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

   1 //===--- SemaExprObjC.cpp - Semantic Analysis for ObjC Expressions --------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 //  This file implements semantic analysis for Objective-C expressions.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "clang/Sema/SemaInternal.h"
  14 #include "clang/AST/ASTContext.h"
  15 #include "clang/AST/DeclObjC.h"
  16 #include "clang/AST/ExprObjC.h"
  17 #include "clang/AST/StmtVisitor.h"
  18 #include "clang/AST/TypeLoc.h"
  19 #include "clang/Analysis/DomainSpecific/CocoaConventions.h"
  20 #include "clang/Edit/Commit.h"
  21 #include "clang/Edit/Rewriters.h"
  22 #include "clang/Lex/Preprocessor.h"
  23 #include "clang/Sema/Initialization.h"
  24 #include "clang/Sema/Lookup.h"
  25 #include "clang/Sema/Scope.h"
  26 #include "clang/Sema/ScopeInfo.h"
  27 #include "llvm/ADT/SmallString.h"
  28 #include "llvm/Support/ConvertUTF.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->getBeginLoc(), 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->getBeginLoc(), diag::err_no_nsconstant_string_class)
 111           << NSIdent << 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 /// 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 /// 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 /// 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 /// 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 /// 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 /// 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 = InitializationKind::CreateCopy(
 403         Element->getBeginLoc(), SourceLocation());
 404     InitializationSequence Seq(S, Entity, Kind, Element);
 405     if (!Seq.Failed())
 406       return Seq.Perform(S, Entity, Kind, Element);
 407   }
 408
 409   Expr *OrigElement = Element;
 410
 411   // Perform lvalue-to-rvalue conversion.
 412   Result = S.DefaultLvalueConversion(Element);
 413   if (Result.isInvalid())
 414     return ExprError();
 415   Element = Result.get();
 416
 417   // Make sure that we have an Objective-C pointer type or block.
 418   if (!Element->getType()->isObjCObjectPointerType() &&
 419       !Element->getType()->isBlockPointerType()) {
 420     bool Recovered = false;
 421
 422     // If this is potentially an Objective-C numeric literal, add the '@'.
 423     if (isa<IntegerLiteral>(OrigElement) ||
 424         isa<CharacterLiteral>(OrigElement) ||
 425         isa<FloatingLiteral>(OrigElement) ||
 426         isa<ObjCBoolLiteralExpr>(OrigElement) ||
 427         isa<CXXBoolLiteralExpr>(OrigElement)) {
 428       if (S.NSAPIObj->getNSNumberFactoryMethodKind(OrigElement->getType())) {
 429         int Which = isa<CharacterLiteral>(OrigElement) ? 1
 430                   : (isa<CXXBoolLiteralExpr>(OrigElement) ||
 431                      isa<ObjCBoolLiteralExpr>(OrigElement)) ? 2
 432                   : 3;
 433
 434         S.Diag(OrigElement->getBeginLoc(), diag::err_box_literal_collection)
 435             << Which << OrigElement->getSourceRange()
 436             << FixItHint::CreateInsertion(OrigElement->getBeginLoc(), "@");
 437
 438         Result =
 439             S.BuildObjCNumericLiteral(OrigElement->getBeginLoc(), OrigElement);
 440         if (Result.isInvalid())
 441           return ExprError();
 442
 443         Element = Result.get();
 444         Recovered = true;
 445       }
 446     }
 447     // If this is potentially an Objective-C string literal, add the '@'.
 448     else if (StringLiteral *String = dyn_cast<StringLiteral>(OrigElement)) {
 449       if (String->isAscii()) {
 450         S.Diag(OrigElement->getBeginLoc(), diag::err_box_literal_collection)
 451             << 0 << OrigElement->getSourceRange()
 452             << FixItHint::CreateInsertion(OrigElement->getBeginLoc(), "@");
 453
 454         Result = S.BuildObjCStringLiteral(OrigElement->getBeginLoc(), String);
 455         if (Result.isInvalid())
 456           return ExprError();
 457
 458         Element = Result.get();
 459         Recovered = true;
 460       }
 461     }
 462
 463     if (!Recovered) {
 464       S.Diag(Element->getBeginLoc(), diag::err_invalid_collection_element)
 465           << Element->getType();
 466       return ExprError();
 467     }
 468   }
 469   if (ArrayLiteral)
 470     if (ObjCStringLiteral *getString =
 471           dyn_cast<ObjCStringLiteral>(OrigElement)) {
 472       if (StringLiteral *SL = getString->getString()) {
 473         unsigned numConcat = SL->getNumConcatenated();
 474         if (numConcat > 1) {
 475           // Only warn if the concatenated string doesn't come from a macro.
 476           bool hasMacro = false;
 477           for (unsigned i = 0; i < numConcat ; ++i)
 478             if (SL->getStrTokenLoc(i).isMacroID()) {
 479               hasMacro = true;
 480               break;
 481             }
 482           if (!hasMacro)
 483             S.Diag(Element->getBeginLoc(),
 484                    diag::warn_concatenated_nsarray_literal)
 485                 << Element->getType();
 486         }
 487       }
 488     }
 489
 490   // Make sure that the element has the type that the container factory
 491   // function expects.
 492   return S.PerformCopyInitialization(
 493       InitializedEntity::InitializeParameter(S.Context, T,
 494                                              /*Consumed=*/false),
 495       Element->getBeginLoc(), Element);
 496 }
 497
 498 ExprResult Sema::BuildObjCBoxedExpr(SourceRange SR, Expr *ValueExpr) {
 499   if (ValueExpr->isTypeDependent()) {
 500     ObjCBoxedExpr *BoxedExpr =
 501       new (Context) ObjCBoxedExpr(ValueExpr, Context.DependentTy, nullptr, SR);
 502     return BoxedExpr;
 503   }
 504   ObjCMethodDecl *BoxingMethod = nullptr;
 505   QualType BoxedType;
 506   // Convert the expression to an RValue, so we can check for pointer types...
 507   ExprResult RValue = DefaultFunctionArrayLvalueConversion(ValueExpr);
 508   if (RValue.isInvalid()) {
 509     return ExprError();
 510   }
 511   SourceLocation Loc = SR.getBegin();
 512   ValueExpr = RValue.get();
 513   QualType ValueType(ValueExpr->getType());
 514   if (const PointerType *PT = ValueType->getAs<PointerType>()) {
 515     QualType PointeeType = PT->getPointeeType();
 516     if (Context.hasSameUnqualifiedType(PointeeType, Context.CharTy)) {
 517
 518       if (!NSStringDecl) {
 519         NSStringDecl = LookupObjCInterfaceDeclForLiteral(*this, Loc,
 520                                                          Sema::LK_String);
 521         if (!NSStringDecl) {
 522           return ExprError();
 523         }
 524         QualType NSStringObject = Context.getObjCInterfaceType(NSStringDecl);
 525         NSStringPointer = Context.getObjCObjectPointerType(NSStringObject);
 526       }
 527
 528       // The boxed expression can be emitted as a compile time constant if it is
 529       // a string literal whose character encoding is compatible with UTF-8.
 530       if (auto *CE = dyn_cast<ImplicitCastExpr>(ValueExpr))
 531         if (CE->getCastKind() == CK_ArrayToPointerDecay)
 532           if (auto *SL =
 533                   dyn_cast<StringLiteral>(CE->getSubExpr()->IgnoreParens())) {
 534             assert((SL->isAscii() || SL->isUTF8()) &&
 535                    "unexpected character encoding");
 536             StringRef Str = SL->getString();
 537             const llvm::UTF8 *StrBegin = Str.bytes_begin();
 538             const llvm::UTF8 *StrEnd = Str.bytes_end();
 539             // Check that this is a valid UTF-8 string.
 540             if (llvm::isLegalUTF8String(&StrBegin, StrEnd)) {
 541               BoxedType = Context.getAttributedType(
 542                   AttributedType::getNullabilityAttrKind(
 543                       NullabilityKind::NonNull),
 544                   NSStringPointer, NSStringPointer);
 545               return new (Context) ObjCBoxedExpr(CE, BoxedType, nullptr, SR);
 546             }
 547
 548             Diag(SL->getBeginLoc(), diag::warn_objc_boxing_invalid_utf8_string)
 549                 << NSStringPointer << SL->getSourceRange();
 550           }
 551
 552       if (!StringWithUTF8StringMethod) {
 553         IdentifierInfo *II = &Context.Idents.get("stringWithUTF8String");
 554         Selector stringWithUTF8String = Context.Selectors.getUnarySelector(II);
 555
 556         // Look for the appropriate method within NSString.
 557         BoxingMethod = NSStringDecl->lookupClassMethod(stringWithUTF8String);
 558         if (!BoxingMethod && getLangOpts().DebuggerObjCLiteral) {
 559           // Debugger needs to work even if NSString hasn't been defined.
 560           TypeSourceInfo *ReturnTInfo = nullptr;
 561           ObjCMethodDecl *M = ObjCMethodDecl::Create(
 562               Context, SourceLocation(), SourceLocation(), stringWithUTF8String,
 563               NSStringPointer, ReturnTInfo, NSStringDecl,
 564               /*isInstance=*/false, /*isVariadic=*/false,
 565               /*isPropertyAccessor=*/false,
 566               /*isImplicitlyDeclared=*/true,
 567               /*isDefined=*/false, ObjCMethodDecl::Required,
 568               /*HasRelatedResultType=*/false);
 569           QualType ConstCharType = Context.CharTy.withConst();
 570           ParmVarDecl *value =
 571             ParmVarDecl::Create(Context, M,
 572                                 SourceLocation(), SourceLocation(),
 573                                 &Context.Idents.get("value"),
 574                                 Context.getPointerType(ConstCharType),
 575                                 /*TInfo=*/nullptr,
 576                                 SC_None, nullptr);
 577           M->setMethodParams(Context, value, None);
 578           BoxingMethod = M;
 579         }
 580
 581         if (!validateBoxingMethod(*this, Loc, NSStringDecl,
 582                                   stringWithUTF8String, BoxingMethod))
 583            return ExprError();
 584
 585         StringWithUTF8StringMethod = BoxingMethod;
 586       }
 587
 588       BoxingMethod = StringWithUTF8StringMethod;
 589       BoxedType = NSStringPointer;
 590       // Transfer the nullability from method's return type.
 591       Optional<NullabilityKind> Nullability =
 592           BoxingMethod->getReturnType()->getNullability(Context);
 593       if (Nullability)
 594         BoxedType = Context.getAttributedType(
 595             AttributedType::getNullabilityAttrKind(*Nullability), BoxedType,
 596             BoxedType);
 597     }
 598   } else if (ValueType->isBuiltinType()) {
 599     // The other types we support are numeric, char and BOOL/bool. We could also
 600     // provide limited support for structure types, such as NSRange, NSRect, and
 601     // NSSize. See NSValue (NSValueGeometryExtensions) in <Foundation/NSGeometry.h>
 602     // for more details.
 603
 604     // Check for a top-level character literal.
 605     if (const CharacterLiteral *Char =
 606         dyn_cast<CharacterLiteral>(ValueExpr->IgnoreParens())) {
 607       // In C, character literals have type 'int'. That's not the type we want
 608       // to use to determine the Objective-c literal kind.
 609       switch (Char->getKind()) {
 610       case CharacterLiteral::Ascii:
 611       case CharacterLiteral::UTF8:
 612         ValueType = Context.CharTy;
 613         break;
 614
 615       case CharacterLiteral::Wide:
 616         ValueType = Context.getWideCharType();
 617         break;
 618
 619       case CharacterLiteral::UTF16:
 620         ValueType = Context.Char16Ty;
 621         break;
 622
 623       case CharacterLiteral::UTF32:
 624         ValueType = Context.Char32Ty;
 625         break;
 626       }
 627     }
 628     // FIXME:  Do I need to do anything special with BoolTy expressions?
 629
 630     // Look for the appropriate method within NSNumber.
 631     BoxingMethod = getNSNumberFactoryMethod(*this, Loc, ValueType);
 632     BoxedType = NSNumberPointer;
 633   } else if (const EnumType *ET = ValueType->getAs<EnumType>()) {
 634     if (!ET->getDecl()->isComplete()) {
 635       Diag(Loc, diag::err_objc_incomplete_boxed_expression_type)
 636         << ValueType << ValueExpr->getSourceRange();
 637       return ExprError();
 638     }
 639
 640     BoxingMethod = getNSNumberFactoryMethod(*this, Loc,
 641                                             ET->getDecl()->getIntegerType());
 642     BoxedType = NSNumberPointer;
 643   } else if (ValueType->isObjCBoxableRecordType()) {
 644     // Support for structure types, that marked as objc_boxable
 645     // struct __attribute__((objc_boxable)) s { ... };
 646
 647     // Look up the NSValue class, if we haven't done so already. It's cached
 648     // in the Sema instance.
 649     if (!NSValueDecl) {
 650       NSValueDecl = LookupObjCInterfaceDeclForLiteral(*this, Loc,
 651                                                       Sema::LK_Boxed);
 652       if (!NSValueDecl) {
 653         return ExprError();
 654       }
 655
 656       // generate the pointer to NSValue type.
 657       QualType NSValueObject = Context.getObjCInterfaceType(NSValueDecl);
 658       NSValuePointer = Context.getObjCObjectPointerType(NSValueObject);
 659     }
 660
 661     if (!ValueWithBytesObjCTypeMethod) {
 662       IdentifierInfo *II[] = {
 663         &Context.Idents.get("valueWithBytes"),
 664         &Context.Idents.get("objCType")
 665       };
 666       Selector ValueWithBytesObjCType = Context.Selectors.getSelector(2, II);
 667
 668       // Look for the appropriate method within NSValue.
 669       BoxingMethod = NSValueDecl->lookupClassMethod(ValueWithBytesObjCType);
 670       if (!BoxingMethod && getLangOpts().DebuggerObjCLiteral) {
 671         // Debugger needs to work even if NSValue hasn't been defined.
 672         TypeSourceInfo *ReturnTInfo = nullptr;
 673         ObjCMethodDecl *M = ObjCMethodDecl::Create(
 674                                                Context,
 675                                                SourceLocation(),
 676                                                SourceLocation(),
 677                                                ValueWithBytesObjCType,
 678                                                NSValuePointer,
 679                                                ReturnTInfo,
 680                                                NSValueDecl,
 681                                                /*isInstance=*/false,
 682                                                /*isVariadic=*/false,
 683                                                /*isPropertyAccessor=*/false,
 684                                                /*isImplicitlyDeclared=*/true,
 685                                                /*isDefined=*/false,
 686                                                ObjCMethodDecl::Required,
 687                                                /*HasRelatedResultType=*/false);
 688
 689         SmallVector<ParmVarDecl *, 2> Params;
 690
 691         ParmVarDecl *bytes =
 692         ParmVarDecl::Create(Context, M,
 693                             SourceLocation(), SourceLocation(),
 694                             &Context.Idents.get("bytes"),
 695                             Context.VoidPtrTy.withConst(),
 696                             /*TInfo=*/nullptr,
 697                             SC_None, nullptr);
 698         Params.push_back(bytes);
 699
 700         QualType ConstCharType = Context.CharTy.withConst();
 701         ParmVarDecl *type =
 702         ParmVarDecl::Create(Context, M,
 703                             SourceLocation(), SourceLocation(),
 704                             &Context.Idents.get("type"),
 705                             Context.getPointerType(ConstCharType),
 706                             /*TInfo=*/nullptr,
 707                             SC_None, nullptr);
 708         Params.push_back(type);
 709
 710         M->setMethodParams(Context, Params, None);
 711         BoxingMethod = M;
 712       }
 713
 714       if (!validateBoxingMethod(*this, Loc, NSValueDecl,
 715                                 ValueWithBytesObjCType, BoxingMethod))
 716         return ExprError();
 717
 718       ValueWithBytesObjCTypeMethod = BoxingMethod;
 719     }
 720
 721     if (!ValueType.isTriviallyCopyableType(Context)) {
 722       Diag(Loc, diag::err_objc_non_trivially_copyable_boxed_expression_type)
 723         << ValueType << ValueExpr->getSourceRange();
 724       return ExprError();
 725     }
 726
 727     BoxingMethod = ValueWithBytesObjCTypeMethod;
 728     BoxedType = NSValuePointer;
 729   }
 730
 731   if (!BoxingMethod) {
 732     Diag(Loc, diag::err_objc_illegal_boxed_expression_type)
 733       << ValueType << ValueExpr->getSourceRange();
 734     return ExprError();
 735   }
 736
 737   DiagnoseUseOfDecl(BoxingMethod, Loc);
 738
 739   ExprResult ConvertedValueExpr;
 740   if (ValueType->isObjCBoxableRecordType()) {
 741     InitializedEntity IE = InitializedEntity::InitializeTemporary(ValueType);
 742     ConvertedValueExpr = PerformCopyInitialization(IE, ValueExpr->getExprLoc(),
 743                                                    ValueExpr);
 744   } else {
 745     // Convert the expression to the type that the parameter requires.
 746     ParmVarDecl *ParamDecl = BoxingMethod->parameters()[0];
 747     InitializedEntity IE = InitializedEntity::InitializeParameter(Context,
 748                                                                   ParamDecl);
 749     ConvertedValueExpr = PerformCopyInitialization(IE, SourceLocation(),
 750                                                    ValueExpr);
 751   }
 752
 753   if (ConvertedValueExpr.isInvalid())
 754     return ExprError();
 755   ValueExpr = ConvertedValueExpr.get();
 756
 757   ObjCBoxedExpr *BoxedExpr =
 758     new (Context) ObjCBoxedExpr(ValueExpr, BoxedType,
 759                                       BoxingMethod, SR);
 760   return MaybeBindToTemporary(BoxedExpr);
 761 }
 762
 763 /// Build an ObjC subscript pseudo-object expression, given that
 764 /// that's supported by the runtime.
 765 ExprResult Sema::BuildObjCSubscriptExpression(SourceLocation RB, Expr *BaseExpr,
 766                                         Expr *IndexExpr,
 767                                         ObjCMethodDecl *getterMethod,
 768                                         ObjCMethodDecl *setterMethod) {
 769   assert(!LangOpts.isSubscriptPointerArithmetic());
 770
 771   // We can't get dependent types here; our callers should have
 772   // filtered them out.
 773   assert((!BaseExpr->isTypeDependent() && !IndexExpr->isTypeDependent()) &&
 774          "base or index cannot have dependent type here");
 775
 776   // Filter out placeholders in the index.  In theory, overloads could
 777   // be preserved here, although that might not actually work correctly.
 778   ExprResult Result = CheckPlaceholderExpr(IndexExpr);
 779   if (Result.isInvalid())
 780     return ExprError();
 781   IndexExpr = Result.get();
 782
 783   // Perform lvalue-to-rvalue conversion on the base.
 784   Result = DefaultLvalueConversion(BaseExpr);
 785   if (Result.isInvalid())
 786     return ExprError();
 787   BaseExpr = Result.get();
 788
 789   // Build the pseudo-object expression.
 790   return new (Context) ObjCSubscriptRefExpr(
 791       BaseExpr, IndexExpr, Context.PseudoObjectTy, VK_LValue, OK_ObjCSubscript,
 792       getterMethod, setterMethod, RB);
 793 }
 794
 795 ExprResult Sema::BuildObjCArrayLiteral(SourceRange SR, MultiExprArg Elements) {
 796   SourceLocation Loc = SR.getBegin();
 797
 798   if (!NSArrayDecl) {
 799     NSArrayDecl = LookupObjCInterfaceDeclForLiteral(*this, Loc,
 800                                                     Sema::LK_Array);
 801     if (!NSArrayDecl) {
 802       return ExprError();
 803     }
 804   }
 805
 806   // Find the arrayWithObjects:count: method, if we haven't done so already.
 807   QualType IdT = Context.getObjCIdType();
 808   if (!ArrayWithObjectsMethod) {
 809     Selector
 810       Sel = NSAPIObj->getNSArraySelector(NSAPI::NSArr_arrayWithObjectsCount);
 811     ObjCMethodDecl *Method = NSArrayDecl->lookupClassMethod(Sel);
 812     if (!Method && getLangOpts().DebuggerObjCLiteral) {
 813       TypeSourceInfo *ReturnTInfo = nullptr;
 814       Method = ObjCMethodDecl::Create(
 815           Context, SourceLocation(), SourceLocation(), Sel, IdT, ReturnTInfo,
 816           Context.getTranslationUnitDecl(), false /*Instance*/,
 817           false /*isVariadic*/,
 818           /*isPropertyAccessor=*/false,
 819           /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
 820           ObjCMethodDecl::Required, false);
 821       SmallVector<ParmVarDecl *, 2> Params;
 822       ParmVarDecl *objects = ParmVarDecl::Create(Context, Method,
 823                                                  SourceLocation(),
 824                                                  SourceLocation(),
 825                                                  &Context.Idents.get("objects"),
 826                                                  Context.getPointerType(IdT),
 827                                                  /*TInfo=*/nullptr,
 828                                                  SC_None, nullptr);
 829       Params.push_back(objects);
 830       ParmVarDecl *cnt = ParmVarDecl::Create(Context, Method,
 831                                              SourceLocation(),
 832                                              SourceLocation(),
 833                                              &Context.Idents.get("cnt"),
 834                                              Context.UnsignedLongTy,
 835                                              /*TInfo=*/nullptr, SC_None,
 836                                              nullptr);
 837       Params.push_back(cnt);
 838       Method->setMethodParams(Context, Params, None);
 839     }
 840
 841     if (!validateBoxingMethod(*this, Loc, NSArrayDecl, Sel, Method))
 842       return ExprError();
 843
 844     // Dig out the type that all elements should be converted to.
 845     QualType T = Method->parameters()[0]->getType();
 846     const PointerType *PtrT = T->getAs<PointerType>();
 847     if (!PtrT ||
 848         !Context.hasSameUnqualifiedType(PtrT->getPointeeType(), IdT)) {
 849       Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
 850         << Sel;
 851       Diag(Method->parameters()[0]->getLocation(),
 852            diag::note_objc_literal_method_param)
 853         << 0 << T
 854         << Context.getPointerType(IdT.withConst());
 855       return ExprError();
 856     }
 857
 858     // Check that the 'count' parameter is integral.
 859     if (!Method->parameters()[1]->getType()->isIntegerType()) {
 860       Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
 861         << Sel;
 862       Diag(Method->parameters()[1]->getLocation(),
 863            diag::note_objc_literal_method_param)
 864         << 1
 865         << Method->parameters()[1]->getType()
 866         << "integral";
 867       return ExprError();
 868     }
 869
 870     // We've found a good +arrayWithObjects:count: method. Save it!
 871     ArrayWithObjectsMethod = Method;
 872   }
 873
 874   QualType ObjectsType = ArrayWithObjectsMethod->parameters()[0]->getType();
 875   QualType RequiredType = ObjectsType->castAs<PointerType>()->getPointeeType();
 876
 877   // Check that each of the elements provided is valid in a collection literal,
 878   // performing conversions as necessary.
 879   Expr **ElementsBuffer = Elements.data();
 880   for (unsigned I = 0, N = Elements.size(); I != N; ++I) {
 881     ExprResult Converted = CheckObjCCollectionLiteralElement(*this,
 882                                                              ElementsBuffer[I],
 883                                                              RequiredType, true);
 884     if (Converted.isInvalid())
 885       return ExprError();
 886
 887     ElementsBuffer[I] = Converted.get();
 888   }
 889
 890   QualType Ty
 891     = Context.getObjCObjectPointerType(
 892                                     Context.getObjCInterfaceType(NSArrayDecl));
 893
 894   return MaybeBindToTemporary(
 895            ObjCArrayLiteral::Create(Context, Elements, Ty,
 896                                     ArrayWithObjectsMethod, SR));
 897 }
 898
 899 ExprResult Sema::BuildObjCDictionaryLiteral(SourceRange SR,
 900                               MutableArrayRef<ObjCDictionaryElement> Elements) {
 901   SourceLocation Loc = SR.getBegin();
 902
 903   if (!NSDictionaryDecl) {
 904     NSDictionaryDecl = LookupObjCInterfaceDeclForLiteral(*this, Loc,
 905                                                          Sema::LK_Dictionary);
 906     if (!NSDictionaryDecl) {
 907       return ExprError();
 908     }
 909   }
 910
 911   // Find the dictionaryWithObjects:forKeys:count: method, if we haven't done
 912   // so already.
