr);
3661     assert(CreateRule != ACC_bottom && "This cast should already be accepted.");
3662     if (CreateRule != ACC_plusOne)
3663     {
3664       DiagnosticBuilder DiagB =
3665         (CCK != Sema::CCK_OtherCast) ? S.Diag(noteLoc, diag::note_arc_bridge)
3666                               : S.Diag(noteLoc, diag::note_arc_cstyle_bridge);
3667
3668       addFixitForObjCARCConversion(S, DiagB, CCK, afterLParen,
3669                                    castType, castExpr, realCast, "__bridge ",
3670                                    nullptr);
3671     }
3672     if (CreateRule != ACC_plusZero)
3673     {
3674       DiagnosticBuilder DiagB =
3675         (CCK == Sema::CCK_OtherCast && !br) ?
3676           S.Diag(noteLoc, diag::note_arc_cstyle_bridge_transfer) << castExprType :
3677           S.Diag(br ? castExpr->getExprLoc() : noteLoc,
3678                  diag::note_arc_bridge_transfer)
3679             << castExprType << br;
3680
3681       addFixitForObjCARCConversion(S, DiagB, CCK, afterLParen,
3682                                    castType, castExpr, realCast, "__bridge_transfer ",
3683                                    br ? "CFBridgingRelease" : nullptr);
3684     }
3685
3686     return;
3687   }
3688
3689   // Bridge from a CF type to an ARC type.
3690   if (exprACTC == ACTC_retainable && isAnyRetainable(castACTC)) {
3691     bool br = S.isKnownName("CFBridgingRetain");
3692     S.Diag(loc, diag::err_arc_cast_requires_bridge)
3693       << unsigned(CCK == Sema::CCK_ImplicitConversion) // cast|implicit
3694       << unsigned(castExprType->isBlockPointerType()) // of ObjC|block type
3695       << castExprType
3696       << 2 // to C pointer type
3697       << castType
3698       << castRange
3699       << castExpr->getSourceRange();
3700     ACCResult CreateRule =
3701       ARCCastChecker(S.Context, exprACTC, castACTC, true).Visit(castExpr);
3702     assert(CreateRule != ACC_bottom && "This cast should already be accepted.");
3703     if (CreateRule != ACC_plusOne)
3704     {
3705       DiagnosticBuilder DiagB =
3706       (CCK != Sema::CCK_OtherCast) ? S.Diag(noteLoc, diag::note_arc_bridge)
3707                                : S.Diag(noteLoc, diag::note_arc_cstyle_bridge);
3708       addFixitForObjCARCConversion(S, DiagB, CCK, afterLParen,
3709                                    castType, castExpr, realCast, "__bridge ",
3710                                    nullptr);
3711     }
3712     if (CreateRule != ACC_plusZero)
3713     {
3714       DiagnosticBuilder DiagB =
3715         (CCK == Sema::CCK_OtherCast && !br) ?
3716           S.Diag(noteLoc, diag::note_arc_cstyle_bridge_retained) << castType :
3717           S.Diag(br ? castExpr->getExprLoc() : noteLoc,
3718                  diag::note_arc_bridge_retained)
3719             << castType << br;
3720
3721       addFixitForObjCARCConversion(S, DiagB, CCK, afterLParen,
3722                                    castType, castExpr, realCast, "__bridge_retained ",
3723                                    br ? "CFBridgingRetain" : nullptr);
3724     }
3725
3726     return;
3727   }
3728
3729   S.Diag(loc, diag::err_arc_mismatched_cast)
3730     << (CCK != Sema::CCK_ImplicitConversion)
3731     << srcKind << castExprType << castType
3732     << castRange << castExpr->getSourceRange();
3733 }
3734
3735 template <typename TB>
3736 static bool CheckObjCBridgeNSCast(Sema &S, QualType castType, Expr *castExpr,
3737                                   bool &HadTheAttribute, bool warn) {
3738   QualType T = castExpr->getType();
3739   HadTheAttribute = false;
3740   while (const TypedefType *TD = dyn_cast<TypedefType>(T.getTypePtr())) {
3741     TypedefNameDecl *TDNDecl = TD->getDecl();
3742     if (TB *ObjCBAttr = getObjCBridgeAttr<TB>(TD)) {
3743       if (IdentifierInfo *Parm = ObjCBAttr->getBridgedType()) {
3744         HadTheAttribute = true;
3745         if (Parm->isStr("id"))
3746           return true;
3747
3748         NamedDecl *Target = nullptr;
3749         // Check for an existing type with this name.
3750         LookupResult R(S, DeclarationName(Parm), SourceLocation(),
3751                        Sema::LookupOrdinaryName);
3752         if (S.LookupName(R, S.TUScope)) {
3753           Target = R.getFoundDecl();
3754           if (Target && isa<ObjCInterfaceDecl>(Target)) {
3755             ObjCInterfaceDecl *ExprClass = cast<ObjCInterfaceDecl>(Target);
3756             if (const ObjCObjectPointerType *InterfacePointerType =
3757                   castType->getAsObjCInterfacePointerType()) {
3758               ObjCInterfaceDecl *CastClass
3759                 = InterfacePointerType->getObjectType()->getInterface();
3760               if ((CastClass == ExprClass) ||
3761                   (CastClass && CastClass->isSuperClassOf(ExprClass)))
3762                 return true;
3763               if (warn)
3764                 S.Diag(castExpr->getLocStart(), diag::warn_objc_invalid_bridge)
3765                   << T << Target->getName() << castType->getPointeeType();
3766               return false;
3767             } else if (castType->isObjCIdType() ||
3768                        (S.Context.ObjCObjectAdoptsQTypeProtocols(
3769                           castType, ExprClass)))
3770               // ok to cast to 'id'.
