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

   1 //===--- SemaExprObjC.cpp - Semantic Analysis for ObjC Expressions --------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 //  This file implements semantic analysis for Objective-C expressions.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "clang/Sema/SemaInternal.h"
  15 #include "clang/AST/ASTContext.h"
  16 #include "clang/AST/DeclObjC.h"
  17 #include "clang/AST/ExprObjC.h"
  18 #include "clang/AST/StmtVisitor.h"
  19 #include "clang/AST/TypeLoc.h"
  20 #include "clang/Analysis/DomainSpecific/CocoaConventions.h"
  21 #include "clang/Edit/Commit.h"
  22 #include "clang/Edit/Rewriters.h"
  23 #include "clang/Lex/Preprocessor.h"
  24 #include "clang/Sema/Initialization.h"
  25 #include "clang/Sema/Lookup.h"
  26 #include "clang/Sema/Scope.h"
  27 #include "clang/Sema/ScopeInfo.h"
  28 #include "llvm/ADT/SmallString.h"
  29
  30 using namespace clang;
  31 using namespace sema;
  32 using llvm::makeArrayRef;
  33
  34 ExprResult Sema::ParseObjCStringLiteral(SourceLocation *AtLocs,
  35                                         ArrayRef<Expr *> Strings) {
  36   // Most ObjC strings are formed out of a single piece.  However, we *can*
  37   // have strings formed out of multiple @ strings with multiple pptokens in
  38   // each one, e.g. @"foo" "bar" @"baz" "qux"   which need to be turned into one
  39   // StringLiteral for ObjCStringLiteral to hold onto.
  40   StringLiteral *S = cast<StringLiteral>(Strings[0]);
  41
  42   // If we have a multi-part string, merge it all together.
  43   if (Strings.size() != 1) {
  44     // Concatenate objc strings.
  45     SmallString<128> StrBuf;
  46     SmallVector<SourceLocation, 8> StrLocs;
  47
  48     for (Expr *E : Strings) {
  49       S = cast<StringLiteral>(E);
  50
  51       // ObjC strings can't be wide or UTF.
  52       if (!S->isAscii()) {
  53         Diag(S->getLocStart(), diag::err_cfstring_literal_not_string_constant)
  54           << S->getSourceRange();
  55         return true;
  56       }
  57
  58       // Append the string.
  59       StrBuf += S->getString();
  60
  61       // Get the locations of the string tokens.
  62       StrLocs.append(S->tokloc_begin(), S->tokloc_end());
  63     }
  64
  65     // Create the aggregate string with the appropriate content and location
  66     // information.
  67     const ConstantArrayType *CAT = Context.getAsConstantArrayType(S->getType());
  68     assert(CAT && "String literal not of constant array type!");
  69     QualType StrTy = Context.getConstantArrayType(
  70         CAT->getElementType(), llvm::APInt(32, StrBuf.size() + 1),
  71         CAT->getSizeModifier(), CAT->getIndexTypeCVRQualifiers());
  72     S = StringLiteral::Create(Context, StrBuf, StringLiteral::Ascii,
  73                               /*Pascal=*/false, StrTy, &StrLocs[0],
  74                               StrLocs.size());
  75   }
  76
  77   return BuildObjCStringLiteral(AtLocs[0], S);
  78 }
  79
  80 ExprResult Sema::BuildObjCStringLiteral(SourceLocation AtLoc, StringLiteral *S){
  81   // Verify that this composite string is acceptable for ObjC strings.
  82   if (CheckObjCString(S))
  83     return true;
  84
  85   // Initialize the constant string interface lazily. This assumes
  86   // the NSString interface is seen in this translation unit. Note: We
  87   // don't use NSConstantString, since the runtime team considers this
  88   // interface private (even though it appears in the header files).
  89   QualType Ty = Context.getObjCConstantStringInterface();
  90   if (!Ty.isNull()) {
  91     Ty = Context.getObjCObjectPointerType(Ty);
  92   } else if (getLangOpts().NoConstantCFStrings) {
  93     IdentifierInfo *NSIdent=nullptr;
  94     std::string StringClass(getLangOpts().ObjCConstantStringClass);
  95
  96     if (StringClass.empty())
  97       NSIdent = &Context.Idents.get("NSConstantString");
  98     else
  99       NSIdent = &Context.Idents.get(StringClass);
 100
 101     NamedDecl *IF = LookupSingleName(TUScope, NSIdent, AtLoc,
 102                                      LookupOrdinaryName);
 103     if (ObjCInterfaceDecl *StrIF = dyn_cast_or_null<ObjCInterfaceDecl>(IF)) {
 104       Context.setObjCConstantStringInterface(StrIF);
 105       Ty = Context.getObjCConstantStringInterface();
 106       Ty = Context.getObjCObjectPointerType(Ty);
 107     } else {
 108       // If there is no NSConstantString interface defined then treat this
 109       // as error and recover from it.
 110       Diag(S->getLocStart(), diag::err_no_nsconstant_string_class) << NSIdent
 111         << S->getSourceRange();
 112       Ty = Context.getObjCIdType();
 113     }
 114   } else {
 115     IdentifierInfo *NSIdent = NSAPIObj->getNSClassId(NSAPI::ClassId_NSString);
 116     NamedDecl *IF = LookupSingleName(TUScope, NSIdent, AtLoc,
 117                                      LookupOrdinaryName);
 118     if (ObjCInterfaceDecl *StrIF = dyn_cast_or_null<ObjCInterfaceDecl>(IF)) {
 119       Context.setObjCConstantStringInterface(StrIF);
 120       Ty = Context.getObjCConstantStringInterface();
 121       Ty = Context.getObjCObjectPointerType(Ty);
 122     } else {
 123       // If there is no NSString interface defined, implicitly declare
 124       // a @class NSString; and use that instead. This is to make sure
 125       // type of an NSString literal is represented correctly, instead of
 126       // being an 'id' type.
 127       Ty = Context.getObjCNSStringType();
 128       if (Ty.isNull()) {
 129         ObjCInterfaceDecl *NSStringIDecl =
 130           ObjCInterfaceDecl::Create (Context,
 131                                      Context.getTranslationUnitDecl(),
 132                                      SourceLocation(), NSIdent,
 133                                      nullptr, nullptr, SourceLocation());
 134         Ty = Context.getObjCInterfaceType(NSStringIDecl);
 135         Context.setObjCNSStringType(Ty);
 136       }
 137       Ty = Context.getObjCObjectPointerType(Ty);
 138     }
 139   }
 140
 141   return new (Context) ObjCStringLiteral(S, Ty, AtLoc);
 142 }
 143
 144 /// \brief Emits an error if the given method does not exist, or if the return
 145 /// type is not an Objective-C object.
 146 static bool validateBoxingMethod(Sema &S, SourceLocation Loc,
 147                                  const ObjCInterfaceDecl *Class,
 148                                  Selector Sel, const ObjCMethodDecl *Method) {
 149   if (!Method) {
 150     // FIXME: Is there a better way to avoid quotes than using getName()?
 151     S.Diag(Loc, diag::err_undeclared_boxing_method) << Sel << Class->getName();
 152     return false;
 153   }
 154
 155   // Make sure the return type is reasonable.
 156   QualType ReturnType = Method->getReturnType();
 157   if (!ReturnType->isObjCObjectPointerType()) {
 158     S.Diag(Loc, diag::err_objc_literal_method_sig)
 159       << Sel;
 160     S.Diag(Method->getLocation(), diag::note_objc_literal_method_return)
 161       << ReturnType;
 162     return false;
 163   }
 164
 165   return true;
 166 }
 167
 168 /// \brief Maps ObjCLiteralKind to NSClassIdKindKind
 169 static NSAPI::NSClassIdKindKind ClassKindFromLiteralKind(
 170                                             Sema::ObjCLiteralKind LiteralKind) {
 171   switch (LiteralKind) {
 172     case Sema::LK_Array:
 173       return NSAPI::ClassId_NSArray;
 174     case Sema::LK_Dictionary:
 175       return NSAPI::ClassId_NSDictionary;
 176     case Sema::LK_Numeric:
 177       return NSAPI::ClassId_NSNumber;
 178     case Sema::LK_String:
 179       return NSAPI::ClassId_NSString;
 180     case Sema::LK_Boxed:
 181       return NSAPI::ClassId_NSValue;
 182
 183     // there is no corresponding matching
 184     // between LK_None/LK_Block and NSClassIdKindKind
 185     case Sema::LK_Block:
 186     case Sema::LK_None:
 187       break;
 188   }
 189   llvm_unreachable("LiteralKind can't be converted into a ClassKind");
 190 }
 191
 192 /// \brief Validates ObjCInterfaceDecl availability.
 193 /// ObjCInterfaceDecl, used to create ObjC literals, should be defined
 194 /// if clang not in a debugger mode.
 195 static bool ValidateObjCLiteralInterfaceDecl(Sema &S, ObjCInterfaceDecl *Decl,
 196                                             SourceLocation Loc,
 197                                             Sema::ObjCLiteralKind LiteralKind) {
 198   if (!Decl) {
 199     NSAPI::NSClassIdKindKind Kind = ClassKindFromLiteralKind(LiteralKind);
 200     IdentifierInfo *II = S.NSAPIObj->getNSClassId(Kind);
 201     S.Diag(Loc, diag::err_undeclared_objc_literal_class)
 202       << II->getName() << LiteralKind;
 203     return false;
 204   } else if (!Decl->hasDefinition() && !S.getLangOpts().DebuggerObjCLiteral) {
 205     S.Diag(Loc, diag::err_undeclared_objc_literal_class)
 206       << Decl->getName() << LiteralKind;
 207     S.Diag(Decl->getLocation(), diag::note_forward_class);
 208     return false;
 209   }
 210
 211   return true;
 212 }
 213
 214 /// \brief Looks up ObjCInterfaceDecl of a given NSClassIdKindKind.
 215 /// Used to create ObjC literals, such as NSDictionary (@{}),
 216 /// NSArray (@[]) and Boxed Expressions (@())
 217 static ObjCInterfaceDecl *LookupObjCInterfaceDeclForLiteral(Sema &S,
 218                                             SourceLocation Loc,
 219                                             Sema::ObjCLiteralKind LiteralKind) {
 220   NSAPI::NSClassIdKindKind ClassKind = ClassKindFromLiteralKind(LiteralKind);
 221   IdentifierInfo *II = S.NSAPIObj->getNSClassId(ClassKind);
 222   NamedDecl *IF = S.LookupSingleName(S.TUScope, II, Loc,
 223                                      Sema::LookupOrdinaryName);
 224   ObjCInterfaceDecl *ID = dyn_cast_or_null<ObjCInterfaceDecl>(IF);
 225   if (!ID && S.getLangOpts().DebuggerObjCLiteral) {
 226     ASTContext &Context = S.Context;
 227     TranslationUnitDecl *TU = Context.getTranslationUnitDecl();
 228     ID = ObjCInterfaceDecl::Create (Context, TU, SourceLocation(), II,
 229                                     nullptr, nullptr, SourceLocation());
 230   }
 231
 232   if (!ValidateObjCLiteralInterfaceDecl(S, ID, Loc, LiteralKind)) {
 233     ID = nullptr;
 234   }
 235
 236   return ID;
 237 }
 238
 239 /// \brief Retrieve the NSNumber factory method that should be used to create
 240 /// an Objective-C literal for the given type.
 241 static ObjCMethodDecl *getNSNumberFactoryMethod(Sema &S, SourceLocation Loc,
 242                                                 QualType NumberType,
 243                                                 bool isLiteral = false,
 244                                                 SourceRange R = SourceRange()) {
 245   Optional<NSAPI::NSNumberLiteralMethodKind> Kind =
 246       S.NSAPIObj->getNSNumberFactoryMethodKind(NumberType);
 247
 248   if (!Kind) {
 249     if (isLiteral) {
 250       S.Diag(Loc, diag::err_invalid_nsnumber_type)
 251         << NumberType << R;
 252     }
 253     return nullptr;
 254   }
 255
 256   // If we already looked up this method, we're done.
 257   if (S.NSNumberLiteralMethods[*Kind])
 258     return S.NSNumberLiteralMethods[*Kind];
 259
 260   Selector Sel = S.NSAPIObj->getNSNumberLiteralSelector(*Kind,
 261                                                         /*Instance=*/false);
 262
 263   ASTContext &CX = S.Context;
 264
 265   // Look up the NSNumber class, if we haven't done so already. It's cached
 266   // in the Sema instance.
 267   if (!S.NSNumberDecl) {
 268     S.NSNumberDecl = LookupObjCInterfaceDeclForLiteral(S, Loc,
 269                                                        Sema::LK_Numeric);
 270     if (!S.NSNumberDecl) {
 271       return nullptr;
 272     }
 273   }
 274
 275   if (S.NSNumberPointer.isNull()) {
 276     // generate the pointer to NSNumber type.
 277     QualType NSNumberObject = CX.getObjCInterfaceType(S.NSNumberDecl);
 278     S.NSNumberPointer = CX.getObjCObjectPointerType(NSNumberObject);
 279   }
 280
 281   // Look for the appropriate method within NSNumber.
 282   ObjCMethodDecl *Method = S.NSNumberDecl->lookupClassMethod(Sel);
 283   if (!Method && S.getLangOpts().DebuggerObjCLiteral) {
 284     // create a stub definition this NSNumber factory method.
 285     TypeSourceInfo *ReturnTInfo = nullptr;
 286     Method =
 287         ObjCMethodDecl::Create(CX, SourceLocation(), SourceLocation(), Sel,
 288                                S.NSNumberPointer, ReturnTInfo, S.NSNumberDecl,
 289                                /*isInstance=*/false, /*isVariadic=*/false,
 290                                /*isPropertyAccessor=*/false,
 291                                /*isImplicitlyDeclared=*/true,
 292                                /*isDefined=*/false, ObjCMethodDecl::Required,
 293                                /*HasRelatedResultType=*/false);
 294     ParmVarDecl *value = ParmVarDecl::Create(S.Context, Method,
 295                                              SourceLocation(), SourceLocation(),
 296                                              &CX.Idents.get("value"),
 297                                              NumberType, /*TInfo=*/nullptr,
 298                                              SC_None, nullptr);
 299     Method->setMethodParams(S.Context, value, None);
 300   }
 301
 302   if (!validateBoxingMethod(S, Loc, S.NSNumberDecl, Sel, Method))
 303     return nullptr;
 304
 305   // Note: if the parameter type is out-of-line, we'll catch it later in the
 306   // implicit conversion.
 307
 308   S.NSNumberLiteralMethods[*Kind] = Method;
 309   return Method;
 310 }
 311
 312 /// BuildObjCNumericLiteral - builds an ObjCBoxedExpr AST node for the
 313 /// numeric literal expression. Type of the expression will be "NSNumber *".
 314 ExprResult Sema::BuildObjCNumericLiteral(SourceLocation AtLoc, Expr *Number) {
 315   // Determine the type of the literal.
 316   QualType NumberType = Number->getType();
 317   if (CharacterLiteral *Char = dyn_cast<CharacterLiteral>(Number)) {
 318     // In C, character literals have type 'int'. That's not the type we want
 319     // to use to determine the Objective-c literal kind.
 320     switch (Char->getKind()) {
 321     case CharacterLiteral::Ascii:
 322     case CharacterLiteral::UTF8:
 323       NumberType = Context.CharTy;
 324       break;
 325
 326     case CharacterLiteral::Wide:
 327       NumberType = Context.getWideCharType();
 328       break;
 329
 330     case CharacterLiteral::UTF16:
 331       NumberType = Context.Char16Ty;
 332       break;
 333
 334     case CharacterLiteral::UTF32:
 335       NumberType = Context.Char32Ty;
 336       break;
 337     }
 338   }
 339
 340   // Look for the appropriate method within NSNumber.
 341   // Construct the literal.
 342   SourceRange NR(Number->getSourceRange());
 343   ObjCMethodDecl *Method = getNSNumberFactoryMethod(*this, AtLoc, NumberType,
 344                                                     true, NR);
 345   if (!Method)
 346     return ExprError();
 347
 348   // Convert the number to the type that the parameter expects.
 349   ParmVarDecl *ParamDecl = Method->parameters()[0];
 350   InitializedEntity Entity = InitializedEntity::InitializeParameter(Context,
 351                                                                     ParamDecl);
 352   ExprResult ConvertedNumber = PerformCopyInitialization(Entity,
 353                                                          SourceLocation(),
 354                                                          Number);
 355   if (ConvertedNumber.isInvalid())
 356     return ExprError();
 357   Number = ConvertedNumber.get();
 358
 359   // Use the effective source range of the literal, including the leading '@'.
 360   return MaybeBindToTemporary(
 361            new (Context) ObjCBoxedExpr(Number, NSNumberPointer, Method,
 362                                        SourceRange(AtLoc, NR.getEnd())));
 363 }
 364
 365 ExprResult Sema::ActOnObjCBoolLiteral(SourceLocation AtLoc,
 366                                       SourceLocation ValueLoc,
 367                                       bool Value) {
 368   ExprResult Inner;
 369   if (getLangOpts().CPlusPlus) {
 370     Inner = ActOnCXXBoolLiteral(ValueLoc, Value? tok::kw_true : tok::kw_false);
 371   } else {
 372     // C doesn't actually have a way to represent literal values of type
 373     // _Bool. So, we'll use 0/1 and implicit cast to _Bool.
 374     Inner = ActOnIntegerConstant(ValueLoc, Value? 1 : 0);
 375     Inner = ImpCastExprToType(Inner.get(), Context.BoolTy,
 376                               CK_IntegralToBoolean);
 377   }
 378
 379   return BuildObjCNumericLiteral(AtLoc, Inner.get());
 380 }
 381
 382 /// \brief Check that the given expression is a valid element of an Objective-C
 383 /// collection literal.
 384 static ExprResult CheckObjCCollectionLiteralElement(Sema &S, Expr *Element,
 385                                                     QualType T,
 386                                                     bool ArrayLiteral = false) {
 387   // If the expression is type-dependent, there's nothing for us to do.
 388   if (Element->isTypeDependent())
 389     return Element;
 390
 391   ExprResult Result = S.CheckPlaceholderExpr(Element);
 392   if (Result.isInvalid())
 393     return ExprError();
 394   Element = Result.get();
 395
 396   // In C++, check for an implicit conversion to an Objective-C object pointer
 397   // type.
 398   if (S.getLangOpts().CPlusPlus && Element->getType()->isRecordType()) {
 399     InitializedEntity Entity
 400       = InitializedEntity::InitializeParameter(S.Context, T,
 401                                                /*Consumed=*/false);
 402     InitializationKind Kind
 403       = InitializationKind::CreateCopy(Element->getLocStart(),
 404                                        SourceLocation());
 405     InitializationSequence Seq(S, Entity, Kind, Element);
 406     if (!Seq.Failed())
 407       return Seq.Perform(S, Entity, Kind, Element);
 408   }
 409
 410   Expr *OrigElement = Element;
 411
 412   // Perform lvalue-to-rvalue conversion.
 413   Result = S.DefaultLvalueConversion(Element);
 414   if (Result.isInvalid())
 415     return ExprError();
 416   Element = Result.get();
 417
 418   // Make sure that we have an Objective-C pointer type or block.
 419   if (!Element->getType()->isObjCObjectPointerType() &&
 420       !Element->getType()->isBlockPointerType()) {
 421     bool Recovered = false;
 422
 423     // If this is potentially an Objective-C numeric literal, add the '@'.
 424     if (isa<IntegerLiteral>(OrigElement) ||
 425         isa<CharacterLiteral>(OrigElement) ||
 426         isa<FloatingLiteral>(OrigElement) ||
 427         isa<ObjCBoolLiteralExpr>(OrigElement) ||
 428         isa<CXXBoolLiteralExpr>(OrigElement)) {
 429       if (S.NSAPIObj->getNSNumberFactoryMethodKind(OrigElement->getType())) {
 430         int Which = isa<CharacterLiteral>(OrigElement) ? 1
 431                   : (isa<CXXBoolLiteralExpr>(OrigElement) ||
 432                      isa<ObjCBoolLiteralExpr>(OrigElement)) ? 2
 433                   : 3;
 434
 435         S.Diag(OrigElement->getLocStart(), diag::err_box_literal_collection)
 436           << Which << OrigElement->getSourceRange()
 437           << FixItHint::CreateInsertion(OrigElement->getLocStart(), "@");
 438
 439         Result = S.BuildObjCNumericLiteral(OrigElement->getLocStart(),
 440                                            OrigElement);
 441         if (Result.isInvalid())
 442           return ExprError();
 443
 444         Element = Result.get();
 445         Recovered = true;
 446       }
 447     }
 448     // If this is potentially an Objective-C string literal, add the '@'.
 449     else if (StringLiteral *String = dyn_cast<StringLiteral>(OrigElement)) {
 450       if (String->isAscii()) {
 451         S.Diag(OrigElement->getLocStart(), diag::err_box_literal_collection)
 452           << 0 << OrigElement->getSourceRange()
 453           << FixItHint::CreateInsertion(OrigElement->getLocStart(), "@");
 454
 455         Result = S.BuildObjCStringLiteral(OrigElement->getLocStart(), String);
 456         if (Result.isInvalid())
 457           return ExprError();
 458
 459         Element = Result.get();
 460         Recovered = true;
 461       }
 462     }
 463
 464     if (!Recovered) {
 465       S.Diag(Element->getLocStart(), diag::err_invalid_collection_element)
 466         << Element->getType();
 467       return ExprError();
 468     }
 469   }
 470   if (ArrayLiteral)
 471     if (ObjCStringLiteral *getString =
 472           dyn_cast<ObjCStringLiteral>(OrigElement)) {
 473       if (StringLiteral *SL = getString->getString()) {
 474         unsigned numConcat = SL->getNumConcatenated();
 475         if (numConcat > 1) {
 476           // Only warn if the concatenated string doesn't come from a macro.
 477           bool hasMacro = false;
 478           for (unsigned i = 0; i < numConcat ; ++i)
 479             if (SL->getStrTokenLoc(i).isMacroID()) {
 480               hasMacro = true;
 481               break;
 482             }
 483           if (!hasMacro)
 484             S.Diag(Element->getLocStart(),
 485                    diag::warn_concatenated_nsarray_literal)
 486               << Element->getType();
 487         }
 488       }
 489     }
 490
 491   // Make sure that the element has the type that the container factory
 492   // function expects.
 493   return S.PerformCopyInitialization(
 494            InitializedEntity::InitializeParameter(S.Context, T,
 495                                                   /*Consumed=*/false),
 496            Element->getLocStart(), Element);
 497 }
 498
 499 ExprResult Sema::BuildObjCBoxedExpr(SourceRange SR, Expr *ValueExpr) {
 500   if (ValueExpr->isTypeDependent()) {
 501     ObjCBoxedExpr *BoxedExpr =
 502       new (Context) ObjCBoxedExpr(ValueExpr, Context.DependentTy, nullptr, SR);
 503     return BoxedExpr;
 504   }
 505   ObjCMethodDecl *BoxingMethod = nullptr;
 506   QualType BoxedType;
 507   // Convert the expression to an RValue, so we can check for pointer types...
 508   ExprResult RValue = DefaultFunctionArrayLvalueConversion(ValueExpr);
 509   if (RValue.isInvalid()) {
 510     return ExprError();
 511   }
 512   SourceLocation Loc = SR.getBegin();
 513   ValueExpr = RValue.get();
 514   QualType ValueType(ValueExpr->getType());
 515   if (const PointerType *PT = ValueType->getAs<PointerType>()) {
 516     QualType PointeeType = PT->getPointeeType();
 517     if (Context.hasSameUnqualifiedType(PointeeType, Context.CharTy)) {
 518
 519       if (!NSStringDecl) {
 520         NSStringDecl = LookupObjCInterfaceDeclForLiteral(*this, Loc,
 521                                                          Sema::LK_String);
 522         if (!NSStringDecl) {
 523           return ExprError();
 524         }
 525         QualType NSStringObject = Context.getObjCInterfaceType(NSStringDecl);
 526         NSStringPointer = Context.getObjCObjectPointerType(NSStringObject);
 527       }
 528
 529       if (!StringWithUTF8StringMethod) {
 530         IdentifierInfo *II = &Context.Idents.get("stringWithUTF8String");
 531         Selector stringWithUTF8String = Context.Selectors.getUnarySelector(II);
 532
 533         // Look for the appropriate method within NSString.
 534         BoxingMethod = NSStringDecl->lookupClassMethod(stringWithUTF8String);
 535         if (!BoxingMethod && getLangOpts().DebuggerObjCLiteral) {
 536           // Debugger needs to work even if NSString hasn't been defined.