 913   QualType IdT = Context.getObjCIdType();
 914   if (!DictionaryWithObjectsMethod) {
 915     Selector Sel = NSAPIObj->getNSDictionarySelector(
 916                                NSAPI::NSDict_dictionaryWithObjectsForKeysCount);
 917     ObjCMethodDecl *Method = NSDictionaryDecl->lookupClassMethod(Sel);
 918     if (!Method && getLangOpts().DebuggerObjCLiteral) {
 919       Method = ObjCMethodDecl::Create(Context,
 920                            SourceLocation(), SourceLocation(), Sel,
 921                            IdT,
 922                            nullptr /*TypeSourceInfo */,
 923                            Context.getTranslationUnitDecl(),
 924                            false /*Instance*/, false/*isVariadic*/,
 925                            /*isPropertyAccessor=*/false,
 926                            /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
 927                            ObjCMethodDecl::Required,
 928                            false);
 929       SmallVector<ParmVarDecl *, 3> Params;
 930       ParmVarDecl *objects = ParmVarDecl::Create(Context, Method,
 931                                                  SourceLocation(),
 932                                                  SourceLocation(),
 933                                                  &Context.Idents.get("objects"),
 934                                                  Context.getPointerType(IdT),
 935                                                  /*TInfo=*/nullptr, SC_None,
 936                                                  nullptr);
 937       Params.push_back(objects);
 938       ParmVarDecl *keys = ParmVarDecl::Create(Context, Method,
 939                                               SourceLocation(),
 940                                               SourceLocation(),
 941                                               &Context.Idents.get("keys"),
 942                                               Context.getPointerType(IdT),
 943                                               /*TInfo=*/nullptr, SC_None,
 944                                               nullptr);
 945       Params.push_back(keys);
 946       ParmVarDecl *cnt = ParmVarDecl::Create(Context, Method,
 947                                              SourceLocation(),
 948                                              SourceLocation(),
 949                                              &Context.Idents.get("cnt"),
 950                                              Context.UnsignedLongTy,
 951                                              /*TInfo=*/nullptr, SC_None,
 952                                              nullptr);
 953       Params.push_back(cnt);
 954       Method->setMethodParams(Context, Params, None);
 955     }
 956
 957     if (!validateBoxingMethod(*this, SR.getBegin(), NSDictionaryDecl, Sel,
 958                               Method))
 959        return ExprError();
 960
 961     // Dig out the type that all values should be converted to.
 962     QualType ValueT = Method->parameters()[0]->getType();
 963     const PointerType *PtrValue = ValueT->getAs<PointerType>();
 964     if (!PtrValue ||
 965         !Context.hasSameUnqualifiedType(PtrValue->getPointeeType(), IdT)) {
 966       Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
 967         << Sel;
 968       Diag(Method->parameters()[0]->getLocation(),
 969            diag::note_objc_literal_method_param)
 970         << 0 << ValueT
 971         << Context.getPointerType(IdT.withConst());
 972       return ExprError();
 973     }
 974
 975     // Dig out the type that all keys should be converted to.
 976     QualType KeyT = Method->parameters()[1]->getType();
 977     const PointerType *PtrKey = KeyT->getAs<PointerType>();
 978     if (!PtrKey ||
 979         !Context.hasSameUnqualifiedType(PtrKey->getPointeeType(),
 980                                         IdT)) {
 981       bool err = true;
 982       if (PtrKey) {
 983         if (QIDNSCopying.isNull()) {
 984           // key argument of selector is id<NSCopying>?
 985           if (ObjCProtocolDecl *NSCopyingPDecl =
 986               LookupProtocol(&Context.Idents.get("NSCopying"), SR.getBegin())) {
 987             ObjCProtocolDecl *PQ[] = {NSCopyingPDecl};
 988             QIDNSCopying =
 989               Context.getObjCObjectType(Context.ObjCBuiltinIdTy, { },
 990                                         llvm::makeArrayRef(
 991                                           (ObjCProtocolDecl**) PQ,
 992                                           1),
 993                                         false);
 994             QIDNSCopying = Context.getObjCObjectPointerType(QIDNSCopying);
 995           }
 996         }
 997         if (!QIDNSCopying.isNull())
 998           err = !Context.hasSameUnqualifiedType(PtrKey->getPointeeType(),
 999                                                 QIDNSCopying);
1000       }
1001
1002       if (err) {
1003         Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
1004           << Sel;
1005         Diag(Method->parameters()[1]->getLocation(),
1006              diag::note_objc_literal_method_param)
1007           << 1 << KeyT
1008           << Context.getPointerType(IdT.withConst());
1009         return ExprError();
1010       }
1011     }
1012
1013     // Check that the 'count' parameter is integral.
1014     QualType CountType = Method->parameters()[2]->getType();
1015     if (!CountType->isIntegerType()) {
1016       Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
1017         << Sel;
1018       Diag(Method->parameters()[2]->getLocation(),
1019            diag::note_objc_literal_method_param)
1020         << 2 << CountType
1021         << "integral";
1022       return ExprError();
1023     }
1024
1025     // We've found a good +dictionaryWithObjects:keys:count: method; save it!
1026     DictionaryWithObjectsMethod = Method;
1027   }
1028
1029   QualType ValuesT = DictionaryWithObjectsMethod->parameters()[0]->getType();
1030   QualType ValueT = ValuesT->castAs<PointerType>()->getPointeeType();
1031   QualType KeysT = DictionaryWithObjectsMethod->parameters()[1]->getType();
1032   QualType KeyT = KeysT->castAs<PointerType>()->getPointeeType();
1033
1034   // Check that each of the keys and values provided is valid in a collection
1035   // literal, performing conversions as necessary.
1036   bool HasPackExpansions = false;
1037   for (ObjCDictionaryElement &Element : Elements) {
1038     // Check the key.
1039     ExprResult Key = CheckObjCCollectionLiteralElement(*this, Element.Key,
1040                                                        KeyT);
1041     if (Key.isInvalid())
1042       return ExprError();
1043
1044     // Check the value.
1045     ExprResult Value
1046       = CheckObjCCollectionLiteralElement(*this, Element.Value, ValueT);
1047     if (Value.isInvalid())
1048       return ExprError();
1049
1050     Element.Key = Key.get();
1051     Element.Value = Value.get();
1052
1053     if (Element.EllipsisLoc.isInvalid())
1054       continue;
1055
1056     if (!Element.Key->containsUnexpandedParameterPack() &&
1057         !Element.Value->containsUnexpandedParameterPack()) {
1058       Diag(Element.EllipsisLoc,
1059            diag::err_pack_expansion_without_parameter_packs)
1060           << SourceRange(Element.Key->getBeginLoc(),
1061                          Element.Value->getEndLoc());
1062       return ExprError();
1063     }
1064
1065     HasPackExpansions = true;
1066   }
1067
1068   QualType Ty
1069     = Context.getObjCObjectPointerType(
1070                                 Context.getObjCInterfaceType(NSDictionaryDecl));
1071   return MaybeBindToTemporary(ObjCDictionaryLiteral::Create(
1072       Context, Elements, HasPackExpansions, Ty,
1073       DictionaryWithObjectsMethod, SR));
1074 }
1075
1076 ExprResult Sema::BuildObjCEncodeExpression(SourceLocation AtLoc,
1077                                       TypeSourceInfo *EncodedTypeInfo,
1078                                       SourceLocation RParenLoc) {
1079   QualType EncodedType = EncodedTypeInfo->getType();
1080   QualType StrTy;
1081   if (EncodedType->isDependentType())
1082     StrTy = Context.DependentTy;
1083   else {
1084     if (!EncodedType->getAsArrayTypeUnsafe() && //// Incomplete array is handled.
1085         !EncodedType->isVoidType()) // void is handled too.
1086       if (RequireCompleteType(AtLoc, EncodedType,
1087                               diag::err_incomplete_type_objc_at_encode,
1088                               EncodedTypeInfo->getTypeLoc()))
1089         return ExprError();
1090
1091     std::string Str;
1092     QualType NotEncodedT;
1093     Context.getObjCEncodingForType(EncodedType, Str, nullptr, &NotEncodedT);
1094     if (!NotEncodedT.isNull())
1095       Diag(AtLoc, diag::warn_incomplete_encoded_type)
1096         << EncodedType << NotEncodedT;
1097
1098     // The type of @encode is the same as the type of the corresponding string,
1099     // which is an array type.
1100     StrTy = Context.getStringLiteralArrayType(Context.CharTy, Str.size());
1101   }
1102
1103   return new (Context) ObjCEncodeExpr(StrTy, EncodedTypeInfo, AtLoc, RParenLoc);
1104 }
1105
1106 ExprResult Sema::ParseObjCEncodeExpression(SourceLocation AtLoc,
1107                                            SourceLocation EncodeLoc,
1108                                            SourceLocation LParenLoc,
1109                                            ParsedType ty,
1110                                            SourceLocation RParenLoc) {
1111   // FIXME: Preserve type source info ?
1112   TypeSourceInfo *TInfo;
1113   QualType EncodedType = GetTypeFromParser(ty, &TInfo);
1114   if (!TInfo)
1115     TInfo = Context.getTrivialTypeSourceInfo(EncodedType,
1116                                              getLocForEndOfToken(LParenLoc));
1117
1118   return BuildObjCEncodeExpression(AtLoc, TInfo, RParenLoc);
1119 }
1120
1121 static bool HelperToDiagnoseMismatchedMethodsInGlobalPool(Sema &S,
1122                                                SourceLocation AtLoc,
1123                                                SourceLocation LParenLoc,
1124                                                SourceLocation RParenLoc,
1125                                                ObjCMethodDecl *Method,
1126                                                ObjCMethodList &MethList) {
1127   ObjCMethodList *M = &MethList;
1128   bool Warned = false;
1129   for (M = M->getNext(); M; M=M->getNext()) {
1130     ObjCMethodDecl *MatchingMethodDecl = M->getMethod();
1131     if (MatchingMethodDecl == Method ||
1132         isa<ObjCImplDecl>(MatchingMethodDecl->getDeclContext()) ||
1133         MatchingMethodDecl->getSelector() != Method->getSelector())
1134       continue;
1135     if (!S.MatchTwoMethodDeclarations(Method,
1136                                       MatchingMethodDecl, Sema::MMS_loose)) {
1137       if (!Warned) {
1138         Warned = true;
1139         S.Diag(AtLoc, diag::warn_multiple_selectors)
1140           << Method->getSelector() << FixItHint::CreateInsertion(LParenLoc, "(")
1141           << FixItHint::CreateInsertion(RParenLoc, ")");
1142         S.Diag(Method->getLocation(), diag::note_method_declared_at)
1143           << Method->getDeclName();
1144       }
1145       S.Diag(MatchingMethodDecl->getLocation(), diag::note_method_declared_at)
1146         << MatchingMethodDecl->getDeclName();
1147     }
1148   }
1149   return Warned;
1150 }
1151
1152 static void DiagnoseMismatchedSelectors(Sema &S, SourceLocation AtLoc,
1153                                         ObjCMethodDecl *Method,
1154                                         SourceLocation LParenLoc,
1155                                         SourceLocation RParenLoc,
1156                                         bool WarnMultipleSelectors) {
1157   if (!WarnMultipleSelectors ||
1158       S.Diags.isIgnored(diag::warn_multiple_selectors, SourceLocation()))
1159     return;
1160   bool Warned = false;
1161   for (Sema::GlobalMethodPool::iterator b = S.MethodPool.begin(),
1162        e = S.MethodPool.end(); b != e; b++) {
1163     // first, instance methods
1164     ObjCMethodList &InstMethList = b->second.first;
1165     if (HelperToDiagnoseMismatchedMethodsInGlobalPool(S, AtLoc, LParenLoc, RParenLoc,
1166                                                       Method, InstMethList))
1167       Warned = true;
1168
1169     // second, class methods
1170     ObjCMethodList &ClsMethList = b->second.second;
1171     if (HelperToDiagnoseMismatchedMethodsInGlobalPool(S, AtLoc, LParenLoc, RParenLoc,
1172                                                       Method, ClsMethList) || Warned)
1173       return;
1174   }
1175 }
1176
1177 ExprResult Sema::ParseObjCSelectorExpression(Selector Sel,
1178                                              SourceLocation AtLoc,
1179                                              SourceLocation SelLoc,
1180                                              SourceLocation LParenLoc,
1181                                              SourceLocation RParenLoc,
1182                                              bool WarnMultipleSelectors) {
1183   ObjCMethodDecl *Method = LookupInstanceMethodInGlobalPool(Sel,
1184                              SourceRange(LParenLoc, RParenLoc));
1185   if (!Method)
1186     Method = LookupFactoryMethodInGlobalPool(Sel,
1187                                           SourceRange(LParenLoc, RParenLoc));
1188   if (!Method) {
1189     if (const ObjCMethodDecl *OM = SelectorsForTypoCorrection(Sel)) {
1190       Selector MatchedSel = OM->getSelector();
1191       SourceRange SelectorRange(LParenLoc.getLocWithOffset(1),
1192                                 RParenLoc.getLocWithOffset(-1));
1193       Diag(SelLoc, diag::warn_undeclared_selector_with_typo)
1194         << Sel << MatchedSel
1195         << FixItHint::CreateReplacement(SelectorRange, MatchedSel.getAsString());
1196
1197     } else
1198         Diag(SelLoc, diag::warn_undeclared_selector) << Sel;
1199   } else
1200     DiagnoseMismatchedSelectors(*this, AtLoc, Method, LParenLoc, RParenLoc,
1201                                 WarnMultipleSelectors);
1202
1203   if (Method &&
1204       Method->getImplementationControl() != ObjCMethodDecl::Optional &&
1205       !getSourceManager().isInSystemHeader(Method->getLocation()))
1206     ReferencedSelectors.insert(std::make_pair(Sel, AtLoc));
1207
1208   // In ARC, forbid the user from using @selector for
1209   // retain/release/autorelease/dealloc/retainCount.
1210   if (getLangOpts().ObjCAutoRefCount) {
1211     switch (Sel.getMethodFamily()) {
1212     case OMF_retain:
1213     case OMF_release:
1214     case OMF_autorelease:
1215     case OMF_retainCount:
1216     case OMF_dealloc:
1217       Diag(AtLoc, diag::err_arc_illegal_selector) <<
1218         Sel << SourceRange(LParenLoc, RParenLoc);
1219       break;
1220
1221     case OMF_None:
1222     case OMF_alloc:
1223     case OMF_copy:
1224     case OMF_finalize:
1225     case OMF_init:
1226     case OMF_mutableCopy:
1227     case OMF_new:
1228     case OMF_self:
1229     case OMF_initialize:
1230     case OMF_performSelector:
1231       break;
1232     }
1233   }
1234   QualType Ty = Context.getObjCSelType();
1235   return new (Context) ObjCSelectorExpr(Ty, Sel, AtLoc, RParenLoc);
1236 }
1237
1238 ExprResult Sema::ParseObjCProtocolExpression(IdentifierInfo *ProtocolId,
1239                                              SourceLocation AtLoc,
1240                                              SourceLocation ProtoLoc,
1241                                              SourceLocation LParenLoc,
1242                                              SourceLocation ProtoIdLoc,
1243                                              SourceLocation RParenLoc) {
1244   ObjCProtocolDecl* PDecl = LookupProtocol(ProtocolId, ProtoIdLoc);
1245   if (!PDecl) {
1246     Diag(ProtoLoc, diag::err_undeclared_protocol) << ProtocolId;
1247     return true;
1248   }
1249   if (!PDecl->hasDefinition()) {
1250     Diag(ProtoLoc, diag::err_atprotocol_protocol) << PDecl;
1251     Diag(PDecl->getLocation(), diag::note_entity_declared_at) << PDecl;
1252   } else {
1253     PDecl = PDecl->getDefinition();
1254   }
1255
1256   QualType Ty = Context.getObjCProtoType();
1257   if (Ty.isNull())
1258     return true;
1259   Ty = Context.getObjCObjectPointerType(Ty);
1260   return new (Context) ObjCProtocolExpr(Ty, PDecl, AtLoc, ProtoIdLoc, RParenLoc);
1261 }
1262
1263 /// Try to capture an implicit reference to 'self'.
1264 ObjCMethodDecl *Sema::tryCaptureObjCSelf(SourceLocation Loc) {
1265   DeclContext *DC = getFunctionLevelDeclContext();
1266
1267   // If we're not in an ObjC method, error out.  Note that, unlike the
1268   // C++ case, we don't require an instance method --- class methods
1269   // still have a 'self', and we really do still need to capture it!
1270   ObjCMethodDecl *method = dyn_cast<ObjCMethodDecl>(DC);
1271   if (!method)
1272     return nullptr;
1273
1274   tryCaptureVariable(method->getSelfDecl(), Loc);
1275
1276   return method;
1277 }
1278
1279 static QualType stripObjCInstanceType(ASTContext &Context, QualType T) {
1280   QualType origType = T;
1281   if (auto nullability = AttributedType::stripOuterNullability(T)) {
1282     if (T == Context.getObjCInstanceType()) {
1283       return Context.getAttributedType(
1284                AttributedType::getNullabilityAttrKind(*nullability),
1285                Context.getObjCIdType(),
1286                Context.getObjCIdType());
1287     }
1288
1289     return origType;
1290   }
1291
1292   if (T == Context.getObjCInstanceType())
1293     return Context.getObjCIdType();
1294
1295   return origType;
1296 }
1297
1298 /// Determine the result type of a message send based on the receiver type,
1299 /// method, and the kind of message send.
1300 ///
1301 /// This is the "base" result type, which will still need to be adjusted
1302 /// to account for nullability.
1303 static QualType getBaseMessageSendResultType(Sema &S,
1304                                              QualType ReceiverType,
1305                                              ObjCMethodDecl *Method,
1306                                              bool isClassMessage,
1307                                              bool isSuperMessage) {
1308   assert(Method && "Must have a method");
1309   if (!Method->hasRelatedResultType())
1310     return Method->getSendResultType(ReceiverType);
1311
1312   ASTContext &Context = S.Context;
1313
1314   // Local function that transfers the nullability of the method's
1315   // result type to the returned result.
1316   auto transferNullability = [&](QualType type) -> QualType {
1317     // If the method's result type has nullability, extract it.
1318     if (auto nullability = Method->getSendResultType(ReceiverType)
1319                              ->getNullability(Context)){
1320       // Strip off any outer nullability sugar from the provided type.
1321       (void)AttributedType::stripOuterNullability(type);
1322
1323       // Form a new attributed type using the method result type's nullability.
1324       return Context.getAttributedType(
1325                AttributedType::getNullabilityAttrKind(*nullability),
1326                type,
1327                type);
1328     }
1329
1330     return type;
1331   };
1332
1333   // If a method has a related return type:
1334   //   - if the method found is an instance method, but the message send
1335   //     was a class message send, T is the declared return type of the method
1336   //     found
1337   if (Method->isInstanceMethod() && isClassMessage)
1338     return stripObjCInstanceType(Context,
1339                                  Method->getSendResultType(ReceiverType));
1340
1341   //   - if the receiver is super, T is a pointer to the class of the
1342   //     enclosing method definition
1343   if (isSuperMessage) {
1344     if (ObjCMethodDecl *CurMethod = S.getCurMethodDecl())
1345       if (ObjCInterfaceDecl *Class = CurMethod->getClassInterface()) {
1346         return transferNullability(
1347                  Context.getObjCObjectPointerType(
1348                    Context.getObjCInterfaceType(Class)));
1349       }
1350   }
1351
1352   //   - if the receiver is the name of a class U, T is a pointer to U
1353   if (ReceiverType->getAsObjCInterfaceType())
1354     return transferNullability(Context.getObjCObjectPointerType(ReceiverType));
1355   //   - if the receiver is of type Class or qualified Class type,
1356   //     T is the declared return type of the method.
1357   if (ReceiverType->isObjCClassType() ||
1358       ReceiverType->isObjCQualifiedClassType())
1359     return stripObjCInstanceType(Context,
1360                                  Method->getSendResultType(ReceiverType));
1361
1362   //   - if the receiver is id, qualified id, Class, or qualified Class, T
1363   //     is the receiver type, otherwise
1364   //   - T is the type of the receiver expression.
1365   return transferNullability(ReceiverType);
1366 }
1367
1368 QualType Sema::getMessageSendResultType(const Expr *Receiver,
1369                                         QualType ReceiverType,
1370                                         ObjCMethodDecl *Method,
1371                                         bool isClassMessage,
1372                                         bool isSuperMessage) {
1373   // Produce the result type.
1374   QualType resultType = getBaseMessageSendResultType(*this, ReceiverType,
1375                                                      Method,
1376                                                      isClassMessage,
1377                                                      isSuperMessage);
1378
1379   // If this is a class message, ignore the nullability of the receiver.
1380   if (isClassMessage) {
1381     // In a class method, class messages to 'self' that return instancetype can
1382     // be typed as the current class.  We can safely do this in ARC because self
1383     // can't be reassigned, and we do it unsafely outside of ARC because in
1384     // practice people never reassign self in class methods and there's some
1385     // virtue in not being aggressively pedantic.
1386     if (Receiver && Receiver->isObjCSelfExpr()) {
1387       assert(ReceiverType->isObjCClassType() && "expected a Class self");
1388       QualType T = Method->getSendResultType(ReceiverType);
1389       AttributedType::stripOuterNullability(T);
1390       if (T == Context.getObjCInstanceType()) {
1391         const ObjCMethodDecl *MD = cast<ObjCMethodDecl>(
1392             cast<ImplicitParamDecl>(
1393                 cast<DeclRefExpr>(Receiver->IgnoreParenImpCasts())->getDecl())
1394                 ->getDeclContext());
1395         assert(MD->isClassMethod() && "expected a class method");
1396         QualType NewResultType = Context.getObjCObjectPointerType(
1397             Context.getObjCInterfaceType(MD->getClassInterface()));
1398         if (auto Nullability = resultType->getNullability(Context))
1399           NewResultType = Context.getAttributedType(
1400               AttributedType::getNullabilityAttrKind(*Nullability),
1401               NewResultType, NewResultType);
1402         return NewResultType;
1403       }
1404     }
1405     return resultType;
1406   }
1407
1408   // There is nothing left to do if the result type cannot have a nullability
1409   // specifier.
1410   if (!resultType->canHaveNullability())
1411     return resultType;
1412
1413   // Map the nullability of the result into a table index.
1414   unsigned receiverNullabilityIdx = 0;
1415   if (auto nullability = ReceiverType->getNullability(Context))
1416     receiverNullabilityIdx = 1 + static_cast<unsigned>(*nullability);
1417
1418   unsigned resultNullabilityIdx = 0;
1419   if (auto nullability = resultType->getNullability(Context))
1420     resultNullabilityIdx = 1 + static_cast<unsigned>(*nullability);
1421
1422   // The table of nullability mappings, indexed by the receiver's nullability
1423   // and then the result type's nullability.