3771               // casting to id<p-list> is ok if bridge type adopts all of
3772               // p-list protocols.
3773               return true;
3774             else {
3775               if (warn) {
3776                 S.Diag(castExpr->getLocStart(), diag::warn_objc_invalid_bridge)
3777                   << T << Target->getName() << castType;
3778                 S.Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3779                 S.Diag(Target->getLocStart(), diag::note_declared_at);
3780               }
3781               return false;
3782            }
3783           }
3784         } else if (!castType->isObjCIdType()) {
3785           S.Diag(castExpr->getLocStart(), diag::err_objc_cf_bridged_not_interface)
3786             << castExpr->getType() << Parm;
3787           S.Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3788           if (Target)
3789             S.Diag(Target->getLocStart(), diag::note_declared_at);
3790         }
3791         return true;
3792       }
3793       return false;
3794     }
3795     T = TDNDecl->getUnderlyingType();
3796   }
3797   return true;
3798 }
3799
3800 template <typename TB>
3801 static bool CheckObjCBridgeCFCast(Sema &S, QualType castType, Expr *castExpr,
3802                                   bool &HadTheAttribute, bool warn) {
3803   QualType T = castType;
3804   HadTheAttribute = false;
3805   while (const TypedefType *TD = dyn_cast<TypedefType>(T.getTypePtr())) {
3806     TypedefNameDecl *TDNDecl = TD->getDecl();
3807     if (TB *ObjCBAttr = getObjCBridgeAttr<TB>(TD)) {
3808       if (IdentifierInfo *Parm = ObjCBAttr->getBridgedType()) {
3809         HadTheAttribute = true;
3810         if (Parm->isStr("id"))
3811           return true;
3812
3813         NamedDecl *Target = nullptr;
3814         // Check for an existing type with this name.
3815         LookupResult R(S, DeclarationName(Parm), SourceLocation(),
3816                        Sema::LookupOrdinaryName);
3817         if (S.LookupName(R, S.TUScope)) {
3818           Target = R.getFoundDecl();
3819           if (Target && isa<ObjCInterfaceDecl>(Target)) {
3820             ObjCInterfaceDecl *CastClass = cast<ObjCInterfaceDecl>(Target);
3821             if (const ObjCObjectPointerType *InterfacePointerType =
3822                   castExpr->getType()->getAsObjCInterfacePointerType()) {
3823               ObjCInterfaceDecl *ExprClass
3824                 = InterfacePointerType->getObjectType()->getInterface();
3825               if ((CastClass == ExprClass) ||
3826                   (ExprClass && CastClass->isSuperClassOf(ExprClass)))
3827                 return true;
3828               if (warn) {
3829                 S.Diag(castExpr->getLocStart(), diag::warn_objc_invalid_bridge_to_cf)
3830                   << castExpr->getType()->getPointeeType() << T;
3831                 S.Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3832               }
3833               return false;
3834             } else if (castExpr->getType()->isObjCIdType() ||
3835                        (S.Context.QIdProtocolsAdoptObjCObjectProtocols(
3836                           castExpr->getType(), CastClass)))
3837               // ok to cast an 'id' expression to a CFtype.
3838               // ok to cast an 'id<plist>' expression to CFtype provided plist
3839               // adopts all of CFtype's ObjetiveC's class plist.
3840               return true;
3841             else {
3842               if (warn) {
3843                 S.Diag(castExpr->getLocStart(), diag::warn_objc_invalid_bridge_to_cf)
3844                   << castExpr->getType() << castType;
3845                 S.Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3846                 S.Diag(Target->getLocStart(), diag::note_declared_at);
3847               }
3848               return false;
3849             }
3850           }
3851         }
3852         S.Diag(castExpr->getLocStart(), diag::err_objc_ns_bridged_invalid_cfobject)
3853         << castExpr->getType() << castType;
3854         S.Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3855         if (Target)
3856           S.Diag(Target->getLocStart(), diag::note_declared_at);
3857         return true;
3858       }
3859       return false;
3860     }
3861     T = TDNDecl->getUnderlyingType();
3862   }
3863   return true;
3864 }
3865
3866 void Sema::CheckTollFreeBridgeCast(QualType castType, Expr *castExpr) {
3867   if (!getLangOpts().ObjC1)
3868     return;
3869   // warn in presence of __bridge casting to or from a toll free bridge cast.