 537           TypeSourceInfo *ReturnTInfo = nullptr;
 538           ObjCMethodDecl *M = ObjCMethodDecl::Create(
 539               Context, SourceLocation(), SourceLocation(), stringWithUTF8String,
 540               NSStringPointer, ReturnTInfo, NSStringDecl,
 541               /*isInstance=*/false, /*isVariadic=*/false,
 542               /*isPropertyAccessor=*/false,
 543               /*isImplicitlyDeclared=*/true,
 544               /*isDefined=*/false, ObjCMethodDecl::Required,
 545               /*HasRelatedResultType=*/false);
 546           QualType ConstCharType = Context.CharTy.withConst();
 547           ParmVarDecl *value =
 548             ParmVarDecl::Create(Context, M,
 549                                 SourceLocation(), SourceLocation(),
 550                                 &Context.Idents.get("value"),
 551                                 Context.getPointerType(ConstCharType),
 552                                 /*TInfo=*/nullptr,
 553                                 SC_None, nullptr);
 554           M->setMethodParams(Context, value, None);
 555           BoxingMethod = M;
 556         }
 557
 558         if (!validateBoxingMethod(*this, Loc, NSStringDecl,
 559                                   stringWithUTF8String, BoxingMethod))
 560            return ExprError();
 561
 562         StringWithUTF8StringMethod = BoxingMethod;
 563       }
 564
 565       BoxingMethod = StringWithUTF8StringMethod;
 566       BoxedType = NSStringPointer;
 567     }
 568   } else if (ValueType->isBuiltinType()) {
 569     // The other types we support are numeric, char and BOOL/bool. We could also
 570     // provide limited support for structure types, such as NSRange, NSRect, and
 571     // NSSize. See NSValue (NSValueGeometryExtensions) in <Foundation/NSGeometry.h>
 572     // for more details.
 573
 574     // Check for a top-level character literal.
 575     if (const CharacterLiteral *Char =
 576         dyn_cast<CharacterLiteral>(ValueExpr->IgnoreParens())) {
 577       // In C, character literals have type 'int'. That's not the type we want
 578       // to use to determine the Objective-c literal kind.
 579       switch (Char->getKind()) {
 580       case CharacterLiteral::Ascii:
 581       case CharacterLiteral::UTF8:
 582         ValueType = Context.CharTy;
 583         break;
 584
 585       case CharacterLiteral::Wide:
 586         ValueType = Context.getWideCharType();
 587         break;
 588
 589       case CharacterLiteral::UTF16:
 590         ValueType = Context.Char16Ty;
 591         break;
 592
 593       case CharacterLiteral::UTF32:
 594         ValueType = Context.Char32Ty;
 595         break;
 596       }
 597     }
 598     CheckForIntOverflow(ValueExpr);
 599     // FIXME:  Do I need to do anything special with BoolTy expressions?
 600
 601     // Look for the appropriate method within NSNumber.
 602     BoxingMethod = getNSNumberFactoryMethod(*this, Loc, ValueType);
 603     BoxedType = NSNumberPointer;
 604   } else if (const EnumType *ET = ValueType->getAs<EnumType>()) {
 605     if (!ET->getDecl()->isComplete()) {
 606       Diag(Loc, diag::err_objc_incomplete_boxed_expression_type)
 607         << ValueType << ValueExpr->getSourceRange();
 608       return ExprError();
 609     }
 610
 611     BoxingMethod = getNSNumberFactoryMethod(*this, Loc,
 612                                             ET->getDecl()->getIntegerType());
 613     BoxedType = NSNumberPointer;
 614   } else if (ValueType->isObjCBoxableRecordType()) {
 615     // Support for structure types, that marked as objc_boxable
 616     // struct __attribute__((objc_boxable)) s { ... };
 617
 618     // Look up the NSValue class, if we haven't done so already. It's cached
 619     // in the Sema instance.
 620     if (!NSValueDecl) {
 621       NSValueDecl = LookupObjCInterfaceDeclForLiteral(*this, Loc,
 622                                                       Sema::LK_Boxed);
 623       if (!NSValueDecl) {
 624         return ExprError();
 625       }
 626
 627       // generate the pointer to NSValue type.
 628       QualType NSValueObject = Context.getObjCInterfaceType(NSValueDecl);
 629       NSValuePointer = Context.getObjCObjectPointerType(NSValueObject);
 630     }
 631
 632     if (!ValueWithBytesObjCTypeMethod) {
 633       IdentifierInfo *II[] = {
 634         &Context.Idents.get("valueWithBytes"),
 635         &Context.Idents.get("objCType")
 636       };
 637       Selector ValueWithBytesObjCType = Context.Selectors.getSelector(2, II);
 638
 639       // Look for the appropriate method within NSValue.
 640       BoxingMethod = NSValueDecl->lookupClassMethod(ValueWithBytesObjCType);
 641       if (!BoxingMethod && getLangOpts().DebuggerObjCLiteral) {
 642         // Debugger needs to work even if NSValue hasn't been defined.
 643         TypeSourceInfo *ReturnTInfo = nullptr;
 644         ObjCMethodDecl *M = ObjCMethodDecl::Create(
 645                                                Context,
 646                                                SourceLocation(),
 647                                                SourceLocation(),
 648                                                ValueWithBytesObjCType,
 649                                                NSValuePointer,
 650                                                ReturnTInfo,
 651                                                NSValueDecl,
 652                                                /*isInstance=*/false,
 653                                                /*isVariadic=*/false,
 654                                                /*isPropertyAccessor=*/false,
 655                                                /*isImplicitlyDeclared=*/true,
 656                                                /*isDefined=*/false,
 657                                                ObjCMethodDecl::Required,
 658                                                /*HasRelatedResultType=*/false);
 659
 660         SmallVector<ParmVarDecl *, 2> Params;
 661
 662         ParmVarDecl *bytes =
 663         ParmVarDecl::Create(Context, M,
 664                             SourceLocation(), SourceLocation(),
 665                             &Context.Idents.get("bytes"),
 666                             Context.VoidPtrTy.withConst(),
 667                             /*TInfo=*/nullptr,
 668                             SC_None, nullptr);
 669         Params.push_back(bytes);
 670
 671         QualType ConstCharType = Context.CharTy.withConst();
 672         ParmVarDecl *type =
 673         ParmVarDecl::Create(Context, M,
 674                             SourceLocation(), SourceLocation(),
 675                             &Context.Idents.get("type"),
 676                             Context.getPointerType(ConstCharType),
 677                             /*TInfo=*/nullptr,
 678                             SC_None, nullptr);
 679         Params.push_back(type);
 680
 681         M->setMethodParams(Context, Params, None);
 682         BoxingMethod = M;
 683       }
 684
 685       if (!validateBoxingMethod(*this, Loc, NSValueDecl,
 686                                 ValueWithBytesObjCType, BoxingMethod))
 687         return ExprError();
 688
 689       ValueWithBytesObjCTypeMethod = BoxingMethod;
 690     }
 691
 692     if (!ValueType.isTriviallyCopyableType(Context)) {
 693       Diag(Loc, diag::err_objc_non_trivially_copyable_boxed_expression_type)
 694         << ValueType << ValueExpr->getSourceRange();
 695       return ExprError();
 696     }
 697
 698     BoxingMethod = ValueWithBytesObjCTypeMethod;
 699     BoxedType = NSValuePointer;
 700   }
 701
 702   if (!BoxingMethod) {
 703     Diag(Loc, diag::err_objc_illegal_boxed_expression_type)
 704       << ValueType << ValueExpr->getSourceRange();
 705     return ExprError();
 706   }
 707
 708   DiagnoseUseOfDecl(BoxingMethod, Loc);
 709
 710   ExprResult ConvertedValueExpr;
 711   if (ValueType->isObjCBoxableRecordType()) {
 712     InitializedEntity IE = InitializedEntity::InitializeTemporary(ValueType);
 713     ConvertedValueExpr = PerformCopyInitialization(IE, ValueExpr->getExprLoc(),
 714                                                    ValueExpr);
 715   } else {
 716     // Convert the expression to the type that the parameter requires.
 717     ParmVarDecl *ParamDecl = BoxingMethod->parameters()[0];
 718     InitializedEntity IE = InitializedEntity::InitializeParameter(Context,
 719                                                                   ParamDecl);
 720     ConvertedValueExpr = PerformCopyInitialization(IE, SourceLocation(),
 721                                                    ValueExpr);
 722   }
 723
 724   if (ConvertedValueExpr.isInvalid())
 725     return ExprError();
 726   ValueExpr = ConvertedValueExpr.get();
 727
 728   ObjCBoxedExpr *BoxedExpr =
 729     new (Context) ObjCBoxedExpr(ValueExpr, BoxedType,
 730                                       BoxingMethod, SR);
 731   return MaybeBindToTemporary(BoxedExpr);
 732 }
 733
 734 /// Build an ObjC subscript pseudo-object expression, given that
 735 /// that's supported by the runtime.
 736 ExprResult Sema::BuildObjCSubscriptExpression(SourceLocation RB, Expr *BaseExpr,
 737                                         Expr *IndexExpr,
 738                                         ObjCMethodDecl *getterMethod,
 739                                         ObjCMethodDecl *setterMethod) {
 740   assert(!LangOpts.isSubscriptPointerArithmetic());
 741
 742   // We can't get dependent types here; our callers should have
 743   // filtered them out.
 744   assert((!BaseExpr->isTypeDependent() && !IndexExpr->isTypeDependent()) &&
 745          "base or index cannot have dependent type here");
 746
 747   // Filter out placeholders in the index.  In theory, overloads could
 748   // be preserved here, although that might not actually work correctly.
 749   ExprResult Result = CheckPlaceholderExpr(IndexExpr);
 750   if (Result.isInvalid())
 751     return ExprError();
 752   IndexExpr = Result.get();
 753
 754   // Perform lvalue-to-rvalue conversion on the base.
 755   Result = DefaultLvalueConversion(BaseExpr);
 756   if (Result.isInvalid())
 757     return ExprError();
 758   BaseExpr = Result.get();
 759
 760   // Build the pseudo-object expression.
 761   return new (Context) ObjCSubscriptRefExpr(
 762       BaseExpr, IndexExpr, Context.PseudoObjectTy, VK_LValue, OK_ObjCSubscript,
 763       getterMethod, setterMethod, RB);
 764 }
 765
 766 ExprResult Sema::BuildObjCArrayLiteral(SourceRange SR, MultiExprArg Elements) {
 767   SourceLocation Loc = SR.getBegin();
 768
 769   if (!NSArrayDecl) {
 770     NSArrayDecl = LookupObjCInterfaceDeclForLiteral(*this, Loc,
 771                                                     Sema::LK_Array);
 772     if (!NSArrayDecl) {
 773       return ExprError();
 774     }
 775   }
 776
 777   // Find the arrayWithObjects:count: method, if we haven't done so already.
 778   QualType IdT = Context.getObjCIdType();
 779   if (!ArrayWithObjectsMethod) {
 780     Selector
 781       Sel = NSAPIObj->getNSArraySelector(NSAPI::NSArr_arrayWithObjectsCount);
 782     ObjCMethodDecl *Method = NSArrayDecl->lookupClassMethod(Sel);
 783     if (!Method && getLangOpts().DebuggerObjCLiteral) {
 784       TypeSourceInfo *ReturnTInfo = nullptr;
 785       Method = ObjCMethodDecl::Create(
 786           Context, SourceLocation(), SourceLocation(), Sel, IdT, ReturnTInfo,
 787           Context.getTranslationUnitDecl(), false /*Instance*/,
 788           false /*isVariadic*/,
 789           /*isPropertyAccessor=*/false,
 790           /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
 791           ObjCMethodDecl::Required, false);
 792       SmallVector<ParmVarDecl *, 2> Params;
 793       ParmVarDecl *objects = ParmVarDecl::Create(Context, Method,
 794                                                  SourceLocation(),
 795                                                  SourceLocation(),
 796                                                  &Context.Idents.get("objects"),
 797                                                  Context.getPointerType(IdT),
 798                                                  /*TInfo=*/nullptr,
 799                                                  SC_None, nullptr);
 800       Params.push_back(objects);
 801       ParmVarDecl *cnt = ParmVarDecl::Create(Context, Method,
 802                                              SourceLocation(),
 803                                              SourceLocation(),
 804                                              &Context.Idents.get("cnt"),
 805                                              Context.UnsignedLongTy,
 806                                              /*TInfo=*/nullptr, SC_None,
 807                                              nullptr);
 808       Params.push_back(cnt);
 809       Method->setMethodParams(Context, Params, None);
 810     }
 811
 812     if (!validateBoxingMethod(*this, Loc, NSArrayDecl, Sel, Method))
 813       return ExprError();
 814
 815     // Dig out the type that all elements should be converted to.
 816     QualType T = Method->parameters()[0]->getType();
 817     const PointerType *PtrT = T->getAs<PointerType>();
 818     if (!PtrT ||
 819         !Context.hasSameUnqualifiedType(PtrT->getPointeeType(), IdT)) {
 820       Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
 821         << Sel;
 822       Diag(Method->parameters()[0]->getLocation(),
 823            diag::note_objc_literal_method_param)
 824         << 0 << T
 825         << Context.getPointerType(IdT.withConst());
 826       return ExprError();
 827     }
 828
 829     // Check that the 'count' parameter is integral.
 830     if (!Method->parameters()[1]->getType()->isIntegerType()) {
 831       Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
 832         << Sel;
 833       Diag(Method->parameters()[1]->getLocation(),
 834            diag::note_objc_literal_method_param)
 835         << 1
 836         << Method->parameters()[1]->getType()
 837         << "integral";
 838       return ExprError();
 839     }
 840
 841     // We've found a good +arrayWithObjects:count: method. Save it!
 842     ArrayWithObjectsMethod = Method;
 843   }
 844
 845   QualType ObjectsType = ArrayWithObjectsMethod->parameters()[0]->getType();
 846   QualType RequiredType = ObjectsType->castAs<PointerType>()->getPointeeType();
 847
 848   // Check that each of the elements provided is valid in a collection literal,
 849   // performing conversions as necessary.
 850   Expr **ElementsBuffer = Elements.data();
 851   for (unsigned I = 0, N = Elements.size(); I != N; ++I) {
 852     ExprResult Converted = CheckObjCCollectionLiteralElement(*this,
 853                                                              ElementsBuffer[I],
 854                                                              RequiredType, true);
 855     if (Converted.isInvalid())
 856       return ExprError();
 857
 858     ElementsBuffer[I] = Converted.get();
 859   }
 860
 861   QualType Ty
 862     = Context.getObjCObjectPointerType(
 863                                     Context.getObjCInterfaceType(NSArrayDecl));
 864
 865   return MaybeBindToTemporary(
 866            ObjCArrayLiteral::Create(Context, Elements, Ty,
 867                                     ArrayWithObjectsMethod, SR));
 868 }
 869
 870 ExprResult Sema::BuildObjCDictionaryLiteral(SourceRange SR,
 871                               MutableArrayRef<ObjCDictionaryElement> Elements) {
 872   SourceLocation Loc = SR.getBegin();
 873
 874   if (!NSDictionaryDecl) {
 875     NSDictionaryDecl = LookupObjCInterfaceDeclForLiteral(*this, Loc,
 876                                                          Sema::LK_Dictionary);
 877     if (!NSDictionaryDecl) {
 878       return ExprError();
 879     }
 880   }
 881
 882   // Find the dictionaryWithObjects:forKeys:count: method, if we haven't done
 883   // so already.
 884   QualType IdT = Context.getObjCIdType();
 885   if (!DictionaryWithObjectsMethod) {
 886     Selector Sel = NSAPIObj->getNSDictionarySelector(
 887                                NSAPI::NSDict_dictionaryWithObjectsForKeysCount);
 888     ObjCMethodDecl *Method = NSDictionaryDecl->lookupClassMethod(Sel);
 889     if (!Method && getLangOpts().DebuggerObjCLiteral) {
 890       Method = ObjCMethodDecl::Create(Context,
 891                            SourceLocation(), SourceLocation(), Sel,
 892                            IdT,
 893                            nullptr /*TypeSourceInfo */,
 894                            Context.getTranslationUnitDecl(),
 895                            false /*Instance*/, false/*isVariadic*/,
 896                            /*isPropertyAccessor=*/false,
 897                            /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
 898                            ObjCMethodDecl::Required,
 899                            false);
 900       SmallVector<ParmVarDecl *, 3> Params;
 901       ParmVarDecl *objects = ParmVarDecl::Create(Context, Method,
 902                                                  SourceLocation(),
 903                                                  SourceLocation(),
 904                                                  &Context.Idents.get("objects"),
 905                                                  Context.getPointerType(IdT),
 906                                                  /*TInfo=*/nullptr, SC_None,
 907                                                  nullptr);
 908       Params.push_back(objects);
 909       ParmVarDecl *keys = ParmVarDecl::Create(Context, Method,
 910                                               SourceLocation(),
 911                                               SourceLocation(),
 912                                               &Context.Idents.get("keys"),
 913                                               Context.getPointerType(IdT),
 914                                               /*TInfo=*/nullptr, SC_None,
 915                                               nullptr);
 916       Params.push_back(keys);
 917       ParmVarDecl *cnt = ParmVarDecl::Create(Context, Method,
 918                                              SourceLocation(),
 919                                              SourceLocation(),
 920                                              &Context.Idents.get("cnt"),
 921                                              Context.UnsignedLongTy,
 922                                              /*TInfo=*/nullptr, SC_None,
 923                                              nullptr);
 924       Params.push_back(cnt);
 925       Method->setMethodParams(Context, Params, None);
 926     }
 927
 928     if (!validateBoxingMethod(*this, SR.getBegin(), NSDictionaryDecl, Sel,
 929                               Method))
 930        return ExprError();
 931
 932     // Dig out the type that all values should be converted to.
 933     QualType ValueT = Method->parameters()[0]->getType();
 934     const PointerType *PtrValue = ValueT->getAs<PointerType>();
 935     if (!PtrValue ||
 936         !Context.hasSameUnqualifiedType(PtrValue->getPointeeType(), IdT)) {
 937       Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
 938         << Sel;
 939       Diag(Method->parameters()[0]->getLocation(),
 940            diag::note_objc_literal_method_param)
 941         << 0 << ValueT
 942         << Context.getPointerType(IdT.withConst());
 943       return ExprError();
 944     }
 945
 946     // Dig out the type that all keys should be converted to.
 947     QualType KeyT = Method->parameters()[1]->getType();
 948     const PointerType *PtrKey = KeyT->getAs<PointerType>();
 949     if (!PtrKey ||
 950         !Context.hasSameUnqualifiedType(PtrKey->getPointeeType(),
 951                                         IdT)) {
 952       bool err = true;
 953       if (PtrKey) {
 954         if (QIDNSCopying.isNull()) {
 955           // key argument of selector is id<NSCopying>?
 956           if (ObjCProtocolDecl *NSCopyingPDecl =
 957               LookupProtocol(&Context.Idents.get("NSCopying"), SR.getBegin())) {
 958             ObjCProtocolDecl *PQ[] = {NSCopyingPDecl};
 959             QIDNSCopying =
 960               Context.getObjCObjectType(Context.ObjCBuiltinIdTy, { },
 961                                         llvm::makeArrayRef(
 962                                           (ObjCProtocolDecl**) PQ,
 963                                           1),
 964                                         false);
 965             QIDNSCopying = Context.getObjCObjectPointerType(QIDNSCopying);
 966           }
 967         }
 968         if (!QIDNSCopying.isNull())
 969           err = !Context.hasSameUnqualifiedType(PtrKey->getPointeeType(),
 970                                                 QIDNSCopying);
 971       }
 972
 973       if (err) {
 974         Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
 975           << Sel;
 976         Diag(Method->parameters()[1]->getLocation(),
 977              diag::note_objc_literal_method_param)
 978           << 1 << KeyT
 979           << Context.getPointerType(IdT.withConst());
 980         return ExprError();
 981       }
 982     }
 983
 984     // Check that the 'count' parameter is integral.
 985     QualType CountType = Method->parameters()[2]->getType();
 986     if (!CountType->isIntegerType()) {
 987       Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
 988         << Sel;
 989       Diag(Method->parameters()[2]->getLocation(),
 990            diag::note_objc_literal_method_param)
 991         << 2 << CountType
 992         << "integral";
 993       return ExprError();
 994     }
 995
 996     // We've found a good +dictionaryWithObjects:keys:count: method; save it!
 997     DictionaryWithObjectsMethod = Method;
 998   }
 999
1000   QualType ValuesT = DictionaryWithObjectsMethod->parameters()[0]->getType();
1001   QualType ValueT = ValuesT->castAs<PointerType>()->getPointeeType();
1002   QualType KeysT = DictionaryWithObjectsMethod->parameters()[1]->getType();
1003   QualType KeyT = KeysT->castAs<PointerType>()->getPointeeType();
1004
1005   // Check that each of the keys and values provided is valid in a collection
1006   // literal, performing conversions as necessary.
1007   bool HasPackExpansions = false;
1008   for (ObjCDictionaryElement &Element : Elements) {
1009     // Check the key.
1010     ExprResult Key = CheckObjCCollectionLiteralElement(*this, Element.Key,
1011                                                        KeyT);
1012     if (Key.isInvalid())
1013       return ExprError();
1014
1015     // Check the value.
1016     ExprResult Value
1017       = CheckObjCCollectionLiteralElement(*this, Element.Value, ValueT);
1018     if (Value.isInvalid())
1019       return ExprError();
1020
1021     Element.Key = Key.get();
1022     Element.Value = Value.get();
1023
1024     if (Element.EllipsisLoc.isInvalid())
1025       continue;
1026
1027     if (!Element.Key->containsUnexpandedParameterPack() &&
1028         !Element.Value->containsUnexpandedParameterPack()) {
1029       Diag(Element.EllipsisLoc,
1030            diag::err_pack_expansion_without_parameter_packs)
1031         << SourceRange(Element.Key->getLocStart(),
1032                        Element.Value->getLocEnd());
1033       return ExprError();
1034     }
1035
1036     HasPackExpansions = true;
1037   }
1038
1039   QualType Ty
1040     = Context.getObjCObjectPointerType(
1041                                 Context.getObjCInterfaceType(NSDictionaryDecl));
1042   return MaybeBindToTemporary(ObjCDictionaryLiteral::Create(
1043       Context, Elements, HasPackExpansions, Ty,
1044       DictionaryWithObjectsMethod, SR));
1045 }
1046
1047 ExprResult Sema::BuildObjCEncodeExpression(SourceLocation AtLoc,
1048                                       TypeSourceInfo *EncodedTypeInfo,
1049                                       SourceLocation RParenLoc) {
1050   QualType EncodedType = EncodedTypeInfo->getType();
1051   QualType StrTy;
1052   if (EncodedType->isDependentType())
1053     StrTy = Context.DependentTy;
1054   else {
1055     if (!EncodedType->getAsArrayTypeUnsafe() && //// Incomplete array is handled.
1056         !EncodedType->isVoidType()) // void is handled too.
1057       if (RequireCompleteType(AtLoc, EncodedType,
1058                               diag::err_incomplete_type_objc_at_encode,
1059                               EncodedTypeInfo->getTypeLoc()))
1060         return ExprError();
1061
1062     std::string Str;
1063     QualType NotEncodedT;
1064     Context.getObjCEncodingForType(EncodedType, Str, nullptr, &NotEncodedT);
1065     if (!NotEncodedT.isNull())
1066       Diag(AtLoc, diag::warn_incomplete_encoded_type)
1067         << EncodedType << NotEncodedT;
1068
1069     // The type of @encode is the same as the type of the corresponding string,
1070     // which is an array type.
1071     StrTy = Context.CharTy;
1072     // A C++ string literal has a const-qualified element type (C++ 2.13.4p1).
1073     if (getLangOpts().CPlusPlus || getLangOpts().ConstStrings)
1074       StrTy.addConst();
1075     StrTy = Context.getConstantArrayType(StrTy, llvm::APInt(32, Str.size()+1),
1076                                          ArrayType::Normal, 0);
1077   }
1078
1079   return new (Context) ObjCEncodeExpr(StrTy, EncodedTypeInfo, AtLoc, RParenLoc);
1080 }
1081
1082 ExprResult Sema::ParseObjCEncodeExpression(SourceLocation AtLoc,
1083                                            SourceLocation EncodeLoc,
1084                                            SourceLocation LParenLoc,
1085                                            ParsedType ty,
1086                                            SourceLocation RParenLoc) {
1087   // FIXME: Preserve type source info ?