1424   static const uint8_t None = 0;
1425   static const uint8_t NonNull = 1;
1426   static const uint8_t Nullable = 2;
1427   static const uint8_t Unspecified = 3;
1428   static const uint8_t nullabilityMap[4][4] = {
1429     //                  None        NonNull       Nullable    Unspecified
1430     /* None */        { None,       None,         Nullable,   None },
1431     /* NonNull */     { None,       NonNull,      Nullable,   Unspecified },
1432     /* Nullable */    { Nullable,   Nullable,     Nullable,   Nullable },
1433     /* Unspecified */ { None,       Unspecified,  Nullable,   Unspecified }
1434   };
1435
1436   unsigned newResultNullabilityIdx
1437     = nullabilityMap[receiverNullabilityIdx][resultNullabilityIdx];
1438   if (newResultNullabilityIdx == resultNullabilityIdx)
1439     return resultType;
1440
1441   // Strip off the existing nullability. This removes as little type sugar as
1442   // possible.
1443   do {
1444     if (auto attributed = dyn_cast<AttributedType>(resultType.getTypePtr())) {
1445       resultType = attributed->getModifiedType();
1446     } else {
1447       resultType = resultType.getDesugaredType(Context);
1448     }
1449   } while (resultType->getNullability(Context));
1450
1451   // Add nullability back if needed.
1452   if (newResultNullabilityIdx > 0) {
1453     auto newNullability
1454       = static_cast<NullabilityKind>(newResultNullabilityIdx-1);
1455     return Context.getAttributedType(
1456              AttributedType::getNullabilityAttrKind(newNullability),
1457              resultType, resultType);
1458   }
1459
1460   return resultType;
1461 }
1462
1463 /// Look for an ObjC method whose result type exactly matches the given type.
1464 static const ObjCMethodDecl *
1465 findExplicitInstancetypeDeclarer(const ObjCMethodDecl *MD,
1466                                  QualType instancetype) {
1467   if (MD->getReturnType() == instancetype)
1468     return MD;
1469
1470   // For these purposes, a method in an @implementation overrides a
1471   // declaration in the @interface.
1472   if (const ObjCImplDecl *impl =
1473         dyn_cast<ObjCImplDecl>(MD->getDeclContext())) {
1474     const ObjCContainerDecl *iface;
1475     if (const ObjCCategoryImplDecl *catImpl =
1476           dyn_cast<ObjCCategoryImplDecl>(impl)) {
1477       iface = catImpl->getCategoryDecl();
1478     } else {
1479       iface = impl->getClassInterface();
1480     }
1481
1482     const ObjCMethodDecl *ifaceMD =
1483       iface->getMethod(MD->getSelector(), MD->isInstanceMethod());
1484     if (ifaceMD) return findExplicitInstancetypeDeclarer(ifaceMD, instancetype);
1485   }
1486
1487   SmallVector<const ObjCMethodDecl *, 4> overrides;
1488   MD->getOverriddenMethods(overrides);
1489   for (unsigned i = 0, e = overrides.size(); i != e; ++i) {
1490     if (const ObjCMethodDecl *result =
1491           findExplicitInstancetypeDeclarer(overrides[i], instancetype))
1492       return result;
1493   }
1494
1495   return nullptr;
1496 }
1497
1498 void Sema::EmitRelatedResultTypeNoteForReturn(QualType destType) {
1499   // Only complain if we're in an ObjC method and the required return
1500   // type doesn't match the method's declared return type.
1501   ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(CurContext);
1502   if (!MD || !MD->hasRelatedResultType() ||
1503       Context.hasSameUnqualifiedType(destType, MD->getReturnType()))
1504     return;
1505
1506   // Look for a method overridden by this method which explicitly uses
1507   // 'instancetype'.
1508   if (const ObjCMethodDecl *overridden =
1509         findExplicitInstancetypeDeclarer(MD, Context.getObjCInstanceType())) {
1510     SourceRange range = overridden->getReturnTypeSourceRange();
1511     SourceLocation loc = range.getBegin();
1512     if (loc.isInvalid())
1513       loc = overridden->getLocation();
1514     Diag(loc, diag::note_related_result_type_explicit)
1515       << /*current method*/ 1 << range;
1516     return;
1517   }
1518
1519   // Otherwise, if we have an interesting method family, note that.
1520   // This should always trigger if the above didn't.
1521   if (ObjCMethodFamily family = MD->getMethodFamily())
1522     Diag(MD->getLocation(), diag::note_related_result_type_family)
1523       << /*current method*/ 1
1524       << family;
1525 }
1526
1527 void Sema::EmitRelatedResultTypeNote(const Expr *E) {
1528   E = E->IgnoreParenImpCasts();
1529   const ObjCMessageExpr *MsgSend = dyn_cast<ObjCMessageExpr>(E);
1530   if (!MsgSend)
1531     return;
1532
1533   const ObjCMethodDecl *Method = MsgSend->getMethodDecl();
1534   if (!Method)
1535     return;
1536
1537   if (!Method->hasRelatedResultType())
1538     return;
1539
1540   if (Context.hasSameUnqualifiedType(
1541           Method->getReturnType().getNonReferenceType(), MsgSend->getType()))
1542     return;
1543
1544   if (!Context.hasSameUnqualifiedType(Method->getReturnType(),
1545                                       Context.getObjCInstanceType()))
1546     return;
1547
1548   Diag(Method->getLocation(), diag::note_related_result_type_inferred)
1549     << Method->isInstanceMethod() << Method->getSelector()
1550     << MsgSend->getType();
1551 }
1552
1553 bool Sema::CheckMessageArgumentTypes(
1554     const Expr *Receiver, QualType ReceiverType, MultiExprArg Args,
1555     Selector Sel, ArrayRef<SourceLocation> SelectorLocs, ObjCMethodDecl *Method,
1556     bool isClassMessage, bool isSuperMessage, SourceLocation lbrac,
1557     SourceLocation rbrac, SourceRange RecRange, QualType &ReturnType,
1558     ExprValueKind &VK) {
1559   SourceLocation SelLoc;
1560   if (!SelectorLocs.empty() && SelectorLocs.front().isValid())
1561     SelLoc = SelectorLocs.front();
1562   else
1563     SelLoc = lbrac;
1564
1565   if (!Method) {
1566     // Apply default argument promotion as for (C99 6.5.2.2p6).
1567     for (unsigned i = 0, e = Args.size(); i != e; i++) {
1568       if (Args[i]->isTypeDependent())
1569         continue;
1570
1571       ExprResult result;
1572       if (getLangOpts().DebuggerSupport) {
1573         QualType paramTy; // ignored
1574         result = checkUnknownAnyArg(SelLoc, Args[i], paramTy);
1575       } else {
1576         result = DefaultArgumentPromotion(Args[i]);
1577       }
1578       if (result.isInvalid())
1579         return true;
1580       Args[i] = result.get();
1581     }
1582
1583     unsigned DiagID;
1584     if (getLangOpts().ObjCAutoRefCount)
1585       DiagID = diag::err_arc_method_not_found;
1586     else
1587       DiagID = isClassMessage ? diag::warn_class_method_not_found
1588                               : diag::warn_inst_method_not_found;
1589     if (!getLangOpts().DebuggerSupport) {
1590       const ObjCMethodDecl *OMD = SelectorsForTypoCorrection(Sel, ReceiverType);
1591       if (OMD && !OMD->isInvalidDecl()) {
1592         if (getLangOpts().ObjCAutoRefCount)
1593           DiagID = diag::err_method_not_found_with_typo;
1594         else
1595           DiagID = isClassMessage ? diag::warn_class_method_not_found_with_typo
1596                                   : diag::warn_instance_method_not_found_with_typo;
1597         Selector MatchedSel = OMD->getSelector();
1598         SourceRange SelectorRange(SelectorLocs.front(), SelectorLocs.back());
1599         if (MatchedSel.isUnarySelector())
1600           Diag(SelLoc, DiagID)
1601             << Sel<< isClassMessage << MatchedSel
1602             << FixItHint::CreateReplacement(SelectorRange, MatchedSel.getAsString());
1603         else
1604           Diag(SelLoc, DiagID) << Sel<< isClassMessage << MatchedSel;
1605       }
1606       else
1607         Diag(SelLoc, DiagID)
1608           << Sel << isClassMessage << SourceRange(SelectorLocs.front(),
1609                                                 SelectorLocs.back());
1610       // Find the class to which we are sending this message.
1611       if (ReceiverType->isObjCObjectPointerType()) {
1612         if (ObjCInterfaceDecl *ThisClass =
1613             ReceiverType->getAs<ObjCObjectPointerType>()->getInterfaceDecl()) {
1614           Diag(ThisClass->getLocation(), diag::note_receiver_class_declared);
1615           if (!RecRange.isInvalid())
1616             if (ThisClass->lookupClassMethod(Sel))
1617               Diag(RecRange.getBegin(),diag::note_receiver_expr_here)
1618                 << FixItHint::CreateReplacement(RecRange,
1619                                                 ThisClass->getNameAsString());
1620         }
1621       }
1622     }
1623
1624     // In debuggers, we want to use __unknown_anytype for these
1625     // results so that clients can cast them.
1626     if (getLangOpts().DebuggerSupport) {
1627       ReturnType = Context.UnknownAnyTy;
1628     } else {
1629       ReturnType = Context.getObjCIdType();
1630     }
1631     VK = VK_RValue;
1632     return false;
1633   }
1634
1635   ReturnType = getMessageSendResultType(Receiver, ReceiverType, Method,
1636                                         isClassMessage, isSuperMessage);
1637   VK = Expr::getValueKindForType(Method->getReturnType());
1638
1639   unsigned NumNamedArgs = Sel.getNumArgs();
1640   // Method might have more arguments than selector indicates. This is due
1641   // to addition of c-style arguments in method.
1642   if (Method->param_size() > Sel.getNumArgs())
1643     NumNamedArgs = Method->param_size();
1644   // FIXME. This need be cleaned up.
1645   if (Args.size() < NumNamedArgs) {
1646     Diag(SelLoc, diag::err_typecheck_call_too_few_args)
1647       << 2 << NumNamedArgs << static_cast<unsigned>(Args.size());
1648     return false;
1649   }
1650
1651   // Compute the set of type arguments to be substituted into each parameter
1652   // type.
1653   Optional<ArrayRef<QualType>> typeArgs
1654     = ReceiverType->getObjCSubstitutions(Method->getDeclContext());
1655   bool IsError = false;
1656   for (unsigned i = 0; i < NumNamedArgs; i++) {
1657     // We can't do any type-checking on a type-dependent argument.
1658     if (Args[i]->isTypeDependent())
1659       continue;
1660
1661     Expr *argExpr = Args[i];
1662
1663     ParmVarDecl *param = Method->parameters()[i];
1664     assert(argExpr && "CheckMessageArgumentTypes(): missing expression");
1665
1666     if (param->hasAttr<NoEscapeAttr>())
1667       if (auto *BE = dyn_cast<BlockExpr>(
1668               argExpr->IgnoreParenNoopCasts(Context)))
1669         BE->getBlockDecl()->setDoesNotEscape();
1670
1671     // Strip the unbridged-cast placeholder expression off unless it's
1672     // a consumed argument.
1673     if (argExpr->hasPlaceholderType(BuiltinType::ARCUnbridgedCast) &&
1674         !param->hasAttr<CFConsumedAttr>())
1675       argExpr = stripARCUnbridgedCast(argExpr);
1676
1677     // If the parameter is __unknown_anytype, infer its type
1678     // from the argument.
1679     if (param->getType() == Context.UnknownAnyTy) {
1680       QualType paramType;
1681       ExprResult argE = checkUnknownAnyArg(SelLoc, argExpr, paramType);
1682       if (argE.isInvalid()) {
1683         IsError = true;
1684       } else {
1685         Args[i] = argE.get();
1686
1687         // Update the parameter type in-place.
1688         param->setType(paramType);
1689       }
1690       continue;
1691     }
1692
1693     QualType origParamType = param->getType();
1694     QualType paramType = param->getType();
1695     if (typeArgs)
1696       paramType = paramType.substObjCTypeArgs(
1697                     Context,
1698                     *typeArgs,
1699                     ObjCSubstitutionContext::Parameter);
1700
1701     if (RequireCompleteType(argExpr->getSourceRange().getBegin(),
1702                             paramType,
1703                             diag::err_call_incomplete_argument, argExpr))
1704       return true;
1705
1706     InitializedEntity Entity
1707       = InitializedEntity::InitializeParameter(Context, param, paramType);
1708     ExprResult ArgE = PerformCopyInitialization(Entity, SourceLocation(), argExpr);
1709     if (ArgE.isInvalid())
1710       IsError = true;
1711     else {
1712       Args[i] = ArgE.getAs<Expr>();
1713
1714       // If we are type-erasing a block to a block-compatible
1715       // Objective-C pointer type, we may need to extend the lifetime
1716       // of the block object.
1717       if (typeArgs && Args[i]->isRValue() && paramType->isBlockPointerType() &&
1718           Args[i]->getType()->isBlockPointerType() &&
1719           origParamType->isObjCObjectPointerType()) {
1720         ExprResult arg = Args[i];
1721         maybeExtendBlockObject(arg);
1722         Args[i] = arg.get();
1723       }
1724     }
1725   }
1726
1727   // Promote additional arguments to variadic methods.
1728   if (Method->isVariadic()) {
1729     for (unsigned i = NumNamedArgs, e = Args.size(); i < e; ++i) {
1730       if (Args[i]->isTypeDependent())
1731         continue;
1732
1733       ExprResult Arg = DefaultVariadicArgumentPromotion(Args[i], VariadicMethod,
1734                                                         nullptr);
1735       IsError |= Arg.isInvalid();
1736       Args[i] = Arg.get();
1737     }
1738   } else {
1739     // Check for extra arguments to non-variadic methods.
1740     if (Args.size() != NumNamedArgs) {
1741       Diag(Args[NumNamedArgs]->getBeginLoc(),
1742            diag::err_typecheck_call_too_many_args)
1743           << 2 /*method*/ << NumNamedArgs << static_cast<unsigned>(Args.size())
1744           << Method->getSourceRange()
1745           << SourceRange(Args[NumNamedArgs]->getBeginLoc(),
1746                          Args.back()->getEndLoc());
1747     }
1748   }
1749
1750   DiagnoseSentinelCalls(Method, SelLoc, Args);
1751
1752   // Do additional checkings on method.
1753   IsError |= CheckObjCMethodCall(
1754       Method, SelLoc, makeArrayRef(Args.data(), Args.size()));
1755
1756   return IsError;
1757 }
1758
1759 bool Sema::isSelfExpr(Expr *RExpr) {
1760   // 'self' is objc 'self' in an objc method only.
1761   ObjCMethodDecl *Method =
1762       dyn_cast_or_null<ObjCMethodDecl>(CurContext->getNonClosureAncestor());
1763   return isSelfExpr(RExpr, Method);
1764 }
1765
1766 bool Sema::isSelfExpr(Expr *receiver, const ObjCMethodDecl *method) {
1767   if (!method) return false;
1768
1769   receiver = receiver->IgnoreParenLValueCasts();
1770   if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(receiver))
1771     if (DRE->getDecl() == method->getSelfDecl())
1772       return true;
1773   return false;
1774 }
1775
1776 /// LookupMethodInType - Look up a method in an ObjCObjectType.
1777 ObjCMethodDecl *Sema::LookupMethodInObjectType(Selector sel, QualType type,
1778                                                bool isInstance) {
1779   const ObjCObjectType *objType = type->castAs<ObjCObjectType>();
1780   if (ObjCInterfaceDecl *iface = objType->getInterface()) {
1781     // Look it up in the main interface (and categories, etc.)
1782     if (ObjCMethodDecl *method = iface->lookupMethod(sel, isInstance))
1783       return method;
1784
1785     // Okay, look for "private" methods declared in any
1786     // @implementations we've seen.
1787     if (ObjCMethodDecl *method = iface->lookupPrivateMethod(sel, isInstance))
1788       return method;
1789   }
1790
1791   // Check qualifiers.
1792   for (const auto *I : objType->quals())
1793     if (ObjCMethodDecl *method = I->lookupMethod(sel, isInstance))
1794       return method;
1795
1796   return nullptr;
1797 }
1798
1799 /// LookupMethodInQualifiedType - Lookups up a method in protocol qualifier
1800 /// list of a qualified objective pointer type.
1801 ObjCMethodDecl *Sema::LookupMethodInQualifiedType(Selector Sel,
1802                                               const ObjCObjectPointerType *OPT,
1803                                               bool Instance)
1804 {
1805   ObjCMethodDecl *MD = nullptr;
1806   for (const auto *PROTO : OPT->quals()) {
1807     if ((MD = PROTO->lookupMethod(Sel, Instance))) {
1808       return MD;
1809     }
1810   }
1811   return nullptr;
1812 }
1813
1814 /// HandleExprPropertyRefExpr - Handle foo.bar where foo is a pointer to an
1815 /// objective C interface.  This is a property reference expression.
1816 ExprResult Sema::
1817 HandleExprPropertyRefExpr(const ObjCObjectPointerType *OPT,
1818                           Expr *BaseExpr, SourceLocation OpLoc,
1819                           DeclarationName MemberName,
1820                           SourceLocation MemberLoc,
1821                           SourceLocation SuperLoc, QualType SuperType,
1822                           bool Super) {
1823   const ObjCInterfaceType *IFaceT = OPT->getInterfaceType();
1824   ObjCInterfaceDecl *IFace = IFaceT->getDecl();
1825
1826   if (!MemberName.isIdentifier()) {
1827     Diag(MemberLoc, diag::err_invalid_property_name)
1828       << MemberName << QualType(OPT, 0);
1829     return ExprError();
1830   }
1831
1832   IdentifierInfo *Member = MemberName.getAsIdentifierInfo();
1833
1834   SourceRange BaseRange = Super? SourceRange(SuperLoc)
1835                                : BaseExpr->getSourceRange();
1836   if (RequireCompleteType(MemberLoc, OPT->getPointeeType(),
1837                           diag::err_property_not_found_forward_class,
1838                           MemberName, BaseRange))
1839     return ExprError();
1840
1841   if (ObjCPropertyDecl *PD = IFace->FindPropertyDeclaration(
1842           Member, ObjCPropertyQueryKind::OBJC_PR_query_instance)) {
1843     // Check whether we can reference this property.
1844     if (DiagnoseUseOfDecl(PD, MemberLoc))
1845       return ExprError();
1846     if (Super)
1847       return new (Context)
1848           ObjCPropertyRefExpr(PD, Context.PseudoObjectTy, VK_LValue,
1849                               OK_ObjCProperty, MemberLoc, SuperLoc, SuperType);
1850     else
1851       return new (Context)
1852           ObjCPropertyRefExpr(PD, Context.PseudoObjectTy, VK_LValue,
1853                               OK_ObjCProperty, MemberLoc, BaseExpr);
1854   }
1855   // Check protocols on qualified interfaces.
1856   for (const auto *I : OPT->quals())
1857     if (ObjCPropertyDecl *PD = I->FindPropertyDeclaration(
1858             Member, ObjCPropertyQueryKind::OBJC_PR_query_instance)) {
1859       // Check whether we can reference this property.
1860       if (DiagnoseUseOfDecl(PD, MemberLoc))
1861         return ExprError();
1862
1863       if (Super)
1864         return new (Context) ObjCPropertyRefExpr(
1865             PD, Context.PseudoObjectTy, VK_LValue, OK_ObjCProperty, MemberLoc,
1866             SuperLoc, SuperType);
1867       else
1868         return new (Context)
1869             ObjCPropertyRefExpr(PD, Context.PseudoObjectTy, VK_LValue,
1870                                 OK_ObjCProperty, MemberLoc, BaseExpr);
1871     }
1872   // If that failed, look for an "implicit" property by seeing if the nullary
1873   // selector is implemented.
1874
1875   // FIXME: The logic for looking up nullary and unary selectors should be
1876   // shared with the code in ActOnInstanceMessage.
1877
1878   Selector Sel = PP.getSelectorTable().getNullarySelector(Member);
1879   ObjCMethodDecl *Getter = IFace->lookupInstanceMethod(Sel);
1880
1881   // May be found in property's qualified list.
1882   if (!Getter)
1883     Getter = LookupMethodInQualifiedType(Sel, OPT, true);
1884
1885   // If this reference is in an @implementation, check for 'private' methods.
1886   if (!Getter)
1887     Getter = IFace->lookupPrivateMethod(Sel);
1888
1889   if (Getter) {
1890     // Check if we can reference this property.
1891     if (DiagnoseUseOfDecl(Getter, MemberLoc))
1892       return ExprError();
1893   }
1894   // If we found a getter then this may be a valid dot-reference, we
1895   // will look for the matching setter, in case it is needed.
1896   Selector SetterSel =
1897     SelectorTable::constructSetterSelector(PP.getIdentifierTable(),
1898                                            PP.getSelectorTable(), Member);
1899   ObjCMethodDecl *Setter = IFace->lookupInstanceMethod(SetterSel);
1900
1901   // May be found in property's qualified list.
1902   if (!Setter)
1903     Setter = LookupMethodInQualifiedType(SetterSel, OPT, true);
1904
1905   if (!Setter) {
1906     // If this reference is in an @implementation, also check for 'private'
1907     // methods.
1908     Setter = IFace->lookupPrivateMethod(SetterSel);
1909   }
1910
1911   if (Setter && DiagnoseUseOfDecl(Setter, MemberLoc))
1912     return ExprError();
1913
1914   // Special warning if member name used in a property-dot for a setter accessor
1915   // does not use a property with same name; e.g. obj.X = ... for a property with
1916   // name 'x'.
1917   if (Setter && Setter->isImplicit() && Setter->isPropertyAccessor() &&
1918       !IFace->FindPropertyDeclaration(
1919           Member, ObjCPropertyQueryKind::OBJC_PR_query_instance)) {
1920       if (const ObjCPropertyDecl *PDecl = Setter->findPropertyDecl()) {
1921         // Do not warn if user is using property-dot syntax to make call to
1922         // user named setter.
1923         if (!(PDecl->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_setter))
1924           Diag(MemberLoc,
1925                diag::warn_property_access_suggest)
1926           << MemberName << QualType(OPT, 0) << PDecl->getName()
1927           << FixItHint::CreateReplacement(MemberLoc, PDecl->getName());
1928       }
1929   }
1930
1931   if (Getter || Setter) {
1932     if (Super)
1933       return new (Context)
1934           ObjCPropertyRefExpr(Getter, Setter, Context.PseudoObjectTy, VK_LValue,
1935                               OK_ObjCProperty, MemberLoc, SuperLoc, SuperType);
1936     else
1937       return new (Context)
1938           ObjCPropertyRefExpr(Getter, Setter, Context.PseudoObjectTy, VK_LValue,
1939                               OK_ObjCProperty, MemberLoc, BaseExpr);
1940
1941   }
1942
1943   // Attempt to correct for typos in property names.
1944   DeclFilterCCC<ObjCPropertyDecl> CCC{};
1945   if (TypoCorrection Corrected = CorrectTypo(
1946           DeclarationNameInfo(MemberName, MemberLoc), LookupOrdinaryName,
1947           nullptr, nullptr, CCC, CTK_ErrorRecovery, IFace, false, OPT)) {
1948     DeclarationName TypoResult = Corrected.getCorrection();
1949     if (TypoResult.isIdentifier() &&
1950         TypoResult.getAsIdentifierInfo() == Member) {
1951       // There is no need to try the correction if it is the same.
1952       NamedDecl *ChosenDecl =
1953         Corrected.isKeyword() ? nullptr : Corrected.getFoundDecl();
1954       if (ChosenDecl && isa<ObjCPropertyDecl>(ChosenDecl))
1955         if (cast<ObjCPropertyDecl>(ChosenDecl)->isClassProperty()) {
1956           // This is a class property, we should not use the instance to
1957           // access it.