3870   ARCConversionTypeClass exprACTC = classifyTypeForARCConversion(castExpr->getType());
3871   ARCConversionTypeClass castACTC = classifyTypeForARCConversion(castType);
3872   if (castACTC == ACTC_retainable && exprACTC == ACTC_coreFoundation) {
3873     bool HasObjCBridgeAttr;
3874     bool ObjCBridgeAttrWillNotWarn =
3875       CheckObjCBridgeNSCast<ObjCBridgeAttr>(*this, castType, castExpr, HasObjCBridgeAttr,
3876                                             false);
3877     if (ObjCBridgeAttrWillNotWarn && HasObjCBridgeAttr)
3878       return;
3879     bool HasObjCBridgeMutableAttr;
3880     bool ObjCBridgeMutableAttrWillNotWarn =
3881       CheckObjCBridgeNSCast<ObjCBridgeMutableAttr>(*this, castType, castExpr,
3882                                                    HasObjCBridgeMutableAttr, false);
3883     if (ObjCBridgeMutableAttrWillNotWarn && HasObjCBridgeMutableAttr)
3884       return;
3885
3886     if (HasObjCBridgeAttr)
3887       CheckObjCBridgeNSCast<ObjCBridgeAttr>(*this, castType, castExpr, HasObjCBridgeAttr,
3888                                             true);
3889     else if (HasObjCBridgeMutableAttr)
3890       CheckObjCBridgeNSCast<ObjCBridgeMutableAttr>(*this, castType, castExpr,
3891                                                    HasObjCBridgeMutableAttr, true);
3892   }
3893   else if (castACTC == ACTC_coreFoundation && exprACTC == ACTC_retainable) {
3894     bool HasObjCBridgeAttr;
3895     bool ObjCBridgeAttrWillNotWarn =
3896       CheckObjCBridgeCFCast<ObjCBridgeAttr>(*this, castType, castExpr, HasObjCBridgeAttr,
3897                                             false);
3898     if (ObjCBridgeAttrWillNotWarn && HasObjCBridgeAttr)
3899       return;
3900     bool HasObjCBridgeMutableAttr;
3901     bool ObjCBridgeMutableAttrWillNotWarn =
3902       CheckObjCBridgeCFCast<ObjCBridgeMutableAttr>(*this, castType, castExpr,
3903                                                    HasObjCBridgeMutableAttr, false);
3904     if (ObjCBridgeMutableAttrWillNotWarn && HasObjCBridgeMutableAttr)
3905       return;
3906
3907     if (HasObjCBridgeAttr)
3908       CheckObjCBridgeCFCast<ObjCBridgeAttr>(*this, castType, castExpr, HasObjCBridgeAttr,
3909                                             true);
3910     else if (HasObjCBridgeMutableAttr)
3911       CheckObjCBridgeCFCast<ObjCBridgeMutableAttr>(*this, castType, castExpr,
3912                                                    HasObjCBridgeMutableAttr, true);
3913   }
3914 }
3915
3916 void Sema::CheckObjCBridgeRelatedCast(QualType castType, Expr *castExpr) {
3917   QualType SrcType = castExpr->getType();
3918   if (ObjCPropertyRefExpr *PRE = dyn_cast<ObjCPropertyRefExpr>(castExpr)) {
3919     if (PRE->isExplicitProperty()) {
3920       if (ObjCPropertyDecl *PDecl = PRE->getExplicitProperty())
3921         SrcType = PDecl->getType();
3922     }
3923     else if (PRE->isImplicitProperty()) {
3924       if (ObjCMethodDecl *Getter = PRE->getImplicitPropertyGetter())
3925         SrcType = Getter->getReturnType();
3926     }
3927   }
3928
3929   ARCConversionTypeClass srcExprACTC = classifyTypeForARCConversion(SrcType);
3930   ARCConversionTypeClass castExprACTC = classifyTypeForARCConversion(castType);
3931   if (srcExprACTC != ACTC_retainable || castExprACTC != ACTC_coreFoundation)
3932     return;
3933   CheckObjCBridgeRelatedConversions(castExpr->getLocStart(),
3934                                     castType, SrcType, castExpr);
3935 }
3936
3937 bool Sema::CheckTollFreeBridgeStaticCast(QualType castType, Expr *castExpr,
3938                                          CastKind &Kind) {
3939   if (!getLangOpts().ObjC1)
3940     return false;
3941   ARCConversionTypeClass exprACTC =
3942     classifyTypeForARCConversion(castExpr->getType());
3943   ARCConversionTypeClass castACTC = classifyTypeForARCConversion(castType);
3944   if ((castACTC == ACTC_retainable && exprACTC == ACTC_coreFoundation) ||
3945       (castACTC == ACTC_coreFoundation && exprACTC == ACTC_retainable)) {
3946     CheckTollFreeBridgeCast(castType, castExpr);
3947     Kind = (castACTC == ACTC_coreFoundation) ? CK_BitCast
3948                                              : CK_CPointerToObjCPointerCast;
3949     return true;
3950   }
3951   return false;
3952 }
3953
3954 bool Sema::checkObjCBridgeRelatedComponents(SourceLocation Loc,
3955                                             QualType DestType, QualType SrcType,
3956                                             ObjCInterfaceDecl *&RelatedClass,
3957                                             ObjCMethodDecl *&ClassMethod,
3958                                             ObjCMethodDecl *&InstanceMethod,
3959                                             TypedefNameDecl *&TDNDecl,
3960                                             bool CfToNs, bool Diagnose) {
3961   QualType T = CfToNs ? SrcType : DestType;
3962   ObjCBridgeRelatedAttr *ObjCBAttr = ObjCBridgeRelatedAttrFromType(T, TDNDecl);
3963   if (!ObjCBAttr)
3964     return false;
3965
3966   IdentifierInfo *RCId = ObjCBAttr->getRelatedClass();
3967   IdentifierInfo *CMId = ObjCBAttr->getClassMethod();
3968   IdentifierInfo *IMId = ObjCBAttr->getInstanceMethod();
3969   if (!RCId)
3970     return false;
3971   NamedDecl *Target = nullptr;
3972   // Check for an existing type with this name.