1088   TypeSourceInfo *TInfo;
1089   QualType EncodedType = GetTypeFromParser(ty, &TInfo);
1090   if (!TInfo)
1091     TInfo = Context.getTrivialTypeSourceInfo(EncodedType,
1092                                              getLocForEndOfToken(LParenLoc));
1093
1094   return BuildObjCEncodeExpression(AtLoc, TInfo, RParenLoc);
1095 }
1096
1097 static bool HelperToDiagnoseMismatchedMethodsInGlobalPool(Sema &S,
1098                                                SourceLocation AtLoc,
1099                                                SourceLocation LParenLoc,
1100                                                SourceLocation RParenLoc,
1101                                                ObjCMethodDecl *Method,
1102                                                ObjCMethodList &MethList) {
1103   ObjCMethodList *M = &MethList;
1104   bool Warned = false;
1105   for (M = M->getNext(); M; M=M->getNext()) {
1106     ObjCMethodDecl *MatchingMethodDecl = M->getMethod();
1107     if (MatchingMethodDecl == Method ||
1108         isa<ObjCImplDecl>(MatchingMethodDecl->getDeclContext()) ||
1109         MatchingMethodDecl->getSelector() != Method->getSelector())
1110       continue;
1111     if (!S.MatchTwoMethodDeclarations(Method,
1112                                       MatchingMethodDecl, Sema::MMS_loose)) {
1113       if (!Warned) {
1114         Warned = true;
1115         S.Diag(AtLoc, diag::warn_multiple_selectors)
1116           << Method->getSelector() << FixItHint::CreateInsertion(LParenLoc, "(")
1117           << FixItHint::CreateInsertion(RParenLoc, ")");
1118         S.Diag(Method->getLocation(), diag::note_method_declared_at)
1119           << Method->getDeclName();
1120       }
1121       S.Diag(MatchingMethodDecl->getLocation(), diag::note_method_declared_at)
1122         << MatchingMethodDecl->getDeclName();
1123     }
1124   }
1125   return Warned;
1126 }
1127
1128 static void DiagnoseMismatchedSelectors(Sema &S, SourceLocation AtLoc,
1129                                         ObjCMethodDecl *Method,
1130                                         SourceLocation LParenLoc,
1131                                         SourceLocation RParenLoc,
1132                                         bool WarnMultipleSelectors) {
1133   if (!WarnMultipleSelectors ||
1134       S.Diags.isIgnored(diag::warn_multiple_selectors, SourceLocation()))
1135     return;
1136   bool Warned = false;
1137   for (Sema::GlobalMethodPool::iterator b = S.MethodPool.begin(),
1138        e = S.MethodPool.end(); b != e; b++) {
1139     // first, instance methods
1140     ObjCMethodList &InstMethList = b->second.first;
1141     if (HelperToDiagnoseMismatchedMethodsInGlobalPool(S, AtLoc, LParenLoc, RParenLoc,
1142                                                       Method, InstMethList))
1143       Warned = true;
1144
1145     // second, class methods
1146     ObjCMethodList &ClsMethList = b->second.second;
1147     if (HelperToDiagnoseMismatchedMethodsInGlobalPool(S, AtLoc, LParenLoc, RParenLoc,
1148                                                       Method, ClsMethList) || Warned)
1149       return;
1150   }
1151 }
1152
1153 ExprResult Sema::ParseObjCSelectorExpression(Selector Sel,
1154                                              SourceLocation AtLoc,
1155                                              SourceLocation SelLoc,
1156                                              SourceLocation LParenLoc,
1157                                              SourceLocation RParenLoc,
1158                                              bool WarnMultipleSelectors) {
1159   ObjCMethodDecl *Method = LookupInstanceMethodInGlobalPool(Sel,
1160                              SourceRange(LParenLoc, RParenLoc));
1161   if (!Method)
1162     Method = LookupFactoryMethodInGlobalPool(Sel,
1163                                           SourceRange(LParenLoc, RParenLoc));
1164   if (!Method) {
1165     if (const ObjCMethodDecl *OM = SelectorsForTypoCorrection(Sel)) {
1166       Selector MatchedSel = OM->getSelector();
1167       SourceRange SelectorRange(LParenLoc.getLocWithOffset(1),
1168                                 RParenLoc.getLocWithOffset(-1));
1169       Diag(SelLoc, diag::warn_undeclared_selector_with_typo)
1170         << Sel << MatchedSel
1171         << FixItHint::CreateReplacement(SelectorRange, MatchedSel.getAsString());
1172
1173     } else
1174         Diag(SelLoc, diag::warn_undeclared_selector) << Sel;
1175   } else
1176     DiagnoseMismatchedSelectors(*this, AtLoc, Method, LParenLoc, RParenLoc,
1177                                 WarnMultipleSelectors);
1178
1179   if (Method &&
1180       Method->getImplementationControl() != ObjCMethodDecl::Optional &&
1181       !getSourceManager().isInSystemHeader(Method->getLocation()))
1182     ReferencedSelectors.insert(std::make_pair(Sel, AtLoc));
1183
1184   // In ARC, forbid the user from using @selector for
1185   // retain/release/autorelease/dealloc/retainCount.
1186   if (getLangOpts().ObjCAutoRefCount) {
1187     switch (Sel.getMethodFamily()) {
1188     case OMF_retain:
1189     case OMF_release:
1190     case OMF_autorelease:
1191     case OMF_retainCount:
1192     case OMF_dealloc:
1193       Diag(AtLoc, diag::err_arc_illegal_selector) <<
1194         Sel << SourceRange(LParenLoc, RParenLoc);
1195       break;
1196
1197     case OMF_None:
1198     case OMF_alloc:
1199     case OMF_copy:
1200     case OMF_finalize:
1201     case OMF_init:
1202     case OMF_mutableCopy:
1203     case OMF_new:
1204     case OMF_self:
1205     case OMF_initialize:
1206     case OMF_performSelector:
1207       break;
1208     }
1209   }
1210   QualType Ty = Context.getObjCSelType();
1211   return new (Context) ObjCSelectorExpr(Ty, Sel, AtLoc, RParenLoc);
1212 }
1213
1214 ExprResult Sema::ParseObjCProtocolExpression(IdentifierInfo *ProtocolId,
1215                                              SourceLocation AtLoc,
1216                                              SourceLocation ProtoLoc,
1217                                              SourceLocation LParenLoc,
1218                                              SourceLocation ProtoIdLoc,
1219                                              SourceLocation RParenLoc) {
1220   ObjCProtocolDecl* PDecl = LookupProtocol(ProtocolId, ProtoIdLoc);
1221   if (!PDecl) {
1222     Diag(ProtoLoc, diag::err_undeclared_protocol) << ProtocolId;
1223     return true;
1224   }
1225   if (PDecl->hasDefinition())
1226     PDecl = PDecl->getDefinition();
1227
1228   QualType Ty = Context.getObjCProtoType();
1229   if (Ty.isNull())
1230     return true;
1231   Ty = Context.getObjCObjectPointerType(Ty);
1232   return new (Context) ObjCProtocolExpr(Ty, PDecl, AtLoc, ProtoIdLoc, RParenLoc);
1233 }
1234
1235 /// Try to capture an implicit reference to 'self'.
1236 ObjCMethodDecl *Sema::tryCaptureObjCSelf(SourceLocation Loc) {
1237   DeclContext *DC = getFunctionLevelDeclContext();
1238
1239   // If we're not in an ObjC method, error out.  Note that, unlike the
1240   // C++ case, we don't require an instance method --- class methods
1241   // still have a 'self', and we really do still need to capture it!
1242   ObjCMethodDecl *method = dyn_cast<ObjCMethodDecl>(DC);
1243   if (!method)
1244     return nullptr;
1245
1246   tryCaptureVariable(method->getSelfDecl(), Loc);
1247
1248   return method;
1249 }
1250
1251 static QualType stripObjCInstanceType(ASTContext &Context, QualType T) {
1252   QualType origType = T;
1253   if (auto nullability = AttributedType::stripOuterNullability(T)) {
1254     if (T == Context.getObjCInstanceType()) {
1255       return Context.getAttributedType(
1256                AttributedType::getNullabilityAttrKind(*nullability),
1257                Context.getObjCIdType(),
1258                Context.getObjCIdType());
1259     }
1260
1261     return origType;
1262   }
1263
1264   if (T == Context.getObjCInstanceType())
1265     return Context.getObjCIdType();
1266
1267   return origType;
1268 }
1269
1270 /// Determine the result type of a message send based on the receiver type,
1271 /// method, and the kind of message send.
1272 ///
1273 /// This is the "base" result type, which will still need to be adjusted
1274 /// to account for nullability.
1275 static QualType getBaseMessageSendResultType(Sema &S,
1276                                              QualType ReceiverType,
1277                                              ObjCMethodDecl *Method,
1278                                              bool isClassMessage,
1279                                              bool isSuperMessage) {
1280   assert(Method && "Must have a method");
1281   if (!Method->hasRelatedResultType())
1282     return Method->getSendResultType(ReceiverType);
1283
1284   ASTContext &Context = S.Context;
1285
1286   // Local function that transfers the nullability of the method's
1287   // result type to the returned result.
1288   auto transferNullability = [&](QualType type) -> QualType {
1289     // If the method's result type has nullability, extract it.
1290     if (auto nullability = Method->getSendResultType(ReceiverType)
1291                              ->getNullability(Context)){
1292       // Strip off any outer nullability sugar from the provided type.
1293       (void)AttributedType::stripOuterNullability(type);
1294
1295       // Form a new attributed type using the method result type's nullability.
1296       return Context.getAttributedType(
1297                AttributedType::getNullabilityAttrKind(*nullability),
1298                type,
1299                type);
1300     }
1301
1302     return type;
1303   };
1304
1305   // If a method has a related return type:
1306   //   - if the method found is an instance method, but the message send
1307   //     was a class message send, T is the declared return type of the method
1308   //     found
1309   if (Method->isInstanceMethod() && isClassMessage)
1310     return stripObjCInstanceType(Context,
1311                                  Method->getSendResultType(ReceiverType));
1312
1313   //   - if the receiver is super, T is a pointer to the class of the
1314   //     enclosing method definition
1315   if (isSuperMessage) {
1316     if (ObjCMethodDecl *CurMethod = S.getCurMethodDecl())
1317       if (ObjCInterfaceDecl *Class = CurMethod->getClassInterface()) {
1318         return transferNullability(
1319                  Context.getObjCObjectPointerType(
1320                    Context.getObjCInterfaceType(Class)));
1321       }
1322   }
1323
1324   //   - if the receiver is the name of a class U, T is a pointer to U
1325   if (ReceiverType->getAsObjCInterfaceType())
1326     return transferNullability(Context.getObjCObjectPointerType(ReceiverType));
1327   //   - if the receiver is of type Class or qualified Class type,
1328   //     T is the declared return type of the method.
1329   if (ReceiverType->isObjCClassType() ||
1330       ReceiverType->isObjCQualifiedClassType())
1331     return stripObjCInstanceType(Context,
1332                                  Method->getSendResultType(ReceiverType));
1333
1334   //   - if the receiver is id, qualified id, Class, or qualified Class, T
1335   //     is the receiver type, otherwise
1336   //   - T is the type of the receiver expression.
1337   return transferNullability(ReceiverType);
1338 }
1339
1340 QualType Sema::getMessageSendResultType(QualType ReceiverType,
1341                                         ObjCMethodDecl *Method,
1342                                         bool isClassMessage,
1343                                         bool isSuperMessage) {
1344   // Produce the result type.
1345   QualType resultType = getBaseMessageSendResultType(*this, ReceiverType,
1346                                                      Method,
1347                                                      isClassMessage,
1348                                                      isSuperMessage);
1349
1350   // If this is a class message, ignore the nullability of the receiver.
1351   if (isClassMessage)
1352     return resultType;
1353
1354   // Map the nullability of the result into a table index.
1355   unsigned receiverNullabilityIdx = 0;
1356   if (auto nullability = ReceiverType->getNullability(Context))
1357     receiverNullabilityIdx = 1 + static_cast<unsigned>(*nullability);
1358
1359   unsigned resultNullabilityIdx = 0;
1360   if (auto nullability = resultType->getNullability(Context))
1361     resultNullabilityIdx = 1 + static_cast<unsigned>(*nullability);
1362
1363   // The table of nullability mappings, indexed by the receiver's nullability
1364   // and then the result type's nullability.
1365   static const uint8_t None = 0;
1366   static const uint8_t NonNull = 1;
1367   static const uint8_t Nullable = 2;
1368   static const uint8_t Unspecified = 3;
1369   static const uint8_t nullabilityMap[4][4] = {
1370     //                  None        NonNull       Nullable    Unspecified
1371     /* None */        { None,       None,         Nullable,   None },
1372     /* NonNull */     { None,       NonNull,      Nullable,   Unspecified },
1373     /* Nullable */    { Nullable,   Nullable,     Nullable,   Nullable },
1374     /* Unspecified */ { None,       Unspecified,  Nullable,   Unspecified }
1375   };
1376
1377   unsigned newResultNullabilityIdx
1378     = nullabilityMap[receiverNullabilityIdx][resultNullabilityIdx];
1379   if (newResultNullabilityIdx == resultNullabilityIdx)
1380     return resultType;
1381
1382   // Strip off the existing nullability. This removes as little type sugar as
1383   // possible.
1384   do {
1385     if (auto attributed = dyn_cast<AttributedType>(resultType.getTypePtr())) {
1386       resultType = attributed->getModifiedType();
1387     } else {
1388       resultType = resultType.getDesugaredType(Context);
1389     }
1390   } while (resultType->getNullability(Context));
1391
1392   // Add nullability back if needed.
1393   if (newResultNullabilityIdx > 0) {
1394     auto newNullability
1395       = static_cast<NullabilityKind>(newResultNullabilityIdx-1);
1396     return Context.getAttributedType(
1397              AttributedType::getNullabilityAttrKind(newNullability),
1398              resultType, resultType);
1399   }
1400
1401   return resultType;
1402 }
1403
1404 /// Look for an ObjC method whose result type exactly matches the given type.
1405 static const ObjCMethodDecl *
1406 findExplicitInstancetypeDeclarer(const ObjCMethodDecl *MD,
1407                                  QualType instancetype) {
1408   if (MD->getReturnType() == instancetype)
1409     return MD;
1410
1411   // For these purposes, a method in an @implementation overrides a
1412   // declaration in the @interface.
1413   if (const ObjCImplDecl *impl =
1414         dyn_cast<ObjCImplDecl>(MD->getDeclContext())) {
1415     const ObjCContainerDecl *iface;
1416     if (const ObjCCategoryImplDecl *catImpl =
1417           dyn_cast<ObjCCategoryImplDecl>(impl)) {
1418       iface = catImpl->getCategoryDecl();
1419     } else {
1420       iface = impl->getClassInterface();
1421     }
1422
1423     const ObjCMethodDecl *ifaceMD =
1424       iface->getMethod(MD->getSelector(), MD->isInstanceMethod());
1425     if (ifaceMD) return findExplicitInstancetypeDeclarer(ifaceMD, instancetype);
1426   }
1427
1428   SmallVector<const ObjCMethodDecl *, 4> overrides;
1429   MD->getOverriddenMethods(overrides);
1430   for (unsigned i = 0, e = overrides.size(); i != e; ++i) {
1431     if (const ObjCMethodDecl *result =
1432           findExplicitInstancetypeDeclarer(overrides[i], instancetype))
1433       return result;
1434   }
1435
1436   return nullptr;
1437 }
1438
1439 void Sema::EmitRelatedResultTypeNoteForReturn(QualType destType) {
1440   // Only complain if we're in an ObjC method and the required return
1441   // type doesn't match the method's declared return type.
1442   ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(CurContext);
1443   if (!MD || !MD->hasRelatedResultType() ||
1444       Context.hasSameUnqualifiedType(destType, MD->getReturnType()))
1445     return;
1446
1447   // Look for a method overridden by this method which explicitly uses
1448   // 'instancetype'.
1449   if (const ObjCMethodDecl *overridden =
1450         findExplicitInstancetypeDeclarer(MD, Context.getObjCInstanceType())) {
1451     SourceRange range = overridden->getReturnTypeSourceRange();
1452     SourceLocation loc = range.getBegin();
1453     if (loc.isInvalid())
1454       loc = overridden->getLocation();
1455     Diag(loc, diag::note_related_result_type_explicit)
1456       << /*current method*/ 1 << range;
1457     return;
1458   }
1459
1460   // Otherwise, if we have an interesting method family, note that.
1461   // This should always trigger if the above didn't.
1462   if (ObjCMethodFamily family = MD->getMethodFamily())
1463     Diag(MD->getLocation(), diag::note_related_result_type_family)
1464       << /*current method*/ 1
1465       << family;
1466 }
1467
1468 void Sema::EmitRelatedResultTypeNote(const Expr *E) {
1469   E = E->IgnoreParenImpCasts();
1470   const ObjCMessageExpr *MsgSend = dyn_cast<ObjCMessageExpr>(E);
1471   if (!MsgSend)
1472     return;
1473
1474   const ObjCMethodDecl *Method = MsgSend->getMethodDecl();
1475   if (!Method)
1476     return;
1477
1478   if (!Method->hasRelatedResultType())
1479     return;
1480
1481   if (Context.hasSameUnqualifiedType(
1482           Method->getReturnType().getNonReferenceType(), MsgSend->getType()))
1483     return;
1484
1485   if (!Context.hasSameUnqualifiedType(Method->getReturnType(),
1486                                       Context.getObjCInstanceType()))
1487     return;
1488
1489   Diag(Method->getLocation(), diag::note_related_result_type_inferred)
1490     << Method->isInstanceMethod() << Method->getSelector()
1491     << MsgSend->getType();
1492 }
1493
1494 bool Sema::CheckMessageArgumentTypes(QualType ReceiverType,
1495                                      MultiExprArg Args,
1496                                      Selector Sel,
1497                                      ArrayRef<SourceLocation> SelectorLocs,
1498                                      ObjCMethodDecl *Method,
1499                                      bool isClassMessage, bool isSuperMessage,
1500                                      SourceLocation lbrac, SourceLocation rbrac,
1501                                      SourceRange RecRange,
1502                                      QualType &ReturnType, ExprValueKind &VK) {
1503   SourceLocation SelLoc;
1504   if (!SelectorLocs.empty() && SelectorLocs.front().isValid())
1505     SelLoc = SelectorLocs.front();
1506   else
1507     SelLoc = lbrac;
1508
1509   if (!Method) {
1510     // Apply default argument promotion as for (C99 6.5.2.2p6).
1511     for (unsigned i = 0, e = Args.size(); i != e; i++) {
1512       if (Args[i]->isTypeDependent())
1513         continue;
1514
1515       ExprResult result;
1516       if (getLangOpts().DebuggerSupport) {
1517         QualType paramTy; // ignored
1518         result = checkUnknownAnyArg(SelLoc, Args[i], paramTy);
1519       } else {
1520         result = DefaultArgumentPromotion(Args[i]);
1521       }
1522       if (result.isInvalid())
1523         return true;
1524       Args[i] = result.get();
1525     }
1526
1527     unsigned DiagID;
1528     if (getLangOpts().ObjCAutoRefCount)
1529       DiagID = diag::err_arc_method_not_found;
1530     else
1531       DiagID = isClassMessage ? diag::warn_class_method_not_found
1532                               : diag::warn_inst_method_not_found;
1533     if (!getLangOpts().DebuggerSupport) {
1534       const ObjCMethodDecl *OMD = SelectorsForTypoCorrection(Sel, ReceiverType);
1535       if (OMD && !OMD->isInvalidDecl()) {
1536         if (getLangOpts().ObjCAutoRefCount)
1537           DiagID = diag::err_method_not_found_with_typo;
1538         else
1539           DiagID = isClassMessage ? diag::warn_class_method_not_found_with_typo
1540                                   : diag::warn_instance_method_not_found_with_typo;
1541         Selector MatchedSel = OMD->getSelector();
1542         SourceRange SelectorRange(SelectorLocs.front(), SelectorLocs.back());
1543         if (MatchedSel.isUnarySelector())
1544           Diag(SelLoc, DiagID)
1545             << Sel<< isClassMessage << MatchedSel
1546             << FixItHint::CreateReplacement(SelectorRange, MatchedSel.getAsString());
1547         else
1548           Diag(SelLoc, DiagID) << Sel<< isClassMessage << MatchedSel;
1549       }
1550       else
1551         Diag(SelLoc, DiagID)
1552           << Sel << isClassMessage << SourceRange(SelectorLocs.front(),
1553                                                 SelectorLocs.back());
1554       // Find the class to which we are sending this message.
1555       if (ReceiverType->isObjCObjectPointerType()) {
1556         if (ObjCInterfaceDecl *ThisClass =
1557             ReceiverType->getAs<ObjCObjectPointerType>()->getInterfaceDecl()) {
1558           Diag(ThisClass->getLocation(), diag::note_receiver_class_declared);
1559           if (!RecRange.isInvalid())
1560             if (ThisClass->lookupClassMethod(Sel))
1561               Diag(RecRange.getBegin(),diag::note_receiver_expr_here)
1562                 << FixItHint::CreateReplacement(RecRange,
1563                                                 ThisClass->getNameAsString());
1564         }
1565       }
1566     }
1567
1568     // In debuggers, we want to use __unknown_anytype for these
1569     // results so that clients can cast them.
1570     if (getLangOpts().DebuggerSupport) {
1571       ReturnType = Context.UnknownAnyTy;
1572     } else {
1573       ReturnType = Context.getObjCIdType();
1574     }
1575     VK = VK_RValue;
1576     return false;
1577   }
1578
1579   ReturnType = getMessageSendResultType(ReceiverType, Method, isClassMessage,
1580                                         isSuperMessage);
1581   VK = Expr::getValueKindForType(Method->getReturnType());
1582
1583   unsigned NumNamedArgs = Sel.getNumArgs();
1584   // Method might have more arguments than selector indicates. This is due
1585   // to addition of c-style arguments in method.
1586   if (Method->param_size() > Sel.getNumArgs())
1587     NumNamedArgs = Method->param_size();
1588   // FIXME. This need be cleaned up.
1589   if (Args.size() < NumNamedArgs) {
1590     Diag(SelLoc, diag::err_typecheck_call_too_few_args)
1591       << 2 << NumNamedArgs << static_cast<unsigned>(Args.size());
1592     return false;
1593   }
1594
1595   // Compute the set of type arguments to be substituted into each parameter
1596   // type.
1597   Optional<ArrayRef<QualType>> typeArgs
1598     = ReceiverType->getObjCSubstitutions(Method->getDeclContext());
1599   bool IsError = false;
1600   for (unsigned i = 0; i < NumNamedArgs; i++) {
1601     // We can't do any type-checking on a type-dependent argument.
1602     if (Args[i]->isTypeDependent())
1603       continue;
1604
1605     Expr *argExpr = Args[i];
1606
1607     ParmVarDecl *param = Method->parameters()[i];
1608     assert(argExpr && "CheckMessageArgumentTypes(): missing expression");
1609
1610     // Strip the unbridged-cast placeholder expression off unless it's
1611     // a consumed argument.
1612     if (argExpr->hasPlaceholderType(BuiltinType::ARCUnbridgedCast) &&
1613         !param->hasAttr<CFConsumedAttr>())
1614       argExpr = stripARCUnbridgedCast(argExpr);
1615
1616     // If the parameter is __unknown_anytype, infer its type
1617     // from the argument.
1618     if (param->getType() == Context.UnknownAnyTy) {
1619       QualType paramType;
1620       ExprResult argE = checkUnknownAnyArg(SelLoc, argExpr, paramType);
1621       if (argE.isInvalid()) {
1622         IsError = true;
1623       } else {
1624         Args[i] = argE.get();
1625
1626         // Update the parameter type in-place.
1627         param->setType(paramType);
1628       }
1629       continue;
1630     }
1631
1632     QualType origParamType = param->getType();
1633     QualType paramType = param->getType();
1634     if (typeArgs)
1635       paramType = paramType.substObjCTypeArgs(
1636                     Context,
1637                     *typeArgs,
1638                     ObjCSubstitutionContext::Parameter);
1639
1640     if (RequireCompleteType(argExpr->getSourceRange().getBegin(),
1641                             paramType,
1642                             diag::err_call_incomplete_argument, argExpr))
1643       return true;
1644
1645     InitializedEntity Entity
1646       = InitializedEntity::InitializeParameter(Context, param, paramType);
1647     ExprResult ArgE = PerformCopyInitialization(Entity, SourceLocation(), argExpr);
1648     if (ArgE.isInvalid())
1649       IsError = true;
1650     else {
1651       Args[i] = ArgE.getAs<Expr>();
1652
1653       // If we are type-erasing a block to a block-compatible
1654       // Objective-C pointer type, we may need to extend the lifetime
1655       // of the block object.