1958           Diag(MemberLoc, diag::err_class_property_found) << MemberName
1959           << OPT->getInterfaceDecl()->getName()
1960           << FixItHint::CreateReplacement(BaseExpr->getSourceRange(),
1961                                           OPT->getInterfaceDecl()->getName());
1962           return ExprError();
1963         }
1964     } else {
1965       diagnoseTypo(Corrected, PDiag(diag::err_property_not_found_suggest)
1966                                 << MemberName << QualType(OPT, 0));
1967       return HandleExprPropertyRefExpr(OPT, BaseExpr, OpLoc,
1968                                        TypoResult, MemberLoc,
1969                                        SuperLoc, SuperType, Super);
1970     }
1971   }
1972   ObjCInterfaceDecl *ClassDeclared;
1973   if (ObjCIvarDecl *Ivar =
1974       IFace->lookupInstanceVariable(Member, ClassDeclared)) {
1975     QualType T = Ivar->getType();
1976     if (const ObjCObjectPointerType * OBJPT =
1977         T->getAsObjCInterfacePointerType()) {
1978       if (RequireCompleteType(MemberLoc, OBJPT->getPointeeType(),
1979                               diag::err_property_not_as_forward_class,
1980                               MemberName, BaseExpr))
1981         return ExprError();
1982     }
1983     Diag(MemberLoc,
1984          diag::err_ivar_access_using_property_syntax_suggest)
1985     << MemberName << QualType(OPT, 0) << Ivar->getDeclName()
1986     << FixItHint::CreateReplacement(OpLoc, "->");
1987     return ExprError();
1988   }
1989
1990   Diag(MemberLoc, diag::err_property_not_found)
1991     << MemberName << QualType(OPT, 0);
1992   if (Setter)
1993     Diag(Setter->getLocation(), diag::note_getter_unavailable)
1994           << MemberName << BaseExpr->getSourceRange();
1995   return ExprError();
1996 }
1997
1998 ExprResult Sema::
1999 ActOnClassPropertyRefExpr(IdentifierInfo &receiverName,
2000                           IdentifierInfo &propertyName,
2001                           SourceLocation receiverNameLoc,
2002                           SourceLocation propertyNameLoc) {
2003
2004   IdentifierInfo *receiverNamePtr = &receiverName;
2005   ObjCInterfaceDecl *IFace = getObjCInterfaceDecl(receiverNamePtr,
2006                                                   receiverNameLoc);
2007
2008   QualType SuperType;
2009   if (!IFace) {
2010     // If the "receiver" is 'super' in a method, handle it as an expression-like
2011     // property reference.
2012     if (receiverNamePtr->isStr("super")) {
2013       if (ObjCMethodDecl *CurMethod = tryCaptureObjCSelf(receiverNameLoc)) {
2014         if (auto classDecl = CurMethod->getClassInterface()) {
2015           SuperType = QualType(classDecl->getSuperClassType(), 0);
2016           if (CurMethod->isInstanceMethod()) {
2017             if (SuperType.isNull()) {
2018               // The current class does not have a superclass.
2019               Diag(receiverNameLoc, diag::err_root_class_cannot_use_super)
2020                 << CurMethod->getClassInterface()->getIdentifier();
2021               return ExprError();
2022             }
2023             QualType T = Context.getObjCObjectPointerType(SuperType);
2024
2025             return HandleExprPropertyRefExpr(T->castAs<ObjCObjectPointerType>(),
2026                                              /*BaseExpr*/nullptr,
2027                                              SourceLocation()/*OpLoc*/,
2028                                              &propertyName,
2029                                              propertyNameLoc,
2030                                              receiverNameLoc, T, true);
2031           }
2032
2033           // Otherwise, if this is a class method, try dispatching to our
2034           // superclass.
2035           IFace = CurMethod->getClassInterface()->getSuperClass();
2036         }
2037       }
2038     }
2039
2040     if (!IFace) {
2041       Diag(receiverNameLoc, diag::err_expected_either) << tok::identifier
2042                                                        << tok::l_paren;
2043       return ExprError();
2044     }
2045   }
2046
2047   Selector GetterSel;
2048   Selector SetterSel;
2049   if (auto PD = IFace->FindPropertyDeclaration(
2050           &propertyName, ObjCPropertyQueryKind::OBJC_PR_query_class)) {
2051     GetterSel = PD->getGetterName();
2052     SetterSel = PD->getSetterName();
2053   } else {
2054     GetterSel = PP.getSelectorTable().getNullarySelector(&propertyName);
2055     SetterSel = SelectorTable::constructSetterSelector(
2056         PP.getIdentifierTable(), PP.getSelectorTable(), &propertyName);
2057   }
2058
2059   // Search for a declared property first.
2060   ObjCMethodDecl *Getter = IFace->lookupClassMethod(GetterSel);
2061
2062   // If this reference is in an @implementation, check for 'private' methods.
2063   if (!Getter)
2064     Getter = IFace->lookupPrivateClassMethod(GetterSel);
2065
2066   if (Getter) {
2067     // FIXME: refactor/share with ActOnMemberReference().
2068     // Check if we can reference this property.
2069     if (DiagnoseUseOfDecl(Getter, propertyNameLoc))
2070       return ExprError();
2071   }
2072
2073   // Look for the matching setter, in case it is needed.
2074   ObjCMethodDecl *Setter = IFace->lookupClassMethod(SetterSel);
2075   if (!Setter) {
2076     // If this reference is in an @implementation, also check for 'private'
2077     // methods.
2078     Setter = IFace->lookupPrivateClassMethod(SetterSel);
2079   }
2080   // Look through local category implementations associated with the class.
2081   if (!Setter)
2082     Setter = IFace->getCategoryClassMethod(SetterSel);
2083
2084   if (Setter && DiagnoseUseOfDecl(Setter, propertyNameLoc))
2085     return ExprError();
2086
2087   if (Getter || Setter) {
2088     if (!SuperType.isNull())
2089       return new (Context)
2090           ObjCPropertyRefExpr(Getter, Setter, Context.PseudoObjectTy, VK_LValue,
2091                               OK_ObjCProperty, propertyNameLoc, receiverNameLoc,
2092                               SuperType);
2093
2094     return new (Context) ObjCPropertyRefExpr(
2095         Getter, Setter, Context.PseudoObjectTy, VK_LValue, OK_ObjCProperty,
2096         propertyNameLoc, receiverNameLoc, IFace);
2097   }
2098   return ExprError(Diag(propertyNameLoc, diag::err_property_not_found)
2099                      << &propertyName << Context.getObjCInterfaceType(IFace));
2100 }
2101
2102 namespace {
2103
2104 class ObjCInterfaceOrSuperCCC final : public CorrectionCandidateCallback {
2105  public:
2106   ObjCInterfaceOrSuperCCC(ObjCMethodDecl *Method) {
2107     // Determine whether "super" is acceptable in the current context.
2108     if (Method && Method->getClassInterface())
2109       WantObjCSuper = Method->getClassInterface()->getSuperClass();
2110   }
2111
2112   bool ValidateCandidate(const TypoCorrection &candidate) override {
2113     return candidate.getCorrectionDeclAs<ObjCInterfaceDecl>() ||
2114         candidate.isKeyword("super");
2115   }
2116
2117   std::unique_ptr<CorrectionCandidateCallback> clone() override {
2118     return llvm::make_unique<ObjCInterfaceOrSuperCCC>(*this);
2119   }
2120 };
2121
2122 } // end anonymous namespace
2123
2124 Sema::ObjCMessageKind Sema::getObjCMessageKind(Scope *S,
2125                                                IdentifierInfo *Name,
2126                                                SourceLocation NameLoc,
2127                                                bool IsSuper,
2128                                                bool HasTrailingDot,
2129                                                ParsedType &ReceiverType) {
2130   ReceiverType = nullptr;
2131
2132   // If the identifier is "super" and there is no trailing dot, we're
2133   // messaging super. If the identifier is "super" and there is a
2134   // trailing dot, it's an instance message.
2135   if (IsSuper && S->isInObjcMethodScope())
2136     return HasTrailingDot? ObjCInstanceMessage : ObjCSuperMessage;
2137
2138   LookupResult Result(*this, Name, NameLoc, LookupOrdinaryName);
2139   LookupName(Result, S);
2140
2141   switch (Result.getResultKind()) {
2142   case LookupResult::NotFound:
2143     // Normal name lookup didn't find anything. If we're in an
2144     // Objective-C method, look for ivars. If we find one, we're done!
2145     // FIXME: This is a hack. Ivar lookup should be part of normal
2146     // lookup.
2147     if (ObjCMethodDecl *Method = getCurMethodDecl()) {
2148       if (!Method->getClassInterface()) {
2149         // Fall back: let the parser try to parse it as an instance message.
2150         return ObjCInstanceMessage;
2151       }
2152
2153       ObjCInterfaceDecl *ClassDeclared;
2154       if (Method->getClassInterface()->lookupInstanceVariable(Name,
2155                                                               ClassDeclared))
2156         return ObjCInstanceMessage;
2157     }
2158
2159     // Break out; we'll perform typo correction below.
2160     break;
2161
2162   case LookupResult::NotFoundInCurrentInstantiation:
2163   case LookupResult::FoundOverloaded:
2164   case LookupResult::FoundUnresolvedValue:
2165   case LookupResult::Ambiguous:
2166     Result.suppressDiagnostics();
2167     return ObjCInstanceMessage;
2168
2169   case LookupResult::Found: {
2170     // If the identifier is a class or not, and there is a trailing dot,
2171     // it's an instance message.
2172     if (HasTrailingDot)
2173       return ObjCInstanceMessage;
2174     // We found something. If it's a type, then we have a class
2175     // message. Otherwise, it's an instance message.
2176     NamedDecl *ND = Result.getFoundDecl();
2177     QualType T;
2178     if (ObjCInterfaceDecl *Class = dyn_cast<ObjCInterfaceDecl>(ND))
2179       T = Context.getObjCInterfaceType(Class);
2180     else if (TypeDecl *Type = dyn_cast<TypeDecl>(ND)) {
2181       T = Context.getTypeDeclType(Type);
2182       DiagnoseUseOfDecl(Type, NameLoc);
2183     }
2184     else
2185       return ObjCInstanceMessage;
2186
2187     //  We have a class message, and T is the type we're
2188     //  messaging. Build source-location information for it.
2189     TypeSourceInfo *TSInfo = Context.getTrivialTypeSourceInfo(T, NameLoc);
2190     ReceiverType = CreateParsedType(T, TSInfo);
2191     return ObjCClassMessage;
2192   }
2193   }
2194
2195   ObjCInterfaceOrSuperCCC CCC(getCurMethodDecl());
2196   if (TypoCorrection Corrected = CorrectTypo(
2197           Result.getLookupNameInfo(), Result.getLookupKind(), S, nullptr, CCC,
2198           CTK_ErrorRecovery, nullptr, false, nullptr, false)) {
2199     if (Corrected.isKeyword()) {
2200       // If we've found the keyword "super" (the only keyword that would be
2201       // returned by CorrectTypo), this is a send to super.
2202       diagnoseTypo(Corrected,
2203                    PDiag(diag::err_unknown_receiver_suggest) << Name);
2204       return ObjCSuperMessage;
2205     } else if (ObjCInterfaceDecl *Class =
2206                    Corrected.getCorrectionDeclAs<ObjCInterfaceDecl>()) {
2207       // If we found a declaration, correct when it refers to an Objective-C
2208       // class.
2209       diagnoseTypo(Corrected,
2210                    PDiag(diag::err_unknown_receiver_suggest) << Name);
2211       QualType T = Context.getObjCInterfaceType(Class);
2212       TypeSourceInfo *TSInfo = Context.getTrivialTypeSourceInfo(T, NameLoc);
2213       ReceiverType = CreateParsedType(T, TSInfo);
2214       return ObjCClassMessage;
2215     }
2216   }
2217
2218   // Fall back: let the parser try to parse it as an instance message.
2219   return ObjCInstanceMessage;
2220 }
2221
2222 ExprResult Sema::ActOnSuperMessage(Scope *S,
2223                                    SourceLocation SuperLoc,
2224                                    Selector Sel,
2225                                    SourceLocation LBracLoc,
2226                                    ArrayRef<SourceLocation> SelectorLocs,
2227                                    SourceLocation RBracLoc,
2228                                    MultiExprArg Args) {
2229   // Determine whether we are inside a method or not.
2230   ObjCMethodDecl *Method = tryCaptureObjCSelf(SuperLoc);
2231   if (!Method) {
2232     Diag(SuperLoc, diag::err_invalid_receiver_to_message_super);
2233     return ExprError();
2234   }
2235
2236   ObjCInterfaceDecl *Class = Method->getClassInterface();
2237   if (!Class) {
2238     Diag(SuperLoc, diag::err_no_super_class_message)
2239       << Method->getDeclName();
2240     return ExprError();
2241   }
2242
2243   QualType SuperTy(Class->getSuperClassType(), 0);
2244   if (SuperTy.isNull()) {
2245     // The current class does not have a superclass.
2246     Diag(SuperLoc, diag::err_root_class_cannot_use_super)
2247       << Class->getIdentifier();
2248     return ExprError();
2249   }
2250
2251   // We are in a method whose class has a superclass, so 'super'
2252   // is acting as a keyword.
2253   if (Method->getSelector() == Sel)
2254     getCurFunction()->ObjCShouldCallSuper = false;
2255
2256   if (Method->isInstanceMethod()) {
2257     // Since we are in an instance method, this is an instance
2258     // message to the superclass instance.
2259     SuperTy = Context.getObjCObjectPointerType(SuperTy);
2260     return BuildInstanceMessage(nullptr, SuperTy, SuperLoc,
2261                                 Sel, /*Method=*/nullptr,
2262                                 LBracLoc, SelectorLocs, RBracLoc, Args);
2263   }
2264
2265   // Since we are in a class method, this is a class message to
2266   // the superclass.
2267   return BuildClassMessage(/*ReceiverTypeInfo=*/nullptr,
2268                            SuperTy,
2269                            SuperLoc, Sel, /*Method=*/nullptr,
2270                            LBracLoc, SelectorLocs, RBracLoc, Args);
2271 }
2272
2273 ExprResult Sema::BuildClassMessageImplicit(QualType ReceiverType,
2274                                            bool isSuperReceiver,
2275                                            SourceLocation Loc,
2276                                            Selector Sel,
2277                                            ObjCMethodDecl *Method,
2278                                            MultiExprArg Args) {
2279   TypeSourceInfo *receiverTypeInfo = nullptr;
2280   if (!ReceiverType.isNull())
2281     receiverTypeInfo = Context.getTrivialTypeSourceInfo(ReceiverType);
2282
2283   return BuildClassMessage(receiverTypeInfo, ReceiverType,
2284                           /*SuperLoc=*/isSuperReceiver ? Loc : SourceLocation(),
2285                            Sel, Method, Loc, Loc, Loc, Args,
2286                            /*isImplicit=*/true);
2287 }
2288
2289 static void applyCocoaAPICheck(Sema &S, const ObjCMessageExpr *Msg,
2290                                unsigned DiagID,
2291                                bool (*refactor)(const ObjCMessageExpr *,
2292                                               const NSAPI &, edit::Commit &)) {
2293   SourceLocation MsgLoc = Msg->getExprLoc();
2294   if (S.Diags.isIgnored(DiagID, MsgLoc))
2295     return;
2296
2297   SourceManager &SM = S.SourceMgr;
2298   edit::Commit ECommit(SM, S.LangOpts);
2299   if (refactor(Msg,*S.NSAPIObj, ECommit)) {
2300     DiagnosticBuilder Builder = S.Diag(MsgLoc, DiagID)
2301                         << Msg->getSelector() << Msg->getSourceRange();
2302     // FIXME: Don't emit diagnostic at all if fixits are non-commitable.
2303     if (!ECommit.isCommitable())
2304       return;
2305     for (edit::Commit::edit_iterator
2306            I = ECommit.edit_begin(), E = ECommit.edit_end(); I != E; ++I) {
2307       const edit::Commit::Edit &Edit = *I;
2308       switch (Edit.Kind) {
2309       case edit::Commit::Act_Insert:
2310         Builder.AddFixItHint(FixItHint::CreateInsertion(Edit.OrigLoc,
2311                                                         Edit.Text,
2312                                                         Edit.BeforePrev));
2313         break;
2314       case edit::Commit::Act_InsertFromRange:
2315         Builder.AddFixItHint(
2316             FixItHint::CreateInsertionFromRange(Edit.OrigLoc,
2317                                                 Edit.getInsertFromRange(SM),
2318                                                 Edit.BeforePrev));
2319         break;
2320       case edit::Commit::Act_Remove:
2321         Builder.AddFixItHint(FixItHint::CreateRemoval(Edit.getFileRange(SM)));
2322         break;
2323       }
2324     }
2325   }
2326 }
2327
2328 static void checkCocoaAPI(Sema &S, const ObjCMessageExpr *Msg) {
2329   applyCocoaAPICheck(S, Msg, diag::warn_objc_redundant_literal_use,
2330                      edit::rewriteObjCRedundantCallWithLiteral);
2331 }
2332
2333 static void checkFoundationAPI(Sema &S, SourceLocation Loc,
2334                                const ObjCMethodDecl *Method,
2335                                ArrayRef<Expr *> Args, QualType ReceiverType,
2336                                bool IsClassObjectCall) {
2337   // Check if this is a performSelector method that uses a selector that returns
2338   // a record or a vector type.
2339   if (Method->getSelector().getMethodFamily() != OMF_performSelector ||
2340       Args.empty())
2341     return;
2342   const auto *SE = dyn_cast<ObjCSelectorExpr>(Args[0]->IgnoreParens());
2343   if (!SE)
2344     return;
2345   ObjCMethodDecl *ImpliedMethod;
2346   if (!IsClassObjectCall) {
2347     const auto *OPT = ReceiverType->getAs<ObjCObjectPointerType>();
2348     if (!OPT || !OPT->getInterfaceDecl())
2349       return;
2350     ImpliedMethod =
2351         OPT->getInterfaceDecl()->lookupInstanceMethod(SE->getSelector());
2352     if (!ImpliedMethod)
2353       ImpliedMethod =
2354           OPT->getInterfaceDecl()->lookupPrivateMethod(SE->getSelector());
2355   } else {
2356     const auto *IT = ReceiverType->getAs<ObjCInterfaceType>();
2357     if (!IT)
2358       return;
2359     ImpliedMethod = IT->getDecl()->lookupClassMethod(SE->getSelector());
2360     if (!ImpliedMethod)
2361       ImpliedMethod =
2362           IT->getDecl()->lookupPrivateClassMethod(SE->getSelector());
2363   }
2364   if (!ImpliedMethod)
2365     return;
2366   QualType Ret = ImpliedMethod->getReturnType();
2367   if (Ret->isRecordType() || Ret->isVectorType() || Ret->isExtVectorType()) {
2368     QualType Ret = ImpliedMethod->getReturnType();
2369     S.Diag(Loc, diag::warn_objc_unsafe_perform_selector)
2370         << Method->getSelector()
2371         << (!Ret->isRecordType()
2372                 ? /*Vector*/ 2
2373                 : Ret->isUnionType() ? /*Union*/ 1 : /*Struct*/ 0);
2374     S.Diag(ImpliedMethod->getBeginLoc(),
2375            diag::note_objc_unsafe_perform_selector_method_declared_here)
2376         << ImpliedMethod->getSelector() << Ret;
2377   }
2378 }
2379
2380 /// Diagnose use of %s directive in an NSString which is being passed
2381 /// as formatting string to formatting method.
2382 static void
2383 DiagnoseCStringFormatDirectiveInObjCAPI(Sema &S,
2384                                         ObjCMethodDecl *Method,
2385                                         Selector Sel,
2386                                         Expr **Args, unsigned NumArgs) {
2387   unsigned Idx = 0;
2388   bool Format = false;
2389   ObjCStringFormatFamily SFFamily = Sel.getStringFormatFamily();
2390   if (SFFamily == ObjCStringFormatFamily::SFF_NSString) {
2391     Idx = 0;
2392     Format = true;
2393   }
2394   else if (Method) {
2395     for (const auto *I : Method->specific_attrs<FormatAttr>()) {
2396       if (S.GetFormatNSStringIdx(I, Idx)) {
2397         Format = true;
2398         break;
2399       }
2400     }
2401   }
2402   if (!Format || NumArgs <= Idx)
2403     return;
2404
2405   Expr *FormatExpr = Args[Idx];
2406   if (ObjCStringLiteral *OSL =
2407       dyn_cast<ObjCStringLiteral>(FormatExpr->IgnoreParenImpCasts())) {
2408     StringLiteral *FormatString = OSL->getString();
2409     if (S.FormatStringHasSArg(FormatString)) {
2410       S.Diag(FormatExpr->getExprLoc(), diag::warn_objc_cdirective_format_string)
2411         << "%s" << 0 << 0;
2412       if (Method)
2413         S.Diag(Method->getLocation(), diag::note_method_declared_at)
2414           << Method->getDeclName();
2415     }
2416   }
2417 }
2418
2419 /// Build an Objective-C class message expression.
2420 ///
2421 /// This routine takes care of both normal class messages and
2422 /// class messages to the superclass.
2423 ///
2424 /// \param ReceiverTypeInfo Type source information that describes the
2425 /// receiver of this message. This may be NULL, in which case we are
2426 /// sending to the superclass and \p SuperLoc must be a valid source
2427 /// location.
2428
2429 /// \param ReceiverType The type of the object receiving the
2430 /// message. When \p ReceiverTypeInfo is non-NULL, this is the same
2431 /// type as that refers to. For a superclass send, this is the type of
2432 /// the superclass.
2433 ///
2434 /// \param SuperLoc The location of the "super" keyword in a
2435 /// superclass message.
2436 ///
2437 /// \param Sel The selector to which the message is being sent.
2438 ///
2439 /// \param Method The method that this class message is invoking, if
2440 /// already known.
2441 ///
2442 /// \param LBracLoc The location of the opening square bracket ']'.
2443 ///
2444 /// \param RBracLoc The location of the closing square bracket ']'.
2445 ///
2446 /// \param ArgsIn The message arguments.
2447 ExprResult Sema::BuildClassMessage(TypeSourceInfo *ReceiverTypeInfo,
2448                                    QualType ReceiverType,
2449                                    SourceLocation SuperLoc,
2450                                    Selector Sel,
2451                                    ObjCMethodDecl *Method,
2452                                    SourceLocation LBracLoc,
2453                                    ArrayRef<SourceLocation> SelectorLocs,
2454                                    SourceLocation RBracLoc,
2455                                    MultiExprArg ArgsIn,
2456                                    bool isImplicit) {
2457   SourceLocation Loc = SuperLoc.isValid()? SuperLoc
2458     : ReceiverTypeInfo->getTypeLoc().getSourceRange().getBegin();
2459   if (LBracLoc.isInvalid()) {
2460     Diag(Loc, diag::err_missing_open_square_message_send)
2461       << FixItHint::CreateInsertion(Loc, "[");
2462     LBracLoc = Loc;
2463   }
2464   ArrayRef<SourceLocation> SelectorSlotLocs;
2465   if (!SelectorLocs.empty() && SelectorLocs.front().isValid())
2466     SelectorSlotLocs = SelectorLocs;
2467   else
2468     SelectorSlotLocs = Loc;
2469   SourceLocation SelLoc = SelectorSlotLocs.front();
2470
2471   if (ReceiverType->isDependentType()) {
2472     // If the receiver type is dependent, we can't type-check anything
2473     // at this point. Build a dependent expression.
2474     unsigned NumArgs = ArgsIn.size();
2475     Expr **Args = ArgsIn.data();
2476     assert(SuperLoc.isInvalid() && "Message to super with dependent type");
2477     return ObjCMessageExpr::Create(
2478         Context, ReceiverType, VK_RValue, LBracLoc, ReceiverTypeInfo, Sel,
2479         SelectorLocs, /*Method=*/nullptr, makeArrayRef(Args, NumArgs), RBracLoc,
2480         isImplicit);
2481   }
2482
2483   // Find the class to which we are sending this message.