3973   LookupResult R(*this, DeclarationName(RCId), SourceLocation(),
3974                  Sema::LookupOrdinaryName);
3975   if (!LookupName(R, TUScope)) {
3976     if (Diagnose) {
3977       Diag(Loc, diag::err_objc_bridged_related_invalid_class) << RCId
3978             << SrcType << DestType;
3979       Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3980     }
3981     return false;
3982   }
3983   Target = R.getFoundDecl();
3984   if (Target && isa<ObjCInterfaceDecl>(Target))
3985     RelatedClass = cast<ObjCInterfaceDecl>(Target);
3986   else {
3987     if (Diagnose) {
3988       Diag(Loc, diag::err_objc_bridged_related_invalid_class_name) << RCId
3989             << SrcType << DestType;
3990       Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3991       if (Target)
3992         Diag(Target->getLocStart(), diag::note_declared_at);
3993     }
3994     return false;
3995   }
3996
3997   // Check for an existing class method with the given selector name.
3998   if (CfToNs && CMId) {
3999     Selector Sel = Context.Selectors.getUnarySelector(CMId);
4000     ClassMethod = RelatedClass->lookupMethod(Sel, false);
4001     if (!ClassMethod) {
4002       if (Diagnose) {
4003         Diag(Loc, diag::err_objc_bridged_related_known_method)
4004               << SrcType << DestType << Sel << false;
4005         Diag(TDNDecl->getLocStart(), diag::note_declared_at);
4006       }
4007       return false;
4008     }
4009   }
4010
4011   // Check for an existing instance method with the given selector name.
4012   if (!CfToNs && IMId) {
4013     Selector Sel = Context.Selectors.getNullarySelector(IMId);
4014     InstanceMethod = RelatedClass->lookupMethod(Sel, true);
4015     if (!InstanceMethod) {
4016       if (Diagnose) {
4017         Diag(Loc, diag::err_objc_bridged_related_known_method)
4018               << SrcType << DestType << Sel << true;
4019         Diag(TDNDecl->getLocStart(), diag::note_declared_at);
4020       }
4021       return false;
4022     }
4023   }
4024   return true;
4025 }
4026
4027 bool
4028 Sema::CheckObjCBridgeRelatedConversions(SourceLocation Loc,
4029                                         QualType DestType, QualType SrcType,
4030                                         Expr *&SrcExpr, bool Diagnose) {
4031   ARCConversionTypeClass rhsExprACTC = classifyTypeForARCConversion(SrcType);
4032   ARCConversionTypeClass lhsExprACTC = classifyTypeForARCConversion(DestType);
4033   bool CfToNs = (rhsExprACTC == ACTC_coreFoundation && lhsExprACTC == ACTC_retainable);
4034   bool NsToCf = (rhsExprACTC == ACTC_retainable && lhsExprACTC == ACTC_coreFoundation);
4035   if (!CfToNs && !NsToCf)
4036     return false;
4037
4038   ObjCInterfaceDecl *RelatedClass;
4039   ObjCMethodDecl *ClassMethod = nullptr;
4040   ObjCMethodDecl *InstanceMethod = nullptr;
4041   TypedefNameDecl *TDNDecl = nullptr;
4042   if (!checkObjCBridgeRelatedComponents(Loc, DestType, SrcType, RelatedClass,
4043                                         ClassMethod, InstanceMethod, TDNDecl,
4044                                         CfToNs, Diagnose))
4045     return false;
4046
4047   if (CfToNs) {
4048     // Implicit conversion from CF to ObjC object is needed.
4049     if (ClassMethod) {
4050       if (Diagnose) {
4051         std::string ExpressionString = "[";
4052         ExpressionString += RelatedClass->getNameAsString();
4053         ExpressionString += " ";
4054         ExpressionString += ClassMethod->getSelector().getAsString();
4055         SourceLocation SrcExprEndLoc = getLocForEndOfToken(SrcExpr->getLocEnd());
4056         // Provide a fixit: [RelatedClass ClassMethod SrcExpr]
4057         Diag(Loc, diag::err_objc_bridged_related_known_method)
4058           << SrcType << DestType << ClassMethod->getSelector() << false
4059           << FixItHint::CreateInsertion(SrcExpr->getLocStart(), ExpressionString)
4060           << FixItHint::CreateInsertion(SrcExprEndLoc, "]");
4061         Diag(RelatedClass->getLocStart(), diag::note_declared_at);
4062         Diag(TDNDecl->getLocStart(), diag::note_declared_at);
4063
4064         QualType receiverType = Context.getObjCInterfaceType(RelatedClass);
4065         // Argument.
