lib/Sema/SemaExprObjC.cpp

   1 //===--- SemaExprObjC.cpp - Semantic Analysis for ObjC Expressions --------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 //  This file implements semantic analysis for Objective-C expressions.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "clang/Sema/SemaInternal.h"
  15 #include "clang/AST/ASTContext.h"
  16 #include "clang/AST/DeclObjC.h"
  17 #include "clang/AST/ExprObjC.h"
  18 #include "clang/AST/StmtVisitor.h"
  19 #include "clang/AST/TypeLoc.h"
  20 #include "clang/Analysis/DomainSpecific/CocoaConventions.h"
  21 #include "clang/Edit/Commit.h"
  22 #include "clang/Edit/Rewriters.h"
  23 #include "clang/Lex/Preprocessor.h"
  24 #include "clang/Sema/Initialization.h"
  25 #include "clang/Sema/Lookup.h"
  26 #include "clang/Sema/Scope.h"
  27 #include "clang/Sema/ScopeInfo.h"
  28 #include "llvm/ADT/SmallString.h"
  29
  30 using namespace clang;
  31 using namespace sema;
  32 using llvm::makeArrayRef;
  33
  34 ExprResult Sema::ParseObjCStringLiteral(SourceLocation *AtLocs,
  35                                         ArrayRef<Expr *> Strings) {
  36   // Most ObjC strings are formed out of a single piece.  However, we *can*
  37   // have strings formed out of multiple @ strings with multiple pptokens in
  38   // each one, e.g. @"foo" "bar" @"baz" "qux"   which need to be turned into one
  39   // StringLiteral for ObjCStringLiteral to hold onto.
  40   StringLiteral *S = cast<StringLiteral>(Strings[0]);
  41
  42   // If we have a multi-part string, merge it all together.
  43   if (Strings.size() != 1) {
  44     // Concatenate objc strings.
  45     SmallString<128> StrBuf;
  46     SmallVector<SourceLocation, 8> StrLocs;
  47
  48     for (Expr *E : Strings) {
  49       S = cast<StringLiteral>(E);
  50
  51       // ObjC strings can't be wide or UTF.
  52       if (!S->isAscii()) {
  53         Diag(S->getLocStart(), diag::err_cfstring_literal_not_string_constant)
  54           << S->getSourceRange();
  55         return true;
  56       }
  57
  58       // Append the string.
  59       StrBuf += S->getString();
  60
  61       // Get the locations of the string tokens.
  62       StrLocs.append(S->tokloc_begin(), S->tokloc_end());
  63     }
  64
  65     // Create the aggregate string with the appropriate content and location
  66     // information.
  67     const ConstantArrayType *CAT = Context.getAsConstantArrayType(S->getType());
  68     assert(CAT && "String literal not of constant array type!");
  69     QualType StrTy = Context.getConstantArrayType(
  70         CAT->getElementType(), llvm::APInt(32, StrBuf.size() + 1),
  71         CAT->getSizeModifier(), CAT->getIndexTypeCVRQualifiers());
  72     S = StringLiteral::Create(Context, StrBuf, StringLiteral::Ascii,
  73                               /*Pascal=*/false, StrTy, &StrLocs[0],
  74                               StrLocs.size());
  75   }
  76
  77   return BuildObjCStringLiteral(AtLocs[0], S);
  78 }
  79
  80 ExprResult Sema::BuildObjCStringLiteral(SourceLocation AtLoc, StringLiteral *S){
  81   // Verify that this composite string is acceptable for ObjC strings.
  82   if (CheckObjCString(S))
  83     return true;
  84
  85   // Initialize the constant string interface lazily. This assumes
  86   // the NSString interface is seen in this translation unit. Note: We
  87   // don't use NSConstantString, since the runtime team considers this
  88   // interface private (even though it appears in the header files).
  89   QualType Ty = Context.getObjCConstantStringInterface();
  90   if (!Ty.isNull()) {
  91     Ty = Context.getObjCObjectPointerType(Ty);
  92   } else if (getLangOpts().NoConstantCFStrings) {
  93     IdentifierInfo *NSIdent=nullptr;
  94     std::string StringClass(getLangOpts().ObjCConstantStringClass);
  95
  96     if (StringClass.empty())
  97       NSIdent = &Context.Idents.get("NSConstantString");
  98     else
  99       NSIdent = &Context.Idents.get(StringClass);
 100
 101     NamedDecl *IF = LookupSingleName(TUScope, NSIdent, AtLoc,
 102                                      LookupOrdinaryName);
 103     if (ObjCInterfaceDecl *StrIF = dyn_cast_or_null<ObjCInterfaceDecl>(IF)) {
 104       Context.setObjCConstantStringInterface(StrIF);
 105       Ty = Context.getObjCConstantStringInterface();
 106       Ty = Context.getObjCObjectPointerType(Ty);
 107     } else {
 108       // If there is no NSConstantString interface defined then treat this
 109       // as error and recover from it.
 110       Diag(S->getLocStart(), diag::err_no_nsconstant_string_class) << NSIdent
 111         << S->getSourceRange();
 112       Ty = Context.getObjCIdType();
 113     }
 114   } else {
 115     IdentifierInfo *NSIdent = NSAPIObj->getNSClassId(NSAPI::ClassId_NSString);
 116     NamedDecl *IF = LookupSingleName(TUScope, NSIdent, AtLoc,
 117                                      LookupOrdinaryName);
 118     if (ObjCInterfaceDecl *StrIF = dyn_cast_or_null<ObjCInterfaceDecl>(IF)) {
 119       Context.setObjCConstantStringInterface(StrIF);
 120       Ty = Context.getObjCConstantStringInterface();
 121       Ty = Context.getObjCObjectPointerType(Ty);
 122     } else {
 123       // If there is no NSString interface defined, implicitly declare
 124       // a @class NSString; and use that instead. This is to make sure
 125       // type of an NSString literal is represented correctly, instead of
 126       // being an 'id' type.
 127       Ty = Context.getObjCNSStringType();
 128       if (Ty.isNull()) {
 129         ObjCInterfaceDecl *NSStringIDecl =
 130           ObjCInterfaceDecl::Create (Context,
 131                                      Context.getTranslationUnitDecl(),
 132                                      SourceLocation(), NSIdent,
 133                                      nullptr, nullptr, SourceLocation());
 134         Ty = Context.getObjCInterfaceType(NSStringIDecl);
 135         Context.setObjCNSStringType(Ty);
 136       }
 137       Ty = Context.getObjCObjectPointerType(Ty);
 138     }
 139   }
 140
 141   return new (Context) ObjCStringLiteral(S, Ty, AtLoc);
 142 }
 143
 144 /// 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
 403       = InitializationKind::CreateCopy(Element->getLocStart(),
 404                                        SourceLocation());
 405     InitializationSequence Seq(S, Entity, Kind, Element);
 406     if (!Seq.Failed())
 407       return Seq.Perform(S, Entity, Kind, Element);
 408   }
 409
 410   Expr *OrigElement = Element;
 411
 412   // Perform lvalue-to-rvalue conversion.