2484   ObjCInterfaceDecl *Class = nullptr;
2485   const ObjCObjectType *ClassType = ReceiverType->getAs<ObjCObjectType>();
2486   if (!ClassType || !(Class = ClassType->getInterface())) {
2487     Diag(Loc, diag::err_invalid_receiver_class_message)
2488       << ReceiverType;
2489     return ExprError();
2490   }
2491   assert(Class && "We don't know which class we're messaging?");
2492   // objc++ diagnoses during typename annotation.
2493   if (!getLangOpts().CPlusPlus)
2494     (void)DiagnoseUseOfDecl(Class, SelectorSlotLocs);
2495   // Find the method we are messaging.
2496   if (!Method) {
2497     SourceRange TypeRange
2498       = SuperLoc.isValid()? SourceRange(SuperLoc)
2499                           : ReceiverTypeInfo->getTypeLoc().getSourceRange();
2500     if (RequireCompleteType(Loc, Context.getObjCInterfaceType(Class),
2501                             (getLangOpts().ObjCAutoRefCount
2502                                ? diag::err_arc_receiver_forward_class
2503                                : diag::warn_receiver_forward_class),
2504                             TypeRange)) {
2505       // A forward class used in messaging is treated as a 'Class'
2506       Method = LookupFactoryMethodInGlobalPool(Sel,
2507                                                SourceRange(LBracLoc, RBracLoc));
2508       if (Method && !getLangOpts().ObjCAutoRefCount)
2509         Diag(Method->getLocation(), diag::note_method_sent_forward_class)
2510           << Method->getDeclName();
2511     }
2512     if (!Method)
2513       Method = Class->lookupClassMethod(Sel);
2514
2515     // If we have an implementation in scope, check "private" methods.
2516     if (!Method)
2517       Method = Class->lookupPrivateClassMethod(Sel);
2518
2519     if (Method && DiagnoseUseOfDecl(Method, SelectorSlotLocs,
2520                                     nullptr, false, false, Class))
2521       return ExprError();
2522   }
2523
2524   // Check the argument types and determine the result type.
2525   QualType ReturnType;
2526   ExprValueKind VK = VK_RValue;
2527
2528   unsigned NumArgs = ArgsIn.size();
2529   Expr **Args = ArgsIn.data();
2530   if (CheckMessageArgumentTypes(/*Receiver=*/nullptr, ReceiverType,
2531                                 MultiExprArg(Args, NumArgs), Sel, SelectorLocs,
2532                                 Method, true, SuperLoc.isValid(), LBracLoc,
2533                                 RBracLoc, SourceRange(), ReturnType, VK))
2534     return ExprError();
2535
2536   if (Method && !Method->getReturnType()->isVoidType() &&
2537       RequireCompleteType(LBracLoc, Method->getReturnType(),
2538                           diag::err_illegal_message_expr_incomplete_type))
2539     return ExprError();
2540
2541   // Warn about explicit call of +initialize on its own class. But not on 'super'.
2542   if (Method && Method->getMethodFamily() == OMF_initialize) {
2543     if (!SuperLoc.isValid()) {
2544       const ObjCInterfaceDecl *ID =
2545         dyn_cast<ObjCInterfaceDecl>(Method->getDeclContext());
2546       if (ID == Class) {
2547         Diag(Loc, diag::warn_direct_initialize_call);
2548         Diag(Method->getLocation(), diag::note_method_declared_at)
2549           << Method->getDeclName();
2550       }
2551     }
2552     else if (ObjCMethodDecl *CurMeth = getCurMethodDecl()) {
2553       // [super initialize] is allowed only within an +initialize implementation
2554       if (CurMeth->getMethodFamily() != OMF_initialize) {
2555         Diag(Loc, diag::warn_direct_super_initialize_call);
2556         Diag(Method->getLocation(), diag::note_method_declared_at)
2557           << Method->getDeclName();
2558         Diag(CurMeth->getLocation(), diag::note_method_declared_at)
2559         << CurMeth->getDeclName();
2560       }
2561     }
2562   }
2563
2564   DiagnoseCStringFormatDirectiveInObjCAPI(*this, Method, Sel, Args, NumArgs);
2565
2566   // Construct the appropriate ObjCMessageExpr.
2567   ObjCMessageExpr *Result;
2568   if (SuperLoc.isValid())
2569     Result = ObjCMessageExpr::Create(Context, ReturnType, VK, LBracLoc,
2570                                      SuperLoc, /*IsInstanceSuper=*/false,
2571                                      ReceiverType, Sel, SelectorLocs,
2572                                      Method, makeArrayRef(Args, NumArgs),
2573                                      RBracLoc, isImplicit);
2574   else {
2575     Result = ObjCMessageExpr::Create(Context, ReturnType, VK, LBracLoc,
2576                                      ReceiverTypeInfo, Sel, SelectorLocs,
2577                                      Method, makeArrayRef(Args, NumArgs),
2578                                      RBracLoc, isImplicit);
2579     if (!isImplicit)
2580       checkCocoaAPI(*this, Result);
2581   }
2582   if (Method)
2583     checkFoundationAPI(*this, SelLoc, Method, makeArrayRef(Args, NumArgs),
2584                        ReceiverType, /*IsClassObjectCall=*/true);
2585   return MaybeBindToTemporary(Result);
2586 }
2587
2588 // ActOnClassMessage - used for both unary and keyword messages.
2589 // ArgExprs is optional - if it is present, the number of expressions
2590 // is obtained from Sel.getNumArgs().
2591 ExprResult Sema::ActOnClassMessage(Scope *S,
2592                                    ParsedType Receiver,
2593                                    Selector Sel,
2594                                    SourceLocation LBracLoc,
2595                                    ArrayRef<SourceLocation> SelectorLocs,
2596                                    SourceLocation RBracLoc,
2597                                    MultiExprArg Args) {
2598   TypeSourceInfo *ReceiverTypeInfo;
2599   QualType ReceiverType = GetTypeFromParser(Receiver, &ReceiverTypeInfo);
2600   if (ReceiverType.isNull())
2601     return ExprError();
2602
2603   if (!ReceiverTypeInfo)
2604     ReceiverTypeInfo = Context.getTrivialTypeSourceInfo(ReceiverType, LBracLoc);
2605
2606   return BuildClassMessage(ReceiverTypeInfo, ReceiverType,
2607                            /*SuperLoc=*/SourceLocation(), Sel,
2608                            /*Method=*/nullptr, LBracLoc, SelectorLocs, RBracLoc,
2609                            Args);
2610 }
2611
2612 ExprResult Sema::BuildInstanceMessageImplicit(Expr *Receiver,
2613                                               QualType ReceiverType,
2614                                               SourceLocation Loc,
2615                                               Selector Sel,
2616                                               ObjCMethodDecl *Method,
2617                                               MultiExprArg Args) {
2618   return BuildInstanceMessage(Receiver, ReceiverType,
2619                               /*SuperLoc=*/!Receiver ? Loc : SourceLocation(),
2620                               Sel, Method, Loc, Loc, Loc, Args,
2621                               /*isImplicit=*/true);
2622 }
2623
2624 static bool isMethodDeclaredInRootProtocol(Sema &S, const ObjCMethodDecl *M) {
2625   if (!S.NSAPIObj)
2626     return false;
2627   const auto *Protocol = dyn_cast<ObjCProtocolDecl>(M->getDeclContext());
2628   if (!Protocol)
2629     return false;
2630   const IdentifierInfo *II = S.NSAPIObj->getNSClassId(NSAPI::ClassId_NSObject);
2631   if (const auto *RootClass = dyn_cast_or_null<ObjCInterfaceDecl>(
2632           S.LookupSingleName(S.TUScope, II, Protocol->getBeginLoc(),
2633                              Sema::LookupOrdinaryName))) {
2634     for (const ObjCProtocolDecl *P : RootClass->all_referenced_protocols()) {
2635       if (P->getCanonicalDecl() == Protocol->getCanonicalDecl())
2636         return true;
2637     }
2638   }
2639   return false;
2640 }
2641
2642 /// Build an Objective-C instance message expression.
2643 ///
2644 /// This routine takes care of both normal instance messages and
2645 /// instance messages to the superclass instance.
2646 ///
2647 /// \param Receiver The expression that computes the object that will
2648 /// receive this message. This may be empty, in which case we are
2649 /// sending to the superclass instance and \p SuperLoc must be a valid
2650 /// source location.
2651 ///
2652 /// \param ReceiverType The (static) type of the object receiving the
2653 /// message. When a \p Receiver expression is provided, this is the
2654 /// same type as that expression. For a superclass instance send, this
2655 /// is a pointer to the type of the superclass.
2656 ///
2657 /// \param SuperLoc The location of the "super" keyword in a
2658 /// superclass instance message.
2659 ///
2660 /// \param Sel The selector to which the message is being sent.
2661 ///
2662 /// \param Method The method that this instance message is invoking, if
2663 /// already known.
2664 ///
2665 /// \param LBracLoc The location of the opening square bracket ']'.
2666 ///
2667 /// \param RBracLoc The location of the closing square bracket ']'.
2668 ///
2669 /// \param ArgsIn The message arguments.
2670 ExprResult Sema::BuildInstanceMessage(Expr *Receiver,
2671                                       QualType ReceiverType,
2672                                       SourceLocation SuperLoc,
2673                                       Selector Sel,
2674                                       ObjCMethodDecl *Method,
2675                                       SourceLocation LBracLoc,
2676                                       ArrayRef<SourceLocation> SelectorLocs,
2677                                       SourceLocation RBracLoc,
2678                                       MultiExprArg ArgsIn,
2679                                       bool isImplicit) {
2680   assert((Receiver || SuperLoc.isValid()) && "If the Receiver is null, the "
2681                                              "SuperLoc must be valid so we can "
2682                                              "use it instead.");
2683
2684   // The location of the receiver.
2685   SourceLocation Loc = SuperLoc.isValid() ? SuperLoc : Receiver->getBeginLoc();
2686   SourceRange RecRange =
2687       SuperLoc.isValid()? SuperLoc : Receiver->getSourceRange();
2688   ArrayRef<SourceLocation> SelectorSlotLocs;
2689   if (!SelectorLocs.empty() && SelectorLocs.front().isValid())
2690     SelectorSlotLocs = SelectorLocs;
2691   else
2692     SelectorSlotLocs = Loc;
2693   SourceLocation SelLoc = SelectorSlotLocs.front();
2694
2695   if (LBracLoc.isInvalid()) {
2696     Diag(Loc, diag::err_missing_open_square_message_send)
2697       << FixItHint::CreateInsertion(Loc, "[");
2698     LBracLoc = Loc;
2699   }
2700
2701   // If we have a receiver expression, perform appropriate promotions
2702   // and determine receiver type.
2703   if (Receiver) {
2704     if (Receiver->hasPlaceholderType()) {
2705       ExprResult Result;
2706       if (Receiver->getType() == Context.UnknownAnyTy)
2707         Result = forceUnknownAnyToType(Receiver, Context.getObjCIdType());
2708       else
2709         Result = CheckPlaceholderExpr(Receiver);
2710       if (Result.isInvalid()) return ExprError();
2711       Receiver = Result.get();
2712     }
2713
2714     if (Receiver->isTypeDependent()) {
2715       // If the receiver is type-dependent, we can't type-check anything
2716       // at this point. Build a dependent expression.
2717       unsigned NumArgs = ArgsIn.size();
2718       Expr **Args = ArgsIn.data();
2719       assert(SuperLoc.isInvalid() && "Message to super with dependent type");
2720       return ObjCMessageExpr::Create(
2721           Context, Context.DependentTy, VK_RValue, LBracLoc, Receiver, Sel,
2722           SelectorLocs, /*Method=*/nullptr, makeArrayRef(Args, NumArgs),
2723           RBracLoc, isImplicit);
2724     }
2725
2726     // If necessary, apply function/array conversion to the receiver.
2727     // C99 6.7.5.3p[7,8].
2728     ExprResult Result = DefaultFunctionArrayLvalueConversion(Receiver);
2729     if (Result.isInvalid())
2730       return ExprError();
2731     Receiver = Result.get();
2732     ReceiverType = Receiver->getType();
2733
2734     // If the receiver is an ObjC pointer, a block pointer, or an
2735     // __attribute__((NSObject)) pointer, we don't need to do any
2736     // special conversion in order to look up a receiver.
2737     if (ReceiverType->isObjCRetainableType()) {
2738       // do nothing
2739     } else if (!getLangOpts().ObjCAutoRefCount &&
2740                !Context.getObjCIdType().isNull() &&
2741                (ReceiverType->isPointerType() ||
2742                 ReceiverType->isIntegerType())) {
2743       // Implicitly convert integers and pointers to 'id' but emit a warning.
2744       // But not in ARC.
2745       Diag(Loc, diag::warn_bad_receiver_type)
2746         << ReceiverType
2747         << Receiver->getSourceRange();
2748       if (ReceiverType->isPointerType()) {
2749         Receiver = ImpCastExprToType(Receiver, Context.getObjCIdType(),
2750                                      CK_CPointerToObjCPointerCast).get();
2751       } else {
2752         // TODO: specialized warning on null receivers?
2753         bool IsNull = Receiver->isNullPointerConstant(Context,
2754                                               Expr::NPC_ValueDependentIsNull);
2755         CastKind Kind = IsNull ? CK_NullToPointer : CK_IntegralToPointer;
2756         Receiver = ImpCastExprToType(Receiver, Context.getObjCIdType(),
2757                                      Kind).get();
2758       }
2759       ReceiverType = Receiver->getType();
2760     } else if (getLangOpts().CPlusPlus) {
2761       // The receiver must be a complete type.
2762       if (RequireCompleteType(Loc, Receiver->getType(),
2763                               diag::err_incomplete_receiver_type))
2764         return ExprError();
2765
2766       ExprResult result = PerformContextuallyConvertToObjCPointer(Receiver);
2767       if (result.isUsable()) {
2768         Receiver = result.get();
2769         ReceiverType = Receiver->getType();
2770       }
2771     }
2772   }
2773
2774   if (ReceiverType->isObjCIdType() && !isImplicit)
2775     Diag(Receiver->getExprLoc(), diag::warn_messaging_unqualified_id);
2776
2777   // There's a somewhat weird interaction here where we assume that we
2778   // won't actually have a method unless we also don't need to do some
2779   // of the more detailed type-checking on the receiver.
2780
2781   if (!Method) {
2782     // Handle messages to id and __kindof types (where we use the
2783     // global method pool).
2784     const ObjCObjectType *typeBound = nullptr;
2785     bool receiverIsIdLike = ReceiverType->isObjCIdOrObjectKindOfType(Context,
2786                                                                      typeBound);
2787     if (receiverIsIdLike || ReceiverType->isBlockPointerType() ||
2788         (Receiver && Context.isObjCNSObjectType(Receiver->getType()))) {
2789       SmallVector<ObjCMethodDecl*, 4> Methods;
2790       // If we have a type bound, further filter the methods.
2791       CollectMultipleMethodsInGlobalPool(Sel, Methods, true/*InstanceFirst*/,
2792                                          true/*CheckTheOther*/, typeBound);
2793       if (!Methods.empty()) {
2794         // We choose the first method as the initial candidate, then try to
2795         // select a better one.
2796         Method = Methods[0];
2797
2798         if (ObjCMethodDecl *BestMethod =
2799             SelectBestMethod(Sel, ArgsIn, Method->isInstanceMethod(), Methods))
2800           Method = BestMethod;
2801
2802         if (!AreMultipleMethodsInGlobalPool(Sel, Method,
2803                                             SourceRange(LBracLoc, RBracLoc),
2804                                             receiverIsIdLike, Methods))
2805           DiagnoseUseOfDecl(Method, SelectorSlotLocs);
2806       }
2807     } else if (ReceiverType->isObjCClassOrClassKindOfType() ||
2808                ReceiverType->isObjCQualifiedClassType()) {
2809       // Handle messages to Class.
2810       // We allow sending a message to a qualified Class ("Class<foo>"), which
2811       // is ok as long as one of the protocols implements the selector (if not,
2812       // warn).
2813       if (!ReceiverType->isObjCClassOrClassKindOfType()) {
2814         const ObjCObjectPointerType *QClassTy
2815           = ReceiverType->getAsObjCQualifiedClassType();
2816         // Search protocols for class methods.
2817         Method = LookupMethodInQualifiedType(Sel, QClassTy, false);
2818         if (!Method) {
2819           Method = LookupMethodInQualifiedType(Sel, QClassTy, true);
2820           // warn if instance method found for a Class message.
2821           if (Method && !isMethodDeclaredInRootProtocol(*this, Method)) {
2822             Diag(SelLoc, diag::warn_instance_method_on_class_found)
2823               << Method->getSelector() << Sel;
2824             Diag(Method->getLocation(), diag::note_method_declared_at)
2825               << Method->getDeclName();
2826           }
2827         }
2828       } else {
2829         if (ObjCMethodDecl *CurMeth = getCurMethodDecl()) {
2830           if (ObjCInterfaceDecl *ClassDecl = CurMeth->getClassInterface()) {
2831             // As a guess, try looking for the method in the current interface.
2832             // This very well may not produce the "right" method.
2833
2834             // First check the public methods in the class interface.
2835             Method = ClassDecl->lookupClassMethod(Sel);
2836
2837             if (!Method)
2838               Method = ClassDecl->lookupPrivateClassMethod(Sel);
2839
2840             if (Method && DiagnoseUseOfDecl(Method, SelectorSlotLocs))
2841               return ExprError();
2842           }
2843         }
2844         if (!Method) {
2845           // If not messaging 'self', look for any factory method named 'Sel'.
2846           if (!Receiver || !isSelfExpr(Receiver)) {
2847             // If no class (factory) method was found, check if an _instance_
2848             // method of the same name exists in the root class only.
2849             SmallVector<ObjCMethodDecl*, 4> Methods;
2850             CollectMultipleMethodsInGlobalPool(Sel, Methods,
2851                                                false/*InstanceFirst*/,
2852                                                true/*CheckTheOther*/);
2853             if (!Methods.empty()) {
2854               // We choose the first method as the initial candidate, then try
2855               // to select a better one.
2856               Method = Methods[0];
2857
2858               // If we find an instance method, emit warning.
2859               if (Method->isInstanceMethod()) {
2860                 if (const ObjCInterfaceDecl *ID =
2861                     dyn_cast<ObjCInterfaceDecl>(Method->getDeclContext())) {
2862                   if (ID->getSuperClass())
2863                     Diag(SelLoc, diag::warn_root_inst_method_not_found)
2864                         << Sel << SourceRange(LBracLoc, RBracLoc);
2865                 }
2866               }
2867
2868              if (ObjCMethodDecl *BestMethod =
2869                  SelectBestMethod(Sel, ArgsIn, Method->isInstanceMethod(),
2870                                   Methods))
2871                Method = BestMethod;
2872             }
2873           }
2874         }
2875       }
2876     } else {
2877       ObjCInterfaceDecl *ClassDecl = nullptr;
2878
2879       // We allow sending a message to a qualified ID ("id<foo>"), which is ok as
2880       // long as one of the protocols implements the selector (if not, warn).
2881       // And as long as message is not deprecated/unavailable (warn if it is).
2882       if (const ObjCObjectPointerType *QIdTy
2883                                    = ReceiverType->getAsObjCQualifiedIdType()) {
2884         // Search protocols for instance methods.
2885         Method = LookupMethodInQualifiedType(Sel, QIdTy, true);
2886         if (!Method)
2887           Method = LookupMethodInQualifiedType(Sel, QIdTy, false);
2888         if (Method && DiagnoseUseOfDecl(Method, SelectorSlotLocs))
2889           return ExprError();
2890       } else if (const ObjCObjectPointerType *OCIType
2891                    = ReceiverType->getAsObjCInterfacePointerType()) {
2892         // We allow sending a message to a pointer to an interface (an object).
2893         ClassDecl = OCIType->getInterfaceDecl();
2894
2895         // Try to complete the type. Under ARC, this is a hard error from which
2896         // we don't try to recover.
2897         // FIXME: In the non-ARC case, this will still be a hard error if the
2898         // definition is found in a module that's not visible.
2899         const ObjCInterfaceDecl *forwardClass = nullptr;
2900         if (RequireCompleteType(Loc, OCIType->getPointeeType(),
2901               getLangOpts().ObjCAutoRefCount
2902                 ? diag::err_arc_receiver_forward_instance
2903                 : diag::warn_receiver_forward_instance,
2904                                 Receiver? Receiver->getSourceRange()
2905                                         : SourceRange(SuperLoc))) {
2906           if (getLangOpts().ObjCAutoRefCount)
2907             return ExprError();
2908
2909           forwardClass = OCIType->getInterfaceDecl();
2910           Diag(Receiver ? Receiver->getBeginLoc() : SuperLoc,
2911                diag::note_receiver_is_id);
2912           Method = nullptr;
2913         } else {
2914           Method = ClassDecl->lookupInstanceMethod(Sel);
2915         }
2916
2917         if (!Method)
2918           // Search protocol qualifiers.
2919           Method = LookupMethodInQualifiedType(Sel, OCIType, true);
2920
2921         if (!Method) {
2922           // If we have implementations in scope, check "private" methods.
2923           Method = ClassDecl->lookupPrivateMethod(Sel);
2924
2925           if (!Method && getLangOpts().ObjCAutoRefCount) {
2926             Diag(SelLoc, diag::err_arc_may_not_respond)
2927               << OCIType->getPointeeType() << Sel << RecRange
2928               << SourceRange(SelectorLocs.front(), SelectorLocs.back());
2929             return ExprError();
2930           }
2931
2932           if (!Method && (!Receiver || !isSelfExpr(Receiver))) {
2933             // If we still haven't found a method, look in the global pool. This
2934             // behavior isn't very desirable, however we need it for GCC
2935             // compatibility. FIXME: should we deviate??
2936             if (OCIType->qual_empty()) {
2937               SmallVector<ObjCMethodDecl*, 4> Methods;
2938               CollectMultipleMethodsInGlobalPool(Sel, Methods,
2939                                                  true/*InstanceFirst*/,
2940                                                  false/*CheckTheOther*/);
2941               if (!Methods.empty()) {
2942                 // We choose the first method as the initial candidate, then try
2943                 // to select a better one.
2944                 Method = Methods[0];
2945
2946                 if (ObjCMethodDecl *BestMethod =
2947                     SelectBestMethod(Sel, ArgsIn, Method->isInstanceMethod(),
2948                                      Methods))
2949                   Method = BestMethod;
2950
2951                 AreMultipleMethodsInGlobalPool(Sel, Method,
2952                                                SourceRange(LBracLoc, RBracLoc),
2953                                                true/*receiverIdOrClass*/,
2954                                                Methods);
2955               }
2956               if (Method && !forwardClass)
2957                 Diag(SelLoc, diag::warn_maynot_respond)
2958                   << OCIType->getInterfaceDecl()->getIdentifier()
2959                   << Sel << RecRange;
2960             }
2961           }
2962         }
2963         if (Method && DiagnoseUseOfDecl(Method, SelectorSlotLocs, forwardClass))
2964           return ExprError();
2965       } else {
2966         // Reject other random receiver types (e.g. structs).
2967         Diag(Loc, diag::err_bad_receiver_type)
2968           << ReceiverType << Receiver->getSourceRange();
2969         return ExprError();
2970       }
2971     }
2972   }
2973
2974   FunctionScopeInfo *DIFunctionScopeInfo =
2975     (Method && Method->getMethodFamily() == OMF_init)
2976       ? getEnclosingFunction() : nullptr;
2977
2978   if (DIFunctionScopeInfo &&
2979       DIFunctionScopeInfo->ObjCIsDesignatedInit &&
2980       (SuperLoc.isValid() || isSelfExpr(Receiver))) {
2981     bool isDesignatedInitChain = false;
2982     if (SuperLoc.isValid()) {
2983       if (const ObjCObjectPointerType *
2984             OCIType = ReceiverType->getAsObjCInterfacePointerType()) {
2985         if (const ObjCInterfaceDecl *ID = OCIType->getInterfaceDecl()) {
2986           // Either we know this is a designated initializer or we
2987           // conservatively assume it because we don't know for sure.