4066         Expr *args[] = { SrcExpr };
4067         ExprResult msg = BuildClassMessageImplicit(receiverType, false,
4068                                       ClassMethod->getLocation(),
4069                                       ClassMethod->getSelector(), ClassMethod,
4070                                       MultiExprArg(args, 1));
4071         SrcExpr = msg.get();
4072       }
4073       return true;
4074     }
4075   }
4076   else {
4077     // Implicit conversion from ObjC type to CF object is needed.
4078     if (InstanceMethod) {
4079       if (Diagnose) {
4080         std::string ExpressionString;
4081         SourceLocation SrcExprEndLoc =
4082             getLocForEndOfToken(SrcExpr->getLocEnd());
4083         if (InstanceMethod->isPropertyAccessor())
4084           if (const ObjCPropertyDecl *PDecl =
4085                   InstanceMethod->findPropertyDecl()) {
4086             // fixit: ObjectExpr.propertyname when it is  aproperty accessor.
4087             ExpressionString = ".";
4088             ExpressionString += PDecl->getNameAsString();
4089             Diag(Loc, diag::err_objc_bridged_related_known_method)
4090                 << SrcType << DestType << InstanceMethod->getSelector() << true
4091                 << FixItHint::CreateInsertion(SrcExprEndLoc, ExpressionString);
4092           }
4093         if (ExpressionString.empty()) {
4094           // Provide a fixit: [ObjectExpr InstanceMethod]
4095           ExpressionString = " ";
4096           ExpressionString += InstanceMethod->getSelector().getAsString();
4097           ExpressionString += "]";
4098
4099           Diag(Loc, diag::err_objc_bridged_related_known_method)
4100               << SrcType << DestType << InstanceMethod->getSelector() << true
4101               << FixItHint::CreateInsertion(SrcExpr->getLocStart(), "[")
4102               << FixItHint::CreateInsertion(SrcExprEndLoc, ExpressionString);
4103         }
4104         Diag(RelatedClass->getLocStart(), diag::note_declared_at);
4105         Diag(TDNDecl->getLocStart(), diag::note_declared_at);
4106
4107         ExprResult msg =
4108           BuildInstanceMessageImplicit(SrcExpr, SrcType,
4109                                        InstanceMethod->getLocation(),
4110                                        InstanceMethod->getSelector(),
4111                                        InstanceMethod, None);
4112         SrcExpr = msg.get();
4113       }
4114       return true;
4115     }
4116   }
4117   return false;
4118 }
4119
4120 Sema::ARCConversionResult
4121 Sema::CheckObjCConversion(SourceRange castRange, QualType castType,
4122                           Expr *&castExpr, CheckedConversionKind CCK,
4123                           bool Diagnose, bool DiagnoseCFAudited,
4124                           BinaryOperatorKind Opc) {
4125   QualType castExprType = castExpr->getType();
4126
4127   // For the purposes of the classification, we assume reference types
4128   // will bind to temporaries.
4129   QualType effCastType = castType;
4130   if (const ReferenceType *ref = castType->getAs<ReferenceType>())
4131     effCastType = ref->getPointeeType();
4132
4133   ARCConversionTypeClass exprACTC = classifyTypeForARCConversion(castExprType);
4134   ARCConversionTypeClass castACTC = classifyTypeForARCConversion(effCastType);
4135   if (exprACTC == castACTC) {
4136     // Check for viability and report error if casting an rvalue to a
4137     // life-time qualifier.
4138     if (castACTC == ACTC_retainable &&
4139         (CCK == CCK_CStyleCast || CCK == CCK_OtherCast) &&
4140         castType != castExprType) {
4141       const Type *DT = castType.getTypePtr();
4142       QualType QDT = castType;
4143       // We desugar some types but not others. We ignore those
4144       // that cannot happen in a cast; i.e. auto, and those which
4145       // should not be de-sugared; i.e typedef.
4146       if (const ParenType *PT = dyn_cast<ParenType>(DT))
4147         QDT = PT->desugar();
4148       else if (const TypeOfType *TP = dyn_cast<TypeOfType>(DT))
4149         QDT = TP->desugar();
4150       else if (const AttributedType *AT = dyn_cast<AttributedType>(DT))
4151         QDT = AT->desugar();
4152       if (QDT != castType &&
4153           QDT.getObjCLifetime() !=  Qualifiers::OCL_None) {
4154         if (Diagnose) {
4155           SourceLocation loc = (castRange.isValid() ? castRange.getBegin()
4156                                                     : castExpr->getExprLoc());
4157           Diag(loc, diag::err_arc_nolifetime_behavior);
4158         }
4159         return ACR_error;
4160       }
4161     }
4162     return ACR_okay;
4163   }
4164
4165   // The life-time qualifier cast check above is all we need for ObjCWeak.
4166   // ObjCAutoRefCount has more restrictions on what is legal.