1656       if (typeArgs && Args[i]->isRValue() && paramType->isBlockPointerType() &&
1657           Args[i]->getType()->isBlockPointerType() &&
1658           origParamType->isObjCObjectPointerType()) {
1659         ExprResult arg = Args[i];
1660         maybeExtendBlockObject(arg);
1661         Args[i] = arg.get();
1662       }
1663     }
1664   }
1665
1666   // Promote additional arguments to variadic methods.
1667   if (Method->isVariadic()) {
1668     for (unsigned i = NumNamedArgs, e = Args.size(); i < e; ++i) {
1669       if (Args[i]->isTypeDependent())
1670         continue;
1671
1672       ExprResult Arg = DefaultVariadicArgumentPromotion(Args[i], VariadicMethod,
1673                                                         nullptr);
1674       IsError |= Arg.isInvalid();
1675       Args[i] = Arg.get();
1676     }
1677   } else {
1678     // Check for extra arguments to non-variadic methods.
1679     if (Args.size() != NumNamedArgs) {
1680       Diag(Args[NumNamedArgs]->getLocStart(),
1681            diag::err_typecheck_call_too_many_args)
1682         << 2 /*method*/ << NumNamedArgs << static_cast<unsigned>(Args.size())
1683         << Method->getSourceRange()
1684         << SourceRange(Args[NumNamedArgs]->getLocStart(),
1685                        Args.back()->getLocEnd());
1686     }
1687   }
1688
1689   DiagnoseSentinelCalls(Method, SelLoc, Args);
1690
1691   // Do additional checkings on method.
1692   IsError |= CheckObjCMethodCall(
1693       Method, SelLoc, makeArrayRef(Args.data(), Args.size()));
1694
1695   return IsError;
1696 }
1697
1698 bool Sema::isSelfExpr(Expr *RExpr) {
1699   // 'self' is objc 'self' in an objc method only.
1700   ObjCMethodDecl *Method =
1701       dyn_cast_or_null<ObjCMethodDecl>(CurContext->getNonClosureAncestor());
1702   return isSelfExpr(RExpr, Method);
1703 }
1704
1705 bool Sema::isSelfExpr(Expr *receiver, const ObjCMethodDecl *method) {
1706   if (!method) return false;
1707
1708   receiver = receiver->IgnoreParenLValueCasts();
1709   if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(receiver))
1710     if (DRE->getDecl() == method->getSelfDecl())
1711       return true;
1712   return false;
1713 }
1714
1715 /// LookupMethodInType - Look up a method in an ObjCObjectType.
1716 ObjCMethodDecl *Sema::LookupMethodInObjectType(Selector sel, QualType type,
1717                                                bool isInstance) {
1718   const ObjCObjectType *objType = type->castAs<ObjCObjectType>();
1719   if (ObjCInterfaceDecl *iface = objType->getInterface()) {
1720     // Look it up in the main interface (and categories, etc.)
1721     if (ObjCMethodDecl *method = iface->lookupMethod(sel, isInstance))
1722       return method;
1723
1724     // Okay, look for "private" methods declared in any
1725     // @implementations we've seen.
1726     if (ObjCMethodDecl *method = iface->lookupPrivateMethod(sel, isInstance))
1727       return method;
1728   }
1729
1730   // Check qualifiers.
1731   for (const auto *I : objType->quals())
1732     if (ObjCMethodDecl *method = I->lookupMethod(sel, isInstance))
1733       return method;
1734
1735   return nullptr;
1736 }
1737
1738 /// LookupMethodInQualifiedType - Lookups up a method in protocol qualifier
1739 /// list of a qualified objective pointer type.
1740 ObjCMethodDecl *Sema::LookupMethodInQualifiedType(Selector Sel,
1741                                               const ObjCObjectPointerType *OPT,
1742                                               bool Instance)
1743 {
1744   ObjCMethodDecl *MD = nullptr;
1745   for (const auto *PROTO : OPT->quals()) {
1746     if ((MD = PROTO->lookupMethod(Sel, Instance))) {
1747       return MD;
1748     }
1749   }
1750   return nullptr;
1751 }
1752
1753 /// HandleExprPropertyRefExpr - Handle foo.bar where foo is a pointer to an
1754 /// objective C interface.  This is a property reference expression.
1755 ExprResult Sema::
1756 HandleExprPropertyRefExpr(const ObjCObjectPointerType *OPT,
1757                           Expr *BaseExpr, SourceLocation OpLoc,
1758                           DeclarationName MemberName,
1759                           SourceLocation MemberLoc,
1760                           SourceLocation SuperLoc, QualType SuperType,
1761                           bool Super) {
1762   const ObjCInterfaceType *IFaceT = OPT->getInterfaceType();
1763   ObjCInterfaceDecl *IFace = IFaceT->getDecl();
1764
1765   if (!MemberName.isIdentifier()) {
1766     Diag(MemberLoc, diag::err_invalid_property_name)
1767       << MemberName << QualType(OPT, 0);
1768     return ExprError();
1769   }
1770
1771   IdentifierInfo *Member = MemberName.getAsIdentifierInfo();
1772
1773   SourceRange BaseRange = Super? SourceRange(SuperLoc)
1774                                : BaseExpr->getSourceRange();
1775   if (RequireCompleteType(MemberLoc, OPT->getPointeeType(),
1776                           diag::err_property_not_found_forward_class,
1777                           MemberName, BaseRange))
1778     return ExprError();
1779
1780   if (ObjCPropertyDecl *PD = IFace->FindPropertyDeclaration(
1781           Member, ObjCPropertyQueryKind::OBJC_PR_query_instance)) {
1782     // Check whether we can reference this property.
1783     if (DiagnoseUseOfDecl(PD, MemberLoc))
1784       return ExprError();
1785     if (Super)
1786       return new (Context)
1787           ObjCPropertyRefExpr(PD, Context.PseudoObjectTy, VK_LValue,
1788                               OK_ObjCProperty, MemberLoc, SuperLoc, SuperType);
1789     else
1790       return new (Context)
1791           ObjCPropertyRefExpr(PD, Context.PseudoObjectTy, VK_LValue,
1792                               OK_ObjCProperty, MemberLoc, BaseExpr);
1793   }
1794   // Check protocols on qualified interfaces.
1795   for (const auto *I : OPT->quals())
1796     if (ObjCPropertyDecl *PD = I->FindPropertyDeclaration(
1797             Member, ObjCPropertyQueryKind::OBJC_PR_query_instance)) {
1798       // Check whether we can reference this property.
1799       if (DiagnoseUseOfDecl(PD, MemberLoc))
1800         return ExprError();
1801
1802       if (Super)
1803         return new (Context) ObjCPropertyRefExpr(
1804             PD, Context.PseudoObjectTy, VK_LValue, OK_ObjCProperty, MemberLoc,
1805             SuperLoc, SuperType);
1806       else
1807         return new (Context)
1808             ObjCPropertyRefExpr(PD, Context.PseudoObjectTy, VK_LValue,
1809                                 OK_ObjCProperty, MemberLoc, BaseExpr);
1810     }
1811   // If that failed, look for an "implicit" property by seeing if the nullary
1812   // selector is implemented.
1813
1814   // FIXME: The logic for looking up nullary and unary selectors should be
1815   // shared with the code in ActOnInstanceMessage.
1816
1817   Selector Sel = PP.getSelectorTable().getNullarySelector(Member);
1818   ObjCMethodDecl *Getter = IFace->lookupInstanceMethod(Sel);
1819
1820   // May be found in property's qualified list.
1821   if (!Getter)
1822     Getter = LookupMethodInQualifiedType(Sel, OPT, true);
1823
1824   // If this reference is in an @implementation, check for 'private' methods.
1825   if (!Getter)
1826     Getter = IFace->lookupPrivateMethod(Sel);
1827
1828   if (Getter) {
1829     // Check if we can reference this property.
1830     if (DiagnoseUseOfDecl(Getter, MemberLoc))
1831       return ExprError();
1832   }
1833   // If we found a getter then this may be a valid dot-reference, we
1834   // will look for the matching setter, in case it is needed.
1835   Selector SetterSel =
1836     SelectorTable::constructSetterSelector(PP.getIdentifierTable(),
1837                                            PP.getSelectorTable(), Member);
1838   ObjCMethodDecl *Setter = IFace->lookupInstanceMethod(SetterSel);
1839
1840   // May be found in property's qualified list.
1841   if (!Setter)
1842     Setter = LookupMethodInQualifiedType(SetterSel, OPT, true);
1843
1844   if (!Setter) {
1845     // If this reference is in an @implementation, also check for 'private'
1846     // methods.
1847     Setter = IFace->lookupPrivateMethod(SetterSel);
1848   }
1849
1850   if (Setter && DiagnoseUseOfDecl(Setter, MemberLoc))
1851     return ExprError();
1852
1853   // Special warning if member name used in a property-dot for a setter accessor
1854   // does not use a property with same name; e.g. obj.X = ... for a property with
1855   // name 'x'.
1856   if (Setter && Setter->isImplicit() && Setter->isPropertyAccessor() &&
1857       !IFace->FindPropertyDeclaration(
1858           Member, ObjCPropertyQueryKind::OBJC_PR_query_instance)) {
1859       if (const ObjCPropertyDecl *PDecl = Setter->findPropertyDecl()) {
1860         // Do not warn if user is using property-dot syntax to make call to
1861         // user named setter.
1862         if (!(PDecl->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_setter))
1863           Diag(MemberLoc,
1864                diag::warn_property_access_suggest)
1865           << MemberName << QualType(OPT, 0) << PDecl->getName()
1866           << FixItHint::CreateReplacement(MemberLoc, PDecl->getName());
1867       }
1868   }
1869
1870   if (Getter || Setter) {
1871     if (Super)
1872       return new (Context)
1873           ObjCPropertyRefExpr(Getter, Setter, Context.PseudoObjectTy, VK_LValue,
1874                               OK_ObjCProperty, MemberLoc, SuperLoc, SuperType);
1875     else
1876       return new (Context)
1877           ObjCPropertyRefExpr(Getter, Setter, Context.PseudoObjectTy, VK_LValue,
1878                               OK_ObjCProperty, MemberLoc, BaseExpr);
1879
1880   }
1881
1882   // Attempt to correct for typos in property names.
1883   if (TypoCorrection Corrected =
1884           CorrectTypo(DeclarationNameInfo(MemberName, MemberLoc),
1885                       LookupOrdinaryName, nullptr, nullptr,
1886                       llvm::make_unique<DeclFilterCCC<ObjCPropertyDecl>>(),
1887                       CTK_ErrorRecovery, IFace, false, OPT)) {
1888     DeclarationName TypoResult = Corrected.getCorrection();
1889     if (TypoResult.isIdentifier() &&
1890         TypoResult.getAsIdentifierInfo() == Member) {
1891       // There is no need to try the correction if it is the same.
1892       NamedDecl *ChosenDecl =
1893         Corrected.isKeyword() ? nullptr : Corrected.getFoundDecl();
1894       if (ChosenDecl && isa<ObjCPropertyDecl>(ChosenDecl))
1895         if (cast<ObjCPropertyDecl>(ChosenDecl)->isClassProperty()) {
1896           // This is a class property, we should not use the instance to
1897           // access it.
1898           Diag(MemberLoc, diag::err_class_property_found) << MemberName
1899           << OPT->getInterfaceDecl()->getName()
1900           << FixItHint::CreateReplacement(BaseExpr->getSourceRange(),
1901                                           OPT->getInterfaceDecl()->getName());
1902           return ExprError();
1903         }
1904     } else {
1905       diagnoseTypo(Corrected, PDiag(diag::err_property_not_found_suggest)
1906                                 << MemberName << QualType(OPT, 0));
1907       return HandleExprPropertyRefExpr(OPT, BaseExpr, OpLoc,
1908                                        TypoResult, MemberLoc,
1909                                        SuperLoc, SuperType, Super);
1910     }
1911   }
1912   ObjCInterfaceDecl *ClassDeclared;
1913   if (ObjCIvarDecl *Ivar =
1914       IFace->lookupInstanceVariable(Member, ClassDeclared)) {
1915     QualType T = Ivar->getType();
1916     if (const ObjCObjectPointerType * OBJPT =
1917         T->getAsObjCInterfacePointerType()) {
1918       if (RequireCompleteType(MemberLoc, OBJPT->getPointeeType(),
1919                               diag::err_property_not_as_forward_class,
1920                               MemberName, BaseExpr))
1921         return ExprError();
1922     }
1923     Diag(MemberLoc,
1924          diag::err_ivar_access_using_property_syntax_suggest)
1925     << MemberName << QualType(OPT, 0) << Ivar->getDeclName()
1926     << FixItHint::CreateReplacement(OpLoc, "->");
1927     return ExprError();
1928   }
1929
1930   Diag(MemberLoc, diag::err_property_not_found)
1931     << MemberName << QualType(OPT, 0);
1932   if (Setter)
1933     Diag(Setter->getLocation(), diag::note_getter_unavailable)
1934           << MemberName << BaseExpr->getSourceRange();
1935   return ExprError();
1936 }
1937
1938 ExprResult Sema::
1939 ActOnClassPropertyRefExpr(IdentifierInfo &receiverName,
1940                           IdentifierInfo &propertyName,
1941                           SourceLocation receiverNameLoc,
1942                           SourceLocation propertyNameLoc) {
1943
1944   IdentifierInfo *receiverNamePtr = &receiverName;
1945   ObjCInterfaceDecl *IFace = getObjCInterfaceDecl(receiverNamePtr,
1946                                                   receiverNameLoc);
1947
1948   QualType SuperType;
1949   if (!IFace) {
1950     // If the "receiver" is 'super' in a method, handle it as an expression-like
1951     // property reference.
1952     if (receiverNamePtr->isStr("super")) {
1953       if (ObjCMethodDecl *CurMethod = tryCaptureObjCSelf(receiverNameLoc)) {
1954         if (auto classDecl = CurMethod->getClassInterface()) {
1955           SuperType = QualType(classDecl->getSuperClassType(), 0);
1956           if (CurMethod->isInstanceMethod()) {
1957             if (SuperType.isNull()) {
1958               // The current class does not have a superclass.
1959               Diag(receiverNameLoc, diag::err_root_class_cannot_use_super)
1960                 << CurMethod->getClassInterface()->getIdentifier();
1961               return ExprError();
1962             }
1963             QualType T = Context.getObjCObjectPointerType(SuperType);
1964
1965             return HandleExprPropertyRefExpr(T->castAs<ObjCObjectPointerType>(),
1966                                              /*BaseExpr*/nullptr,
1967                                              SourceLocation()/*OpLoc*/,
1968                                              &propertyName,
1969                                              propertyNameLoc,
1970                                              receiverNameLoc, T, true);
1971           }
1972
1973           // Otherwise, if this is a class method, try dispatching to our
1974           // superclass.
1975           IFace = CurMethod->getClassInterface()->getSuperClass();
1976         }
1977       }
1978     }
1979
1980     if (!IFace) {
1981       Diag(receiverNameLoc, diag::err_expected_either) << tok::identifier
1982                                                        << tok::l_paren;
1983       return ExprError();
1984     }
1985   }
1986
1987   // Search for a declared property first.
1988   Selector Sel = PP.getSelectorTable().getNullarySelector(&propertyName);
1989   ObjCMethodDecl *Getter = IFace->lookupClassMethod(Sel);
1990
1991   // If this reference is in an @implementation, check for 'private' methods.
1992   if (!Getter)
1993     Getter = IFace->lookupPrivateClassMethod(Sel);
1994
1995   if (Getter) {
1996     // FIXME: refactor/share with ActOnMemberReference().
1997     // Check if we can reference this property.
1998     if (DiagnoseUseOfDecl(Getter, propertyNameLoc))
1999       return ExprError();
2000   }
2001
2002   // Look for the matching setter, in case it is needed.
2003   Selector SetterSel =
2004     SelectorTable::constructSetterSelector(PP.getIdentifierTable(),
2005                                             PP.getSelectorTable(),
2006                                            &propertyName);
2007
2008   ObjCMethodDecl *Setter = IFace->lookupClassMethod(SetterSel);
2009   if (!Setter) {
2010     // If this reference is in an @implementation, also check for 'private'
2011     // methods.
2012     Setter = IFace->lookupPrivateClassMethod(SetterSel);
2013   }
2014   // Look through local category implementations associated with the class.
2015   if (!Setter)
2016     Setter = IFace->getCategoryClassMethod(SetterSel);
2017
2018   if (Setter && DiagnoseUseOfDecl(Setter, propertyNameLoc))
2019     return ExprError();
2020
2021   if (Getter || Setter) {
2022     if (!SuperType.isNull())
2023       return new (Context)
2024           ObjCPropertyRefExpr(Getter, Setter, Context.PseudoObjectTy, VK_LValue,
2025                               OK_ObjCProperty, propertyNameLoc, receiverNameLoc,
2026                               SuperType);
2027
2028     return new (Context) ObjCPropertyRefExpr(
2029         Getter, Setter, Context.PseudoObjectTy, VK_LValue, OK_ObjCProperty,
2030         propertyNameLoc, receiverNameLoc, IFace);
2031   }
2032   return ExprError(Diag(propertyNameLoc, diag::err_property_not_found)
2033                      << &propertyName << Context.getObjCInterfaceType(IFace));
2034 }
2035
2036 namespace {
2037
2038 class ObjCInterfaceOrSuperCCC : public CorrectionCandidateCallback {
2039  public:
2040   ObjCInterfaceOrSuperCCC(ObjCMethodDecl *Method) {
2041     // Determine whether "super" is acceptable in the current context.
2042     if (Method && Method->getClassInterface())
2043       WantObjCSuper = Method->getClassInterface()->getSuperClass();
2044   }
2045
2046   bool ValidateCandidate(const TypoCorrection &candidate) override {
2047     return candidate.getCorrectionDeclAs<ObjCInterfaceDecl>() ||
2048         candidate.isKeyword("super");
2049   }
2050 };
2051
2052 } // end anonymous namespace
2053
2054 Sema::ObjCMessageKind Sema::getObjCMessageKind(Scope *S,
2055                                                IdentifierInfo *Name,
2056                                                SourceLocation NameLoc,
2057                                                bool IsSuper,
2058                                                bool HasTrailingDot,
2059                                                ParsedType &ReceiverType) {
2060   ReceiverType = nullptr;
2061
2062   // If the identifier is "super" and there is no trailing dot, we're
2063   // messaging super. If the identifier is "super" and there is a
2064   // trailing dot, it's an instance message.
2065   if (IsSuper && S->isInObjcMethodScope())
2066     return HasTrailingDot? ObjCInstanceMessage : ObjCSuperMessage;
2067
2068   LookupResult Result(*this, Name, NameLoc, LookupOrdinaryName);
2069   LookupName(Result, S);
2070
2071   switch (Result.getResultKind()) {
2072   case LookupResult::NotFound:
2073     // Normal name lookup didn't find anything. If we're in an
2074     // Objective-C method, look for ivars. If we find one, we're done!
2075     // FIXME: This is a hack. Ivar lookup should be part of normal
2076     // lookup.
2077     if (ObjCMethodDecl *Method = getCurMethodDecl()) {
2078       if (!Method->getClassInterface()) {
2079         // Fall back: let the parser try to parse it as an instance message.
2080         return ObjCInstanceMessage;
2081       }
2082
2083       ObjCInterfaceDecl *ClassDeclared;
2084       if (Method->getClassInterface()->lookupInstanceVariable(Name,
2085                                                               ClassDeclared))
2086         return ObjCInstanceMessage;
2087     }
2088
2089     // Break out; we'll perform typo correction below.
2090     break;
2091
2092   case LookupResult::NotFoundInCurrentInstantiation:
2093   case LookupResult::FoundOverloaded:
2094   case LookupResult::FoundUnresolvedValue:
2095   case LookupResult::Ambiguous:
2096     Result.suppressDiagnostics();
2097     return ObjCInstanceMessage;
2098
2099   case LookupResult::Found: {
2100     // If the identifier is a class or not, and there is a trailing dot,
2101     // it's an instance message.
2102     if (HasTrailingDot)
2103       return ObjCInstanceMessage;
2104     // We found something. If it's a type, then we have a class
2105     // message. Otherwise, it's an instance message.
2106     NamedDecl *ND = Result.getFoundDecl();
2107     QualType T;
2108     if (ObjCInterfaceDecl *Class = dyn_cast<ObjCInterfaceDecl>(ND))
2109       T = Context.getObjCInterfaceType(Class);
2110     else if (TypeDecl *Type = dyn_cast<TypeDecl>(ND)) {
2111       T = Context.getTypeDeclType(Type);
2112       DiagnoseUseOfDecl(Type, NameLoc);
2113     }
2114     else
2115       return ObjCInstanceMessage;
2116
2117     //  We have a class message, and T is the type we're
2118     //  messaging. Build source-location information for it.
2119     TypeSourceInfo *TSInfo = Context.getTrivialTypeSourceInfo(T, NameLoc);
2120     ReceiverType = CreateParsedType(T, TSInfo);
2121     return ObjCClassMessage;
2122   }
2123   }
2124
2125   if (TypoCorrection Corrected = CorrectTypo(
2126           Result.getLookupNameInfo(), Result.getLookupKind(), S, nullptr,
2127           llvm::make_unique<ObjCInterfaceOrSuperCCC>(getCurMethodDecl()),
2128           CTK_ErrorRecovery, nullptr, false, nullptr, false)) {
2129     if (Corrected.isKeyword()) {
2130       // If we've found the keyword "super" (the only keyword that would be
2131       // returned by CorrectTypo), this is a send to super.
2132       diagnoseTypo(Corrected,
2133                    PDiag(diag::err_unknown_receiver_suggest) << Name);
2134       return ObjCSuperMessage;
2135     } else if (ObjCInterfaceDecl *Class =
2136                    Corrected.getCorrectionDeclAs<ObjCInterfaceDecl>()) {
2137       // If we found a declaration, correct when it refers to an Objective-C
2138       // class.
2139       diagnoseTypo(Corrected,
2140                    PDiag(diag::err_unknown_receiver_suggest) << Name);
2141       QualType T = Context.getObjCInterfaceType(Class);
2142       TypeSourceInfo *TSInfo = Context.getTrivialTypeSourceInfo(T, NameLoc);
2143       ReceiverType = CreateParsedType(T, TSInfo);
2144       return ObjCClassMessage;
2145     }
2146   }
2147
2148   // Fall back: let the parser try to parse it as an instance message.
2149   return ObjCInstanceMessage;
2150 }
2151
2152 ExprResult Sema::ActOnSuperMessage(Scope *S,
2153                                    SourceLocation SuperLoc,
2154                                    Selector Sel,
2155                                    SourceLocation LBracLoc,
2156                                    ArrayRef<SourceLocation> SelectorLocs,
2157                                    SourceLocation RBracLoc,
2158                                    MultiExprArg Args) {
2159   // Determine whether we are inside a method or not.
2160   ObjCMethodDecl *Method = tryCaptureObjCSelf(SuperLoc);
2161   if (!Method) {
2162     Diag(SuperLoc, diag::err_invalid_receiver_to_message_super);
2163     return ExprError();
2164   }
2165
2166   ObjCInterfaceDecl *Class = Method->getClassInterface();
2167   if (!Class) {
2168     Diag(SuperLoc, diag::err_no_super_class_message)
2169       << Method->getDeclName();
2170     return ExprError();
2171   }
2172
2173   QualType SuperTy(Class->getSuperClassType(), 0);
2174   if (SuperTy.isNull()) {
2175     // The current class does not have a superclass.
2176     Diag(SuperLoc, diag::err_root_class_cannot_use_super)
2177       << Class->getIdentifier();
2178     return ExprError();
2179   }
2180
2181   // We are in a method whose class has a superclass, so 'super'
2182   // is acting as a keyword.
2183   if (Method->getSelector() == Sel)
2184     getCurFunction()->ObjCShouldCallSuper = false;
2185
2186   if (Method->isInstanceMethod()) {
2187     // Since we are in an instance method, this is an instance
2188     // message to the superclass instance.
2189     SuperTy = Context.getObjCObjectPointerType(SuperTy);
2190     return BuildInstanceMessage(nullptr, SuperTy, SuperLoc,
2191                                 Sel, /*Method=*/nullptr,
2192                                 LBracLoc, SelectorLocs, RBracLoc, Args);
2193   }
2194
2195   // Since we are in a class method, this is a class message to
2196   // the superclass.