2988           if (!ID->declaresOrInheritsDesignatedInitializers() ||
2989               ID->isDesignatedInitializer(Sel)) {
2990             isDesignatedInitChain = true;
2991             DIFunctionScopeInfo->ObjCWarnForNoDesignatedInitChain = false;
2992           }
2993         }
2994       }
2995     }
2996     if (!isDesignatedInitChain) {
2997       const ObjCMethodDecl *InitMethod = nullptr;
2998       bool isDesignated =
2999         getCurMethodDecl()->isDesignatedInitializerForTheInterface(&InitMethod);
3000       assert(isDesignated && InitMethod);
3001       (void)isDesignated;
3002       Diag(SelLoc, SuperLoc.isValid() ?
3003              diag::warn_objc_designated_init_non_designated_init_call :
3004              diag::warn_objc_designated_init_non_super_designated_init_call);
3005       Diag(InitMethod->getLocation(),
3006            diag::note_objc_designated_init_marked_here);
3007     }
3008   }
3009
3010   if (DIFunctionScopeInfo &&
3011       DIFunctionScopeInfo->ObjCIsSecondaryInit &&
3012       (SuperLoc.isValid() || isSelfExpr(Receiver))) {
3013     if (SuperLoc.isValid()) {
3014       Diag(SelLoc, diag::warn_objc_secondary_init_super_init_call);
3015     } else {
3016       DIFunctionScopeInfo->ObjCWarnForNoInitDelegation = false;
3017     }
3018   }
3019
3020   // Check the message arguments.
3021   unsigned NumArgs = ArgsIn.size();
3022   Expr **Args = ArgsIn.data();
3023   QualType ReturnType;
3024   ExprValueKind VK = VK_RValue;
3025   bool ClassMessage = (ReceiverType->isObjCClassType() ||
3026                        ReceiverType->isObjCQualifiedClassType());
3027   if (CheckMessageArgumentTypes(Receiver, ReceiverType,
3028                                 MultiExprArg(Args, NumArgs), Sel, SelectorLocs,
3029                                 Method, ClassMessage, SuperLoc.isValid(),
3030                                 LBracLoc, RBracLoc, RecRange, ReturnType, VK))
3031     return ExprError();
3032
3033   if (Method && !Method->getReturnType()->isVoidType() &&
3034       RequireCompleteType(LBracLoc, Method->getReturnType(),
3035                           diag::err_illegal_message_expr_incomplete_type))
3036     return ExprError();
3037
3038   // In ARC, forbid the user from sending messages to
3039   // retain/release/autorelease/dealloc/retainCount explicitly.
3040   if (getLangOpts().ObjCAutoRefCount) {
3041     ObjCMethodFamily family =
3042       (Method ? Method->getMethodFamily() : Sel.getMethodFamily());
3043     switch (family) {
3044     case OMF_init:
3045       if (Method)
3046         checkInitMethod(Method, ReceiverType);
3047       break;
3048
3049     case OMF_None:
3050     case OMF_alloc:
3051     case OMF_copy:
3052     case OMF_finalize:
3053     case OMF_mutableCopy:
3054     case OMF_new:
3055     case OMF_self:
3056     case OMF_initialize:
3057       break;
3058
3059     case OMF_dealloc:
3060     case OMF_retain:
3061     case OMF_release:
3062     case OMF_autorelease:
3063     case OMF_retainCount:
3064       Diag(SelLoc, diag::err_arc_illegal_explicit_message)
3065         << Sel << RecRange;
3066       break;
3067
3068     case OMF_performSelector:
3069       if (Method && NumArgs >= 1) {
3070         if (const auto *SelExp =
3071                 dyn_cast<ObjCSelectorExpr>(Args[0]->IgnoreParens())) {
3072           Selector ArgSel = SelExp->getSelector();
3073           ObjCMethodDecl *SelMethod =
3074             LookupInstanceMethodInGlobalPool(ArgSel,
3075                                              SelExp->getSourceRange());
3076           if (!SelMethod)
3077             SelMethod =
3078               LookupFactoryMethodInGlobalPool(ArgSel,
3079                                               SelExp->getSourceRange());
3080           if (SelMethod) {
3081             ObjCMethodFamily SelFamily = SelMethod->getMethodFamily();
3082             switch (SelFamily) {
3083               case OMF_alloc:
3084               case OMF_copy:
3085               case OMF_mutableCopy:
3086               case OMF_new:
3087               case OMF_init:
3088                 // Issue error, unless ns_returns_not_retained.
3089                 if (!SelMethod->hasAttr<NSReturnsNotRetainedAttr>()) {
3090                   // selector names a +1 method
3091                   Diag(SelLoc,
3092                        diag::err_arc_perform_selector_retains);
3093                   Diag(SelMethod->getLocation(), diag::note_method_declared_at)
3094                     << SelMethod->getDeclName();
3095                 }
3096                 break;
3097               default:
3098                 // +0 call. OK. unless ns_returns_retained.
3099                 if (SelMethod->hasAttr<NSReturnsRetainedAttr>()) {
3100                   // selector names a +1 method
3101                   Diag(SelLoc,
3102                        diag::err_arc_perform_selector_retains);
3103                   Diag(SelMethod->getLocation(), diag::note_method_declared_at)
3104                     << SelMethod->getDeclName();
3105                 }
3106                 break;
3107             }
3108           }
3109         } else {
3110           // error (may leak).
3111           Diag(SelLoc, diag::warn_arc_perform_selector_leaks);
3112           Diag(Args[0]->getExprLoc(), diag::note_used_here);
3113         }
3114       }
3115       break;
3116     }
3117   }
3118
3119   DiagnoseCStringFormatDirectiveInObjCAPI(*this, Method, Sel, Args, NumArgs);
3120
3121   // Construct the appropriate ObjCMessageExpr instance.
3122   ObjCMessageExpr *Result;
3123   if (SuperLoc.isValid())
3124     Result = ObjCMessageExpr::Create(Context, ReturnType, VK, LBracLoc,
3125                                      SuperLoc,  /*IsInstanceSuper=*/true,
3126                                      ReceiverType, Sel, SelectorLocs, Method,
3127                                      makeArrayRef(Args, NumArgs), RBracLoc,
3128                                      isImplicit);
3129   else {
3130     Result = ObjCMessageExpr::Create(Context, ReturnType, VK, LBracLoc,
3131                                      Receiver, Sel, SelectorLocs, Method,
3132                                      makeArrayRef(Args, NumArgs), RBracLoc,
3133                                      isImplicit);
3134     if (!isImplicit)
3135       checkCocoaAPI(*this, Result);
3136   }
3137   if (Method) {
3138     bool IsClassObjectCall = ClassMessage;
3139     // 'self' message receivers in class methods should be treated as message
3140     // sends to the class object in order for the semantic checks to be
3141     // performed correctly. Messages to 'super' already count as class messages,
3142     // so they don't need to be handled here.
3143     if (Receiver && isSelfExpr(Receiver)) {
3144       if (const auto *OPT = ReceiverType->getAs<ObjCObjectPointerType>()) {
3145         if (OPT->getObjectType()->isObjCClass()) {
3146           if (const auto *CurMeth = getCurMethodDecl()) {
3147             IsClassObjectCall = true;
3148             ReceiverType =
3149                 Context.getObjCInterfaceType(CurMeth->getClassInterface());
3150           }
3151         }
3152       }
3153     }
3154     checkFoundationAPI(*this, SelLoc, Method, makeArrayRef(Args, NumArgs),
3155                        ReceiverType, IsClassObjectCall);
3156   }
3157
3158   if (getLangOpts().ObjCAutoRefCount) {
3159     // In ARC, annotate delegate init calls.
3160     if (Result->getMethodFamily() == OMF_init &&
3161         (SuperLoc.isValid() || isSelfExpr(Receiver))) {
3162       // Only consider init calls *directly* in init implementations,
3163       // not within blocks.
3164       ObjCMethodDecl *method = dyn_cast<ObjCMethodDecl>(CurContext);
3165       if (method && method->getMethodFamily() == OMF_init) {
3166         // The implicit assignment to self means we also don't want to
3167         // consume the result.
3168         Result->setDelegateInitCall(true);
3169         return Result;
3170       }
3171     }
3172
3173     // In ARC, check for message sends which are likely to introduce
3174     // retain cycles.
3175     checkRetainCycles(Result);
3176   }
3177
3178   if (getLangOpts().ObjCWeak) {
3179     if (!isImplicit && Method) {
3180       if (const ObjCPropertyDecl *Prop = Method->findPropertyDecl()) {
3181         bool IsWeak =
3182           Prop->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_weak;
3183         if (!IsWeak && Sel.isUnarySelector())
3184           IsWeak = ReturnType.getObjCLifetime() & Qualifiers::OCL_Weak;
3185         if (IsWeak && !isUnevaluatedContext() &&
3186             !Diags.isIgnored(diag::warn_arc_repeated_use_of_weak, LBracLoc))
3187           getCurFunction()->recordUseOfWeak(Result, Prop);
3188       }
3189     }
3190   }
3191
3192   CheckObjCCircularContainer(Result);
3193
3194   return MaybeBindToTemporary(Result);
3195 }
3196
3197 static void RemoveSelectorFromWarningCache(Sema &S, Expr* Arg) {
3198   if (ObjCSelectorExpr *OSE =
3199       dyn_cast<ObjCSelectorExpr>(Arg->IgnoreParenCasts())) {
3200     Selector Sel = OSE->getSelector();
3201     SourceLocation Loc = OSE->getAtLoc();
3202     auto Pos = S.ReferencedSelectors.find(Sel);
3203     if (Pos != S.ReferencedSelectors.end() && Pos->second == Loc)
3204       S.ReferencedSelectors.erase(Pos);
3205   }
3206 }
3207
3208 // ActOnInstanceMessage - used for both unary and keyword messages.
3209 // ArgExprs is optional - if it is present, the number of expressions
3210 // is obtained from Sel.getNumArgs().
3211 ExprResult Sema::ActOnInstanceMessage(Scope *S,
3212                                       Expr *Receiver,
3213                                       Selector Sel,
3214                                       SourceLocation LBracLoc,
3215                                       ArrayRef<SourceLocation> SelectorLocs,
3216                                       SourceLocation RBracLoc,
3217                                       MultiExprArg Args) {
3218   if (!Receiver)
3219     return ExprError();
3220
3221   // A ParenListExpr can show up while doing error recovery with invalid code.
3222   if (isa<ParenListExpr>(Receiver)) {
3223     ExprResult Result = MaybeConvertParenListExprToParenExpr(S, Receiver);
3224     if (Result.isInvalid()) return ExprError();
3225     Receiver = Result.get();
3226   }
3227
3228   if (RespondsToSelectorSel.isNull()) {
3229     IdentifierInfo *SelectorId = &Context.Idents.get("respondsToSelector");
3230     RespondsToSelectorSel = Context.Selectors.getUnarySelector(SelectorId);
3231   }
3232   if (Sel == RespondsToSelectorSel)
3233     RemoveSelectorFromWarningCache(*this, Args[0]);
3234
3235   return BuildInstanceMessage(Receiver, Receiver->getType(),
3236                               /*SuperLoc=*/SourceLocation(), Sel,
3237                               /*Method=*/nullptr, LBracLoc, SelectorLocs,
3238                               RBracLoc, Args);
3239 }
3240
3241 enum ARCConversionTypeClass {
3242   /// int, void, struct A
3243   ACTC_none,
3244
3245   /// id, void (^)()
3246   ACTC_retainable,
3247
3248   /// id*, id***, void (^*)(),
3249   ACTC_indirectRetainable,
3250
3251   /// void* might be a normal C type, or it might a CF type.
3252   ACTC_voidPtr,
3253
3254   /// struct A*
3255   ACTC_coreFoundation
3256 };
3257
3258 static bool isAnyRetainable(ARCConversionTypeClass ACTC) {
3259   return (ACTC == ACTC_retainable ||
3260           ACTC == ACTC_coreFoundation ||
3261           ACTC == ACTC_voidPtr);
3262 }
3263
3264 static bool isAnyCLike(ARCConversionTypeClass ACTC) {
3265   return ACTC == ACTC_none ||
3266          ACTC == ACTC_voidPtr ||
3267          ACTC == ACTC_coreFoundation;
3268 }
3269
3270 static ARCConversionTypeClass classifyTypeForARCConversion(QualType type) {
3271   bool isIndirect = false;
3272
3273   // Ignore an outermost reference type.
3274   if (const ReferenceType *ref = type->getAs<ReferenceType>()) {
3275     type = ref->getPointeeType();
3276     isIndirect = true;
3277   }
3278
3279   // Drill through pointers and arrays recursively.
3280   while (true) {
3281     if (const PointerType *ptr = type->getAs<PointerType>()) {
3282       type = ptr->getPointeeType();
3283
3284       // The first level of pointer may be the innermost pointer on a CF type.
3285       if (!isIndirect) {
3286         if (type->isVoidType()) return ACTC_voidPtr;
3287         if (type->isRecordType()) return ACTC_coreFoundation;
3288       }
3289     } else if (const ArrayType *array = type->getAsArrayTypeUnsafe()) {
3290       type = QualType(array->getElementType()->getBaseElementTypeUnsafe(), 0);
3291     } else {
3292       break;
3293     }
3294     isIndirect = true;
3295   }
3296
3297   if (isIndirect) {
3298     if (type->isObjCARCBridgableType())
3299       return ACTC_indirectRetainable;
3300     return ACTC_none;
3301   }
3302
3303   if (type->isObjCARCBridgableType())
3304     return ACTC_retainable;
3305
3306   return ACTC_none;
3307 }
3308
3309 namespace {
3310   /// A result from the cast checker.
3311   enum ACCResult {
3312     /// Cannot be casted.
3313     ACC_invalid,
3314
3315     /// Can be safely retained or not retained.
3316     ACC_bottom,
3317
3318     /// Can be casted at +0.
3319     ACC_plusZero,
3320
3321     /// Can be casted at +1.
3322     ACC_plusOne
3323   };
3324   ACCResult merge(ACCResult left, ACCResult right) {
3325     if (left == right) return left;
3326     if (left == ACC_bottom) return right;
3327     if (right == ACC_bottom) return left;
3328     return ACC_invalid;
3329   }
3330
3331   /// A checker which white-lists certain expressions whose conversion
3332   /// to or from retainable type would otherwise be forbidden in ARC.
3333   class ARCCastChecker : public StmtVisitor<ARCCastChecker, ACCResult> {
3334     typedef StmtVisitor<ARCCastChecker, ACCResult> super;
3335
3336     ASTContext &Context;
3337     ARCConversionTypeClass SourceClass;
3338     ARCConversionTypeClass TargetClass;
3339     bool Diagnose;
3340
3341     static bool isCFType(QualType type) {
3342       // Someday this can use ns_bridged.  For now, it has to do this.
3343       return type->isCARCBridgableType();
3344     }
3345
3346   public:
3347     ARCCastChecker(ASTContext &Context, ARCConversionTypeClass source,
3348                    ARCConversionTypeClass target, bool diagnose)
3349       : Context(Context), SourceClass(source), TargetClass(target),
3350         Diagnose(diagnose) {}
3351
3352     using super::Visit;
3353     ACCResult Visit(Expr *e) {
3354       return super::Visit(e->IgnoreParens());
3355     }
3356
3357     ACCResult VisitStmt(Stmt *s) {
3358       return ACC_invalid;
3359     }
3360
3361     /// Null pointer constants can be casted however you please.
3362     ACCResult VisitExpr(Expr *e) {
3363       if (e->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNotNull))
3364         return ACC_bottom;
3365       return ACC_invalid;
3366     }
3367
3368     /// Objective-C string literals can be safely casted.
3369     ACCResult VisitObjCStringLiteral(ObjCStringLiteral *e) {
3370       // If we're casting to any retainable type, go ahead.  Global
3371       // strings are immune to retains, so this is bottom.
3372       if (isAnyRetainable(TargetClass)) return ACC_bottom;
3373
3374       return ACC_invalid;
3375     }
3376
3377     /// Look through certain implicit and explicit casts.
3378     ACCResult VisitCastExpr(CastExpr *e) {
3379       switch (e->getCastKind()) {
3380         case CK_NullToPointer:
3381           return ACC_bottom;
3382
3383         case CK_NoOp:
3384         case CK_LValueToRValue:
3385         case CK_BitCast:
3386         case CK_CPointerToObjCPointerCast:
3387         case CK_BlockPointerToObjCPointerCast:
3388         case CK_AnyPointerToBlockPointerCast:
3389           return Visit(e->getSubExpr());
3390
3391         default:
3392           return ACC_invalid;
3393       }
3394     }
3395
3396     /// Look through unary extension.
3397     ACCResult VisitUnaryExtension(UnaryOperator *e) {
3398       return Visit(e->getSubExpr());
3399     }
3400
3401     /// Ignore the LHS of a comma operator.
3402     ACCResult VisitBinComma(BinaryOperator *e) {
3403       return Visit(e->getRHS());
3404     }
3405
3406     /// Conditional operators are okay if both sides are okay.
3407     ACCResult VisitConditionalOperator(ConditionalOperator *e) {
3408       ACCResult left = Visit(e->getTrueExpr());
3409       if (left == ACC_invalid) return ACC_invalid;
3410       return merge(left, Visit(e->getFalseExpr()));
3411     }
3412
3413     /// Look through pseudo-objects.
3414     ACCResult VisitPseudoObjectExpr(PseudoObjectExpr *e) {
3415       // If we're getting here, we should always have a result.
3416       return Visit(e->getResultExpr());
3417     }
3418
3419     /// Statement expressions are okay if their result expression is okay.
3420     ACCResult VisitStmtExpr(StmtExpr *e) {
3421       return Visit(e->getSubStmt()->body_back());
3422     }
3423
3424     /// Some declaration references are okay.
3425     ACCResult VisitDeclRefExpr(DeclRefExpr *e) {
3426       VarDecl *var = dyn_cast<VarDecl>(e->getDecl());
3427       // References to global constants are okay.
3428       if (isAnyRetainable(TargetClass) &&
3429           isAnyRetainable(SourceClass) &&
3430           var &&
3431           !var->hasDefinition(Context) &&
3432           var->getType().isConstQualified()) {
3433
3434         // In system headers, they can also be assumed to be immune to retains.
3435         // These are things like 'kCFStringTransformToLatin'.
3436         if (Context.getSourceManager().isInSystemHeader(var->getLocation()))
3437           return ACC_bottom;
3438
3439         return ACC_plusZero;
3440       }
3441
3442       // Nothing else.
3443       return ACC_invalid;
3444     }
3445
3446     /// Some calls are okay.
3447     ACCResult VisitCallExpr(CallExpr *e) {
3448       if (FunctionDecl *fn = e->getDirectCallee())
3449         if (ACCResult result = checkCallToFunction(fn))
3450           return result;
3451
3452       return super::VisitCallExpr(e);
3453     }
3454
3455     ACCResult checkCallToFunction(FunctionDecl *fn) {
3456       // Require a CF*Ref return type.
3457       if (!isCFType(fn->getReturnType()))
3458         return ACC_invalid;
3459
3460       if (!isAnyRetainable(TargetClass))
3461         return ACC_invalid;
3462
3463       // Honor an explicit 'not retained' attribute.
3464       if (fn->hasAttr<CFReturnsNotRetainedAttr>())
3465         return ACC_plusZero;
3466
3467       // Honor an explicit 'retained' attribute, except that for
3468       // now we're not going to permit implicit handling of +1 results,
3469       // because it's a bit frightening.
3470       if (fn->hasAttr<CFReturnsRetainedAttr>())
3471         return Diagnose ? ACC_plusOne
3472                         : ACC_invalid; // ACC_plusOne if we start accepting this
3473
3474       // Recognize this specific builtin function, which is used by CFSTR.
3475       unsigned builtinID = fn->getBuiltinID();
3476       if (builtinID == Builtin::BI__builtin___CFStringMakeConstantString)
3477         return ACC_bottom;
3478
3479       // Otherwise, don't do anything implicit with an unaudited function.
3480       if (!fn->hasAttr<CFAuditedTransferAttr>())
3481         return ACC_invalid;
3482
3483       // Otherwise, it's +0 unless it follows the create convention.
3484       if (ento::coreFoundation::followsCreateRule(fn))
3485         return Diagnose ? ACC_plusOne
3486                         : ACC_invalid; // ACC_plusOne if we start accepting this
3487
3488       return ACC_plusZero;
3489     }
3490
3491     ACCResult VisitObjCMessageExpr(ObjCMessageExpr *e) {
3492       return checkCallToMethod(e->getMethodDecl());
3493     }
3494
3495     ACCResult VisitObjCPropertyRefExpr(ObjCPropertyRefExpr *e) {
3496       ObjCMethodDecl *method;
3497       if (e->isExplicitProperty())
3498         method = e->getExplicitProperty()->getGetterMethodDecl();
3499       else
3500         method = e->getImplicitPropertyGetter();
3501       return checkCallToMethod(method);
3502     }
3503
3504     ACCResult checkCallToMethod(ObjCMethodDecl *method) {
3505       if (!method) return ACC_invalid;
3506
3507       // Check for message sends to functions returning CF types.  We
3508       // just obey the Cocoa conventions with these, even though the
3509       // return type is CF.
3510       if (!isAnyRetainable(TargetClass) || !isCFType(method->getReturnType()))
3511         return ACC_invalid;
3512
3513       // If the method is explicitly marked not-retained, it's +0.
3514       if (method->hasAttr<CFReturnsNotRetainedAttr>())
3515         return ACC_plusZero;
3516
3517       // If the method is explicitly marked as returning retained, or its
3518       // selector follows a +1 Cocoa convention, treat it as +1.
3519       if (method->hasAttr<CFReturnsRetainedAttr>())
3520         return ACC_plusOne;
3521
3522       switch (method->getSelector().getMethodFamily()) {
3523       case OMF_alloc:
3524       case OMF_copy:
3525       case OMF_mutableCopy:
3526       case OMF_new:
3527         return ACC_plusOne;
3528
3529       default:
3530         // Otherwise, treat it as +0.
3531         return ACC_plusZero;
3532       }
3533     }
3534   };
3535 } // end anonymous namespace
3536
3537 bool Sema::isKnownName(StringRef name) {
3538   if (name.empty())
3539     return false;
3540   LookupResult R(*this, &Context.Idents.get(name), SourceLocation(),
3541                  Sema::LookupOrdinaryName);
3542   return LookupName(R, TUScope, false);
3543 }
3544
3545 static void addFixitForObjCARCConversion(Sema &S,
3546                                          DiagnosticBuilder &DiagB,
3547                                          Sema::CheckedConversionKind CCK,
3548                                          SourceLocation afterLParen,
3549                                          QualType castType,
3550                                          Expr *castExpr,
3551                                          Expr *realCast,
3552                                          const char *bridgeKeyword,
3553                                          const char *CFBridgeName) {
3554   // We handle C-style and implicit casts here.