4167   if (!getLangOpts().ObjCAutoRefCount)
4168     return ACR_okay;
4169
4170   if (isAnyCLike(exprACTC) && isAnyCLike(castACTC)) return ACR_okay;
4171
4172   // Allow all of these types to be cast to integer types (but not
4173   // vice-versa).
4174   if (castACTC == ACTC_none && castType->isIntegralType(Context))
4175     return ACR_okay;
4176
4177   // Allow casts between pointers to lifetime types (e.g., __strong id*)
4178   // and pointers to void (e.g., cv void *). Casting from void* to lifetime*
4179   // must be explicit.
4180   if (exprACTC == ACTC_indirectRetainable && castACTC == ACTC_voidPtr)
4181     return ACR_okay;
4182   if (castACTC == ACTC_indirectRetainable && exprACTC == ACTC_voidPtr &&
4183       CCK != CCK_ImplicitConversion)
4184     return ACR_okay;
4185
4186   switch (ARCCastChecker(Context, exprACTC, castACTC, false).Visit(castExpr)) {
4187   // For invalid casts, fall through.
4188   case ACC_invalid:
4189     break;
4190
4191   // Do nothing for both bottom and +0.
4192   case ACC_bottom:
4193   case ACC_plusZero:
4194     return ACR_okay;
4195
4196   // If the result is +1, consume it here.
4197   case ACC_plusOne:
4198     castExpr = ImplicitCastExpr::Create(Context, castExpr->getType(),
4199                                         CK_ARCConsumeObject, castExpr,
4200                                         nullptr, VK_RValue);
4201     Cleanup.setExprNeedsCleanups(true);
4202     return ACR_okay;
4203   }
4204
4205   // If this is a non-implicit cast from id or block type to a
4206   // CoreFoundation type, delay complaining in case the cast is used
4207   // in an acceptable context.
4208   if (exprACTC == ACTC_retainable && isAnyRetainable(castACTC) &&
4209       CCK != CCK_ImplicitConversion)
4210     return ACR_unbridged;
4211
4212   // Issue a diagnostic about a missing @-sign when implicit casting a cstring
4213   // to 'NSString *', instead of falling through to report a "bridge cast"
4214   // diagnostic.
4215   if (castACTC == ACTC_retainable && exprACTC == ACTC_none &&
4216       ConversionToObjCStringLiteralCheck(castType, castExpr, Diagnose))
4217     return ACR_error;
4218
4219   // Do not issue "bridge cast" diagnostic when implicit casting
4220   // a retainable object to a CF type parameter belonging to an audited
4221   // CF API function. Let caller issue a normal type mismatched diagnostic
4222   // instead.
4223   if ((!DiagnoseCFAudited || exprACTC != ACTC_retainable ||
4224        castACTC != ACTC_coreFoundation) &&
4225       !(exprACTC == ACTC_voidPtr && castACTC == ACTC_retainable &&
4226         (Opc == BO_NE || Opc == BO_EQ))) {
4227     if (Diagnose)
4228       diagnoseObjCARCConversion(*this, castRange, castType, castACTC, castExpr,
4229                                 castExpr, exprACTC, CCK);
4230     return ACR_error;
4231   }
4232   return ACR_okay;
4233 }
4234
4235 /// Given that we saw an expression with the ARCUnbridgedCastTy
4236 /// placeholder type, complain bitterly.
4237 void Sema::diagnoseARCUnbridgedCast(Expr *e) {
4238   // We expect the spurious ImplicitCastExpr to already have been stripped.
4239   assert(!e->hasPlaceholderType(BuiltinType::ARCUnbridgedCast));
4240   CastExpr *realCast = cast<CastExpr>(e->IgnoreParens());
4241
4242   SourceRange castRange;
4243   QualType castType;
4244   CheckedConversionKind CCK;
4245
4246   if (CStyleCastExpr *cast = dyn_cast<CStyleCastExpr>(realCast)) {
4247     castRange = SourceRange(cast->getLParenLoc(), cast->getRParenLoc());
4248     castType = cast->getTypeAsWritten();
4249     CCK = CCK_CStyleCast;
4250   } else if (ExplicitCastExpr *cast = dyn_cast<ExplicitCastExpr>(realCast)) {
4251     castRange = cast->getTypeInfoAsWritten()->getTypeLoc().getSourceRange();
4252     castType = cast->getTypeAsWritten();
4253     CCK = CCK_OtherCast;
4254   } else {
4255     llvm_unreachable("Unexpected ImplicitCastExpr");
4256   }
4257
4258   ARCConversionTypeClass castACTC =
4259     classifyTypeForARCConversion(castType.getNonReferenceType());
4260
4261   Expr *castExpr = realCast->getSubExpr();
4262   assert(classifyTypeForARCConversion(castExpr->getType()) == ACTC_retainable);
4263
4264   diagnoseObjCARCConversion(*this, castRange, castType, castACTC,
4265                             castExpr, realCast, ACTC_retainable, CCK);
4266 }
4267
4268 /// stripARCUnbridgedCast - Given an expression of ARCUnbridgedCast
4269 /// type, remove the placeholder cast.