2197   return BuildClassMessage(/*ReceiverTypeInfo=*/nullptr,
2198                            SuperTy,
2199                            SuperLoc, Sel, /*Method=*/nullptr,
2200                            LBracLoc, SelectorLocs, RBracLoc, Args);
2201 }
2202
2203 ExprResult Sema::BuildClassMessageImplicit(QualType ReceiverType,
2204                                            bool isSuperReceiver,
2205                                            SourceLocation Loc,
2206                                            Selector Sel,
2207                                            ObjCMethodDecl *Method,
2208                                            MultiExprArg Args) {
2209   TypeSourceInfo *receiverTypeInfo = nullptr;
2210   if (!ReceiverType.isNull())
2211     receiverTypeInfo = Context.getTrivialTypeSourceInfo(ReceiverType);
2212
2213   return BuildClassMessage(receiverTypeInfo, ReceiverType,
2214                           /*SuperLoc=*/isSuperReceiver ? Loc : SourceLocation(),
2215                            Sel, Method, Loc, Loc, Loc, Args,
2216                            /*isImplicit=*/true);
2217 }
2218
2219 static void applyCocoaAPICheck(Sema &S, const ObjCMessageExpr *Msg,
2220                                unsigned DiagID,
2221                                bool (*refactor)(const ObjCMessageExpr *,
2222                                               const NSAPI &, edit::Commit &)) {
2223   SourceLocation MsgLoc = Msg->getExprLoc();
2224   if (S.Diags.isIgnored(DiagID, MsgLoc))
2225     return;
2226
2227   SourceManager &SM = S.SourceMgr;
2228   edit::Commit ECommit(SM, S.LangOpts);
2229   if (refactor(Msg,*S.NSAPIObj, ECommit)) {
2230     DiagnosticBuilder Builder = S.Diag(MsgLoc, DiagID)
2231                         << Msg->getSelector() << Msg->getSourceRange();
2232     // FIXME: Don't emit diagnostic at all if fixits are non-commitable.
2233     if (!ECommit.isCommitable())
2234       return;
2235     for (edit::Commit::edit_iterator
2236            I = ECommit.edit_begin(), E = ECommit.edit_end(); I != E; ++I) {
2237       const edit::Commit::Edit &Edit = *I;
2238       switch (Edit.Kind) {
2239       case edit::Commit::Act_Insert:
2240         Builder.AddFixItHint(FixItHint::CreateInsertion(Edit.OrigLoc,
2241                                                         Edit.Text,
2242                                                         Edit.BeforePrev));
2243         break;
2244       case edit::Commit::Act_InsertFromRange:
2245         Builder.AddFixItHint(
2246             FixItHint::CreateInsertionFromRange(Edit.OrigLoc,
2247                                                 Edit.getInsertFromRange(SM),
2248                                                 Edit.BeforePrev));
2249         break;
2250       case edit::Commit::Act_Remove:
2251         Builder.AddFixItHint(FixItHint::CreateRemoval(Edit.getFileRange(SM)));
2252         break;
2253       }
2254     }
2255   }
2256 }
2257
2258 static void checkCocoaAPI(Sema &S, const ObjCMessageExpr *Msg) {
2259   applyCocoaAPICheck(S, Msg, diag::warn_objc_redundant_literal_use,
2260                      edit::rewriteObjCRedundantCallWithLiteral);
2261 }
2262
2263 /// \brief Diagnose use of %s directive in an NSString which is being passed
2264 /// as formatting string to formatting method.
2265 static void
2266 DiagnoseCStringFormatDirectiveInObjCAPI(Sema &S,
2267                                         ObjCMethodDecl *Method,
2268                                         Selector Sel,
2269                                         Expr **Args, unsigned NumArgs) {
2270   unsigned Idx = 0;
2271   bool Format = false;
2272   ObjCStringFormatFamily SFFamily = Sel.getStringFormatFamily();
2273   if (SFFamily == ObjCStringFormatFamily::SFF_NSString) {
2274     Idx = 0;
2275     Format = true;
2276   }
2277   else if (Method) {
2278     for (const auto *I : Method->specific_attrs<FormatAttr>()) {
2279       if (S.GetFormatNSStringIdx(I, Idx)) {
2280         Format = true;
2281         break;
2282       }
2283     }
2284   }
2285   if (!Format || NumArgs <= Idx)
2286     return;
2287
2288   Expr *FormatExpr = Args[Idx];
2289   if (ObjCStringLiteral *OSL =
2290       dyn_cast<ObjCStringLiteral>(FormatExpr->IgnoreParenImpCasts())) {
2291     StringLiteral *FormatString = OSL->getString();
2292     if (S.FormatStringHasSArg(FormatString)) {
2293       S.Diag(FormatExpr->getExprLoc(), diag::warn_objc_cdirective_format_string)
2294         << "%s" << 0 << 0;
2295       if (Method)
2296         S.Diag(Method->getLocation(), diag::note_method_declared_at)
2297           << Method->getDeclName();
2298     }
2299   }
2300 }
2301
2302 /// \brief Build an Objective-C class message expression.
2303 ///
2304 /// This routine takes care of both normal class messages and
2305 /// class messages to the superclass.
2306 ///
2307 /// \param ReceiverTypeInfo Type source information that describes the
2308 /// receiver of this message. This may be NULL, in which case we are
2309 /// sending to the superclass and \p SuperLoc must be a valid source
2310 /// location.
2311
2312 /// \param ReceiverType The type of the object receiving the
2313 /// message. When \p ReceiverTypeInfo is non-NULL, this is the same
2314 /// type as that refers to. For a superclass send, this is the type of
2315 /// the superclass.
2316 ///
2317 /// \param SuperLoc The location of the "super" keyword in a
2318 /// superclass message.
2319 ///
2320 /// \param Sel The selector to which the message is being sent.
2321 ///
2322 /// \param Method The method that this class message is invoking, if
2323 /// already known.
2324 ///
2325 /// \param LBracLoc The location of the opening square bracket ']'.
2326 ///
2327 /// \param RBracLoc The location of the closing square bracket ']'.
2328 ///
2329 /// \param ArgsIn The message arguments.
2330 ExprResult Sema::BuildClassMessage(TypeSourceInfo *ReceiverTypeInfo,
2331                                    QualType ReceiverType,
2332                                    SourceLocation SuperLoc,
2333                                    Selector Sel,
2334                                    ObjCMethodDecl *Method,
2335                                    SourceLocation LBracLoc,
2336                                    ArrayRef<SourceLocation> SelectorLocs,
2337                                    SourceLocation RBracLoc,
2338                                    MultiExprArg ArgsIn,
2339                                    bool isImplicit) {
2340   SourceLocation Loc = SuperLoc.isValid()? SuperLoc
2341     : ReceiverTypeInfo->getTypeLoc().getSourceRange().getBegin();
2342   if (LBracLoc.isInvalid()) {
2343     Diag(Loc, diag::err_missing_open_square_message_send)
2344       << FixItHint::CreateInsertion(Loc, "[");
2345     LBracLoc = Loc;
2346   }
2347   SourceLocation SelLoc;
2348   if (!SelectorLocs.empty() && SelectorLocs.front().isValid())
2349     SelLoc = SelectorLocs.front();
2350   else
2351     SelLoc = Loc;
2352
2353   if (ReceiverType->isDependentType()) {
2354     // If the receiver type is dependent, we can't type-check anything
2355     // at this point. Build a dependent expression.
2356     unsigned NumArgs = ArgsIn.size();
2357     Expr **Args = ArgsIn.data();
2358     assert(SuperLoc.isInvalid() && "Message to super with dependent type");
2359     return ObjCMessageExpr::Create(
2360         Context, ReceiverType, VK_RValue, LBracLoc, ReceiverTypeInfo, Sel,
2361         SelectorLocs, /*Method=*/nullptr, makeArrayRef(Args, NumArgs), RBracLoc,
2362         isImplicit);
2363   }
2364
2365   // Find the class to which we are sending this message.
2366   ObjCInterfaceDecl *Class = nullptr;
2367   const ObjCObjectType *ClassType = ReceiverType->getAs<ObjCObjectType>();
2368   if (!ClassType || !(Class = ClassType->getInterface())) {
2369     Diag(Loc, diag::err_invalid_receiver_class_message)
2370       << ReceiverType;
2371     return ExprError();
2372   }
2373   assert(Class && "We don't know which class we're messaging?");
2374   // objc++ diagnoses during typename annotation.
2375   if (!getLangOpts().CPlusPlus)
2376     (void)DiagnoseUseOfDecl(Class, SelLoc);
2377   // Find the method we are messaging.
2378   if (!Method) {
2379     SourceRange TypeRange
2380       = SuperLoc.isValid()? SourceRange(SuperLoc)
2381                           : ReceiverTypeInfo->getTypeLoc().getSourceRange();
2382     if (RequireCompleteType(Loc, Context.getObjCInterfaceType(Class),
2383                             (getLangOpts().ObjCAutoRefCount
2384                                ? diag::err_arc_receiver_forward_class
2385                                : diag::warn_receiver_forward_class),
2386                             TypeRange)) {
2387       // A forward class used in messaging is treated as a 'Class'
2388       Method = LookupFactoryMethodInGlobalPool(Sel,
2389                                                SourceRange(LBracLoc, RBracLoc));
2390       if (Method && !getLangOpts().ObjCAutoRefCount)
2391         Diag(Method->getLocation(), diag::note_method_sent_forward_class)
2392           << Method->getDeclName();
2393     }
2394     if (!Method)
2395       Method = Class->lookupClassMethod(Sel);
2396
2397     // If we have an implementation in scope, check "private" methods.
2398     if (!Method)
2399       Method = Class->lookupPrivateClassMethod(Sel);
2400
2401     if (Method && DiagnoseUseOfDecl(Method, SelLoc))
2402       return ExprError();
2403   }
2404
2405   // Check the argument types and determine the result type.
2406   QualType ReturnType;
2407   ExprValueKind VK = VK_RValue;
2408
2409   unsigned NumArgs = ArgsIn.size();
2410   Expr **Args = ArgsIn.data();
2411   if (CheckMessageArgumentTypes(ReceiverType, MultiExprArg(Args, NumArgs),
2412                                 Sel, SelectorLocs,
2413                                 Method, true,
2414                                 SuperLoc.isValid(), LBracLoc, RBracLoc,
2415                                 SourceRange(),
2416                                 ReturnType, VK))
2417     return ExprError();
2418
2419   if (Method && !Method->getReturnType()->isVoidType() &&
2420       RequireCompleteType(LBracLoc, Method->getReturnType(),
2421                           diag::err_illegal_message_expr_incomplete_type))
2422     return ExprError();
2423
2424   // Warn about explicit call of +initialize on its own class. But not on 'super'.
2425   if (Method && Method->getMethodFamily() == OMF_initialize) {
2426     if (!SuperLoc.isValid()) {
2427       const ObjCInterfaceDecl *ID =
2428         dyn_cast<ObjCInterfaceDecl>(Method->getDeclContext());
2429       if (ID == Class) {
2430         Diag(Loc, diag::warn_direct_initialize_call);
2431         Diag(Method->getLocation(), diag::note_method_declared_at)
2432           << Method->getDeclName();
2433       }
2434     }
2435     else if (ObjCMethodDecl *CurMeth = getCurMethodDecl()) {
2436       // [super initialize] is allowed only within an +initialize implementation
2437       if (CurMeth->getMethodFamily() != OMF_initialize) {
2438         Diag(Loc, diag::warn_direct_super_initialize_call);
2439         Diag(Method->getLocation(), diag::note_method_declared_at)
2440           << Method->getDeclName();
2441         Diag(CurMeth->getLocation(), diag::note_method_declared_at)
2442         << CurMeth->getDeclName();
2443       }
2444     }
2445   }
2446
2447   DiagnoseCStringFormatDirectiveInObjCAPI(*this, Method, Sel, Args, NumArgs);
2448
2449   // Construct the appropriate ObjCMessageExpr.
2450   ObjCMessageExpr *Result;
2451   if (SuperLoc.isValid())
2452     Result = ObjCMessageExpr::Create(Context, ReturnType, VK, LBracLoc,
2453                                      SuperLoc, /*IsInstanceSuper=*/false,
2454                                      ReceiverType, Sel, SelectorLocs,
2455                                      Method, makeArrayRef(Args, NumArgs),
2456                                      RBracLoc, isImplicit);
2457   else {
2458     Result = ObjCMessageExpr::Create(Context, ReturnType, VK, LBracLoc,
2459                                      ReceiverTypeInfo, Sel, SelectorLocs,
2460                                      Method, makeArrayRef(Args, NumArgs),
2461                                      RBracLoc, isImplicit);
2462     if (!isImplicit)
2463       checkCocoaAPI(*this, Result);
2464   }
2465   return MaybeBindToTemporary(Result);
2466 }
2467
2468 // ActOnClassMessage - used for both unary and keyword messages.
2469 // ArgExprs is optional - if it is present, the number of expressions
2470 // is obtained from Sel.getNumArgs().
2471 ExprResult Sema::ActOnClassMessage(Scope *S,
2472                                    ParsedType Receiver,
2473                                    Selector Sel,
2474                                    SourceLocation LBracLoc,
2475                                    ArrayRef<SourceLocation> SelectorLocs,
2476                                    SourceLocation RBracLoc,
2477                                    MultiExprArg Args) {
2478   TypeSourceInfo *ReceiverTypeInfo;
2479   QualType ReceiverType = GetTypeFromParser(Receiver, &ReceiverTypeInfo);
2480   if (ReceiverType.isNull())
2481     return ExprError();
2482
2483   if (!ReceiverTypeInfo)
2484     ReceiverTypeInfo = Context.getTrivialTypeSourceInfo(ReceiverType, LBracLoc);
2485
2486   return BuildClassMessage(ReceiverTypeInfo, ReceiverType,
2487                            /*SuperLoc=*/SourceLocation(), Sel,
2488                            /*Method=*/nullptr, LBracLoc, SelectorLocs, RBracLoc,
2489                            Args);
2490 }
2491
2492 ExprResult Sema::BuildInstanceMessageImplicit(Expr *Receiver,
2493                                               QualType ReceiverType,
2494                                               SourceLocation Loc,
2495                                               Selector Sel,
2496                                               ObjCMethodDecl *Method,
2497                                               MultiExprArg Args) {
2498   return BuildInstanceMessage(Receiver, ReceiverType,
2499                               /*SuperLoc=*/!Receiver ? Loc : SourceLocation(),
2500                               Sel, Method, Loc, Loc, Loc, Args,
2501                               /*isImplicit=*/true);
2502 }
2503
2504 /// \brief Build an Objective-C instance message expression.
2505 ///
2506 /// This routine takes care of both normal instance messages and
2507 /// instance messages to the superclass instance.
2508 ///
2509 /// \param Receiver The expression that computes the object that will
2510 /// receive this message. This may be empty, in which case we are
2511 /// sending to the superclass instance and \p SuperLoc must be a valid
2512 /// source location.
2513 ///
2514 /// \param ReceiverType The (static) type of the object receiving the
2515 /// message. When a \p Receiver expression is provided, this is the
2516 /// same type as that expression. For a superclass instance send, this
2517 /// is a pointer to the type of the superclass.
2518 ///
2519 /// \param SuperLoc The location of the "super" keyword in a
2520 /// superclass instance message.
2521 ///
2522 /// \param Sel The selector to which the message is being sent.
2523 ///
2524 /// \param Method The method that this instance message is invoking, if
2525 /// already known.
2526 ///
2527 /// \param LBracLoc The location of the opening square bracket ']'.
2528 ///
2529 /// \param RBracLoc The location of the closing square bracket ']'.
2530 ///
2531 /// \param ArgsIn The message arguments.
2532 ExprResult Sema::BuildInstanceMessage(Expr *Receiver,
2533                                       QualType ReceiverType,
2534                                       SourceLocation SuperLoc,
2535                                       Selector Sel,
2536                                       ObjCMethodDecl *Method,
2537                                       SourceLocation LBracLoc,
2538                                       ArrayRef<SourceLocation> SelectorLocs,
2539                                       SourceLocation RBracLoc,
2540                                       MultiExprArg ArgsIn,
2541                                       bool isImplicit) {
2542   assert((Receiver || SuperLoc.isValid()) && "If the Receiver is null, the "
2543                                              "SuperLoc must be valid so we can "
2544                                              "use it instead.");
2545
2546   // The location of the receiver.
2547   SourceLocation Loc = SuperLoc.isValid()? SuperLoc : Receiver->getLocStart();
2548   SourceRange RecRange =
2549       SuperLoc.isValid()? SuperLoc : Receiver->getSourceRange();
2550   SourceLocation SelLoc;
2551   if (!SelectorLocs.empty() && SelectorLocs.front().isValid())
2552     SelLoc = SelectorLocs.front();
2553   else
2554     SelLoc = Loc;
2555
2556   if (LBracLoc.isInvalid()) {
2557     Diag(Loc, diag::err_missing_open_square_message_send)
2558       << FixItHint::CreateInsertion(Loc, "[");
2559     LBracLoc = Loc;
2560   }
2561
2562   // If we have a receiver expression, perform appropriate promotions
2563   // and determine receiver type.
2564   if (Receiver) {
2565     if (Receiver->hasPlaceholderType()) {
2566       ExprResult Result;
2567       if (Receiver->getType() == Context.UnknownAnyTy)
2568         Result = forceUnknownAnyToType(Receiver, Context.getObjCIdType());
2569       else
2570         Result = CheckPlaceholderExpr(Receiver);
2571       if (Result.isInvalid()) return ExprError();
2572       Receiver = Result.get();
2573     }
2574
2575     if (Receiver->isTypeDependent()) {
2576       // If the receiver is type-dependent, we can't type-check anything
2577       // at this point. Build a dependent expression.
2578       unsigned NumArgs = ArgsIn.size();
2579       Expr **Args = ArgsIn.data();
2580       assert(SuperLoc.isInvalid() && "Message to super with dependent type");
2581       return ObjCMessageExpr::Create(
2582           Context, Context.DependentTy, VK_RValue, LBracLoc, Receiver, Sel,
2583           SelectorLocs, /*Method=*/nullptr, makeArrayRef(Args, NumArgs),
2584           RBracLoc, isImplicit);
2585     }
2586
2587     // If necessary, apply function/array conversion to the receiver.
2588     // C99 6.7.5.3p[7,8].
2589     ExprResult Result = DefaultFunctionArrayLvalueConversion(Receiver);
2590     if (Result.isInvalid())
2591       return ExprError();
2592     Receiver = Result.get();
2593     ReceiverType = Receiver->getType();
2594
2595     // If the receiver is an ObjC pointer, a block pointer, or an
2596     // __attribute__((NSObject)) pointer, we don't need to do any
2597     // special conversion in order to look up a receiver.
2598     if (ReceiverType->isObjCRetainableType()) {
2599       // do nothing
2600     } else if (!getLangOpts().ObjCAutoRefCount &&
2601                !Context.getObjCIdType().isNull() &&
2602                (ReceiverType->isPointerType() ||
2603                 ReceiverType->isIntegerType())) {
2604       // Implicitly convert integers and pointers to 'id' but emit a warning.
2605       // But not in ARC.
2606       Diag(Loc, diag::warn_bad_receiver_type)
2607         << ReceiverType
2608         << Receiver->getSourceRange();
2609       if (ReceiverType->isPointerType()) {
2610         Receiver = ImpCastExprToType(Receiver, Context.getObjCIdType(),
2611                                      CK_CPointerToObjCPointerCast).get();
2612       } else {
2613         // TODO: specialized warning on null receivers?
2614         bool IsNull = Receiver->isNullPointerConstant(Context,
2615                                               Expr::NPC_ValueDependentIsNull);
2616         CastKind Kind = IsNull ? CK_NullToPointer : CK_IntegralToPointer;
2617         Receiver = ImpCastExprToType(Receiver, Context.getObjCIdType(),
2618                                      Kind).get();
2619       }
2620       ReceiverType = Receiver->getType();
2621     } else if (getLangOpts().CPlusPlus) {
2622       // The receiver must be a complete type.
2623       if (RequireCompleteType(Loc, Receiver->getType(),
2624                               diag::err_incomplete_receiver_type))
2625         return ExprError();
2626
2627       ExprResult result = PerformContextuallyConvertToObjCPointer(Receiver);
2628       if (result.isUsable()) {
2629         Receiver = result.get();
2630         ReceiverType = Receiver->getType();
2631       }
2632     }
2633   }
2634
2635   // There's a somewhat weird interaction here where we assume that we
2636   // won't actually have a method unless we also don't need to do some
2637   // of the more detailed type-checking on the receiver.
2638
2639   if (!Method) {
2640     // Handle messages to id and __kindof types (where we use the
2641     // global method pool).
2642     const ObjCObjectType *typeBound = nullptr;
2643     bool receiverIsIdLike = ReceiverType->isObjCIdOrObjectKindOfType(Context,
2644                                                                      typeBound);
2645     if (receiverIsIdLike || ReceiverType->isBlockPointerType() ||
2646         (Receiver && Context.isObjCNSObjectType(Receiver->getType()))) {
2647       SmallVector<ObjCMethodDecl*, 4> Methods;
2648       // If we have a type bound, further filter the methods.
2649       CollectMultipleMethodsInGlobalPool(Sel, Methods, true/*InstanceFirst*/,
2650                                          true/*CheckTheOther*/, typeBound);
2651       if (!Methods.empty()) {
2652         // We choose the first method as the initial candidate, then try to
2653         // select a better one.
2654         Method = Methods[0];
2655
2656         if (ObjCMethodDecl *BestMethod =
2657             SelectBestMethod(Sel, ArgsIn, Method->isInstanceMethod(), Methods))
2658           Method = BestMethod;
2659
2660         if (!AreMultipleMethodsInGlobalPool(Sel, Method,
2661                                             SourceRange(LBracLoc, RBracLoc),
2662                                             receiverIsIdLike, Methods))
2663            DiagnoseUseOfDecl(Method, SelLoc);
2664       }
2665     } else if (ReceiverType->isObjCClassOrClassKindOfType() ||
2666                ReceiverType->isObjCQualifiedClassType()) {
2667       // Handle messages to Class.
2668       // We allow sending a message to a qualified Class ("Class<foo>"), which
2669       // is ok as long as one of the protocols implements the selector (if not,
2670       // warn).
2671       if (!ReceiverType->isObjCClassOrClassKindOfType()) {
2672         const ObjCObjectPointerType *QClassTy
2673           = ReceiverType->getAsObjCQualifiedClassType();
2674         // Search protocols for class methods.
2675         Method = LookupMethodInQualifiedType(Sel, QClassTy, false);
2676         if (!Method) {
2677           Method = LookupMethodInQualifiedType(Sel, QClassTy, true);
2678           // warn if instance method found for a Class message.
2679           if (Method) {
2680             Diag(SelLoc, diag::warn_instance_method_on_class_found)
2681               << Method->getSelector() << Sel;
2682             Diag(Method->getLocation(), diag::note_method_declared_at)
2683               << Method->getDeclName();
2684           }
2685         }
2686       } else {
2687         if (ObjCMethodDecl *CurMeth = getCurMethodDecl()) {
2688           if (ObjCInterfaceDecl *ClassDecl = CurMeth->getClassInterface()) {
2689             // First check the public methods in the class interface.
2690             Method = ClassDecl->lookupClassMethod(Sel);
2691
2692             if (!Method)
2693               Method = ClassDecl->lookupPrivateClassMethod(Sel);
2694           }
2695           if (Method && DiagnoseUseOfDecl(Method, SelLoc))
2696             return ExprError();
2697         }
2698         if (!Method) {
2699           // If not messaging 'self', look for any factory method named 'Sel'.
2700           if (!Receiver || !isSelfExpr(Receiver)) {
2701             // If no class (factory) method was found, check if an _instance_
2702             // method of the same name exists in the root class only.
2703             SmallVector<ObjCMethodDecl*, 4> Methods;
2704             CollectMultipleMethodsInGlobalPool(Sel, Methods,
2705                                                false/*InstanceFirst*/,
2706                                                true/*CheckTheOther*/);
2707             if (!Methods.empty()) {
2708               // We choose the first method as the initial candidate, then try
2709               // to select a better one.
2710               Method = Methods[0];
2711
2712               // If we find an instance method, emit waring.
2713               if (Method->isInstanceMethod()) {
2714                 if (const ObjCInterfaceDecl *ID =
2715                     dyn_cast<ObjCInterfaceDecl>(Method->getDeclContext())) {
2716                   if (ID->getSuperClass())
2717                     Diag(SelLoc, diag::warn_root_inst_method_not_found)
2718                         << Sel << SourceRange(LBracLoc, RBracLoc);
2719                 }
2720               }
2721
2722              if (ObjCMethodDecl *BestMethod =
2723                  SelectBestMethod(Sel, ArgsIn, Method->isInstanceMethod(),
2724                                   Methods))
2725                Method = BestMethod;
2726             }
2727           }
2728         }
2729       }
2730     } else {
2731       ObjCInterfaceDecl *ClassDecl = nullptr;
2732
2733       // We allow sending a message to a qualified ID ("id<foo>"), which is ok as
2734       // long as one of the protocols implements the selector (if not, warn).