 413   Result = S.DefaultLvalueConversion(Element);
 414   if (Result.isInvalid())
 415     return ExprError();
 416   Element = Result.get();
 417
 418   // Make sure that we have an Objective-C pointer type or block.
 419   if (!Element->getType()->isObjCObjectPointerType() &&
 420       !Element->getType()->isBlockPointerType()) {
 421     bool Recovered = false;
 422
 423     // If this is potentially an Objective-C numeric literal, add the '@'.
 424     if (isa<IntegerLiteral>(OrigElement) ||
 425         isa<CharacterLiteral>(OrigElement) ||
 426         isa<FloatingLiteral>(OrigElement) ||
 427         isa<ObjCBoolLiteralExpr>(OrigElement) ||
 428         isa<CXXBoolLiteralExpr>(OrigElement)) {
 429       if (S.NSAPIObj->getNSNumberFactoryMethodKind(OrigElement->getType())) {
 430         int Which = isa<CharacterLiteral>(OrigElement) ? 1
 431                   : (isa<CXXBoolLiteralExpr>(OrigElement) ||
 432                      isa<ObjCBoolLiteralExpr>(OrigElement)) ? 2
 433                   : 3;
 434
 435         S.Diag(OrigElement->getLocStart(), diag::err_box_literal_collection)
 436           << Which << OrigElement->getSourceRange()
 437           << FixItHint::CreateInsertion(OrigElement->getLocStart(), "@");
 438
 439         Result = S.BuildObjCNumericLiteral(OrigElement->getLocStart(),
 440                                            OrigElement);
 441         if (Result.isInvalid())
 442           return ExprError();
 443
 444         Element = Result.get();
 445         Recovered = true;
 446       }
 447     }
 448     // If this is potentially an Objective-C string literal, add the '@'.
 449     else if (StringLiteral *String = dyn_cast<StringLiteral>(OrigElement)) {
 450       if (String->isAscii()) {
 451         S.Diag(OrigElement->getLocStart(), diag::err_box_literal_collection)
 452           << 0 << OrigElement->getSourceRange()
 453           << FixItHint::CreateInsertion(OrigElement->getLocStart(), "@");
 454
 455         Result = S.BuildObjCStringLiteral(OrigElement->getLocStart(), String);
 456         if (Result.isInvalid())
 457           return ExprError();
 458
 459         Element = Result.get();
 460         Recovered = true;
 461       }
 462     }
 463
 464     if (!Recovered) {
 465       S.Diag(Element->getLocStart(), diag::err_invalid_collection_element)
 466         << Element->getType();
 467       return ExprError();
 468     }
 469   }
 470   if (ArrayLiteral)
 471     if (ObjCStringLiteral *getString =
 472           dyn_cast<ObjCStringLiteral>(OrigElement)) {
 473       if (StringLiteral *SL = getString->getString()) {
 474         unsigned numConcat = SL->getNumConcatenated();
 475         if (numConcat > 1) {
 476           // Only warn if the concatenated string doesn't come from a macro.
 477           bool hasMacro = false;
 478           for (unsigned i = 0; i < numConcat ; ++i)
 479             if (SL->getStrTokenLoc(i).isMacroID()) {
 480               hasMacro = true;
 481               break;
 482             }
 483           if (!hasMacro)
 484             S.Diag(Element->getLocStart(),
 485                    diag::warn_concatenated_nsarray_literal)
 486               << Element->getType();
 487         }
 488       }
 489     }
 490
 491   // Make sure that the element has the type that the container factory
 492   // function expects.
 493   return S.PerformCopyInitialization(
 494            InitializedEntity::InitializeParameter(S.Context, T,
 495                                                   /*Consumed=*/false),
 496            Element->getLocStart(), Element);
 497 }
 498
 499 ExprResult Sema::BuildObjCBoxedExpr(SourceRange SR, Expr *ValueExpr) {
 500   if (ValueExpr->isTypeDependent()) {
 501     ObjCBoxedExpr *BoxedExpr =
 502       new (Context) ObjCBoxedExpr(ValueExpr, Context.DependentTy, nullptr, SR);
 503     return BoxedExpr;
 504   }
 505   ObjCMethodDecl *BoxingMethod = nullptr;
 506   QualType BoxedType;
 507   // Convert the expression to an RValue, so we can check for pointer types...
 508   ExprResult RValue = DefaultFunctionArrayLvalueConversion(ValueExpr);
 509   if (RValue.isInvalid()) {
 510     return ExprError();
 511   }
 512   SourceLocation Loc = SR.getBegin();
 513   ValueExpr = RValue.get();
 514   QualType ValueType(ValueExpr->getType());
 515   if (const PointerType *PT = ValueType->getAs<PointerType>()) {
 516     QualType PointeeType = PT->getPointeeType();
 517     if (Context.hasSameUnqualifiedType(PointeeType, Context.CharTy)) {
 518
 519       if (!NSStringDecl) {
 520         NSStringDecl = LookupObjCInterfaceDeclForLiteral(*this, Loc,
 521                                                          Sema::LK_String);
 522         if (!NSStringDecl) {
 523           return ExprError();
 524         }
 525         QualType NSStringObject = Context.getObjCInterfaceType(NSStringDecl);
 526         NSStringPointer = Context.getObjCObjectPointerType(NSStringObject);
 527       }
 528
 529       if (!StringWithUTF8StringMethod) {
 530         IdentifierInfo *II = &Context.Idents.get("stringWithUTF8String");
 531         Selector stringWithUTF8String = Context.Selectors.getUnarySelector(II);
 532
 533         // Look for the appropriate method within NSString.
 534         BoxingMethod = NSStringDecl->lookupClassMethod(stringWithUTF8String);
 535         if (!BoxingMethod && getLangOpts().DebuggerObjCLiteral) {
 536           // Debugger needs to work even if NSString hasn't been defined.