3555   switch (CCK) {
3556   case Sema::CCK_ImplicitConversion:
3557   case Sema::CCK_ForBuiltinOverloadedOp:
3558   case Sema::CCK_CStyleCast:
3559   case Sema::CCK_OtherCast:
3560     break;
3561   case Sema::CCK_FunctionalCast:
3562     return;
3563   }
3564
3565   if (CFBridgeName) {
3566     if (CCK == Sema::CCK_OtherCast) {
3567       if (const CXXNamedCastExpr *NCE = dyn_cast<CXXNamedCastExpr>(realCast)) {
3568         SourceRange range(NCE->getOperatorLoc(),
3569                           NCE->getAngleBrackets().getEnd());
3570         SmallString<32> BridgeCall;
3571
3572         SourceManager &SM = S.getSourceManager();
3573         char PrevChar = *SM.getCharacterData(range.getBegin().getLocWithOffset(-1));
3574         if (Lexer::isIdentifierBodyChar(PrevChar, S.getLangOpts()))
3575           BridgeCall += ' ';
3576
3577         BridgeCall += CFBridgeName;
3578         DiagB.AddFixItHint(FixItHint::CreateReplacement(range, BridgeCall));
3579       }
3580       return;
3581     }
3582     Expr *castedE = castExpr;
3583     if (CStyleCastExpr *CCE = dyn_cast<CStyleCastExpr>(castedE))
3584       castedE = CCE->getSubExpr();
3585     castedE = castedE->IgnoreImpCasts();
3586     SourceRange range = castedE->getSourceRange();
3587
3588     SmallString<32> BridgeCall;
3589
3590     SourceManager &SM = S.getSourceManager();
3591     char PrevChar = *SM.getCharacterData(range.getBegin().getLocWithOffset(-1));
3592     if (Lexer::isIdentifierBodyChar(PrevChar, S.getLangOpts()))
3593       BridgeCall += ' ';
3594
3595     BridgeCall += CFBridgeName;
3596
3597     if (isa<ParenExpr>(castedE)) {
3598       DiagB.AddFixItHint(FixItHint::CreateInsertion(range.getBegin(),
3599                          BridgeCall));
3600     } else {
3601       BridgeCall += '(';
3602       DiagB.AddFixItHint(FixItHint::CreateInsertion(range.getBegin(),
3603                                                     BridgeCall));
3604       DiagB.AddFixItHint(FixItHint::CreateInsertion(
3605                                        S.getLocForEndOfToken(range.getEnd()),
3606                                        ")"));
3607     }
3608     return;
3609   }
3610
3611   if (CCK == Sema::CCK_CStyleCast) {
3612     DiagB.AddFixItHint(FixItHint::CreateInsertion(afterLParen, bridgeKeyword));
3613   } else if (CCK == Sema::CCK_OtherCast) {
3614     if (const CXXNamedCastExpr *NCE = dyn_cast<CXXNamedCastExpr>(realCast)) {
3615       std::string castCode = "(";
3616       castCode += bridgeKeyword;
3617       castCode += castType.getAsString();
3618       castCode += ")";
3619       SourceRange Range(NCE->getOperatorLoc(),
3620                         NCE->getAngleBrackets().getEnd());
3621       DiagB.AddFixItHint(FixItHint::CreateReplacement(Range, castCode));
3622     }
3623   } else {
3624     std::string castCode = "(";
3625     castCode += bridgeKeyword;
3626     castCode += castType.getAsString();
3627     castCode += ")";
3628     Expr *castedE = castExpr->IgnoreImpCasts();
3629     SourceRange range = castedE->getSourceRange();
3630     if (isa<ParenExpr>(castedE)) {
3631       DiagB.AddFixItHint(FixItHint::CreateInsertion(range.getBegin(),
3632                          castCode));
3633     } else {
3634       castCode += "(";
3635       DiagB.AddFixItHint(FixItHint::CreateInsertion(range.getBegin(),
3636                                                     castCode));
3637       DiagB.AddFixItHint(FixItHint::CreateInsertion(
3638                                        S.getLocForEndOfToken(range.getEnd()),
3639                                        ")"));
3640     }
3641   }
3642 }
3643
3644 template <typename T>
3645 static inline T *getObjCBridgeAttr(const TypedefType *TD) {
3646   TypedefNameDecl *TDNDecl = TD->getDecl();
3647   QualType QT = TDNDecl->getUnderlyingType();
3648   if (QT->isPointerType()) {
3649     QT = QT->getPointeeType();
3650     if (const RecordType *RT = QT->getAs<RecordType>())
3651       if (RecordDecl *RD = RT->getDecl()->getMostRecentDecl())
3652         return RD->getAttr<T>();
3653   }
3654   return nullptr;
3655 }
3656
3657 static ObjCBridgeRelatedAttr *ObjCBridgeRelatedAttrFromType(QualType T,
3658                                                             TypedefNameDecl *&TDNDecl) {
3659   while (const TypedefType *TD = dyn_cast<TypedefType>(T.getTypePtr())) {
3660     TDNDecl = TD->getDecl();
3661     if (ObjCBridgeRelatedAttr *ObjCBAttr =
3662         getObjCBridgeAttr<ObjCBridgeRelatedAttr>(TD))
3663       return ObjCBAttr;
3664     T = TDNDecl->getUnderlyingType();
3665   }
3666   return nullptr;
3667 }
3668
3669 static void
3670 diagnoseObjCARCConversion(Sema &S, SourceRange castRange,
3671                           QualType castType, ARCConversionTypeClass castACTC,
3672                           Expr *castExpr, Expr *realCast,
3673                           ARCConversionTypeClass exprACTC,
3674                           Sema::CheckedConversionKind CCK) {
3675   SourceLocation loc =
3676     (castRange.isValid() ? castRange.getBegin() : castExpr->getExprLoc());
3677
3678   if (S.makeUnavailableInSystemHeader(loc,
3679                                  UnavailableAttr::IR_ARCForbiddenConversion))
3680     return;
3681
3682   QualType castExprType = castExpr->getType();
3683   // Defer emitting a diagnostic for bridge-related casts; that will be
3684   // handled by CheckObjCBridgeRelatedConversions.
3685   TypedefNameDecl *TDNDecl = nullptr;
3686   if ((castACTC == ACTC_coreFoundation &&  exprACTC == ACTC_retainable &&
3687        ObjCBridgeRelatedAttrFromType(castType, TDNDecl)) ||
3688       (exprACTC == ACTC_coreFoundation && castACTC == ACTC_retainable &&
3689        ObjCBridgeRelatedAttrFromType(castExprType, TDNDecl)))
3690     return;
3691
3692   unsigned srcKind = 0;
3693   switch (exprACTC) {
3694   case ACTC_none:
3695   case ACTC_coreFoundation:
3696   case ACTC_voidPtr:
3697     srcKind = (castExprType->isPointerType() ? 1 : 0);
3698     break;
3699   case ACTC_retainable:
3700     srcKind = (castExprType->isBlockPointerType() ? 2 : 3);
3701     break;
3702   case ACTC_indirectRetainable:
3703     srcKind = 4;
3704     break;
3705   }
3706
3707   // Check whether this could be fixed with a bridge cast.
3708   SourceLocation afterLParen = S.getLocForEndOfToken(castRange.getBegin());
3709   SourceLocation noteLoc = afterLParen.isValid() ? afterLParen : loc;
3710
3711   unsigned convKindForDiag = Sema::isCast(CCK) ? 0 : 1;
3712
3713   // Bridge from an ARC type to a CF type.
3714   if (castACTC == ACTC_retainable && isAnyRetainable(exprACTC)) {
3715
3716     S.Diag(loc, diag::err_arc_cast_requires_bridge)
3717       << convKindForDiag
3718       << 2 // of C pointer type
3719       << castExprType
3720       << unsigned(castType->isBlockPointerType()) // to ObjC|block type
3721       << castType
3722       << castRange
3723       << castExpr->getSourceRange();
3724     bool br = S.isKnownName("CFBridgingRelease");
3725     ACCResult CreateRule =
3726       ARCCastChecker(S.Context, exprACTC, castACTC, true).Visit(castExpr);
3727     assert(CreateRule != ACC_bottom && "This cast should already be accepted.");
3728     if (CreateRule != ACC_plusOne)
3729     {
3730       DiagnosticBuilder DiagB =
3731         (CCK != Sema::CCK_OtherCast) ? S.Diag(noteLoc, diag::note_arc_bridge)
3732                               : S.Diag(noteLoc, diag::note_arc_cstyle_bridge);
3733
3734       addFixitForObjCARCConversion(S, DiagB, CCK, afterLParen,
3735                                    castType, castExpr, realCast, "__bridge ",
3736                                    nullptr);
3737     }
3738     if (CreateRule != ACC_plusZero)
3739     {
3740       DiagnosticBuilder DiagB =
3741         (CCK == Sema::CCK_OtherCast && !br) ?
3742           S.Diag(noteLoc, diag::note_arc_cstyle_bridge_transfer) << castExprType :
3743           S.Diag(br ? castExpr->getExprLoc() : noteLoc,
3744                  diag::note_arc_bridge_transfer)
3745             << castExprType << br;
3746
3747       addFixitForObjCARCConversion(S, DiagB, CCK, afterLParen,
3748                                    castType, castExpr, realCast, "__bridge_transfer ",
3749                                    br ? "CFBridgingRelease" : nullptr);
3750     }
3751
3752     return;
3753   }
3754
3755   // Bridge from a CF type to an ARC type.
3756   if (exprACTC == ACTC_retainable && isAnyRetainable(castACTC)) {
3757     bool br = S.isKnownName("CFBridgingRetain");
3758     S.Diag(loc, diag::err_arc_cast_requires_bridge)
3759       << convKindForDiag
3760       << unsigned(castExprType->isBlockPointerType()) // of ObjC|block type
3761       << castExprType
3762       << 2 // to C pointer type
3763       << castType
3764       << castRange
3765       << castExpr->getSourceRange();
3766     ACCResult CreateRule =
3767       ARCCastChecker(S.Context, exprACTC, castACTC, true).Visit(castExpr);
3768     assert(CreateRule != ACC_bottom && "This cast should already be accepted.");
3769     if (CreateRule != ACC_plusOne)
3770     {
3771       DiagnosticBuilder DiagB =
3772       (CCK != Sema::CCK_OtherCast) ? S.Diag(noteLoc, diag::note_arc_bridge)
3773                                : S.Diag(noteLoc, diag::note_arc_cstyle_bridge);
3774       addFixitForObjCARCConversion(S, DiagB, CCK, afterLParen,
3775                                    castType, castExpr, realCast, "__bridge ",
3776                                    nullptr);
3777     }
3778     if (CreateRule != ACC_plusZero)
3779     {
3780       DiagnosticBuilder DiagB =
3781         (CCK == Sema::CCK_OtherCast && !br) ?
3782           S.Diag(noteLoc, diag::note_arc_cstyle_bridge_retained) << castType :
3783           S.Diag(br ? castExpr->getExprLoc() : noteLoc,
3784                  diag::note_arc_bridge_retained)
3785             << castType << br;
3786
3787       addFixitForObjCARCConversion(S, DiagB, CCK, afterLParen,
3788                                    castType, castExpr, realCast, "__bridge_retained ",
3789                                    br ? "CFBridgingRetain" : nullptr);
3790     }
3791
3792     return;
3793   }
3794
3795   S.Diag(loc, diag::err_arc_mismatched_cast)
3796     << !convKindForDiag
3797     << srcKind << castExprType << castType
3798     << castRange << castExpr->getSourceRange();
3799 }
3800
3801 template <typename TB>
3802 static bool CheckObjCBridgeNSCast(Sema &S, QualType castType, Expr *castExpr,
3803                                   bool &HadTheAttribute, bool warn) {
3804   QualType T = castExpr->getType();
3805   HadTheAttribute = false;
3806   while (const TypedefType *TD = dyn_cast<TypedefType>(T.getTypePtr())) {
3807     TypedefNameDecl *TDNDecl = TD->getDecl();
3808     if (TB *ObjCBAttr = getObjCBridgeAttr<TB>(TD)) {
3809       if (IdentifierInfo *Parm = ObjCBAttr->getBridgedType()) {
3810         HadTheAttribute = true;
3811         if (Parm->isStr("id"))
3812           return true;
3813
3814         NamedDecl *Target = nullptr;
3815         // Check for an existing type with this name.
3816         LookupResult R(S, DeclarationName(Parm), SourceLocation(),
3817                        Sema::LookupOrdinaryName);
3818         if (S.LookupName(R, S.TUScope)) {
3819           Target = R.getFoundDecl();
3820           if (Target && isa<ObjCInterfaceDecl>(Target)) {
3821             ObjCInterfaceDecl *ExprClass = cast<ObjCInterfaceDecl>(Target);
3822             if (const ObjCObjectPointerType *InterfacePointerType =
3823                   castType->getAsObjCInterfacePointerType()) {
3824               ObjCInterfaceDecl *CastClass
3825                 = InterfacePointerType->getObjectType()->getInterface();
3826               if ((CastClass == ExprClass) ||
3827                   (CastClass && CastClass->isSuperClassOf(ExprClass)))
3828                 return true;
3829               if (warn)
3830                 S.Diag(castExpr->getBeginLoc(), diag::warn_objc_invalid_bridge)
3831                     << T << Target->getName() << castType->getPointeeType();
3832               return false;
3833             } else if (castType->isObjCIdType() ||
3834                        (S.Context.ObjCObjectAdoptsQTypeProtocols(
3835                           castType, ExprClass)))
3836               // ok to cast to 'id'.
3837               // casting to id<p-list> is ok if bridge type adopts all of
3838               // p-list protocols.
3839               return true;
3840             else {
3841               if (warn) {
3842                 S.Diag(castExpr->getBeginLoc(), diag::warn_objc_invalid_bridge)
3843                     << T << Target->getName() << castType;
3844                 S.Diag(TDNDecl->getBeginLoc(), diag::note_declared_at);
3845                 S.Diag(Target->getBeginLoc(), diag::note_declared_at);
3846               }
3847               return false;
3848            }
3849           }
3850         } else if (!castType->isObjCIdType()) {
3851           S.Diag(castExpr->getBeginLoc(),
3852                  diag::err_objc_cf_bridged_not_interface)
3853               << castExpr->getType() << Parm;
3854           S.Diag(TDNDecl->getBeginLoc(), diag::note_declared_at);
3855           if (Target)
3856             S.Diag(Target->getBeginLoc(), diag::note_declared_at);
3857         }
3858         return true;
3859       }
3860       return false;
3861     }
3862     T = TDNDecl->getUnderlyingType();
3863   }
3864   return true;
3865 }
3866
3867 template <typename TB>
3868 static bool CheckObjCBridgeCFCast(Sema &S, QualType castType, Expr *castExpr,
3869                                   bool &HadTheAttribute, bool warn) {
3870   QualType T = castType;
3871   HadTheAttribute = false;
3872   while (const TypedefType *TD = dyn_cast<TypedefType>(T.getTypePtr())) {
3873     TypedefNameDecl *TDNDecl = TD->getDecl();
3874     if (TB *ObjCBAttr = getObjCBridgeAttr<TB>(TD)) {
3875       if (IdentifierInfo *Parm = ObjCBAttr->getBridgedType()) {
3876         HadTheAttribute = true;
3877         if (Parm->isStr("id"))
3878           return true;
3879
3880         NamedDecl *Target = nullptr;
3881         // Check for an existing type with this name.
3882         LookupResult R(S, DeclarationName(Parm), SourceLocation(),
3883                        Sema::LookupOrdinaryName);
3884         if (S.LookupName(R, S.TUScope)) {
3885           Target = R.getFoundDecl();
3886           if (Target && isa<ObjCInterfaceDecl>(Target)) {
3887             ObjCInterfaceDecl *CastClass = cast<ObjCInterfaceDecl>(Target);
3888             if (const ObjCObjectPointerType *InterfacePointerType =
3889                   castExpr->getType()->getAsObjCInterfacePointerType()) {
3890               ObjCInterfaceDecl *ExprClass
3891                 = InterfacePointerType->getObjectType()->getInterface();
3892               if ((CastClass == ExprClass) ||
3893                   (ExprClass && CastClass->isSuperClassOf(ExprClass)))
3894                 return true;
3895               if (warn) {
3896                 S.Diag(castExpr->getBeginLoc(),
3897                        diag::warn_objc_invalid_bridge_to_cf)
3898                     << castExpr->getType()->getPointeeType() << T;
3899                 S.Diag(TDNDecl->getBeginLoc(), diag::note_declared_at);
3900               }
3901               return false;
3902             } else if (castExpr->getType()->isObjCIdType() ||
3903                        (S.Context.QIdProtocolsAdoptObjCObjectProtocols(
3904                           castExpr->getType(), CastClass)))
3905               // ok to cast an 'id' expression to a CFtype.
3906               // ok to cast an 'id<plist>' expression to CFtype provided plist
3907               // adopts all of CFtype's ObjetiveC's class plist.
3908               return true;
3909             else {
3910               if (warn) {
3911                 S.Diag(castExpr->getBeginLoc(),
3912                        diag::warn_objc_invalid_bridge_to_cf)
3913                     << castExpr->getType() << castType;
3914                 S.Diag(TDNDecl->getBeginLoc(), diag::note_declared_at);
3915                 S.Diag(Target->getBeginLoc(), diag::note_declared_at);
3916               }
3917               return false;
3918             }
3919           }
3920         }
3921         S.Diag(castExpr->getBeginLoc(),
3922                diag::err_objc_ns_bridged_invalid_cfobject)
3923             << castExpr->getType() << castType;
3924         S.Diag(TDNDecl->getBeginLoc(), diag::note_declared_at);
3925         if (Target)
3926           S.Diag(Target->getBeginLoc(), diag::note_declared_at);
3927         return true;
3928       }
3929       return false;
3930     }
3931     T = TDNDecl->getUnderlyingType();
3932   }
3933   return true;
3934 }
3935
3936 void Sema::CheckTollFreeBridgeCast(QualType castType, Expr *castExpr) {
3937   if (!getLangOpts().ObjC)
3938     return;
3939   // warn in presence of __bridge casting to or from a toll free bridge cast.
3940   ARCConversionTypeClass exprACTC = classifyTypeForARCConversion(castExpr->getType());
3941   ARCConversionTypeClass castACTC = classifyTypeForARCConversion(castType);
3942   if (castACTC == ACTC_retainable && exprACTC == ACTC_coreFoundation) {
3943     bool HasObjCBridgeAttr;
3944     bool ObjCBridgeAttrWillNotWarn =
3945       CheckObjCBridgeNSCast<ObjCBridgeAttr>(*this, castType, castExpr, HasObjCBridgeAttr,
3946                                             false);
3947     if (ObjCBridgeAttrWillNotWarn && HasObjCBridgeAttr)
3948       return;
3949     bool HasObjCBridgeMutableAttr;
3950     bool ObjCBridgeMutableAttrWillNotWarn =
3951       CheckObjCBridgeNSCast<ObjCBridgeMutableAttr>(*this, castType, castExpr,
3952                                                    HasObjCBridgeMutableAttr, false);
3953     if (ObjCBridgeMutableAttrWillNotWarn && HasObjCBridgeMutableAttr)
3954       return;
3955
3956     if (HasObjCBridgeAttr)
3957       CheckObjCBridgeNSCast<ObjCBridgeAttr>(*this, castType, castExpr, HasObjCBridgeAttr,
3958                                             true);
3959     else if (HasObjCBridgeMutableAttr)
3960       CheckObjCBridgeNSCast<ObjCBridgeMutableAttr>(*this, castType, castExpr,
3961                                                    HasObjCBridgeMutableAttr, true);
3962   }
3963   else if (castACTC == ACTC_coreFoundation && exprACTC == ACTC_retainable) {
3964     bool HasObjCBridgeAttr;
3965     bool ObjCBridgeAttrWillNotWarn =
3966       CheckObjCBridgeCFCast<ObjCBridgeAttr>(*this, castType, castExpr, HasObjCBridgeAttr,
3967                                             false);
3968     if (ObjCBridgeAttrWillNotWarn && HasObjCBridgeAttr)
3969       return;
3970     bool HasObjCBridgeMutableAttr;
3971     bool ObjCBridgeMutableAttrWillNotWarn =
3972       CheckObjCBridgeCFCast<ObjCBridgeMutableAttr>(*this, castType, castExpr,
3973                                                    HasObjCBridgeMutableAttr, false);
3974     if (ObjCBridgeMutableAttrWillNotWarn && HasObjCBridgeMutableAttr)
3975       return;
3976
3977     if (HasObjCBridgeAttr)
3978       CheckObjCBridgeCFCast<ObjCBridgeAttr>(*this, castType, castExpr, HasObjCBridgeAttr,
3979                                             true);
3980     else if (HasObjCBridgeMutableAttr)
3981       CheckObjCBridgeCFCast<ObjCBridgeMutableAttr>(*this, castType, castExpr,
3982                                                    HasObjCBridgeMutableAttr, true);
3983   }
3984 }
3985
3986 void Sema::CheckObjCBridgeRelatedCast(QualType castType, Expr *castExpr) {
3987   QualType SrcType = castExpr->getType();
3988   if (ObjCPropertyRefExpr *PRE = dyn_cast<ObjCPropertyRefExpr>(castExpr)) {
3989     if (PRE->isExplicitProperty()) {
3990       if (ObjCPropertyDecl *PDecl = PRE->getExplicitProperty())
3991         SrcType = PDecl->getType();
3992     }
3993     else if (PRE->isImplicitProperty()) {
3994       if (ObjCMethodDecl *Getter = PRE->getImplicitPropertyGetter())
3995         SrcType = Getter->getReturnType();
3996     }
3997   }
3998
3999   ARCConversionTypeClass srcExprACTC = classifyTypeForARCConversion(SrcType);
4000   ARCConversionTypeClass castExprACTC = classifyTypeForARCConversion(castType);
4001   if (srcExprACTC != ACTC_retainable || castExprACTC != ACTC_coreFoundation)
4002     return;
4003   CheckObjCBridgeRelatedConversions(castExpr->getBeginLoc(), castType, SrcType,
4004                                     castExpr);
4005 }
4006
4007 bool Sema::CheckTollFreeBridgeStaticCast(QualType castType, Expr *castExpr,
4008                                          CastKind &Kind) {
4009   if (!getLangOpts().ObjC)
4010     return false;
4011   ARCConversionTypeClass exprACTC =
4012     classifyTypeForARCConversion(castExpr->getType());
4013   ARCConversionTypeClass castACTC = classifyTypeForARCConversion(castType);
4014   if ((castACTC == ACTC_retainable && exprACTC == ACTC_coreFoundation) ||
4015       (castACTC == ACTC_coreFoundation && exprACTC == ACTC_retainable)) {
4016     CheckTollFreeBridgeCast(castType, castExpr);
4017     Kind = (castACTC == ACTC_coreFoundation) ? CK_BitCast
4018                                              : CK_CPointerToObjCPointerCast;
4019     return true;
4020   }
4021   return false;
4022 }
4023
4024 bool Sema::checkObjCBridgeRelatedComponents(SourceLocation Loc,
4025                                             QualType DestType, QualType SrcType,
4026                                             ObjCInterfaceDecl *&RelatedClass,
4027                                             ObjCMethodDecl *&ClassMethod,
4028                                             ObjCMethodDecl *&InstanceMethod,
4029                                             TypedefNameDecl *&TDNDecl,
4030                                             bool CfToNs, bool Diagnose) {
4031   QualType T = CfToNs ? SrcType : DestType;
4032   ObjCBridgeRelatedAttr *ObjCBAttr = ObjCBridgeRelatedAttrFromType(T, TDNDecl);
4033   if (!ObjCBAttr)
4034     return false;
4035
4036   IdentifierInfo *RCId = ObjCBAttr->getRelatedClass();
4037   IdentifierInfo *CMId = ObjCBAttr->getClassMethod();
4038   IdentifierInfo *IMId = ObjCBAttr->getInstanceMethod();
4039   if (!RCId)
4040     return false;
4041   NamedDecl *Target = nullptr;
4042   // Check for an existing type with this name.