2735       // And as long as message is not deprecated/unavailable (warn if it is).
2736       if (const ObjCObjectPointerType *QIdTy
2737                                    = ReceiverType->getAsObjCQualifiedIdType()) {
2738         // Search protocols for instance methods.
2739         Method = LookupMethodInQualifiedType(Sel, QIdTy, true);
2740         if (!Method)
2741           Method = LookupMethodInQualifiedType(Sel, QIdTy, false);
2742         if (Method && DiagnoseUseOfDecl(Method, SelLoc))
2743           return ExprError();
2744       } else if (const ObjCObjectPointerType *OCIType
2745                    = ReceiverType->getAsObjCInterfacePointerType()) {
2746         // We allow sending a message to a pointer to an interface (an object).
2747         ClassDecl = OCIType->getInterfaceDecl();
2748
2749         // Try to complete the type. Under ARC, this is a hard error from which
2750         // we don't try to recover.
2751         // FIXME: In the non-ARC case, this will still be a hard error if the
2752         // definition is found in a module that's not visible.
2753         const ObjCInterfaceDecl *forwardClass = nullptr;
2754         if (RequireCompleteType(Loc, OCIType->getPointeeType(),
2755               getLangOpts().ObjCAutoRefCount
2756                 ? diag::err_arc_receiver_forward_instance
2757                 : diag::warn_receiver_forward_instance,
2758                                 Receiver? Receiver->getSourceRange()
2759                                         : SourceRange(SuperLoc))) {
2760           if (getLangOpts().ObjCAutoRefCount)
2761             return ExprError();
2762
2763           forwardClass = OCIType->getInterfaceDecl();
2764           Diag(Receiver ? Receiver->getLocStart()
2765                         : SuperLoc, diag::note_receiver_is_id);
2766           Method = nullptr;
2767         } else {
2768           Method = ClassDecl->lookupInstanceMethod(Sel);
2769         }
2770
2771         if (!Method)
2772           // Search protocol qualifiers.
2773           Method = LookupMethodInQualifiedType(Sel, OCIType, true);
2774
2775         if (!Method) {
2776           // If we have implementations in scope, check "private" methods.
2777           Method = ClassDecl->lookupPrivateMethod(Sel);
2778
2779           if (!Method && getLangOpts().ObjCAutoRefCount) {
2780             Diag(SelLoc, diag::err_arc_may_not_respond)
2781               << OCIType->getPointeeType() << Sel << RecRange
2782               << SourceRange(SelectorLocs.front(), SelectorLocs.back());
2783             return ExprError();
2784           }
2785
2786           if (!Method && (!Receiver || !isSelfExpr(Receiver))) {
2787             // If we still haven't found a method, look in the global pool. This
2788             // behavior isn't very desirable, however we need it for GCC
2789             // compatibility. FIXME: should we deviate??
2790             if (OCIType->qual_empty()) {
2791               SmallVector<ObjCMethodDecl*, 4> Methods;
2792               CollectMultipleMethodsInGlobalPool(Sel, Methods,
2793                                                  true/*InstanceFirst*/,
2794                                                  false/*CheckTheOther*/);
2795               if (!Methods.empty()) {
2796                 // We choose the first method as the initial candidate, then try
2797                 // to select a better one.
2798                 Method = Methods[0];
2799
2800                 if (ObjCMethodDecl *BestMethod =
2801                     SelectBestMethod(Sel, ArgsIn, Method->isInstanceMethod(),
2802                                      Methods))
2803                   Method = BestMethod;
2804
2805                 AreMultipleMethodsInGlobalPool(Sel, Method,
2806                                                SourceRange(LBracLoc, RBracLoc),
2807                                                true/*receiverIdOrClass*/,
2808                                                Methods);
2809               }
2810               if (Method && !forwardClass)
2811                 Diag(SelLoc, diag::warn_maynot_respond)
2812                   << OCIType->getInterfaceDecl()->getIdentifier()
2813                   << Sel << RecRange;
2814             }
2815           }
2816         }
2817         if (Method && DiagnoseUseOfDecl(Method, SelLoc, forwardClass))
2818           return ExprError();
2819       } else {
2820         // Reject other random receiver types (e.g. structs).
2821         Diag(Loc, diag::err_bad_receiver_type)
2822           << ReceiverType << Receiver->getSourceRange();
2823         return ExprError();
2824       }
2825     }
2826   }
2827
2828   FunctionScopeInfo *DIFunctionScopeInfo =
2829     (Method && Method->getMethodFamily() == OMF_init)
2830       ? getEnclosingFunction() : nullptr;
2831
2832   if (DIFunctionScopeInfo &&
2833       DIFunctionScopeInfo->ObjCIsDesignatedInit &&
2834       (SuperLoc.isValid() || isSelfExpr(Receiver))) {
2835     bool isDesignatedInitChain = false;
2836     if (SuperLoc.isValid()) {
2837       if (const ObjCObjectPointerType *
2838             OCIType = ReceiverType->getAsObjCInterfacePointerType()) {
2839         if (const ObjCInterfaceDecl *ID = OCIType->getInterfaceDecl()) {
2840           // Either we know this is a designated initializer or we
2841           // conservatively assume it because we don't know for sure.
2842           if (!ID->declaresOrInheritsDesignatedInitializers() ||
2843               ID->isDesignatedInitializer(Sel)) {
2844             isDesignatedInitChain = true;
2845             DIFunctionScopeInfo->ObjCWarnForNoDesignatedInitChain = false;
2846           }
2847         }
2848       }
2849     }
2850     if (!isDesignatedInitChain) {
2851       const ObjCMethodDecl *InitMethod = nullptr;
2852       bool isDesignated =
2853         getCurMethodDecl()->isDesignatedInitializerForTheInterface(&InitMethod);
2854       assert(isDesignated && InitMethod);
2855       (void)isDesignated;
2856       Diag(SelLoc, SuperLoc.isValid() ?
2857              diag::warn_objc_designated_init_non_designated_init_call :
2858              diag::warn_objc_designated_init_non_super_designated_init_call);
2859       Diag(InitMethod->getLocation(),
2860            diag::note_objc_designated_init_marked_here);
2861     }
2862   }
2863
2864   if (DIFunctionScopeInfo &&
2865       DIFunctionScopeInfo->ObjCIsSecondaryInit &&
2866       (SuperLoc.isValid() || isSelfExpr(Receiver))) {
2867     if (SuperLoc.isValid()) {
2868       Diag(SelLoc, diag::warn_objc_secondary_init_super_init_call);
2869     } else {
2870       DIFunctionScopeInfo->ObjCWarnForNoInitDelegation = false;
2871     }
2872   }
2873
2874   // Check the message arguments.
2875   unsigned NumArgs = ArgsIn.size();
2876   Expr **Args = ArgsIn.data();
2877   QualType ReturnType;
2878   ExprValueKind VK = VK_RValue;
2879   bool ClassMessage = (ReceiverType->isObjCClassType() ||
2880                        ReceiverType->isObjCQualifiedClassType());
2881   if (CheckMessageArgumentTypes(ReceiverType, MultiExprArg(Args, NumArgs),
2882                                 Sel, SelectorLocs, Method,
2883                                 ClassMessage, SuperLoc.isValid(),
2884                                 LBracLoc, RBracLoc, RecRange, ReturnType, VK))
2885     return ExprError();
2886
2887   if (Method && !Method->getReturnType()->isVoidType() &&
2888       RequireCompleteType(LBracLoc, Method->getReturnType(),
2889                           diag::err_illegal_message_expr_incomplete_type))
2890     return ExprError();
2891
2892   // In ARC, forbid the user from sending messages to
2893   // retain/release/autorelease/dealloc/retainCount explicitly.
2894   if (getLangOpts().ObjCAutoRefCount) {
2895     ObjCMethodFamily family =
2896       (Method ? Method->getMethodFamily() : Sel.getMethodFamily());
2897     switch (family) {
2898     case OMF_init:
2899       if (Method)
2900         checkInitMethod(Method, ReceiverType);
2901
2902     case OMF_None:
2903     case OMF_alloc:
2904     case OMF_copy:
2905     case OMF_finalize:
2906     case OMF_mutableCopy:
2907     case OMF_new:
2908     case OMF_self:
2909     case OMF_initialize:
2910       break;
2911
2912     case OMF_dealloc:
2913     case OMF_retain:
2914     case OMF_release:
2915     case OMF_autorelease:
2916     case OMF_retainCount:
2917       Diag(SelLoc, diag::err_arc_illegal_explicit_message)
2918         << Sel << RecRange;
2919       break;
2920
2921     case OMF_performSelector:
2922       if (Method && NumArgs >= 1) {
2923         if (ObjCSelectorExpr *SelExp = dyn_cast<ObjCSelectorExpr>(Args[0])) {
2924           Selector ArgSel = SelExp->getSelector();
2925           ObjCMethodDecl *SelMethod =
2926             LookupInstanceMethodInGlobalPool(ArgSel,
2927                                              SelExp->getSourceRange());
2928           if (!SelMethod)
2929             SelMethod =
2930               LookupFactoryMethodInGlobalPool(ArgSel,
2931                                               SelExp->getSourceRange());
2932           if (SelMethod) {
2933             ObjCMethodFamily SelFamily = SelMethod->getMethodFamily();
2934             switch (SelFamily) {
2935               case OMF_alloc:
2936               case OMF_copy:
2937               case OMF_mutableCopy:
2938               case OMF_new:
2939               case OMF_self:
2940               case OMF_init:
2941                 // Issue error, unless ns_returns_not_retained.
2942                 if (!SelMethod->hasAttr<NSReturnsNotRetainedAttr>()) {
2943                   // selector names a +1 method
2944                   Diag(SelLoc,
2945                        diag::err_arc_perform_selector_retains);
2946                   Diag(SelMethod->getLocation(), diag::note_method_declared_at)
2947                     << SelMethod->getDeclName();
2948                 }
2949                 break;
2950               default:
2951                 // +0 call. OK. unless ns_returns_retained.
2952                 if (SelMethod->hasAttr<NSReturnsRetainedAttr>()) {
2953                   // selector names a +1 method
2954                   Diag(SelLoc,
2955                        diag::err_arc_perform_selector_retains);
2956                   Diag(SelMethod->getLocation(), diag::note_method_declared_at)
2957                     << SelMethod->getDeclName();
2958                 }
2959                 break;
2960             }
2961           }
2962         } else {
2963           // error (may leak).
2964           Diag(SelLoc, diag::warn_arc_perform_selector_leaks);
2965           Diag(Args[0]->getExprLoc(), diag::note_used_here);
2966         }
2967       }
2968       break;
2969     }
2970   }
2971
2972   DiagnoseCStringFormatDirectiveInObjCAPI(*this, Method, Sel, Args, NumArgs);
2973
2974   // Construct the appropriate ObjCMessageExpr instance.
2975   ObjCMessageExpr *Result;
2976   if (SuperLoc.isValid())
2977     Result = ObjCMessageExpr::Create(Context, ReturnType, VK, LBracLoc,
2978                                      SuperLoc,  /*IsInstanceSuper=*/true,
2979                                      ReceiverType, Sel, SelectorLocs, Method,
2980                                      makeArrayRef(Args, NumArgs), RBracLoc,
2981                                      isImplicit);
2982   else {
2983     Result = ObjCMessageExpr::Create(Context, ReturnType, VK, LBracLoc,
2984                                      Receiver, Sel, SelectorLocs, Method,
2985                                      makeArrayRef(Args, NumArgs), RBracLoc,
2986                                      isImplicit);
2987     if (!isImplicit)
2988       checkCocoaAPI(*this, Result);
2989   }
2990
2991   if (getLangOpts().ObjCAutoRefCount) {
2992     // In ARC, annotate delegate init calls.
2993     if (Result->getMethodFamily() == OMF_init &&
2994         (SuperLoc.isValid() || isSelfExpr(Receiver))) {
2995       // Only consider init calls *directly* in init implementations,
2996       // not within blocks.
2997       ObjCMethodDecl *method = dyn_cast<ObjCMethodDecl>(CurContext);
2998       if (method && method->getMethodFamily() == OMF_init) {
2999         // The implicit assignment to self means we also don't want to
3000         // consume the result.
3001         Result->setDelegateInitCall(true);
3002         return Result;
3003       }
3004     }
3005
3006     // In ARC, check for message sends which are likely to introduce
3007     // retain cycles.
3008     checkRetainCycles(Result);
3009
3010     if (!isImplicit && Method) {
3011       if (const ObjCPropertyDecl *Prop = Method->findPropertyDecl()) {
3012         bool IsWeak =
3013           Prop->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_weak;
3014         if (!IsWeak && Sel.isUnarySelector())
3015           IsWeak = ReturnType.getObjCLifetime() & Qualifiers::OCL_Weak;
3016         if (IsWeak &&
3017             !Diags.isIgnored(diag::warn_arc_repeated_use_of_weak, LBracLoc))
3018           getCurFunction()->recordUseOfWeak(Result, Prop);
3019       }
3020     }
3021   }
3022
3023   CheckObjCCircularContainer(Result);
3024
3025   return MaybeBindToTemporary(Result);
3026 }
3027
3028 static void RemoveSelectorFromWarningCache(Sema &S, Expr* Arg) {
3029   if (ObjCSelectorExpr *OSE =
3030       dyn_cast<ObjCSelectorExpr>(Arg->IgnoreParenCasts())) {
3031     Selector Sel = OSE->getSelector();
3032     SourceLocation Loc = OSE->getAtLoc();
3033     auto Pos = S.ReferencedSelectors.find(Sel);
3034     if (Pos != S.ReferencedSelectors.end() && Pos->second == Loc)
3035       S.ReferencedSelectors.erase(Pos);
3036   }
3037 }
3038
3039 // ActOnInstanceMessage - used for both unary and keyword messages.
3040 // ArgExprs is optional - if it is present, the number of expressions
3041 // is obtained from Sel.getNumArgs().
3042 ExprResult Sema::ActOnInstanceMessage(Scope *S,
3043                                       Expr *Receiver,
3044                                       Selector Sel,
3045                                       SourceLocation LBracLoc,
3046                                       ArrayRef<SourceLocation> SelectorLocs,
3047                                       SourceLocation RBracLoc,
3048                                       MultiExprArg Args) {
3049   if (!Receiver)
3050     return ExprError();
3051
3052   // A ParenListExpr can show up while doing error recovery with invalid code.
3053   if (isa<ParenListExpr>(Receiver)) {
3054     ExprResult Result = MaybeConvertParenListExprToParenExpr(S, Receiver);
3055     if (Result.isInvalid()) return ExprError();
3056     Receiver = Result.get();
3057   }
3058
3059   if (RespondsToSelectorSel.isNull()) {
3060     IdentifierInfo *SelectorId = &Context.Idents.get("respondsToSelector");
3061     RespondsToSelectorSel = Context.Selectors.getUnarySelector(SelectorId);
3062   }
3063   if (Sel == RespondsToSelectorSel)
3064     RemoveSelectorFromWarningCache(*this, Args[0]);
3065
3066   return BuildInstanceMessage(Receiver, Receiver->getType(),
3067                               /*SuperLoc=*/SourceLocation(), Sel,
3068                               /*Method=*/nullptr, LBracLoc, SelectorLocs,
3069                               RBracLoc, Args);
3070 }
3071
3072 enum ARCConversionTypeClass {
3073   /// int, void, struct A
3074   ACTC_none,
3075
3076   /// id, void (^)()
3077   ACTC_retainable,
3078
3079   /// id*, id***, void (^*)(),
3080   ACTC_indirectRetainable,
3081
3082   /// void* might be a normal C type, or it might a CF type.
3083   ACTC_voidPtr,
3084
3085   /// struct A*
3086   ACTC_coreFoundation
3087 };
3088
3089 static bool isAnyRetainable(ARCConversionTypeClass ACTC) {
3090   return (ACTC == ACTC_retainable ||
3091           ACTC == ACTC_coreFoundation ||
3092           ACTC == ACTC_voidPtr);
3093 }
3094
3095 static bool isAnyCLike(ARCConversionTypeClass ACTC) {
3096   return ACTC == ACTC_none ||
3097          ACTC == ACTC_voidPtr ||
3098          ACTC == ACTC_coreFoundation;
3099 }
3100
3101 static ARCConversionTypeClass classifyTypeForARCConversion(QualType type) {
3102   bool isIndirect = false;
3103
3104   // Ignore an outermost reference type.
3105   if (const ReferenceType *ref = type->getAs<ReferenceType>()) {
3106     type = ref->getPointeeType();
3107     isIndirect = true;
3108   }
3109
3110   // Drill through pointers and arrays recursively.
3111   while (true) {
3112     if (const PointerType *ptr = type->getAs<PointerType>()) {
3113       type = ptr->getPointeeType();
3114
3115       // The first level of pointer may be the innermost pointer on a CF type.
3116       if (!isIndirect) {
3117         if (type->isVoidType()) return ACTC_voidPtr;
3118         if (type->isRecordType()) return ACTC_coreFoundation;
3119       }
3120     } else if (const ArrayType *array = type->getAsArrayTypeUnsafe()) {
3121       type = QualType(array->getElementType()->getBaseElementTypeUnsafe(), 0);
3122     } else {
3123       break;
3124     }
3125     isIndirect = true;
3126   }
3127
3128   if (isIndirect) {
3129     if (type->isObjCARCBridgableType())
3130       return ACTC_indirectRetainable;
3131     return ACTC_none;
3132   }
3133
3134   if (type->isObjCARCBridgableType())
3135     return ACTC_retainable;
3136
3137   return ACTC_none;
3138 }
3139
3140 namespace {
3141   /// A result from the cast checker.
3142   enum ACCResult {
3143     /// Cannot be casted.
3144     ACC_invalid,
3145
3146     /// Can be safely retained or not retained.
3147     ACC_bottom,
3148
3149     /// Can be casted at +0.
3150     ACC_plusZero,
3151
3152     /// Can be casted at +1.
3153     ACC_plusOne
3154   };
3155   ACCResult merge(ACCResult left, ACCResult right) {
3156     if (left == right) return left;
3157     if (left == ACC_bottom) return right;
3158     if (right == ACC_bottom) return left;
3159     return ACC_invalid;
3160   }
3161
3162   /// A checker which white-lists certain expressions whose conversion
3163   /// to or from retainable type would otherwise be forbidden in ARC.
3164   class ARCCastChecker : public StmtVisitor<ARCCastChecker, ACCResult> {
3165     typedef StmtVisitor<ARCCastChecker, ACCResult> super;
3166
3167     ASTContext &Context;
3168     ARCConversionTypeClass SourceClass;
3169     ARCConversionTypeClass TargetClass;
3170     bool Diagnose;
3171
3172     static bool isCFType(QualType type) {
3173       // Someday this can use ns_bridged.  For now, it has to do this.
3174       return type->isCARCBridgableType();
3175     }
3176
3177   public:
3178     ARCCastChecker(ASTContext &Context, ARCConversionTypeClass source,
3179                    ARCConversionTypeClass target, bool diagnose)
3180       : Context(Context), SourceClass(source), TargetClass(target),
3181         Diagnose(diagnose) {}
3182
3183     using super::Visit;
3184     ACCResult Visit(Expr *e) {
3185       return super::Visit(e->IgnoreParens());
3186     }
3187
3188     ACCResult VisitStmt(Stmt *s) {
3189       return ACC_invalid;
3190     }
3191
3192     /// Null pointer constants can be casted however you please.
3193     ACCResult VisitExpr(Expr *e) {
3194       if (e->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNotNull))
3195         return ACC_bottom;
3196       return ACC_invalid;
3197     }
3198
3199     /// Objective-C string literals can be safely casted.
3200     ACCResult VisitObjCStringLiteral(ObjCStringLiteral *e) {
3201       // If we're casting to any retainable type, go ahead.  Global
3202       // strings are immune to retains, so this is bottom.
3203       if (isAnyRetainable(TargetClass)) return ACC_bottom;
3204
3205       return ACC_invalid;
3206     }
3207
3208     /// Look through certain implicit and explicit casts.
3209     ACCResult VisitCastExpr(CastExpr *e) {
3210       switch (e->getCastKind()) {
3211         case CK_NullToPointer:
3212           return ACC_bottom;
3213
3214         case CK_NoOp:
3215         case CK_LValueToRValue:
3216         case CK_BitCast:
3217         case CK_CPointerToObjCPointerCast:
3218         case CK_BlockPointerToObjCPointerCast:
3219         case CK_AnyPointerToBlockPointerCast:
3220           return Visit(e->getSubExpr());
3221
3222         default:
3223           return ACC_invalid;
3224       }
3225     }
3226
3227     /// Look through unary extension.
3228     ACCResult VisitUnaryExtension(UnaryOperator *e) {
3229       return Visit(e->getSubExpr());
3230     }
3231
3232     /// Ignore the LHS of a comma operator.
3233     ACCResult VisitBinComma(BinaryOperator *e) {
3234       return Visit(e->getRHS());
3235     }
3236
3237     /// Conditional operators are okay if both sides are okay.
3238     ACCResult VisitConditionalOperator(ConditionalOperator *e) {
3239       ACCResult left = Visit(e->getTrueExpr());
3240       if (left == ACC_invalid) return ACC_invalid;
3241       return merge(left, Visit(e->getFalseExpr()));
3242     }
3243
3244     /// Look through pseudo-objects.
3245     ACCResult VisitPseudoObjectExpr(PseudoObjectExpr *e) {
3246       // If we're getting here, we should always have a result.
3247       return Visit(e->getResultExpr());
3248     }
3249
3250     /// Statement expressions are okay if their result expression is okay.
3251     ACCResult VisitStmtExpr(StmtExpr *e) {
3252       return Visit(e->getSubStmt()->body_back());
3253     }
3254
3255     /// Some declaration references are okay.
3256     ACCResult VisitDeclRefExpr(DeclRefExpr *e) {
3257       VarDecl *var = dyn_cast<VarDecl>(e->getDecl());
3258       // References to global constants are okay.
3259       if (isAnyRetainable(TargetClass) &&
3260           isAnyRetainable(SourceClass) &&
3261           var &&
3262           var->getStorageClass() == SC_Extern &&
3263           var->getType().isConstQualified()) {
3264
3265         // In system headers, they can also be assumed to be immune to retains.
3266         // These are things like 'kCFStringTransformToLatin'.
3267         if (Context.getSourceManager().isInSystemHeader(var->getLocation()))
3268           return ACC_bottom;
3269
3270         return ACC_plusZero;
3271       }
3272
3273       // Nothing else.
3274       return ACC_invalid;
3275     }
3276
3277     /// Some calls are okay.
3278     ACCResult VisitCallExpr(CallExpr *e) {
3279       if (FunctionDecl *fn = e->getDirectCallee())
3280         if (ACCResult result = checkCallToFunction(fn))
3281           return result;
3282
3283       return super::VisitCallExpr(e);
3284     }
3285
3286     ACCResult checkCallToFunction(FunctionDecl *fn) {
3287       // Require a CF*Ref return type.
3288       if (!isCFType(fn->getReturnType()))
3289         return ACC_invalid;
3290
3291       if (!isAnyRetainable(TargetClass))
3292         return ACC_invalid;
3293
3294       // Honor an explicit 'not retained' attribute.
3295       if (fn->hasAttr<CFReturnsNotRetainedAttr>())
3296         return ACC_plusZero;
3297
3298       // Honor an explicit 'retained' attribute, except that for
3299       // now we're not going to permit implicit handling of +1 results,
3300       // because it's a bit frightening.
3301       if (fn->hasAttr<CFReturnsRetainedAttr>())
3302         return Diagnose ? ACC_plusOne
3303                         : ACC_invalid; // ACC_plusOne if we start accepting this
3304
3305       // Recognize this specific builtin function, which is used by CFSTR.
3306       unsigned builtinID = fn->getBuiltinID();
3307       if (builtinID == Builtin::BI__builtin___CFStringMakeConstantString)
3308         return ACC_bottom;
3309
3310       // Otherwise, don't do anything implicit with an unaudited function.
3311       if (!fn->hasAttr<CFAuditedTransferAttr>())
3312         return ACC_invalid;
3313
3314       // Otherwise, it's +0 unless it follows the create convention.