 537           TypeSourceInfo *ReturnTInfo = nullptr;
 538           ObjCMethodDecl *M = ObjCMethodDecl::Create(
 539               Context, SourceLocation(), SourceLocation(), stringWithUTF8String,
 540               NSStringPointer, ReturnTInfo, NSStringDecl,
 541               /*isInstance=*/false, /*isVariadic=*/false,
 542               /*isPropertyAccessor=*/false,
 543               /*isImplicitlyDeclared=*/true,
 544               /*isDefined=*/false, ObjCMethodDecl::Required,
 545               /*HasRelatedResultType=*/false);
 546           QualType ConstCharType = Context.CharTy.withConst();
 547           ParmVarDecl *value =
 548             ParmVarDecl::Create(Context, M,
 549                                 SourceLocation(), SourceLocation(),
 550                                 &Context.Idents.get("value"),
 551                                 Context.getPointerType(ConstCharType),
 552                                 /*TInfo=*/nullptr,
 553                                 SC_None, nullptr);
 554           M->setMethodParams(Context, value, None);
 555           BoxingMethod = M;
 556         }
 557
 558         if (!validateBoxingMethod(*this, Loc, NSStringDecl,
 559                                   stringWithUTF8String, BoxingMethod))
 560            return ExprError();
 561
 562         StringWithUTF8StringMethod = BoxingMethod;
 563       }
 564
 565       BoxingMethod = StringWithUTF8StringMethod;
 566       BoxedType = NSStringPointer;
 567       // Transfer the nullability from method's return type.
 568       Optional<NullabilityKind> Nullability =
 569           BoxingMethod->getReturnType()->getNullability(Context);
 570       if (Nullability)
 571         BoxedType = Context.getAttributedType(
 572             AttributedType::getNullabilityAttrKind(*Nullability), BoxedType,
 573             BoxedType);
 574     }
 575   } else if (ValueType->isBuiltinType()) {
 576     // The other types we support are numeric, char and BOOL/bool. We could also
 577     // provide limited support for structure types, such as NSRange, NSRect, and
 578     // NSSize. See NSValue (NSValueGeometryExtensions) in <Foundation/NSGeometry.h>
 579     // for more details.
 580
 581     // Check for a top-level character literal.
 582     if (const CharacterLiteral *Char =
 583         dyn_cast<CharacterLiteral>(ValueExpr->IgnoreParens())) {
 584       // In C, character literals have type 'int'. That's not the type we want
 585       // to use to determine the Objective-c literal kind.
 586       switch (Char->getKind()) {
 587       case CharacterLiteral::Ascii:
 588       case CharacterLiteral::UTF8:
 589         ValueType = Context.CharTy;
 590         break;
 591
 592       case CharacterLiteral::Wide:
 593         ValueType = Context.getWideCharType();
 594         break;
 595
 596       case CharacterLiteral::UTF16:
 597         ValueType = Context.Char16Ty;
 598         break;
 599
 600       case CharacterLiteral::UTF32:
 601         ValueType = Context.Char32Ty;
 602         break;
 603       }
 604     }
 605     // FIXME:  Do I need to do anything special with BoolTy expressions?
 606
 607     // Look for the appropriate method within NSNumber.
 608     BoxingMethod = getNSNumberFactoryMethod(*this, Loc, ValueType);
 609     BoxedType = NSNumberPointer;
 610   } else if (const EnumType *ET = ValueType->getAs<EnumType>()) {
 611     if (!ET->getDecl()->isComplete()) {
 612       Diag(Loc, diag::err_objc_incomplete_boxed_expression_type)
 613         << ValueType << ValueExpr->getSourceRange();
 614       return ExprError();
 615     }
 616
 617     BoxingMethod = getNSNumberFactoryMethod(*this, Loc,
 618                                             ET->getDecl()->getIntegerType());
 619     BoxedType = NSNumberPointer;
 620   } else if (ValueType->isObjCBoxableRecordType()) {
 621     // Support for structure types, that marked as objc_boxable
 622     // struct __attribute__((objc_boxable)) s { ... };
 623
 624     // Look up the NSValue class, if we haven't done so already. It's cached
 625     // in the Sema instance.
 626     if (!NSValueDecl) {
 627       NSValueDecl = LookupObjCInterfaceDeclForLiteral(*this, Loc,
 628                                                       Sema::LK_Boxed);
 629       if (!NSValueDecl) {
 630         return ExprError();
 631       }
 632
 633       // generate the pointer to NSValue type.
 634       QualType NSValueObject = Context.getObjCInterfaceType(NSValueDecl);
 635       NSValuePointer = Context.getObjCObjectPointerType(NSValueObject);
 636     }
 637
 638     if (!ValueWithBytesObjCTypeMethod) {
 639       IdentifierInfo *II[] = {
 640         &Context.Idents.get("valueWithBytes"),
 641         &Context.Idents.get("objCType")
 642       };
 643       Selector ValueWithBytesObjCType = Context.Selectors.getSelector(2, II);
 644
 645       // Look for the appropriate method within NSValue.
 646       BoxingMethod = NSValueDecl->lookupClassMethod(ValueWithBytesObjCType);
 647       if (!BoxingMethod && getLangOpts().DebuggerObjCLiteral) {
 648         // Debugger needs to work even if NSValue hasn't been defined.