4043   LookupResult R(*this, DeclarationName(RCId), SourceLocation(),
4044                  Sema::LookupOrdinaryName);
4045   if (!LookupName(R, TUScope)) {
4046     if (Diagnose) {
4047       Diag(Loc, diag::err_objc_bridged_related_invalid_class) << RCId
4048             << SrcType << DestType;
4049       Diag(TDNDecl->getBeginLoc(), diag::note_declared_at);
4050     }
4051     return false;
4052   }
4053   Target = R.getFoundDecl();
4054   if (Target && isa<ObjCInterfaceDecl>(Target))
4055     RelatedClass = cast<ObjCInterfaceDecl>(Target);
4056   else {
4057     if (Diagnose) {
4058       Diag(Loc, diag::err_objc_bridged_related_invalid_class_name) << RCId
4059             << SrcType << DestType;
4060       Diag(TDNDecl->getBeginLoc(), diag::note_declared_at);
4061       if (Target)
4062         Diag(Target->getBeginLoc(), diag::note_declared_at);
4063     }
4064     return false;
4065   }
4066
4067   // Check for an existing class method with the given selector name.
4068   if (CfToNs && CMId) {
4069     Selector Sel = Context.Selectors.getUnarySelector(CMId);
4070     ClassMethod = RelatedClass->lookupMethod(Sel, false);
4071     if (!ClassMethod) {
4072       if (Diagnose) {
4073         Diag(Loc, diag::err_objc_bridged_related_known_method)
4074               << SrcType << DestType << Sel << false;
4075         Diag(TDNDecl->getBeginLoc(), diag::note_declared_at);
4076       }
4077       return false;
4078     }
4079   }
4080
4081   // Check for an existing instance method with the given selector name.
4082   if (!CfToNs && IMId) {
4083     Selector Sel = Context.Selectors.getNullarySelector(IMId);
4084     InstanceMethod = RelatedClass->lookupMethod(Sel, true);
4085     if (!InstanceMethod) {
4086       if (Diagnose) {
4087         Diag(Loc, diag::err_objc_bridged_related_known_method)
4088               << SrcType << DestType << Sel << true;
4089         Diag(TDNDecl->getBeginLoc(), diag::note_declared_at);
4090       }
4091       return false;
4092     }
4093   }
4094   return true;
4095 }
4096
4097 bool
4098 Sema::CheckObjCBridgeRelatedConversions(SourceLocation Loc,
4099                                         QualType DestType, QualType SrcType,
4100                                         Expr *&SrcExpr, bool Diagnose) {
4101   ARCConversionTypeClass rhsExprACTC = classifyTypeForARCConversion(SrcType);
4102   ARCConversionTypeClass lhsExprACTC = classifyTypeForARCConversion(DestType);
4103   bool CfToNs = (rhsExprACTC == ACTC_coreFoundation && lhsExprACTC == ACTC_retainable);
4104   bool NsToCf = (rhsExprACTC == ACTC_retainable && lhsExprACTC == ACTC_coreFoundation);
4105   if (!CfToNs && !NsToCf)
4106     return false;
4107
4108   ObjCInterfaceDecl *RelatedClass;
4109   ObjCMethodDecl *ClassMethod = nullptr;
4110   ObjCMethodDecl *InstanceMethod = nullptr;
4111   TypedefNameDecl *TDNDecl = nullptr;
4112   if (!checkObjCBridgeRelatedComponents(Loc, DestType, SrcType, RelatedClass,
4113                                         ClassMethod, InstanceMethod, TDNDecl,
4114                                         CfToNs, Diagnose))
4115     return false;
4116
4117   if (CfToNs) {
4118     // Implicit conversion from CF to ObjC object is needed.
4119     if (ClassMethod) {
4120       if (Diagnose) {
4121         std::string ExpressionString = "[";
4122         ExpressionString += RelatedClass->getNameAsString();
4123         ExpressionString += " ";
4124         ExpressionString += ClassMethod->getSelector().getAsString();
4125         SourceLocation SrcExprEndLoc =
4126             getLocForEndOfToken(SrcExpr->getEndLoc());
4127         // Provide a fixit: [RelatedClass ClassMethod SrcExpr]
4128         Diag(Loc, diag::err_objc_bridged_related_known_method)
4129             << SrcType << DestType << ClassMethod->getSelector() << false
4130             << FixItHint::CreateInsertion(SrcExpr->getBeginLoc(),
4131                                           ExpressionString)
4132             << FixItHint::CreateInsertion(SrcExprEndLoc, "]");
4133         Diag(RelatedClass->getBeginLoc(), diag::note_declared_at);
4134         Diag(TDNDecl->getBeginLoc(), diag::note_declared_at);
4135
4136         QualType receiverType = Context.getObjCInterfaceType(RelatedClass);
4137         // Argument.
4138         Expr *args[] = { SrcExpr };
4139         ExprResult msg = BuildClassMessageImplicit(receiverType, false,
4140                                       ClassMethod->getLocation(),
4141                                       ClassMethod->getSelector(), ClassMethod,
4142                                       MultiExprArg(args, 1));
4143         SrcExpr = msg.get();
4144       }
4145       return true;
4146     }
4147   }
4148   else {
4149     // Implicit conversion from ObjC type to CF object is needed.
4150     if (InstanceMethod) {
4151       if (Diagnose) {
4152         std::string ExpressionString;
4153         SourceLocation SrcExprEndLoc =
4154             getLocForEndOfToken(SrcExpr->getEndLoc());
4155         if (InstanceMethod->isPropertyAccessor())
4156           if (const ObjCPropertyDecl *PDecl =
4157                   InstanceMethod->findPropertyDecl()) {
4158             // fixit: ObjectExpr.propertyname when it is  aproperty accessor.
4159             ExpressionString = ".";
4160             ExpressionString += PDecl->getNameAsString();
4161             Diag(Loc, diag::err_objc_bridged_related_known_method)
4162                 << SrcType << DestType << InstanceMethod->getSelector() << true
4163                 << FixItHint::CreateInsertion(SrcExprEndLoc, ExpressionString);
4164           }
4165         if (ExpressionString.empty()) {
4166           // Provide a fixit: [ObjectExpr InstanceMethod]
4167           ExpressionString = " ";
4168           ExpressionString += InstanceMethod->getSelector().getAsString();
4169           ExpressionString += "]";
4170
4171           Diag(Loc, diag::err_objc_bridged_related_known_method)
4172               << SrcType << DestType << InstanceMethod->getSelector() << true
4173               << FixItHint::CreateInsertion(SrcExpr->getBeginLoc(), "[")
4174               << FixItHint::CreateInsertion(SrcExprEndLoc, ExpressionString);
4175         }
4176         Diag(RelatedClass->getBeginLoc(), diag::note_declared_at);
4177         Diag(TDNDecl->getBeginLoc(), diag::note_declared_at);
4178
4179         ExprResult msg =
4180           BuildInstanceMessageImplicit(SrcExpr, SrcType,
4181                                        InstanceMethod->getLocation(),
4182                                        InstanceMethod->getSelector(),
4183                                        InstanceMethod, None);
4184         SrcExpr = msg.get();
4185       }
4186       return true;
4187     }
4188   }
4189   return false;
4190 }
4191
4192 Sema::ARCConversionResult
4193 Sema::CheckObjCConversion(SourceRange castRange, QualType castType,
4194                           Expr *&castExpr, CheckedConversionKind CCK,
4195                           bool Diagnose, bool DiagnoseCFAudited,
4196                           BinaryOperatorKind Opc) {
4197   QualType castExprType = castExpr->getType();
4198
4199   // For the purposes of the classification, we assume reference types
4200   // will bind to temporaries.
4201   QualType effCastType = castType;
4202   if (const ReferenceType *ref = castType->getAs<ReferenceType>())
4203     effCastType = ref->getPointeeType();
4204
4205   ARCConversionTypeClass exprACTC = classifyTypeForARCConversion(castExprType);
4206   ARCConversionTypeClass castACTC = classifyTypeForARCConversion(effCastType);
4207   if (exprACTC == castACTC) {
4208     // Check for viability and report error if casting an rvalue to a
4209     // life-time qualifier.
4210     if (castACTC == ACTC_retainable &&
4211         (CCK == CCK_CStyleCast || CCK == CCK_OtherCast) &&
4212         castType != castExprType) {
4213       const Type *DT = castType.getTypePtr();
4214       QualType QDT = castType;
4215       // We desugar some types but not others. We ignore those
4216       // that cannot happen in a cast; i.e. auto, and those which
4217       // should not be de-sugared; i.e typedef.
4218       if (const ParenType *PT = dyn_cast<ParenType>(DT))
4219         QDT = PT->desugar();
4220       else if (const TypeOfType *TP = dyn_cast<TypeOfType>(DT))
4221         QDT = TP->desugar();
4222       else if (const AttributedType *AT = dyn_cast<AttributedType>(DT))
4223         QDT = AT->desugar();
4224       if (QDT != castType &&
4225           QDT.getObjCLifetime() !=  Qualifiers::OCL_None) {
4226         if (Diagnose) {
4227           SourceLocation loc = (castRange.isValid() ? castRange.getBegin()
4228                                                     : castExpr->getExprLoc());
4229           Diag(loc, diag::err_arc_nolifetime_behavior);
4230         }
4231         return ACR_error;
4232       }
4233     }
4234     return ACR_okay;
4235   }
4236
4237   // The life-time qualifier cast check above is all we need for ObjCWeak.
4238   // ObjCAutoRefCount has more restrictions on what is legal.
4239   if (!getLangOpts().ObjCAutoRefCount)
4240     return ACR_okay;
4241
4242   if (isAnyCLike(exprACTC) && isAnyCLike(castACTC)) return ACR_okay;
4243
4244   // Allow all of these types to be cast to integer types (but not
4245   // vice-versa).
4246   if (castACTC == ACTC_none && castType->isIntegralType(Context))
4247     return ACR_okay;
4248
4249   // Allow casts between pointers to lifetime types (e.g., __strong id*)
4250   // and pointers to void (e.g., cv void *). Casting from void* to lifetime*
4251   // must be explicit.
4252   if (exprACTC == ACTC_indirectRetainable && castACTC == ACTC_voidPtr)
4253     return ACR_okay;
4254   if (castACTC == ACTC_indirectRetainable && exprACTC == ACTC_voidPtr &&
4255       isCast(CCK))
4256     return ACR_okay;
4257
4258   switch (ARCCastChecker(Context, exprACTC, castACTC, false).Visit(castExpr)) {
4259   // For invalid casts, fall through.
4260   case ACC_invalid:
4261     break;
4262
4263   // Do nothing for both bottom and +0.
4264   case ACC_bottom:
4265   case ACC_plusZero:
4266     return ACR_okay;
4267
4268   // If the result is +1, consume it here.
4269   case ACC_plusOne:
4270     castExpr = ImplicitCastExpr::Create(Context, castExpr->getType(),
4271                                         CK_ARCConsumeObject, castExpr,
4272                                         nullptr, VK_RValue);
4273     Cleanup.setExprNeedsCleanups(true);
4274     return ACR_okay;
4275   }
4276
4277   // If this is a non-implicit cast from id or block type to a
4278   // CoreFoundation type, delay complaining in case the cast is used
4279   // in an acceptable context.
4280   if (exprACTC == ACTC_retainable && isAnyRetainable(castACTC) && isCast(CCK))
4281     return ACR_unbridged;
4282
4283   // Issue a diagnostic about a missing @-sign when implicit casting a cstring
4284   // to 'NSString *', instead of falling through to report a "bridge cast"
4285   // diagnostic.
4286   if (castACTC == ACTC_retainable && exprACTC == ACTC_none &&
4287       ConversionToObjCStringLiteralCheck(castType, castExpr, Diagnose))
4288     return ACR_error;
4289
4290   // Do not issue "bridge cast" diagnostic when implicit casting
4291   // a retainable object to a CF type parameter belonging to an audited
4292   // CF API function. Let caller issue a normal type mismatched diagnostic
4293   // instead.
4294   if ((!DiagnoseCFAudited || exprACTC != ACTC_retainable ||
4295        castACTC != ACTC_coreFoundation) &&
4296       !(exprACTC == ACTC_voidPtr && castACTC == ACTC_retainable &&
4297         (Opc == BO_NE || Opc == BO_EQ))) {
4298     if (Diagnose)
4299       diagnoseObjCARCConversion(*this, castRange, castType, castACTC, castExpr,
4300                                 castExpr, exprACTC, CCK);
4301     return ACR_error;
4302   }
4303   return ACR_okay;
4304 }
4305
4306 /// Given that we saw an expression with the ARCUnbridgedCastTy
4307 /// placeholder type, complain bitterly.
4308 void Sema::diagnoseARCUnbridgedCast(Expr *e) {
4309   // We expect the spurious ImplicitCastExpr to already have been stripped.
4310   assert(!e->hasPlaceholderType(BuiltinType::ARCUnbridgedCast));
4311   CastExpr *realCast = cast<CastExpr>(e->IgnoreParens());
4312
4313   SourceRange castRange;
4314   QualType castType;
4315   CheckedConversionKind CCK;
4316
4317   if (CStyleCastExpr *cast = dyn_cast<CStyleCastExpr>(realCast)) {
4318     castRange = SourceRange(cast->getLParenLoc(), cast->getRParenLoc());
4319     castType = cast->getTypeAsWritten();
4320     CCK = CCK_CStyleCast;
4321   } else if (ExplicitCastExpr *cast = dyn_cast<ExplicitCastExpr>(realCast)) {
4322     castRange = cast->getTypeInfoAsWritten()->getTypeLoc().getSourceRange();
4323     castType = cast->getTypeAsWritten();
4324     CCK = CCK_OtherCast;
4325   } else {
4326     llvm_unreachable("Unexpected ImplicitCastExpr");
4327   }
4328
4329   ARCConversionTypeClass castACTC =
4330     classifyTypeForARCConversion(castType.getNonReferenceType());
4331
4332   Expr *castExpr = realCast->getSubExpr();
4333   assert(classifyTypeForARCConversion(castExpr->getType()) == ACTC_retainable);
4334
4335   diagnoseObjCARCConversion(*this, castRange, castType, castACTC,
4336                             castExpr, realCast, ACTC_retainable, CCK);
4337 }
4338
4339 /// stripARCUnbridgedCast - Given an expression of ARCUnbridgedCast
4340 /// type, remove the placeholder cast.
4341 Expr *Sema::stripARCUnbridgedCast(Expr *e) {
4342   assert(e->hasPlaceholderType(BuiltinType::ARCUnbridgedCast));
4343
4344   if (ParenExpr *pe = dyn_cast<ParenExpr>(e)) {
4345     Expr *sub = stripARCUnbridgedCast(pe->getSubExpr());
4346     return new (Context) ParenExpr(pe->getLParen(), pe->getRParen(), sub);
4347   } else if (UnaryOperator *uo = dyn_cast<UnaryOperator>(e)) {
4348     assert(uo->getOpcode() == UO_Extension);
4349     Expr *sub = stripARCUnbridgedCast(uo->getSubExpr());
4350     return new (Context)
4351         UnaryOperator(sub, UO_Extension, sub->getType(), sub->getValueKind(),
4352                       sub->getObjectKind(), uo->getOperatorLoc(), false);
4353   } else if (GenericSelectionExpr *gse = dyn_cast<GenericSelectionExpr>(e)) {
4354     assert(!gse->isResultDependent());
4355
4356     unsigned n = gse->getNumAssocs();
4357     SmallVector<Expr *, 4> subExprs;
4358     SmallVector<TypeSourceInfo *, 4> subTypes;
4359     subExprs.reserve(n);
4360     subTypes.reserve(n);
4361     for (const GenericSelectionExpr::Association &assoc : gse->associations()) {
4362       subTypes.push_back(assoc.getTypeSourceInfo());
4363       Expr *sub = assoc.getAssociationExpr();
4364       if (assoc.isSelected())
4365         sub = stripARCUnbridgedCast(sub);
4366       subExprs.push_back(sub);
4367     }
4368
4369     return GenericSelectionExpr::Create(
4370         Context, gse->getGenericLoc(), gse->getControllingExpr(), subTypes,
4371         subExprs, gse->getDefaultLoc(), gse->getRParenLoc(),
4372         gse->containsUnexpandedParameterPack(), gse->getResultIndex());
4373   } else {
4374     assert(isa<ImplicitCastExpr>(e) && "bad form of unbridged cast!");
4375     return cast<ImplicitCastExpr>(e)->getSubExpr();
4376   }
4377 }
4378
4379 bool Sema::CheckObjCARCUnavailableWeakConversion(QualType castType,
4380                                                  QualType exprType) {
4381   QualType canCastType =
4382     Context.getCanonicalType(castType).getUnqualifiedType();
4383   QualType canExprType =
4384     Context.getCanonicalType(exprType).getUnqualifiedType();
4385   if (isa<ObjCObjectPointerType>(canCastType) &&
4386       castType.getObjCLifetime() == Qualifiers::OCL_Weak &&
4387       canExprType->isObjCObjectPointerType()) {
4388     if (const ObjCObjectPointerType *ObjT =
4389         canExprType->getAs<ObjCObjectPointerType>())
4390       if (const ObjCInterfaceDecl *ObjI = ObjT->getInterfaceDecl())
4391         return !ObjI->isArcWeakrefUnavailable();
4392   }
4393   return true;
4394 }
4395
4396 /// Look for an ObjCReclaimReturnedObject cast and destroy it.
4397 static Expr *maybeUndoReclaimObject(Expr *e) {
4398   Expr *curExpr = e, *prevExpr = nullptr;
4399
4400   // Walk down the expression until we hit an implicit cast of kind
4401   // ARCReclaimReturnedObject or an Expr that is neither a Paren nor a Cast.
4402   while (true) {
4403     if (auto *pe = dyn_cast<ParenExpr>(curExpr)) {
4404       prevExpr = curExpr;
4405       curExpr = pe->getSubExpr();
4406       continue;
4407     }
4408
4409     if (auto *ce = dyn_cast<CastExpr>(curExpr)) {
4410       if (auto *ice = dyn_cast<ImplicitCastExpr>(ce))
4411         if (ice->getCastKind() == CK_ARCReclaimReturnedObject) {
4412           if (!prevExpr)
4413             return ice->getSubExpr();
4414           if (auto *pe = dyn_cast<ParenExpr>(prevExpr))
4415             pe->setSubExpr(ice->getSubExpr());
4416           else
4417             cast<CastExpr>(prevExpr)->setSubExpr(ice->getSubExpr());
4418           return e;
4419         }
4420
4421       prevExpr = curExpr;
4422       curExpr = ce->getSubExpr();
4423       continue;
4424     }
4425
4426     // Break out of the loop if curExpr is neither a Paren nor a Cast.
4427     break;
4428   }
4429
4430   return e;
4431 }
4432
4433 ExprResult Sema::BuildObjCBridgedCast(SourceLocation LParenLoc,
4434                                       ObjCBridgeCastKind Kind,
4435                                       SourceLocation BridgeKeywordLoc,
4436                                       TypeSourceInfo *TSInfo,
4437                                       Expr *SubExpr) {
4438   ExprResult SubResult = UsualUnaryConversions(SubExpr);
4439   if (SubResult.isInvalid()) return ExprError();
4440   SubExpr = SubResult.get();
4441
4442   QualType T = TSInfo->getType();
4443   QualType FromType = SubExpr->getType();
4444
4445   CastKind CK;
4446
4447   bool MustConsume = false;
4448   if (T->isDependentType() || SubExpr->isTypeDependent()) {
4449     // Okay: we'll build a dependent expression type.
4450     CK = CK_Dependent;
4451   } else if (T->isObjCARCBridgableType() && FromType->isCARCBridgableType()) {
4452     // Casting CF -> id
4453     CK = (T->isBlockPointerType() ? CK_AnyPointerToBlockPointerCast
4454                                   : CK_CPointerToObjCPointerCast);
4455     switch (Kind) {
4456     case OBC_Bridge:
4457       break;
4458
4459     case OBC_BridgeRetained: {
4460       bool br = isKnownName("CFBridgingRelease");
4461       Diag(BridgeKeywordLoc, diag::err_arc_bridge_cast_wrong_kind)
4462         << 2
4463         << FromType
4464         << (T->isBlockPointerType()? 1 : 0)
4465         << T
4466         << SubExpr->getSourceRange()
4467         << Kind;
4468       Diag(BridgeKeywordLoc, diag::note_arc_bridge)
4469         << FixItHint::CreateReplacement(BridgeKeywordLoc, "__bridge");
4470       Diag(BridgeKeywordLoc, diag::note_arc_bridge_transfer)
4471         << FromType << br
4472         << FixItHint::CreateReplacement(BridgeKeywordLoc,
4473                                         br ? "CFBridgingRelease "
4474                                            : "__bridge_transfer ");
4475
4476       Kind = OBC_Bridge;
4477       break;
4478     }
4479
4480     case OBC_BridgeTransfer:
4481       // We must consume the Objective-C object produced by the cast.
4482       MustConsume = true;
4483       break;
4484     }
4485   } else if (T->isCARCBridgableType() && FromType->isObjCARCBridgableType()) {
4486     // Okay: id -> CF
4487     CK = CK_BitCast;
4488     switch (Kind) {
4489     case OBC_Bridge:
4490       // Reclaiming a value that's going to be __bridge-casted to CF
4491       // is very dangerous, so we don't do it.
4492       SubExpr = maybeUndoReclaimObject(SubExpr);
4493       break;
4494
4495     case OBC_BridgeRetained:
4496       // Produce the object before casting it.
4497       SubExpr = ImplicitCastExpr::Create(Context, FromType,
4498                                          CK_ARCProduceObject,
4499                                          SubExpr, nullptr, VK_RValue);
4500       break;
4501
4502     case OBC_BridgeTransfer: {
4503       bool br = isKnownName("CFBridgingRetain");
4504       Diag(BridgeKeywordLoc, diag::err_arc_bridge_cast_wrong_kind)
4505         << (FromType->isBlockPointerType()? 1 : 0)
4506         << FromType
4507         << 2
4508         << T
4509         << SubExpr->getSourceRange()
4510         << Kind;
4511
4512       Diag(BridgeKeywordLoc, diag::note_arc_bridge)
4513         << FixItHint::CreateReplacement(BridgeKeywordLoc, "__bridge ");
4514       Diag(BridgeKeywordLoc, diag::note_arc_bridge_retained)
4515         << T << br
4516         << FixItHint::CreateReplacement(BridgeKeywordLoc,
4517                           br ? "CFBridgingRetain " : "__bridge_retained");
4518
4519       Kind = OBC_Bridge;
4520       break;
4521     }
4522     }
4523   } else {
4524     Diag(LParenLoc, diag::err_arc_bridge_cast_incompatible)
4525       << FromType << T << Kind
4526       << SubExpr->getSourceRange()
4527       << TSInfo->getTypeLoc().getSourceRange();
4528     return ExprError();
4529   }
4530
4531   Expr *Result = new (Context) ObjCBridgedCastExpr(LParenLoc, Kind, CK,
4532                                                    BridgeKeywordLoc,
4533                                                    TSInfo, SubExpr);
4534
4535   if (MustConsume) {
4536     Cleanup.setExprNeedsCleanups(true);
4537     Result = ImplicitCastExpr::Create(Context, T, CK_ARCConsumeObject, Result,
4538                                       nullptr, VK_RValue);
4539   }
4540
4541   return Result;
4542 }
4543
4544 ExprResult Sema::ActOnObjCBridgedCast(Scope *S,
4545                                       SourceLocation LParenLoc,
4546                                       ObjCBridgeCastKind Kind,
4547                                       SourceLocation BridgeKeywordLoc,
4548                                       ParsedType Type,
4549                                       SourceLocation RParenLoc,
4550                                       Expr *SubExpr) {
4551   TypeSourceInfo *TSInfo = nullptr;
4552   QualType T = GetTypeFromParser(Type, &TSInfo);
4553   if (Kind == OBC_Bridge)
4554     CheckTollFreeBridgeCast(T, SubExpr);
4555   if (!TSInfo)
4556     TSInfo = Context.getTrivialTypeSourceInfo(T, LParenLoc);
4557   return BuildObjCBridgedCast(LParenLoc, Kind, BridgeKeywordLoc, TSInfo,
4558                               SubExpr);
4559 }