3315       if (ento::coreFoundation::followsCreateRule(fn))
3316         return Diagnose ? ACC_plusOne
3317                         : ACC_invalid; // ACC_plusOne if we start accepting this
3318
3319       return ACC_plusZero;
3320     }
3321
3322     ACCResult VisitObjCMessageExpr(ObjCMessageExpr *e) {
3323       return checkCallToMethod(e->getMethodDecl());
3324     }
3325
3326     ACCResult VisitObjCPropertyRefExpr(ObjCPropertyRefExpr *e) {
3327       ObjCMethodDecl *method;
3328       if (e->isExplicitProperty())
3329         method = e->getExplicitProperty()->getGetterMethodDecl();
3330       else
3331         method = e->getImplicitPropertyGetter();
3332       return checkCallToMethod(method);
3333     }
3334
3335     ACCResult checkCallToMethod(ObjCMethodDecl *method) {
3336       if (!method) return ACC_invalid;
3337
3338       // Check for message sends to functions returning CF types.  We
3339       // just obey the Cocoa conventions with these, even though the
3340       // return type is CF.
3341       if (!isAnyRetainable(TargetClass) || !isCFType(method->getReturnType()))
3342         return ACC_invalid;
3343
3344       // If the method is explicitly marked not-retained, it's +0.
3345       if (method->hasAttr<CFReturnsNotRetainedAttr>())
3346         return ACC_plusZero;
3347
3348       // If the method is explicitly marked as returning retained, or its
3349       // selector follows a +1 Cocoa convention, treat it as +1.
3350       if (method->hasAttr<CFReturnsRetainedAttr>())
3351         return ACC_plusOne;
3352
3353       switch (method->getSelector().getMethodFamily()) {
3354       case OMF_alloc:
3355       case OMF_copy:
3356       case OMF_mutableCopy:
3357       case OMF_new:
3358         return ACC_plusOne;
3359
3360       default:
3361         // Otherwise, treat it as +0.
3362         return ACC_plusZero;
3363       }
3364     }
3365   };
3366 } // end anonymous namespace
3367
3368 bool Sema::isKnownName(StringRef name) {
3369   if (name.empty())
3370     return false;
3371   LookupResult R(*this, &Context.Idents.get(name), SourceLocation(),
3372                  Sema::LookupOrdinaryName);
3373   return LookupName(R, TUScope, false);
3374 }
3375
3376 static void addFixitForObjCARCConversion(Sema &S,
3377                                          DiagnosticBuilder &DiagB,
3378                                          Sema::CheckedConversionKind CCK,
3379                                          SourceLocation afterLParen,
3380                                          QualType castType,
3381                                          Expr *castExpr,
3382                                          Expr *realCast,
3383                                          const char *bridgeKeyword,
3384                                          const char *CFBridgeName) {
3385   // We handle C-style and implicit casts here.
3386   switch (CCK) {
3387   case Sema::CCK_ImplicitConversion:
3388   case Sema::CCK_CStyleCast:
3389   case Sema::CCK_OtherCast:
3390     break;
3391   case Sema::CCK_FunctionalCast:
3392     return;
3393   }
3394
3395   if (CFBridgeName) {
3396     if (CCK == Sema::CCK_OtherCast) {
3397       if (const CXXNamedCastExpr *NCE = dyn_cast<CXXNamedCastExpr>(realCast)) {
3398         SourceRange range(NCE->getOperatorLoc(),
3399                           NCE->getAngleBrackets().getEnd());
3400         SmallString<32> BridgeCall;
3401
3402         SourceManager &SM = S.getSourceManager();
3403         char PrevChar = *SM.getCharacterData(range.getBegin().getLocWithOffset(-1));
3404         if (Lexer::isIdentifierBodyChar(PrevChar, S.getLangOpts()))
3405           BridgeCall += ' ';
3406
3407         BridgeCall += CFBridgeName;
3408         DiagB.AddFixItHint(FixItHint::CreateReplacement(range, BridgeCall));
3409       }
3410       return;
3411     }
3412     Expr *castedE = castExpr;
3413     if (CStyleCastExpr *CCE = dyn_cast<CStyleCastExpr>(castedE))
3414       castedE = CCE->getSubExpr();
3415     castedE = castedE->IgnoreImpCasts();
3416     SourceRange range = castedE->getSourceRange();
3417
3418     SmallString<32> BridgeCall;
3419
3420     SourceManager &SM = S.getSourceManager();
3421     char PrevChar = *SM.getCharacterData(range.getBegin().getLocWithOffset(-1));
3422     if (Lexer::isIdentifierBodyChar(PrevChar, S.getLangOpts()))
3423       BridgeCall += ' ';
3424
3425     BridgeCall += CFBridgeName;
3426
3427     if (isa<ParenExpr>(castedE)) {
3428       DiagB.AddFixItHint(FixItHint::CreateInsertion(range.getBegin(),
3429                          BridgeCall));
3430     } else {
3431       BridgeCall += '(';
3432       DiagB.AddFixItHint(FixItHint::CreateInsertion(range.getBegin(),
3433                                                     BridgeCall));
3434       DiagB.AddFixItHint(FixItHint::CreateInsertion(
3435                                        S.getLocForEndOfToken(range.getEnd()),
3436                                        ")"));
3437     }
3438     return;
3439   }
3440
3441   if (CCK == Sema::CCK_CStyleCast) {
3442     DiagB.AddFixItHint(FixItHint::CreateInsertion(afterLParen, bridgeKeyword));
3443   } else if (CCK == Sema::CCK_OtherCast) {
3444     if (const CXXNamedCastExpr *NCE = dyn_cast<CXXNamedCastExpr>(realCast)) {
3445       std::string castCode = "(";
3446       castCode += bridgeKeyword;
3447       castCode += castType.getAsString();
3448       castCode += ")";
3449       SourceRange Range(NCE->getOperatorLoc(),
3450                         NCE->getAngleBrackets().getEnd());
3451       DiagB.AddFixItHint(FixItHint::CreateReplacement(Range, castCode));
3452     }
3453   } else {
3454     std::string castCode = "(";
3455     castCode += bridgeKeyword;
3456     castCode += castType.getAsString();
3457     castCode += ")";
3458     Expr *castedE = castExpr->IgnoreImpCasts();
3459     SourceRange range = castedE->getSourceRange();
3460     if (isa<ParenExpr>(castedE)) {
3461       DiagB.AddFixItHint(FixItHint::CreateInsertion(range.getBegin(),
3462                          castCode));
3463     } else {
3464       castCode += "(";
3465       DiagB.AddFixItHint(FixItHint::CreateInsertion(range.getBegin(),
3466                                                     castCode));
3467       DiagB.AddFixItHint(FixItHint::CreateInsertion(
3468                                        S.getLocForEndOfToken(range.getEnd()),
3469                                        ")"));
3470     }
3471   }
3472 }
3473
3474 template <typename T>
3475 static inline T *getObjCBridgeAttr(const TypedefType *TD) {
3476   TypedefNameDecl *TDNDecl = TD->getDecl();
3477   QualType QT = TDNDecl->getUnderlyingType();
3478   if (QT->isPointerType()) {
3479     QT = QT->getPointeeType();
3480     if (const RecordType *RT = QT->getAs<RecordType>())
3481       if (RecordDecl *RD = RT->getDecl()->getMostRecentDecl())
3482         return RD->getAttr<T>();
3483   }
3484   return nullptr;
3485 }
3486
3487 static ObjCBridgeRelatedAttr *ObjCBridgeRelatedAttrFromType(QualType T,
3488                                                             TypedefNameDecl *&TDNDecl) {
3489   while (const TypedefType *TD = dyn_cast<TypedefType>(T.getTypePtr())) {
3490     TDNDecl = TD->getDecl();
3491     if (ObjCBridgeRelatedAttr *ObjCBAttr =
3492         getObjCBridgeAttr<ObjCBridgeRelatedAttr>(TD))
3493       return ObjCBAttr;
3494     T = TDNDecl->getUnderlyingType();
3495   }
3496   return nullptr;
3497 }
3498
3499 static void
3500 diagnoseObjCARCConversion(Sema &S, SourceRange castRange,
3501                           QualType castType, ARCConversionTypeClass castACTC,
3502                           Expr *castExpr, Expr *realCast,
3503                           ARCConversionTypeClass exprACTC,
3504                           Sema::CheckedConversionKind CCK) {
3505   SourceLocation loc =
3506     (castRange.isValid() ? castRange.getBegin() : castExpr->getExprLoc());
3507
3508   if (S.makeUnavailableInSystemHeader(loc,
3509                                  UnavailableAttr::IR_ARCForbiddenConversion))
3510     return;
3511
3512   QualType castExprType = castExpr->getType();
3513   // Defer emitting a diagnostic for bridge-related casts; that will be
3514   // handled by CheckObjCBridgeRelatedConversions.
3515   TypedefNameDecl *TDNDecl = nullptr;
3516   if ((castACTC == ACTC_coreFoundation &&  exprACTC == ACTC_retainable &&
3517        ObjCBridgeRelatedAttrFromType(castType, TDNDecl)) ||
3518       (exprACTC == ACTC_coreFoundation && castACTC == ACTC_retainable &&
3519        ObjCBridgeRelatedAttrFromType(castExprType, TDNDecl)))
3520     return;
3521
3522   unsigned srcKind = 0;
3523   switch (exprACTC) {
3524   case ACTC_none:
3525   case ACTC_coreFoundation:
3526   case ACTC_voidPtr:
3527     srcKind = (castExprType->isPointerType() ? 1 : 0);
3528     break;
3529   case ACTC_retainable:
3530     srcKind = (castExprType->isBlockPointerType() ? 2 : 3);
3531     break;
3532   case ACTC_indirectRetainable:
3533     srcKind = 4;
3534     break;
3535   }
3536
3537   // Check whether this could be fixed with a bridge cast.
3538   SourceLocation afterLParen = S.getLocForEndOfToken(castRange.getBegin());
3539   SourceLocation noteLoc = afterLParen.isValid() ? afterLParen : loc;
3540
3541   // Bridge from an ARC type to a CF type.
3542   if (castACTC == ACTC_retainable && isAnyRetainable(exprACTC)) {
3543
3544     S.Diag(loc, diag::err_arc_cast_requires_bridge)
3545       << unsigned(CCK == Sema::CCK_ImplicitConversion) // cast|implicit
3546       << 2 // of C pointer type
3547       << castExprType
3548       << unsigned(castType->isBlockPointerType()) // to ObjC|block type
3549       << castType
3550       << castRange
3551       << castExpr->getSourceRange();
3552     bool br = S.isKnownName("CFBridgingRelease");
3553     ACCResult CreateRule =
3554       ARCCastChecker(S.Context, exprACTC, castACTC, true).Visit(castExpr);
3555     assert(CreateRule != ACC_bottom && "This cast should already be accepted.");
3556     if (CreateRule != ACC_plusOne)
3557     {
3558       DiagnosticBuilder DiagB =
3559         (CCK != Sema::CCK_OtherCast) ? S.Diag(noteLoc, diag::note_arc_bridge)
3560                               : S.Diag(noteLoc, diag::note_arc_cstyle_bridge);
3561
3562       addFixitForObjCARCConversion(S, DiagB, CCK, afterLParen,
3563                                    castType, castExpr, realCast, "__bridge ",
3564                                    nullptr);
3565     }
3566     if (CreateRule != ACC_plusZero)
3567     {
3568       DiagnosticBuilder DiagB =
3569         (CCK == Sema::CCK_OtherCast && !br) ?
3570           S.Diag(noteLoc, diag::note_arc_cstyle_bridge_transfer) << castExprType :
3571           S.Diag(br ? castExpr->getExprLoc() : noteLoc,
3572                  diag::note_arc_bridge_transfer)
3573             << castExprType << br;
3574
3575       addFixitForObjCARCConversion(S, DiagB, CCK, afterLParen,
3576                                    castType, castExpr, realCast, "__bridge_transfer ",
3577                                    br ? "CFBridgingRelease" : nullptr);
3578     }
3579
3580     return;
3581   }
3582
3583   // Bridge from a CF type to an ARC type.
3584   if (exprACTC == ACTC_retainable && isAnyRetainable(castACTC)) {
3585     bool br = S.isKnownName("CFBridgingRetain");
3586     S.Diag(loc, diag::err_arc_cast_requires_bridge)
3587       << unsigned(CCK == Sema::CCK_ImplicitConversion) // cast|implicit
3588       << unsigned(castExprType->isBlockPointerType()) // of ObjC|block type
3589       << castExprType
3590       << 2 // to C pointer type
3591       << castType
3592       << castRange
3593       << castExpr->getSourceRange();
3594     ACCResult CreateRule =
3595       ARCCastChecker(S.Context, exprACTC, castACTC, true).Visit(castExpr);
3596     assert(CreateRule != ACC_bottom && "This cast should already be accepted.");
3597     if (CreateRule != ACC_plusOne)
3598     {
3599       DiagnosticBuilder DiagB =
3600       (CCK != Sema::CCK_OtherCast) ? S.Diag(noteLoc, diag::note_arc_bridge)
3601                                : S.Diag(noteLoc, diag::note_arc_cstyle_bridge);
3602       addFixitForObjCARCConversion(S, DiagB, CCK, afterLParen,
3603                                    castType, castExpr, realCast, "__bridge ",
3604                                    nullptr);
3605     }
3606     if (CreateRule != ACC_plusZero)
3607     {
3608       DiagnosticBuilder DiagB =
3609         (CCK == Sema::CCK_OtherCast && !br) ?
3610           S.Diag(noteLoc, diag::note_arc_cstyle_bridge_retained) << castType :
3611           S.Diag(br ? castExpr->getExprLoc() : noteLoc,
3612                  diag::note_arc_bridge_retained)
3613             << castType << br;
3614
3615       addFixitForObjCARCConversion(S, DiagB, CCK, afterLParen,
3616                                    castType, castExpr, realCast, "__bridge_retained ",
3617                                    br ? "CFBridgingRetain" : nullptr);
3618     }
3619
3620     return;
3621   }
3622
3623   S.Diag(loc, diag::err_arc_mismatched_cast)
3624     << (CCK != Sema::CCK_ImplicitConversion)
3625     << srcKind << castExprType << castType
3626     << castRange << castExpr->getSourceRange();
3627 }
3628
3629 template <typename TB>
3630 static bool CheckObjCBridgeNSCast(Sema &S, QualType castType, Expr *castExpr,
3631                                   bool &HadTheAttribute, bool warn) {
3632   QualType T = castExpr->getType();
3633   HadTheAttribute = false;
3634   while (const TypedefType *TD = dyn_cast<TypedefType>(T.getTypePtr())) {
3635     TypedefNameDecl *TDNDecl = TD->getDecl();
3636     if (TB *ObjCBAttr = getObjCBridgeAttr<TB>(TD)) {
3637       if (IdentifierInfo *Parm = ObjCBAttr->getBridgedType()) {
3638         HadTheAttribute = true;
3639         if (Parm->isStr("id"))
3640           return true;
3641
3642         NamedDecl *Target = nullptr;
3643         // Check for an existing type with this name.
3644         LookupResult R(S, DeclarationName(Parm), SourceLocation(),
3645                        Sema::LookupOrdinaryName);
3646         if (S.LookupName(R, S.TUScope)) {
3647           Target = R.getFoundDecl();
3648           if (Target && isa<ObjCInterfaceDecl>(Target)) {
3649             ObjCInterfaceDecl *ExprClass = cast<ObjCInterfaceDecl>(Target);
3650             if (const ObjCObjectPointerType *InterfacePointerType =
3651                   castType->getAsObjCInterfacePointerType()) {
3652               ObjCInterfaceDecl *CastClass
3653                 = InterfacePointerType->getObjectType()->getInterface();
3654               if ((CastClass == ExprClass) ||
3655                   (CastClass && CastClass->isSuperClassOf(ExprClass)))
3656                 return true;
3657               if (warn)
3658                 S.Diag(castExpr->getLocStart(), diag::warn_objc_invalid_bridge)
3659                   << T << Target->getName() << castType->getPointeeType();
3660               return false;
3661             } else if (castType->isObjCIdType() ||
3662                        (S.Context.ObjCObjectAdoptsQTypeProtocols(
3663                           castType, ExprClass)))
3664               // ok to cast to 'id'.
3665               // casting to id<p-list> is ok if bridge type adopts all of
3666               // p-list protocols.
3667               return true;
3668             else {
3669               if (warn) {
3670                 S.Diag(castExpr->getLocStart(), diag::warn_objc_invalid_bridge)
3671                   << T << Target->getName() << castType;
3672                 S.Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3673                 S.Diag(Target->getLocStart(), diag::note_declared_at);
3674               }
3675               return false;
3676            }
3677           }
3678         } else if (!castType->isObjCIdType()) {
3679           S.Diag(castExpr->getLocStart(), diag::err_objc_cf_bridged_not_interface)
3680             << castExpr->getType() << Parm;
3681           S.Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3682           if (Target)
3683             S.Diag(Target->getLocStart(), diag::note_declared_at);
3684         }
3685         return true;
3686       }
3687       return false;
3688     }
3689     T = TDNDecl->getUnderlyingType();
3690   }
3691   return true;
3692 }
3693
3694 template <typename TB>
3695 static bool CheckObjCBridgeCFCast(Sema &S, QualType castType, Expr *castExpr,
3696                                   bool &HadTheAttribute, bool warn) {
3697   QualType T = castType;
3698   HadTheAttribute = false;
3699   while (const TypedefType *TD = dyn_cast<TypedefType>(T.getTypePtr())) {
3700     TypedefNameDecl *TDNDecl = TD->getDecl();
3701     if (TB *ObjCBAttr = getObjCBridgeAttr<TB>(TD)) {
3702       if (IdentifierInfo *Parm = ObjCBAttr->getBridgedType()) {
3703         HadTheAttribute = true;
3704         if (Parm->isStr("id"))
3705           return true;
3706
3707         NamedDecl *Target = nullptr;
3708         // Check for an existing type with this name.
3709         LookupResult R(S, DeclarationName(Parm), SourceLocation(),
3710                        Sema::LookupOrdinaryName);
3711         if (S.LookupName(R, S.TUScope)) {
3712           Target = R.getFoundDecl();
3713           if (Target && isa<ObjCInterfaceDecl>(Target)) {
3714             ObjCInterfaceDecl *CastClass = cast<ObjCInterfaceDecl>(Target);
3715             if (const ObjCObjectPointerType *InterfacePointerType =
3716                   castExpr->getType()->getAsObjCInterfacePointerType()) {
3717               ObjCInterfaceDecl *ExprClass
3718                 = InterfacePointerType->getObjectType()->getInterface();
3719               if ((CastClass == ExprClass) ||
3720                   (ExprClass && CastClass->isSuperClassOf(ExprClass)))
3721                 return true;
3722               if (warn) {
3723                 S.Diag(castExpr->getLocStart(), diag::warn_objc_invalid_bridge_to_cf)
3724                   << castExpr->getType()->getPointeeType() << T;
3725                 S.Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3726               }
3727               return false;
3728             } else if (castExpr->getType()->isObjCIdType() ||
3729                        (S.Context.QIdProtocolsAdoptObjCObjectProtocols(
3730                           castExpr->getType(), CastClass)))
3731               // ok to cast an 'id' expression to a CFtype.
3732               // ok to cast an 'id<plist>' expression to CFtype provided plist
3733               // adopts all of CFtype's ObjetiveC's class plist.
3734               return true;
3735             else {
3736               if (warn) {
3737                 S.Diag(castExpr->getLocStart(), diag::warn_objc_invalid_bridge_to_cf)
3738                   << castExpr->getType() << castType;
3739                 S.Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3740                 S.Diag(Target->getLocStart(), diag::note_declared_at);
3741               }
3742               return false;
3743             }
3744           }
3745         }
3746         S.Diag(castExpr->getLocStart(), diag::err_objc_ns_bridged_invalid_cfobject)
3747         << castExpr->getType() << castType;
3748         S.Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3749         if (Target)
3750           S.Diag(Target->getLocStart(), diag::note_declared_at);
3751         return true;
3752       }
3753       return false;
3754     }
3755     T = TDNDecl->getUnderlyingType();
3756   }
3757   return true;
3758 }
3759
3760 void Sema::CheckTollFreeBridgeCast(QualType castType, Expr *castExpr) {
3761   if (!getLangOpts().ObjC1)
3762     return;
3763   // warn in presence of __bridge casting to or from a toll free bridge cast.
3764   ARCConversionTypeClass exprACTC = classifyTypeForARCConversion(castExpr->getType());
3765   ARCConversionTypeClass castACTC = classifyTypeForARCConversion(castType);
3766   if (castACTC == ACTC_retainable && exprACTC == ACTC_coreFoundation) {
3767     bool HasObjCBridgeAttr;
3768     bool ObjCBridgeAttrWillNotWarn =
3769       CheckObjCBridgeNSCast<ObjCBridgeAttr>(*this, castType, castExpr, HasObjCBridgeAttr,
3770                                             false);
3771     if (ObjCBridgeAttrWillNotWarn && HasObjCBridgeAttr)
3772       return;
3773     bool HasObjCBridgeMutableAttr;
3774     bool ObjCBridgeMutableAttrWillNotWarn =
3775       CheckObjCBridgeNSCast<ObjCBridgeMutableAttr>(*this, castType, castExpr,
3776                                                    HasObjCBridgeMutableAttr, false);
3777     if (ObjCBridgeMutableAttrWillNotWarn && HasObjCBridgeMutableAttr)
3778       return;
3779
3780     if (HasObjCBridgeAttr)
3781       CheckObjCBridgeNSCast<ObjCBridgeAttr>(*this, castType, castExpr, HasObjCBridgeAttr,
3782                                             true);
3783     else if (HasObjCBridgeMutableAttr)
3784       CheckObjCBridgeNSCast<ObjCBridgeMutableAttr>(*this, castType, castExpr,
3785                                                    HasObjCBridgeMutableAttr, true);
3786   }
3787   else if (castACTC == ACTC_coreFoundation && exprACTC == ACTC_retainable) {
3788     bool HasObjCBridgeAttr;
3789     bool ObjCBridgeAttrWillNotWarn =
3790       CheckObjCBridgeCFCast<ObjCBridgeAttr>(*this, castType, castExpr, HasObjCBridgeAttr,
3791                                             false);
3792     if (ObjCBridgeAttrWillNotWarn && HasObjCBridgeAttr)
3793       return;
3794     bool HasObjCBridgeMutableAttr;
3795     bool ObjCBridgeMutableAttrWillNotWarn =
3796       CheckObjCBridgeCFCast<ObjCBridgeMutableAttr>(*this, castType, castExpr,
3797                                                    HasObjCBridgeMutableAttr, false);
3798     if (ObjCBridgeMutableAttrWillNotWarn && HasObjCBridgeMutableAttr)
3799       return;
3800
3801     if (HasObjCBridgeAttr)
3802       CheckObjCBridgeCFCast<ObjCBridgeAttr>(*this, castType, castExpr, HasObjCBridgeAttr,
3803                                             true);
3804     else if (HasObjCBridgeMutableAttr)
3805       CheckObjCBridgeCFCast<ObjCBridgeMutableAttr>(*this, castType, castExpr,
3806                                                    HasObjCBridgeMutableAttr, true);
3807   }
3808 }
3809
3810 void Sema::CheckObjCBridgeRelatedCast(QualType castType, Expr *castExpr) {
3811   QualType SrcType = castExpr->getType();
3812   if (ObjCPropertyRefExpr *PRE = dyn_cast<ObjCPropertyRefExpr>(castExpr)) {
3813     if (PRE->isExplicitProperty()) {
3814       if (ObjCPropertyDecl *PDecl = PRE->getExplicitProperty())
3815         SrcType = PDecl->getType();
3816     }
3817     else if (PRE->isImplicitProperty()) {
3818       if (ObjCMethodDecl *Getter = PRE->getImplicitPropertyGetter())
3819         SrcType = Getter->getReturnType();
3820     }
3821   }
3822
3823   ARCConversionTypeClass srcExprACTC = classifyTypeForARCConversion(SrcType);
3824   ARCConversionTypeClass castExprACTC = classifyTypeForARCConversion(castType);
3825   if (srcExprACTC != ACTC_retainable || castExprACTC != ACTC_coreFoundation)
3826     return;
3827   CheckObjCBridgeRelatedConversions(castExpr->getLocStart(),
3828                                     castType, SrcType, castExpr);
3829 }
3830
3831 bool Sema::CheckTollFreeBridgeStaticCast(QualType castType, Expr *castExpr,
3832                                          CastKind &Kind) {
3833   if (!getLangOpts().ObjC1)
3834     return false;
3835   ARCConversionTypeClass exprACTC =
3836     classifyTypeForARCConversion(castExpr->getType());
3837   ARCConversionTypeClass castACTC = classifyTypeForARCConversion(castType);
3838   if ((castACTC == ACTC_retainable && exprACTC == ACTC_coreFoundation) ||
3839       (castACTC == ACTC_coreFoundation && exprACTC == ACTC_retainable)) {
3840     CheckTollFreeBridgeCast(castType, castExpr);
3841     Kind = (castACTC == ACTC_coreFoundation) ? CK_BitCast
3842                                              : CK_CPointerToObjCPointerCast;
3843     return true;
3844   }
3845   return false;
3846 }
3847
3848 bool Sema::checkObjCBridgeRelatedComponents(SourceLocation Loc,
3849                                             QualType DestType, QualType SrcType,
3850                                             ObjCInterfaceDecl *&RelatedClass,
3851                                             ObjCMethodDecl *&ClassMethod,
3852                                             ObjCMethodDecl *&InstanceMethod,
3853                                             TypedefNameDecl *&TDNDecl,
3854                                             bool CfToNs, bool Diagnose) {
3855   QualType T = CfToNs ? SrcType : DestType;
3856   ObjCBridgeRelatedAttr *ObjCBAttr = ObjCBridgeRelatedAttrFromType(T, TDNDecl);
3857   if (!ObjCBAttr)
3858     return false;
3859
3860   IdentifierInfo *RCId = ObjCBAttr->getRelatedClass();
3861   IdentifierInfo *CMId = ObjCBAttr->getClassMethod();
3862   IdentifierInfo *IMId = ObjCBAttr->getInstanceMethod();
3863   if (!RCId)
3864     return false;
3865   NamedDecl *Target = nullptr;
3866   // Check for an existing type with this name.