 649         TypeSourceInfo *ReturnTInfo = nullptr;
 650         ObjCMethodDecl *M = ObjCMethodDecl::Create(
 651                                                Context,
 652                                                SourceLocation(),
 653                                                SourceLocation(),
 654                                                ValueWithBytesObjCType,
 655                                                NSValuePointer,
 656                                                ReturnTInfo,
 657                                                NSValueDecl,
 658                                                /*isInstance=*/false,
 659                                                /*isVariadic=*/false,
 660                                                /*isPropertyAccessor=*/false,
 661                                                /*isImplicitlyDeclared=*/true,
 662                                                /*isDefined=*/false,
 663                                                ObjCMethodDecl::Required,
 664                                                /*HasRelatedResultType=*/false);
 665
 666         SmallVector<ParmVarDecl *, 2> Params;
 667
 668         ParmVarDecl *bytes =
 669         ParmVarDecl::Create(Context, M,
 670                             SourceLocation(), SourceLocation(),
 671                             &Context.Idents.get("bytes"),
 672                             Context.VoidPtrTy.withConst(),
 673                             /*TInfo=*/nullptr,
 674                             SC_None, nullptr);
 675         Params.push_back(bytes);
 676
 677         QualType ConstCharType = Context.CharTy.withConst();
 678         ParmVarDecl *type =
 679         ParmVarDecl::Create(Context, M,
 680                             SourceLocation(), SourceLocation(),
 681                             &Context.Idents.get("type"),
 682                             Context.getPointerType(ConstCharType),
 683                             /*TInfo=*/nullptr,
 684                             SC_None, nullptr);
 685         Params.push_back(type);
 686
 687         M->setMethodParams(Context, Params, None);
 688         BoxingMethod = M;
 689       }
 690
 691       if (!validateBoxingMethod(*this, Loc, NSValueDecl,
 692                                 ValueWithBytesObjCType, BoxingMethod))
 693         return ExprError();
 694
 695       ValueWithBytesObjCTypeMethod = BoxingMethod;
 696     }
 697
 698     if (!ValueType.isTriviallyCopyableType(Context)) {
 699       Diag(Loc, diag::err_objc_non_trivially_copyable_boxed_expression_type)
 700         << ValueType << ValueExpr->getSourceRange();
 701       return ExprError();
 702     }
 703
 704     BoxingMethod = ValueWithBytesObjCTypeMethod;
 705     BoxedType = NSValuePointer;
 706   }
 707
 708   if (!BoxingMethod) {
 709     Diag(Loc, diag::err_objc_illegal_boxed_expression_type)
 710       << ValueType << ValueExpr->getSourceRange();
 711     return ExprError();
 712   }
 713
 714   DiagnoseUseOfDecl(BoxingMethod, Loc);
 715
 716   ExprResult ConvertedValueExpr;
 717   if (ValueType->isObjCBoxableRecordType()) {
 718     InitializedEntity IE = InitializedEntity::InitializeTemporary(ValueType);
 719     ConvertedValueExpr = PerformCopyInitialization(IE, ValueExpr->getExprLoc(),
 720                                                    ValueExpr);
 721   } else {
 722     // Convert the expression to the type that the parameter requires.
 723     ParmVarDecl *ParamDecl = BoxingMethod->parameters()[0];
 724     InitializedEntity IE = InitializedEntity::InitializeParameter(Context,
 725                                                                   ParamDecl);
 726     ConvertedValueExpr = PerformCopyInitialization(IE, SourceLocation(),
 727                                                    ValueExpr);
 728   }
 729
 730   if (ConvertedValueExpr.isInvalid())
 731     return ExprError();
 732   ValueExpr = ConvertedValueExpr.get();
 733
 734   ObjCBoxedExpr *BoxedExpr =
 735     new (Context) ObjCBoxedExpr(ValueExpr, BoxedType,
 736                                       BoxingMethod, SR);
 737   return MaybeBindToTemporary(BoxedExpr);
 738 }
 739
 740 /// Build an ObjC subscript pseudo-object expression, given that
 741 /// that's supported by the runtime.
 742 ExprResult Sema::BuildObjCSubscriptExpression(SourceLocation RB, Expr *BaseExpr,
 743                                         Expr *IndexExpr,
 744                                         ObjCMethodDecl *getterMethod,
 745                                         ObjCMethodDecl *setterMethod) {
 746   assert(!LangOpts.isSubscriptPointerArithmetic());
 747
 748   // We can't get dependent types here; our callers should have
 749   // filtered them out.
 750   assert((!BaseExpr->isTypeDependent() && !IndexExpr->isTypeDependent()) &&
 751          "base or index cannot have dependent type here");
 752
 753   // Filter out placeholders in the index.  In theory, overloads could
 754   // be preserved here, although that might not actually work correctly.
 755   ExprResult Result = CheckPlaceholderExpr(IndexExpr);
 756   if (Result.isInvalid())
 757     return ExprError();
 758   IndexExpr = Result.get();
 759
 760   // Perform lvalue-to-rvalue conversion on the base.
 761   Result = DefaultLvalueConversion(BaseExpr);
 762   if (Result.isInvalid())
 763     return ExprError();
 764   BaseExpr = Result.get();
 765
 766   // Build the pseudo-object expression.
 767   return new (Context) ObjCSubscriptRefExpr(
 768       BaseExpr, IndexExpr, Context.PseudoObjectTy, VK_LValue, OK_ObjCSubscript,
 769       getterMethod, setterMethod, RB);
 770 }
 771
 772 ExprResult Sema::BuildObjCArrayLiteral(SourceRange SR, MultiExprArg Elements) {
 773   SourceLocation Loc = SR.getBegin();
 774
 775   if (!NSArrayDecl) {
 776     NSArrayDecl = LookupObjCInterfaceDeclForLiteral(*this, Loc,
 777                                                     Sema::LK_Array);
 778     if (!NSArrayDecl) {
 779       return ExprError();
 780     }
 781   }
 782
 783   // Find the arrayWithObjects:count: method, if we haven't done so already.
 784   QualType IdT = Context.getObjCIdType();
 785   if (!ArrayWithObjectsMethod) {
 786     Selector
 787       Sel = NSAPIObj->getNSArraySelector(NSAPI::NSArr_arrayWithObjectsCount);
 788     ObjCMethodDecl *Method = NSArrayDecl->lookupClassMethod(Sel);
 789     if (!Method && getLangOpts().DebuggerObjCLiteral) {
 790       TypeSourceInfo *ReturnTInfo = nullptr;
 791       Method = ObjCMethodDecl::Create(
 792           Context, SourceLocation(), SourceLocation(), Sel, IdT, ReturnTInfo,
 793           Context.getTranslationUnitDecl(), false /*Instance*/,
 794           false /*isVariadic*/,
 795           /*isPropertyAccessor=*/false,
 796           /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
 797           ObjCMethodDecl::Required, false);
 798       SmallVector<ParmVarDecl *, 2> Params;
 799       ParmVarDecl *objects = ParmVarDecl::Create(Context, Method,
 800                                                  SourceLocation(),
 801                                                  SourceLocation(),
 802                                                  &Context.Idents.get("objects"),
 803                                                  Context.getPointerType(IdT),
 804                                                  /*TInfo=*/nullptr,
 805                                                  SC_None, nullptr);
 806       Params.push_back(objects);
 807       ParmVarDecl *cnt = ParmVarDecl::Create(Context, Method,
 808                                              SourceLocation(),
 809                                              SourceLocation(),
 810                                              &Context.Idents.get("cnt"),
 811                                              Context.UnsignedLongTy,
 812                                              /*TInfo=*/nullptr, SC_None,
 813                                              nullptr);
 814       Params.push_back(cnt);
 815       Method->setMethodParams(Context, Params, None);
 816     }
 817
 818     if (!validateBoxingMethod(*this, Loc, NSArrayDecl, Sel, Method))
 819       return ExprError();
 820
 821     // Dig out the type that all elements should be converted to.