4270 Expr *Sema::stripARCUnbridgedCast(Expr *e) {
4271   assert(e->hasPlaceholderType(BuiltinType::ARCUnbridgedCast));
4272
4273   if (ParenExpr *pe = dyn_cast<ParenExpr>(e)) {
4274     Expr *sub = stripARCUnbridgedCast(pe->getSubExpr());
4275     return new (Context) ParenExpr(pe->getLParen(), pe->getRParen(), sub);
4276   } else if (UnaryOperator *uo = dyn_cast<UnaryOperator>(e)) {
4277     assert(uo->getOpcode() == UO_Extension);
4278     Expr *sub = stripARCUnbridgedCast(uo->getSubExpr());
4279     return new (Context) UnaryOperator(sub, UO_Extension, sub->getType(),
4280                                    sub->getValueKind(), sub->getObjectKind(),
4281                                        uo->getOperatorLoc());
4282   } else if (GenericSelectionExpr *gse = dyn_cast<GenericSelectionExpr>(e)) {
4283     assert(!gse->isResultDependent());
4284
4285     unsigned n = gse->getNumAssocs();
4286     SmallVector<Expr*, 4> subExprs(n);
4287     SmallVector<TypeSourceInfo*, 4> subTypes(n);
4288     for (unsigned i = 0; i != n; ++i) {
4289       subTypes[i] = gse->getAssocTypeSourceInfo(i);
4290       Expr *sub = gse->getAssocExpr(i);
4291       if (i == gse->getResultIndex())
4292         sub = stripARCUnbridgedCast(sub);
4293       subExprs[i] = sub;
4294     }
4295
4296     return new (Context) GenericSelectionExpr(Context, gse->getGenericLoc(),
4297                                               gse->getControllingExpr(),
4298                                               subTypes, subExprs,
4299                                               gse->getDefaultLoc(),
4300                                               gse->getRParenLoc(),
4301                                        gse->containsUnexpandedParameterPack(),
4302                                               gse->getResultIndex());
4303   } else {
4304     assert(isa<ImplicitCastExpr>(e) && "bad form of unbridged cast!");
4305     return cast<ImplicitCastExpr>(e)->getSubExpr();
4306   }
4307 }
4308
4309 bool Sema::CheckObjCARCUnavailableWeakConversion(QualType castType,
4310                                                  QualType exprType) {
4311   QualType canCastType =
4312     Context.getCanonicalType(castType).getUnqualifiedType();
4313   QualType canExprType =
4314     Context.getCanonicalType(exprType).getUnqualifiedType();
4315   if (isa<ObjCObjectPointerType>(canCastType) &&
4316       castType.getObjCLifetime() == Qualifiers::OCL_Weak &&
4317       canExprType->isObjCObjectPointerType()) {
4318     if (const ObjCObjectPointerType *ObjT =
4319         canExprType->getAs<ObjCObjectPointerType>())
4320       if (const ObjCInterfaceDecl *ObjI = ObjT->getInterfaceDecl())
4321         return !ObjI->isArcWeakrefUnavailable();
4322   }
4323   return true;
4324 }
4325
4326 /// Look for an ObjCReclaimReturnedObject cast and destroy it.
4327 static Expr *maybeUndoReclaimObject(Expr *e) {
4328   Expr *curExpr = e, *prevExpr = nullptr;
4329
4330   // Walk down the expression until we hit an implicit cast of kind
4331   // ARCReclaimReturnedObject or an Expr that is neither a Paren nor a Cast.
4332   while (true) {
4333     if (auto *pe = dyn_cast<ParenExpr>(curExpr)) {
4334       prevExpr = curExpr;
4335       curExpr = pe->getSubExpr();
4336       continue;
4337     }
4338
4339     if (auto *ce = dyn_cast<CastExpr>(curExpr)) {
4340       if (auto *ice = dyn_cast<ImplicitCastExpr>(ce))
4341         if (ice->getCastKind() == CK_ARCReclaimReturnedObject) {
4342           if (!prevExpr)
4343             return ice->getSubExpr();
4344           if (auto *pe = dyn_cast<ParenExpr>(prevExpr))
4345             pe->setSubExpr(ice->getSubExpr());
4346           else
4347             cast<CastExpr>(prevExpr)->setSubExpr(ice->getSubExpr());
4348           return e;
4349         }
4350
4351       prevExpr = curExpr;
4352       curExpr = ce->getSubExpr();
4353       continue;
4354     }
4355
4356     // Break out of the loop if curExpr is neither a Paren nor a Cast.
4357     break;
4358   }
4359
4360   return e;
4361 }
4362
4363 ExprResult Sema::BuildObjCBridgedCast(SourceLocation LParenLoc,
4364                                       ObjCBridgeCastKind Kind,
4365                                       SourceLocation BridgeKeywordLoc,
4366                                       TypeSourceInfo *TSInfo,
4367                                       Expr *SubExpr) {
4368   ExprResult SubResult = UsualUnaryConversions(SubExpr);
4369   if (SubResult.isInvalid()) return ExprError();
4370   SubExpr = SubResult.get();
4371
4372   QualType T = TSInfo->getType();
4373   QualType FromType = SubExpr->getType();
4374
4375   CastKind CK;
4376
4377   bool MustConsume = false;
4378   if (T->isDependentType() || SubExpr->isTypeDependent()) {
4379     // Okay: we'll build a dependent expression type.