3867   LookupResult R(*this, DeclarationName(RCId), SourceLocation(),
3868                  Sema::LookupOrdinaryName);
3869   if (!LookupName(R, TUScope)) {
3870     if (Diagnose) {
3871       Diag(Loc, diag::err_objc_bridged_related_invalid_class) << RCId
3872             << SrcType << DestType;
3873       Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3874     }
3875     return false;
3876   }
3877   Target = R.getFoundDecl();
3878   if (Target && isa<ObjCInterfaceDecl>(Target))
3879     RelatedClass = cast<ObjCInterfaceDecl>(Target);
3880   else {
3881     if (Diagnose) {
3882       Diag(Loc, diag::err_objc_bridged_related_invalid_class_name) << RCId
3883             << SrcType << DestType;
3884       Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3885       if (Target)
3886         Diag(Target->getLocStart(), diag::note_declared_at);
3887     }
3888     return false;
3889   }
3890
3891   // Check for an existing class method with the given selector name.
3892   if (CfToNs && CMId) {
3893     Selector Sel = Context.Selectors.getUnarySelector(CMId);
3894     ClassMethod = RelatedClass->lookupMethod(Sel, false);
3895     if (!ClassMethod) {
3896       if (Diagnose) {
3897         Diag(Loc, diag::err_objc_bridged_related_known_method)
3898               << SrcType << DestType << Sel << false;
3899         Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3900       }
3901       return false;
3902     }
3903   }
3904
3905   // Check for an existing instance method with the given selector name.
3906   if (!CfToNs && IMId) {
3907     Selector Sel = Context.Selectors.getNullarySelector(IMId);
3908     InstanceMethod = RelatedClass->lookupMethod(Sel, true);
3909     if (!InstanceMethod) {
3910       if (Diagnose) {
3911         Diag(Loc, diag::err_objc_bridged_related_known_method)
3912               << SrcType << DestType << Sel << true;
3913         Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3914       }
3915       return false;
3916     }
3917   }
3918   return true;
3919 }
3920
3921 bool
3922 Sema::CheckObjCBridgeRelatedConversions(SourceLocation Loc,
3923                                         QualType DestType, QualType SrcType,
3924                                         Expr *&SrcExpr, bool Diagnose) {
3925   ARCConversionTypeClass rhsExprACTC = classifyTypeForARCConversion(SrcType);
3926   ARCConversionTypeClass lhsExprACTC = classifyTypeForARCConversion(DestType);
3927   bool CfToNs = (rhsExprACTC == ACTC_coreFoundation && lhsExprACTC == ACTC_retainable);
3928   bool NsToCf = (rhsExprACTC == ACTC_retainable && lhsExprACTC == ACTC_coreFoundation);
3929   if (!CfToNs && !NsToCf)
3930     return false;
3931
3932   ObjCInterfaceDecl *RelatedClass;
3933   ObjCMethodDecl *ClassMethod = nullptr;
3934   ObjCMethodDecl *InstanceMethod = nullptr;
3935   TypedefNameDecl *TDNDecl = nullptr;
3936   if (!checkObjCBridgeRelatedComponents(Loc, DestType, SrcType, RelatedClass,
3937                                         ClassMethod, InstanceMethod, TDNDecl,
3938                                         CfToNs, Diagnose))
3939     return false;
3940
3941   if (CfToNs) {
3942     // Implicit conversion from CF to ObjC object is needed.
3943     if (ClassMethod) {
3944       if (Diagnose) {
3945         std::string ExpressionString = "[";
3946         ExpressionString += RelatedClass->getNameAsString();
3947         ExpressionString += " ";
3948         ExpressionString += ClassMethod->getSelector().getAsString();
3949         SourceLocation SrcExprEndLoc = getLocForEndOfToken(SrcExpr->getLocEnd());
3950         // Provide a fixit: [RelatedClass ClassMethod SrcExpr]
3951         Diag(Loc, diag::err_objc_bridged_related_known_method)
3952           << SrcType << DestType << ClassMethod->getSelector() << false
3953           << FixItHint::CreateInsertion(SrcExpr->getLocStart(), ExpressionString)
3954           << FixItHint::CreateInsertion(SrcExprEndLoc, "]");
3955         Diag(RelatedClass->getLocStart(), diag::note_declared_at);
3956         Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3957
3958         QualType receiverType = Context.getObjCInterfaceType(RelatedClass);
3959         // Argument.
3960         Expr *args[] = { SrcExpr };
3961         ExprResult msg = BuildClassMessageImplicit(receiverType, false,
3962                                       ClassMethod->getLocation(),
3963                                       ClassMethod->getSelector(), ClassMethod,
3964                                       MultiExprArg(args, 1));
3965         SrcExpr = msg.get();
3966       }
3967       return true;
3968     }
3969   }
3970   else {
3971     // Implicit conversion from ObjC type to CF object is needed.
3972     if (InstanceMethod) {
3973       if (Diagnose) {
3974         std::string ExpressionString;
3975         SourceLocation SrcExprEndLoc =
3976             getLocForEndOfToken(SrcExpr->getLocEnd());
3977         if (InstanceMethod->isPropertyAccessor())
3978           if (const ObjCPropertyDecl *PDecl =
3979                   InstanceMethod->findPropertyDecl()) {
3980             // fixit: ObjectExpr.propertyname when it is  aproperty accessor.
3981             ExpressionString = ".";
3982             ExpressionString += PDecl->getNameAsString();
3983             Diag(Loc, diag::err_objc_bridged_related_known_method)
3984                 << SrcType << DestType << InstanceMethod->getSelector() << true
3985                 << FixItHint::CreateInsertion(SrcExprEndLoc, ExpressionString);
3986           }
3987         if (ExpressionString.empty()) {
3988           // Provide a fixit: [ObjectExpr InstanceMethod]
3989           ExpressionString = " ";
3990           ExpressionString += InstanceMethod->getSelector().getAsString();
3991           ExpressionString += "]";
3992
3993           Diag(Loc, diag::err_objc_bridged_related_known_method)
3994               << SrcType << DestType << InstanceMethod->getSelector() << true
3995               << FixItHint::CreateInsertion(SrcExpr->getLocStart(), "[")
3996               << FixItHint::CreateInsertion(SrcExprEndLoc, ExpressionString);
3997         }
3998         Diag(RelatedClass->getLocStart(), diag::note_declared_at);
3999         Diag(TDNDecl->getLocStart(), diag::note_declared_at);
4000
4001         ExprResult msg =
4002           BuildInstanceMessageImplicit(SrcExpr, SrcType,
4003                                        InstanceMethod->getLocation(),
4004                                        InstanceMethod->getSelector(),
4005                                        InstanceMethod, None);
4006         SrcExpr = msg.get();
4007       }
4008       return true;
4009     }
4010   }
4011   return false;
4012 }
4013
4014 Sema::ARCConversionResult
4015 Sema::CheckObjCARCConversion(SourceRange castRange, QualType castType,
4016                              Expr *&castExpr, CheckedConversionKind CCK,
4017                              bool Diagnose,
4018                              bool DiagnoseCFAudited,
4019                              BinaryOperatorKind Opc) {
4020   QualType castExprType = castExpr->getType();
4021
4022   // For the purposes of the classification, we assume reference types
4023   // will bind to temporaries.
4024   QualType effCastType = castType;
4025   if (const ReferenceType *ref = castType->getAs<ReferenceType>())
4026     effCastType = ref->getPointeeType();
4027
4028   ARCConversionTypeClass exprACTC = classifyTypeForARCConversion(castExprType);
4029   ARCConversionTypeClass castACTC = classifyTypeForARCConversion(effCastType);
4030   if (exprACTC == castACTC) {
4031     // Check for viability and report error if casting an rvalue to a
4032     // life-time qualifier.
4033     if (castACTC == ACTC_retainable &&
4034         (CCK == CCK_CStyleCast || CCK == CCK_OtherCast) &&
4035         castType != castExprType) {
4036       const Type *DT = castType.getTypePtr();
4037       QualType QDT = castType;
4038       // We desugar some types but not others. We ignore those
4039       // that cannot happen in a cast; i.e. auto, and those which
4040       // should not be de-sugared; i.e typedef.
4041       if (const ParenType *PT = dyn_cast<ParenType>(DT))
4042         QDT = PT->desugar();
4043       else if (const TypeOfType *TP = dyn_cast<TypeOfType>(DT))
4044         QDT = TP->desugar();
4045       else if (const AttributedType *AT = dyn_cast<AttributedType>(DT))
4046         QDT = AT->desugar();
4047       if (QDT != castType &&
4048           QDT.getObjCLifetime() !=  Qualifiers::OCL_None) {
4049         if (Diagnose) {
4050           SourceLocation loc = (castRange.isValid() ? castRange.getBegin()
4051                                                     : castExpr->getExprLoc());
4052           Diag(loc, diag::err_arc_nolifetime_behavior);
4053         }
4054         return ACR_error;
4055       }
4056     }
4057     return ACR_okay;
4058   }
4059
4060   if (isAnyCLike(exprACTC) && isAnyCLike(castACTC)) return ACR_okay;
4061
4062   // Allow all of these types to be cast to integer types (but not
4063   // vice-versa).
4064   if (castACTC == ACTC_none && castType->isIntegralType(Context))
4065     return ACR_okay;
4066
4067   // Allow casts between pointers to lifetime types (e.g., __strong id*)
4068   // and pointers to void (e.g., cv void *). Casting from void* to lifetime*
4069   // must be explicit.
4070   if (exprACTC == ACTC_indirectRetainable && castACTC == ACTC_voidPtr)
4071     return ACR_okay;
4072   if (castACTC == ACTC_indirectRetainable && exprACTC == ACTC_voidPtr &&
4073       CCK != CCK_ImplicitConversion)
4074     return ACR_okay;
4075
4076   switch (ARCCastChecker(Context, exprACTC, castACTC, false).Visit(castExpr)) {
4077   // For invalid casts, fall through.
4078   case ACC_invalid:
4079     break;
4080
4081   // Do nothing for both bottom and +0.
4082   case ACC_bottom:
4083   case ACC_plusZero:
4084     return ACR_okay;
4085
4086   // If the result is +1, consume it here.
4087   case ACC_plusOne:
4088     castExpr = ImplicitCastExpr::Create(Context, castExpr->getType(),
4089                                         CK_ARCConsumeObject, castExpr,
4090                                         nullptr, VK_RValue);
4091     Cleanup.setExprNeedsCleanups(true);
4092     return ACR_okay;
4093   }
4094
4095   // If this is a non-implicit cast from id or block type to a
4096   // CoreFoundation type, delay complaining in case the cast is used
4097   // in an acceptable context.
4098   if (exprACTC == ACTC_retainable && isAnyRetainable(castACTC) &&
4099       CCK != CCK_ImplicitConversion)
4100     return ACR_unbridged;
4101
4102   // Issue a diagnostic about a missing @-sign when implicit casting a cstring
4103   // to 'NSString *', instead of falling through to report a "bridge cast"
4104   // diagnostic.
4105   if (castACTC == ACTC_retainable && exprACTC == ACTC_none &&
4106       ConversionToObjCStringLiteralCheck(castType, castExpr, Diagnose))
4107     return ACR_error;
4108
4109   // Do not issue "bridge cast" diagnostic when implicit casting
4110   // a retainable object to a CF type parameter belonging to an audited
4111   // CF API function. Let caller issue a normal type mismatched diagnostic
4112   // instead.
4113   if ((!DiagnoseCFAudited || exprACTC != ACTC_retainable ||
4114        castACTC != ACTC_coreFoundation) &&
4115       !(exprACTC == ACTC_voidPtr && castACTC == ACTC_retainable &&
4116         (Opc == BO_NE || Opc == BO_EQ))) {
4117     if (Diagnose)
4118       diagnoseObjCARCConversion(*this, castRange, castType, castACTC, castExpr,
4119                                 castExpr, exprACTC, CCK);
4120     return ACR_error;
4121   }
4122   return ACR_okay;
4123 }
4124
4125 /// Given that we saw an expression with the ARCUnbridgedCastTy
4126 /// placeholder type, complain bitterly.
4127 void Sema::diagnoseARCUnbridgedCast(Expr *e) {
4128   // We expect the spurious ImplicitCastExpr to already have been stripped.
4129   assert(!e->hasPlaceholderType(BuiltinType::ARCUnbridgedCast));
4130   CastExpr *realCast = cast<CastExpr>(e->IgnoreParens());
4131
4132   SourceRange castRange;
4133   QualType castType;
4134   CheckedConversionKind CCK;
4135
4136   if (CStyleCastExpr *cast = dyn_cast<CStyleCastExpr>(realCast)) {
4137     castRange = SourceRange(cast->getLParenLoc(), cast->getRParenLoc());
4138     castType = cast->getTypeAsWritten();
4139     CCK = CCK_CStyleCast;
4140   } else if (ExplicitCastExpr *cast = dyn_cast<ExplicitCastExpr>(realCast)) {
4141     castRange = cast->getTypeInfoAsWritten()->getTypeLoc().getSourceRange();
4142     castType = cast->getTypeAsWritten();
4143     CCK = CCK_OtherCast;
4144   } else {
4145     castType = cast->getType();
4146     CCK = CCK_ImplicitConversion;
4147   }
4148
4149   ARCConversionTypeClass castACTC =
4150     classifyTypeForARCConversion(castType.getNonReferenceType());
4151
4152   Expr *castExpr = realCast->getSubExpr();
4153   assert(classifyTypeForARCConversion(castExpr->getType()) == ACTC_retainable);
4154
4155   diagnoseObjCARCConversion(*this, castRange, castType, castACTC,
4156                             castExpr, realCast, ACTC_retainable, CCK);
4157 }
4158
4159 /// stripARCUnbridgedCast - Given an expression of ARCUnbridgedCast
4160 /// type, remove the placeholder cast.
4161 Expr *Sema::stripARCUnbridgedCast(Expr *e) {
4162   assert(e->hasPlaceholderType(BuiltinType::ARCUnbridgedCast));
4163
4164   if (ParenExpr *pe = dyn_cast<ParenExpr>(e)) {
4165     Expr *sub = stripARCUnbridgedCast(pe->getSubExpr());
4166     return new (Context) ParenExpr(pe->getLParen(), pe->getRParen(), sub);
4167   } else if (UnaryOperator *uo = dyn_cast<UnaryOperator>(e)) {
4168     assert(uo->getOpcode() == UO_Extension);
4169     Expr *sub = stripARCUnbridgedCast(uo->getSubExpr());
4170     return new (Context) UnaryOperator(sub, UO_Extension, sub->getType(),
4171                                    sub->getValueKind(), sub->getObjectKind(),
4172                                        uo->getOperatorLoc());
4173   } else if (GenericSelectionExpr *gse = dyn_cast<GenericSelectionExpr>(e)) {
4174     assert(!gse->isResultDependent());
4175
4176     unsigned n = gse->getNumAssocs();
4177     SmallVector<Expr*, 4> subExprs(n);
4178     SmallVector<TypeSourceInfo*, 4> subTypes(n);
4179     for (unsigned i = 0; i != n; ++i) {
4180       subTypes[i] = gse->getAssocTypeSourceInfo(i);
4181       Expr *sub = gse->getAssocExpr(i);
4182       if (i == gse->getResultIndex())
4183         sub = stripARCUnbridgedCast(sub);
4184       subExprs[i] = sub;
4185     }
4186
4187     return new (Context) GenericSelectionExpr(Context, gse->getGenericLoc(),
4188                                               gse->getControllingExpr(),
4189                                               subTypes, subExprs,
4190                                               gse->getDefaultLoc(),
4191                                               gse->getRParenLoc(),
4192                                        gse->containsUnexpandedParameterPack(),
4193                                               gse->getResultIndex());
4194   } else {
4195     assert(isa<ImplicitCastExpr>(e) && "bad form of unbridged cast!");
4196     return cast<ImplicitCastExpr>(e)->getSubExpr();
4197   }
4198 }
4199
4200 bool Sema::CheckObjCARCUnavailableWeakConversion(QualType castType,
4201                                                  QualType exprType) {
4202   QualType canCastType =
4203     Context.getCanonicalType(castType).getUnqualifiedType();
4204   QualType canExprType =
4205     Context.getCanonicalType(exprType).getUnqualifiedType();
4206   if (isa<ObjCObjectPointerType>(canCastType) &&
4207       castType.getObjCLifetime() == Qualifiers::OCL_Weak &&
4208       canExprType->isObjCObjectPointerType()) {
4209     if (const ObjCObjectPointerType *ObjT =
4210         canExprType->getAs<ObjCObjectPointerType>())
4211       if (const ObjCInterfaceDecl *ObjI = ObjT->getInterfaceDecl())
4212         return !ObjI->isArcWeakrefUnavailable();
4213   }
4214   return true;
4215 }
4216
4217 /// Look for an ObjCReclaimReturnedObject cast and destroy it.
4218 static Expr *maybeUndoReclaimObject(Expr *e) {
4219   // For now, we just undo operands that are *immediately* reclaim
4220   // expressions, which prevents the vast majority of potential
4221   // problems here.  To catch them all, we'd need to rebuild arbitrary
4222   // value-propagating subexpressions --- we can't reliably rebuild
4223   // in-place because of expression sharing.
4224   if (ImplicitCastExpr *ice = dyn_cast<ImplicitCastExpr>(e))
4225     if (ice->getCastKind() == CK_ARCReclaimReturnedObject)
4226       return ice->getSubExpr();
4227
4228   return e;
4229 }
4230
4231 ExprResult Sema::BuildObjCBridgedCast(SourceLocation LParenLoc,
4232                                       ObjCBridgeCastKind Kind,
4233                                       SourceLocation BridgeKeywordLoc,
4234                                       TypeSourceInfo *TSInfo,
4235                                       Expr *SubExpr) {
4236   ExprResult SubResult = UsualUnaryConversions(SubExpr);
4237   if (SubResult.isInvalid()) return ExprError();
4238   SubExpr = SubResult.get();
4239
4240   QualType T = TSInfo->getType();
4241   QualType FromType = SubExpr->getType();
4242
4243   CastKind CK;
4244
4245   bool MustConsume = false;
4246   if (T->isDependentType() || SubExpr->isTypeDependent()) {
4247     // Okay: we'll build a dependent expression type.
4248     CK = CK_Dependent;
4249   } else if (T->isObjCARCBridgableType() && FromType->isCARCBridgableType()) {
4250     // Casting CF -> id
4251     CK = (T->isBlockPointerType() ? CK_AnyPointerToBlockPointerCast
4252                                   : CK_CPointerToObjCPointerCast);
4253     switch (Kind) {
4254     case OBC_Bridge:
4255       break;
4256
4257     case OBC_BridgeRetained: {
4258       bool br = isKnownName("CFBridgingRelease");
4259       Diag(BridgeKeywordLoc, diag::err_arc_bridge_cast_wrong_kind)
4260         << 2
4261         << FromType
4262         << (T->isBlockPointerType()? 1 : 0)
4263         << T
4264         << SubExpr->getSourceRange()
4265         << Kind;
4266       Diag(BridgeKeywordLoc, diag::note_arc_bridge)
4267         << FixItHint::CreateReplacement(BridgeKeywordLoc, "__bridge");
4268       Diag(BridgeKeywordLoc, diag::note_arc_bridge_transfer)
4269         << FromType << br
4270         << FixItHint::CreateReplacement(BridgeKeywordLoc,
4271                                         br ? "CFBridgingRelease "
4272                                            : "__bridge_transfer ");
4273
4274       Kind = OBC_Bridge;
4275       break;
4276     }
4277
4278     case OBC_BridgeTransfer:
4279       // We must consume the Objective-C object produced by the cast.
4280       MustConsume = true;
4281       break;
4282     }
4283   } else if (T->isCARCBridgableType() && FromType->isObjCARCBridgableType()) {
4284     // Okay: id -> CF
4285     CK = CK_BitCast;
4286     switch (Kind) {
4287     case OBC_Bridge:
4288       // Reclaiming a value that's going to be __bridge-casted to CF
4289       // is very dangerous, so we don't do it.
4290       SubExpr = maybeUndoReclaimObject(SubExpr);
4291       break;
4292
4293     case OBC_BridgeRetained:
4294       // Produce the object before casting it.
4295       SubExpr = ImplicitCastExpr::Create(Context, FromType,
4296                                          CK_ARCProduceObject,
4297                                          SubExpr, nullptr, VK_RValue);
4298       break;
4299
4300     case OBC_BridgeTransfer: {
4301       bool br = isKnownName("CFBridgingRetain");
4302       Diag(BridgeKeywordLoc, diag::err_arc_bridge_cast_wrong_kind)
4303         << (FromType->isBlockPointerType()? 1 : 0)
4304         << FromType
4305         << 2
4306         << T
4307         << SubExpr->getSourceRange()
4308         << Kind;
4309
4310       Diag(BridgeKeywordLoc, diag::note_arc_bridge)
4311         << FixItHint::CreateReplacement(BridgeKeywordLoc, "__bridge ");
4312       Diag(BridgeKeywordLoc, diag::note_arc_bridge_retained)
4313         << T << br
4314         << FixItHint::CreateReplacement(BridgeKeywordLoc,
4315                           br ? "CFBridgingRetain " : "__bridge_retained");
4316
4317       Kind = OBC_Bridge;
4318       break;
4319     }
4320     }
4321   } else {
4322     Diag(LParenLoc, diag::err_arc_bridge_cast_incompatible)
4323       << FromType << T << Kind
4324       << SubExpr->getSourceRange()
4325       << TSInfo->getTypeLoc().getSourceRange();
4326     return ExprError();
4327   }
4328
4329   Expr *Result = new (Context) ObjCBridgedCastExpr(LParenLoc, Kind, CK,
4330                                                    BridgeKeywordLoc,
4331                                                    TSInfo, SubExpr);
4332
4333   if (MustConsume) {
4334     Cleanup.setExprNeedsCleanups(true);
4335     Result = ImplicitCastExpr::Create(Context, T, CK_ARCConsumeObject, Result,
4336                                       nullptr, VK_RValue);
4337   }
4338
4339   return Result;
4340 }
4341
4342 ExprResult Sema::ActOnObjCBridgedCast(Scope *S,
4343                                       SourceLocation LParenLoc,
4344                                       ObjCBridgeCastKind Kind,
4345                                       SourceLocation BridgeKeywordLoc,
4346                                       ParsedType Type,
4347                                       SourceLocation RParenLoc,
4348                                       Expr *SubExpr) {
4349   TypeSourceInfo *TSInfo = nullptr;
4350   QualType T = GetTypeFromParser(Type, &TSInfo);
4351   if (Kind == OBC_Bridge)
4352     CheckTollFreeBridgeCast(T, SubExpr);
4353   if (!TSInfo)
4354     TSInfo = Context.getTrivialTypeSourceInfo(T, LParenLoc);
4355   return BuildObjCBridgedCast(LParenLoc, Kind, BridgeKeywordLoc, TSInfo,
4356                               SubExpr);
4357 }