 822     QualType T = Method->parameters()[0]->getType();
 823     const PointerType *PtrT = T->getAs<PointerType>();
 824     if (!PtrT ||
 825         !Context.hasSameUnqualifiedType(PtrT->getPointeeType(), IdT)) {
 826       Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
 827         << Sel;
 828       Diag(Method->parameters()[0]->getLocation(),
 829            diag::note_objc_literal_method_param)
 830         << 0 << T
 831         << Context.getPointerType(IdT.withConst());
 832       return ExprError();
 833     }
 834
 835     // Check that the 'count' parameter is integral.
 836     if (!Method->parameters()[1]->getType()->isIntegerType()) {
 837       Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
 838         << Sel;
 839       Diag(Method->parameters()[1]->getLocation(),
 840            diag::note_objc_literal_method_param)
 841         << 1
 842         << Method->parameters()[1]->getType()
 843         << "integral";
 844       return ExprError();
 845     }
 846
 847     // We've found a good +arrayWithObjects:count: method. Save it!
 848     ArrayWithObjectsMethod = Method;
 849   }
 850
 851   QualType ObjectsType = ArrayWithObjectsMethod->parameters()[0]->getType();
 852   QualType RequiredType = ObjectsType->castAs<PointerType>()->getPointeeType();
 853
 854   // Check that each of the elements provided is valid in a collection literal,
 855   // performing conversions as necessary.
 856   Expr **ElementsBuffer = Elements.data();
 857   for (unsigned I = 0, N = Elements.size(); I != N; ++I) {
 858     ExprResult Converted = CheckObjCCollectionLiteralElement(*this,
 859                                                              ElementsBuffer[I],
 860                                                              RequiredType, true);
 861     if (Converted.isInvalid())
 862       return ExprError();
 863
 864     ElementsBuffer[I] = Converted.get();
 865   }
 866
 867   QualType Ty
 868     = Context.getObjCObjectPointerType(
 869                                     Context.getObjCInterfaceType(NSArrayDecl));
 870
 871   return MaybeBindToTemporary(
 872            ObjCArrayLiteral::Create(Context, Elements, Ty,
 873                                     ArrayWithObjectsMethod, SR));
 874 }
 875
 876 ExprResult Sema::BuildObjCDictionaryLiteral(SourceRange SR,
 877                               MutableArrayRef<ObjCDictionaryElement> Elements) {
 878   SourceLocation Loc = SR.getBegin();
 879
 880   if (!NSDictionaryDecl) {
 881     NSDictionaryDecl = LookupObjCInterfaceDeclForLiteral(*this, Loc,
 882                                                          Sema::LK_Dictionary);
 883     if (!NSDictionaryDecl) {
 884       return ExprError();
 885     }
 886   }
 887
 888   // Find the dictionaryWithObjects:forKeys:count: method, if we haven't done
 889   // so already.
 890   QualType IdT = Context.getObjCIdType();
 891   if (!DictionaryWithObjectsMethod) {
 892     Selector Sel = NSAPIObj->getNSDictionarySelector(
 893                                NSAPI::NSDict_dictionaryWithObjectsForKeysCount);
 894     ObjCMethodDecl *Method = NSDictionaryDecl->lookupClassMethod(Sel);
 895     if (!Method && getLangOpts().DebuggerObjCLiteral) {
 896       Method = ObjCMethodDecl::Create(Context,
 897                            SourceLocation(), SourceLocation(), Sel,
 898                            IdT,
 899                            nullptr /*TypeSourceInfo */,
 900                            Context.getTranslationUnitDecl(),
 901                            false /*Instance*/, false/*isVariadic*/,
 902                            /*isPropertyAccessor=*/false,
 903                            /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
 904                            ObjCMethodDecl::Required,
 905                            false);
 906       SmallVector<ParmVarDecl *, 3> Params;
 907       ParmVarDecl *objects = ParmVarDecl::Create(Context, Method,
 908                                                  SourceLocation(),
 909                                                  SourceLocation(),
 910                                                  &Context.Idents.get("objects"),
 911                                                  Context.getPointerType(IdT),
 912                                                  /*TInfo=*/nullptr, SC_None,
 913                                                  nullptr);
 914       Params.push_back(objects);
 915       ParmVarDecl *keys = ParmVarDecl::Create(Context, Method,
 916                                               SourceLocation(),
 917                                               SourceLocation(),
 918                                               &Context.Idents.get("keys"),
 919                                               Context.getPointerType(IdT),
 920                                               /*TInfo=*/nullptr, SC_None,
 921                                               nullptr);
 922       Params.push_back(keys);
 923       ParmVarDecl *cnt = ParmVarDecl::Create(Context, Method,
 924                                              SourceLocation(),
 925                                              SourceLocation(),
 926                                              &Context.Idents.get("cnt"),
 927                                              Context.UnsignedLongTy,
 928                                              /*TInfo=*/nullptr, SC_None,
 929                                              nullptr);
 930       Params.push_back(cnt);
 931       Method->setMethodParams(Context, Params, None);
 932     }
 933
 934     if (!validateBoxingMethod(*this, SR.getBegin(), NSDictionaryDecl, Sel,
 935                               Method))
 936        return ExprError();
 937
 938     // Dig out the type that all values should be converted to.
 939     QualType ValueT = Method->parameters()[0]->getType();
 940     const PointerType *PtrValue = ValueT->getAs<PointerType>();
 941     if (!PtrValue ||
 942         !Context.hasSameUnqualifiedType(PtrValue->getPointeeType(), IdT)) {
 943       Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
 944         << Sel;
 945       Diag(Method->parameters()[0]->getLocation(),
 946            diag::note_objc_literal_method_param)
 947         << 0 << ValueT
 948         << Context.getPointerType(IdT.withConst());
 949       return ExprError();
 950     }
 951
 952     // Dig out the type that all keys should be converted to.
 953     QualType KeyT = Method->parameters()[1]->getType();
 954     const PointerType *PtrKey = KeyT->getAs<PointerType>();
 955     if (!PtrKey ||
 956         !Context.hasSameUnqualifiedType(PtrKey->getPointeeType(),
 957                                         IdT)) {
 958       bool err = true;
 959       if (PtrKey) {
 960         if (QIDNSCopying.isNull()) {
 961           // key argument of selector is id<NSCopying>?