4380     CK = CK_Dependent;
4381   } else if (T->isObjCARCBridgableType() && FromType->isCARCBridgableType()) {
4382     // Casting CF -> id
4383     CK = (T->isBlockPointerType() ? CK_AnyPointerToBlockPointerCast
4384                                   : CK_CPointerToObjCPointerCast);
4385     switch (Kind) {
4386     case OBC_Bridge:
4387       break;
4388
4389     case OBC_BridgeRetained: {
4390       bool br = isKnownName("CFBridgingRelease");
4391       Diag(BridgeKeywordLoc, diag::err_arc_bridge_cast_wrong_kind)
4392         << 2
4393         << FromType
4394         << (T->isBlockPointerType()? 1 : 0)
4395         << T
4396         << SubExpr->getSourceRange()
4397         << Kind;
4398       Diag(BridgeKeywordLoc, diag::note_arc_bridge)
4399         << FixItHint::CreateReplacement(BridgeKeywordLoc, "__bridge");
4400       Diag(BridgeKeywordLoc, diag::note_arc_bridge_transfer)
4401         << FromType << br
4402         << FixItHint::CreateReplacement(BridgeKeywordLoc,
4403                                         br ? "CFBridgingRelease "
4404                                            : "__bridge_transfer ");
4405
4406       Kind = OBC_Bridge;
4407       break;
4408     }
4409
4410     case OBC_BridgeTransfer:
4411       // We must consume the Objective-C object produced by the cast.
4412       MustConsume = true;
4413       break;
4414     }
4415   } else if (T->isCARCBridgableType() && FromType->isObjCARCBridgableType()) {
4416     // Okay: id -> CF
4417     CK = CK_BitCast;
4418     switch (Kind) {
4419     case OBC_Bridge:
4420       // Reclaiming a value that's going to be __bridge-casted to CF
4421       // is very dangerous, so we don't do it.
4422       SubExpr = maybeUndoReclaimObject(SubExpr);
4423       break;
4424
4425     case OBC_BridgeRetained:
4426       // Produce the object before casting it.
4427       SubExpr = ImplicitCastExpr::Create(Context, FromType,
4428                                          CK_ARCProduceObject,
4429                                          SubExpr, nullptr, VK_RValue);
4430       break;
4431
4432     case OBC_BridgeTransfer: {
4433       bool br = isKnownName("CFBridgingRetain");
4434       Diag(BridgeKeywordLoc, diag::err_arc_bridge_cast_wrong_kind)
4435         << (FromType->isBlockPointerType()? 1 : 0)
4436         << FromType
4437         << 2
4438         << T
4439         << SubExpr->getSourceRange()
4440         << Kind;
4441
4442       Diag(BridgeKeywordLoc, diag::note_arc_bridge)
4443         << FixItHint::CreateReplacement(BridgeKeywordLoc, "__bridge ");
4444       Diag(BridgeKeywordLoc, diag::note_arc_bridge_retained)
4445         << T << br
4446         << FixItHint::CreateReplacement(BridgeKeywordLoc,
4447                           br ? "CFBridgingRetain " : "__bridge_retained");
4448
4449       Kind = OBC_Bridge;
4450       break;
4451     }
4452     }
4453   } else {
4454     Diag(LParenLoc, diag::err_arc_bridge_cast_incompatible)
4455       << FromType << T << Kind
4456       << SubExpr->getSourceRange()
4457       << TSInfo->getTypeLoc().getSourceRange();
4458     return ExprError();
4459   }
4460
4461   Expr *Result = new (Context) ObjCBridgedCastExpr(LParenLoc, Kind, CK,
4462                                                    BridgeKeywordLoc,
4463                                                    TSInfo, SubExpr);
4464
4465   if (MustConsume) {
4466     Cleanup.setExprNeedsCleanups(true);
4467     Result = ImplicitCastExpr::Create(Context, T, CK_ARCConsumeObject, Result,
4468                                       nullptr, VK_RValue);
4469   }
4470
4471   return Result;
4472 }
4473
4474 ExprResult Sema::ActOnObjCBridgedCast(Scope *S,
4475                                       SourceLocation LParenLoc,
4476                                       ObjCBridgeCastKind Kind,
4477                                       SourceLocation BridgeKeywordLoc,
4478                                       ParsedType Type,
4479                                       SourceLocation RParenLoc,
4480                                       Expr *SubExpr) {
4481   TypeSourceInfo *TSInfo = nullptr;
4482   QualType T = GetTypeFromParser(Type, &TSInfo);
4483   if (Kind == OBC_Bridge)
4484     CheckTollFreeBridgeCast(T, SubExpr);
4485   if (!TSInfo)
4486     TSInfo = Context.getTrivialTypeSourceInfo(T, LParenLoc);
4487   return BuildObjCBridgedCast(LParenLoc, Kind, BridgeKeywordLoc, TSInfo,
4488                               SubExpr);
4489 }