 962           if (ObjCProtocolDecl *NSCopyingPDecl =
 963               LookupProtocol(&Context.Idents.get("NSCopying"), SR.getBegin())) {
 964             ObjCProtocolDecl *PQ[] = {NSCopyingPDecl};
 965             QIDNSCopying =
 966               Context.getObjCObjectType(Context.ObjCBuiltinIdTy, { },
 967                                         llvm::makeArrayRef(
 968                                           (ObjCProtocolDecl**) PQ,
 969                                           1),
 970                                         false);
 971             QIDNSCopying = Context.getObjCObjectPointerType(QIDNSCopying);
 972           }
 973         }
 974         if (!QIDNSCopying.isNull())
 975           err = !Context.hasSameUnqualifiedType(PtrKey->getPointeeType(),
 976                                                 QIDNSCopying);
 977       }
 978
 979       if (err) {
 980         Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
 981           << Sel;
 982         Diag(Method->parameters()[1]->getLocation(),
 983              diag::note_objc_literal_method_param)
 984           << 1 << KeyT
 985           << Context.getPointerType(IdT.withConst());
 986         return ExprError();
 987       }
 988     }
 989
 990     // Check that the 'count' parameter is integral.
 991     QualType CountType = Method->parameters()[2]->getType();
 992     if (!CountType->isIntegerType()) {
 993       Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
 994         << Sel;
 995       Diag(Method->parameters()[2]->getLocation(),
 996            diag::note_objc_literal_method_param)
 997         << 2 << CountType
 998         << "integral";
 999       return ExprError();
1000     }
1001
1002     // We've found a good +dictionaryWithObjects:keys:count: method; save it!
1003     DictionaryWithObjectsMethod = Method;
1004   }
1005
1006   QualType ValuesT = DictionaryWithObjectsMethod->parameters()[0]->getType();
1007   QualType ValueT = ValuesT->castAs<PointerType>()->getPointeeType();
1008   QualType KeysT = DictionaryWithObjectsMethod->parameters()[1]->getType();
1009   QualType KeyT = KeysT->castAs<PointerType>()->getPointeeType();
1010
1011   // Check that each of the keys and values provided is valid in a collection
1012   // literal, performing conversions as necessary.
1013   bool HasPackExpansions = false;
1014   for (ObjCDictionaryElement &Element : Elements) {
1015     // Check the key.
1016     ExprResult Key = CheckObjCCollectionLiteralElement(*this, Element.Key,
1017                                                        KeyT);
1018     if (Key.isInvalid())
1019       return ExprError();
1020
1021     // Check the value.
1022     ExprResult Value
1023       = CheckObjCCollectionLiteralElement(*this, Element.Value, ValueT);
1024     if (Value.isInvalid())
1025       return ExprError();
1026
1027     Element.Key = Key.get();
1028     Element.Value = Value.get();
1029
1030     if (Element.EllipsisLoc.isInvalid())
1031       continue;
1032
1033     if (!Element.Key->containsUnexpandedParameterPack() &&
1034         !Element.Value->containsUnexpandedParameterPack()) {
1035       Diag(Element.EllipsisLoc,
1036            diag::err_pack_expansion_without_parameter_packs)
1037         << SourceRange(Element.Key->getLocStart(),
1038                        Element.Value->getLocEnd());
1039       return ExprError();
1040     }
1041
1042     HasPackExpansions = true;
1043   }
1044
1045   QualType Ty
1046     = Context.getObjCObjectPointerType(
1047                                 Context.getObjCInterfaceType(NSDictionaryDecl));
1048   return MaybeBindToTemporary(ObjCDictionaryLiteral::Create(
1049       Context, Elements, HasPackExpansions, Ty,
1050       DictionaryWithObjectsMethod, SR));
1051 }
1052
1053 ExprResult Sema::BuildObjCEncodeExpression(SourceLocation AtLoc,
1054                                       TypeSourceInfo *EncodedTypeInfo,
1055                                       SourceLocation RParenLoc) {
1056   QualType EncodedType = EncodedTypeInfo->getType();
1057   QualType StrTy;
1058   if (EncodedType->isDependentType())
1059     StrTy = Context.DependentTy;
1060   else {
1061     if (!EncodedType->getAsArrayTypeUnsafe() && //// Incomplete array is handled.
1062         !EncodedType->isVoidType()) // void is handled too.
1063       if (RequireCompleteType(AtLoc, EncodedType,
1064                               diag::err_incomplete_type_objc_at_encode,
1065                               EncodedTypeInfo->getTypeLoc()))
1066         return ExprError();
1067
1068     std::string Str;
1069     QualType NotEncodedT;
1070     Context.getObjCEncodingForType(EncodedType, Str, nullptr, &NotEncodedT);
1071     if (!NotEncodedT.isNull())
1072       Diag(AtLoc, diag::warn_incomplete_encoded_type)
1073         << EncodedType << NotEncodedT;
1074
1075     // The type of @encode is the same as the type of the corresponding string,
1076     // which is an array type.
1077     StrTy = Context.CharTy;
1078     // A C++ string literal has a const-qualified element type (C++ 2.13.4p1).
1079     if (getLangOpts().CPlusPlus || getLangOpts().ConstStrings)
1080       StrTy.addConst();
1081     StrTy = Context.getConstantArrayType(StrTy, llvm::APInt(32, Str.size()+1),
1082                                          ArrayType::Normal, 0);
1083   }
1084
1085   return new (Context) ObjCEncodeExpr(StrTy, EncodedTypeInfo, AtLoc, RParenLoc);
1086 }
1087
1088 ExprResult Sema::ParseObjCEncodeExpression(SourceLocation AtLoc,
1089                                            SourceLocation EncodeLoc,
1090                                            SourceLocation LParenLoc,
1091                                            ParsedType ty,
1092                                            SourceLocation RParenLoc) {
1093   // FIXME: Preserve type source info ?
1094   TypeSourceInfo *TInfo;
1095   QualType EncodedType = GetTypeFromParser(ty, &TInfo);
1096   if (!TInfo)
1097     TInfo = Context.getTrivialTypeSourceInfo(EncodedType,
1098                                              getLocForEndOfToken(LParenLoc));
1099
1100   return BuildObjCEncodeExpression(AtLoc, TInfo, RParenLoc);
1101 }
1102
1103 static bool HelperToDiagnoseMismatchedMethodsInGlobalPool(Sema &S,
1104                                                SourceLocation AtLoc,
1105                                                SourceLocation LParenLoc,
1106                                                SourceLocation RParenLoc,
1107                                                ObjCMethodDecl *Method,
1108                                                ObjCMethodList &MethList) {
1109   ObjCMethodList *M = &MethList;
1110   bool Warned = false;
1111   for (M = M->getNext(); M; M=M->getNext()) {
1112     ObjCMethodDecl *MatchingMethodDecl = M->getMethod();
1113     if (MatchingMethodDecl == Method ||
1114         isa<ObjCImplDecl>(MatchingMethodDecl->getDeclContext()) ||
1115         MatchingMethodDecl->getSelector() != Method->getSelector())
1116       continue;
1117     if (!S.MatchTwoMethodDeclarations(Method,
1118                                       MatchingMethodDecl, Sema::MMS_loose)) {
1119       if (!Warned) {
1120         Warned = true;
1121         S.Diag(AtLoc, diag::warn_multiple_selectors)
1122           << Method->getSelector() << FixItHint::CreateInsertion(LParenLoc, "(")
1123           << FixItHint::CreateInsertion(RParenLoc, ")");
1124         S.Diag(Method->getLocation(), diag::note_method_declared_at)
1125           << Method->getDeclName();
1126       }
1127       S.Diag(MatchingMethodDecl->getLocation(), diag::note_method_declared_at)
1128         << MatchingMethodDecl->getDeclName();
1129     }
1130   }
1131   return Warned;
1132 }
1133
1134 static void DiagnoseMismatchedSelectors(Sema &S, SourceLocation AtLoc,
1135                                         ObjCMethodDecl *Method,
1136                                         SourceLocation LParenLoc,
1137                                         SourceLocation RParenLoc,
1138                                         bool WarnMultipleSelectors) {
1139   if (!WarnMultipleSelectors ||
1140       S.Diags.isIgnored(diag::warn_multiple_selectors, SourceLocation()))
1141     return;
1142   bool Warned = false;
1143   for (Sema::GlobalMethodPool::iterator b = S.MethodPool.begin(),
1144        e = S.MethodPool.end(); b != e; b++) {
1145     // first, instance methods
1146     ObjCMethodList &InstMethList = b->second.first;
1147     if (HelperToDiagnoseMismatchedMethodsInGlobalPool(S, AtLoc, LParenLoc, RParenLoc,
1148                                                       Method, InstMethList))
1149       Warned = true;
1150
1151     // second, class methods
1152     ObjCMethodList &ClsMethList = b->second.second;
1153     if (HelperToDiagnoseMismatchedMethodsInGlobalPool(S, AtLoc, LParenLoc, RParenLoc,
1154                                                       Method, ClsMethList) || Warned)
1155       return;
1156   }
1157 }
1158
1159 ExprResult Sema::ParseObjCSelectorExpression(Selector Sel,
1160                                              SourceLocation AtLoc,
1161                                              SourceLocation SelLoc,
1162                                              SourceLocation LParenLoc,
1163                                              SourceLocation RParenLoc,
1164                                              bool WarnMultipleSelectors) {
1165   ObjCMethodDecl *Method = LookupInstanceMethodInGlobalPool(Sel,
1166                              SourceRange(LParenLoc, RParenLoc));
1167   if (!Method)
1168     Method = LookupFactoryMethodInGlobalPool(Sel,
1169                                           SourceRange(LParenLoc, RParenLoc));
1170   if (!Method) {
1171     if (const ObjCMethodDecl *OM = SelectorsForTypoCorrection(Sel)) {
1172       Selector MatchedSel = OM->getSelector();
1173       SourceRange SelectorRange(LParenLoc.getLocWithOffset(1),
1174                                 RParenLoc.getLocWithOffset(-1));
1175       Diag(SelLoc, diag::warn_undeclared_selector_with_typo)
1176         << Sel << MatchedSel
1177         << FixItHint::CreateReplacement(SelectorRange, MatchedSel.getAsString());
1178
1179     } else
1180         Diag(SelLoc, diag::warn_undeclared_selector) << Sel;
1181   } else
1182     DiagnoseMismatchedSelectors(*this, AtLoc, Method, LParenLoc, RParenLoc,
1183                                 WarnMultipleSelectors);
1184
1185   if (Method &&
1186       Method->getImplementationControl() != ObjCMethodDecl::Optional &&
1187       !getSourceManager().isInSystemHeader(Method->getLocation()))
1188     ReferencedSelectors.insert(std::make_pair(Sel, AtLoc));
1189
1190   // In ARC, forbid the user from using @selector for
1191   // retain/release/autorelease/dealloc/retainCount.
1192   if (getLangOpts().ObjCAutoRefCount) {
1193     switch (Sel.getMethodFamily()) {
1194     case OMF_retain:
1195     case OMF_release:
1196     case OMF_autorelease:
1197     case OMF_retainCount:
1198     case OMF_dealloc:
1199       Diag(AtLoc, diag::err_arc_illegal_selector) <<
1200         Sel << SourceRange(LParenLoc, RParenLoc);
1201       break;
1202
1203     case OMF_None:
1204     case OMF_alloc:
1205     case OMF_copy:
1206     case OMF_finalize:
1207     case OMF_init:
1208     case OMF_mutableCopy:
1209     case OMF_new:
1210     case OMF_self:
1211     case OMF_initialize:
1212     case OMF_performSelector:
1213       break;
1214     }
1215   }
1216   QualType Ty = Context.getObjCSelType();
1217   return new (Context) ObjCSelectorExpr(Ty, Sel, AtLoc, RParenLoc);
1218 }
1219
1220 ExprResult Sema::ParseObjCProtocolExpression(IdentifierInfo *ProtocolId,
1221                                              SourceLocation AtLoc,
1222                                              SourceLocation ProtoLoc,
1223                                              SourceLocation LParenLoc,
1224                                              SourceLocation ProtoIdLoc,
1225                                              SourceLocation RParenLoc) {
1226   ObjCProtocolDecl* PDecl = LookupProtocol(ProtocolId, ProtoIdLoc);
1227   if (!PDecl) {
1228     Diag(ProtoLoc, diag::err_undeclared_protocol) << ProtocolId;
1229     return true;
1230   }
1231   if (PDecl->hasDefinition())
1232     PDecl = PDecl->getDefinition();
1233
1234   QualType Ty = Context.getObjCProtoType();
1235   if (Ty.isNull())
1236     return true;
1237   Ty = Context.getObjCObjectPointerType(Ty);
1238   return new (Context) ObjCProtocolExpr(Ty, PDecl, AtLoc, ProtoIdLoc, RParenLoc);
1239 }
1240
1241 /// Try to capture an implicit reference to 'self'.
1242 ObjCMethodDecl *Sema::tryCaptureObjCSelf(SourceLocation Loc) {
1243   DeclContext *DC = getFunctionLevelDeclContext();
1244
1245   // If we're not in an ObjC method, error out.  Note that, unlike the
1246   // C++ case, we don't require an instance method --- class methods
1247   // still have a 'self', and we really do still need to capture it!
1248   ObjCMethodDecl *method = dyn_cast<ObjCMethodDecl>(DC);
1249   if (!method)
1250     return nullptr;
1251
1252   tryCaptureVariable(method->getSelfDecl(), Loc);
1253
1254   return method;
1255 }
1256
1257 static QualType stripObjCInstanceType(ASTContext &Context, QualType T) {
1258   QualType origType = T;
1259   if (auto nullability = AttributedType::stripOuterNullability(T)) {
1260     if (T == Context.getObjCInstanceType()) {
1261       return Context.getAttributedType(
1262                AttributedType::getNullabilityAttrKind(*nullability),
1263                Context.getObjCIdType(),
1264                Context.getObjCIdType());
1265     }
1266
1267     return origType;
1268   }
1269
1270   if (T == Context.getObjCInstanceType())
1271     return Context.getObjCIdType();
1272
1273   return origType;
1274 }
1275
1276 /// Determine the result type of a message send based on the receiver type,
1277 /// method, and the kind of message send.
1278 ///
1279 /// This is the "base" result type, which will still need to be adjusted
1280 /// to account for nullability.
1281 static QualType getBaseMessageSendResultType(Sema &S,
1282                                              QualType ReceiverType,
1283                                              ObjCMethodDecl *Method,
1284                                              bool isClassMessage,
1285                                              bool isSuperMessage) {
1286   assert(Method && "Must have a method");
1287   if (!Method->hasRelatedResultType())
1288     return Method->getSendResultType(ReceiverType);
1289
1290   ASTContext &Context = S.Context;
1291
1292   // Local function that transfers the nullability of the method's
1293   // result type to the returned result.
1294   auto transferNullability = [&](QualType type) -> QualType {
1295     // If the method's result type has nullability, extract it.
1296     if (auto nullability = Method->getSendResultType(ReceiverType)
1297                              ->getNullability(Context)){
1298       // Strip off any outer nullability sugar from the provided type.
1299       (void)AttributedType::stripOuterNullability(type);
1300
1301       // Form a new attributed type using the method result type's nullability.
1302       return Context.getAttributedType(
1303                AttributedType::getNullabilityAttrKind(*nullability),
1304                type,
1305                type);
1306     }
1307
1308     return type;
1309   };
1310
1311   // If a method has a related return type:
1312   //   - if the method found is an instance method, but the message send
1313   //     was a class message send, T is the declared return type of the method
1314   //     found
1315   if (Method->isInstanceMethod() && isClassMessage)
1316     return stripObjCInstanceType(Context,
1317                                  Method->getSendResultType(ReceiverType));
1318
1319   //   - if the receiver is super, T is a pointer to the class of the
1320   //     enclosing method definition
1321   if (isSuperMessage) {
1322     if (ObjCMethodDecl *CurMethod = S.getCurMethodDecl())
1323       if (ObjCInterfaceDecl *Class = CurMethod->getClassInterface()) {
1324         return transferNullability(
1325                  Context.getObjCObjectPointerType(
1326                    Context.getObjCInterfaceType(Class)));
1327       }
1328   }
1329
1330   //   - if the receiver is the name of a class U, T is a pointer to U
1331   if (ReceiverType->getAsObjCInterfaceType())
1332     return transferNullability(Context.getObjCObjectPointerType(ReceiverType));
1333   //   - if the receiver is of type Class or qualified Class type,
1334   //     T is the declared return type of the method.
1335   if (ReceiverType->isObjCClassType() ||
1336       ReceiverType->isObjCQualifiedClassType())
1337     return stripObjCInstanceType(Context,
1338                                  Method->getSendResultType(ReceiverType));
1339
1340   //   - if the receiver is id, qualified id, Class, or qualified Class, T
1341   //     is the receiver type, otherwise
1342   //   - T is the type of the receiver expression.
1343   return transferNullability(ReceiverType);
1344 }
1345
1346 QualType Sema::getMessageSendResultType(QualType ReceiverType,
1347                                         ObjCMethodDecl *Method,
1348                                         bool isClassMessage,
1349                                         bool isSuperMessage) {
1350   // Produce the result type.
1351   QualType resultType = getBaseMessageSendResultType(*this, ReceiverType,
1352                                                      Method,
1353                                                      isClassMessage,
1354                                                      isSuperMessage);
1355
1356   // If this is a class message, ignore the nullability of the receiver.
1357   if (isClassMessage)
1358     return resultType;
1359
1360   // There is nothing left to do if the result type cannot have a nullability
1361   // specifier.
1362   if (!resultType->canHaveNullability())
1363     return resultType;
1364
1365   // Map the nullability of the result into a table index.
1366   unsigned receiverNullabilityIdx = 0;
1367   if (auto nullability = ReceiverType->getNullability(Context))
1368     receiverNullabilityIdx = 1 + static_cast<unsigned>(*nullability);
1369
1370   unsigned resultNullabilityIdx = 0;
1371   if (auto nullability = resultType->getNullability(Context))
1372     resultNullabilityIdx = 1 + static_cast<unsigned>(*nullability);
1373
1374   // The table of nullability mappings, indexed by the receiver's nullability
1375   // and then the result type's nullability.
1376   static const uint8_t None = 0;
1377   static const uint8_t NonNull = 1;
1378   static const uint8_t Nullable = 2;
1379   static const uint8_t Unspecified = 3;
1380   static const uint8_t nullabilityMap[4][4] = {
1381     //                  None        NonNull       Nullable    Unspecified
1382     /* None */        { None,       None,         Nullable,   None },
1383     /* NonNull */     { None,       NonNull,      Nullable,   Unspecified },
1384     /* Nullable */    { Nullable,   Nullable,     Nullable,   Nullable },
1385     /* Unspecified */ { None,       Unspecified,  Nullable,   Unspecified }
1386   };
1387
1388   unsigned newResultNullabilityIdx
1389     = nullabilityMap[receiverNullabilityIdx][resultNullabilityIdx];
1390   if (newResultNullabilityIdx == resultNullabilityIdx)
1391     return resultType;
1392
1393   // Strip off the existing nullability. This removes as little type sugar as
1394   // possible.
1395   do {
1396     if (auto attributed = dyn_cast<AttributedType>(resultType.getTypePtr())) {
1397       resultType = attributed->getModifiedType();
1398     } else {
1399       resultType = resultType.getDesugaredType(Context);
1400     }
1401   } while (resultType->getNullability(Context));
1402
1403   // Add nullability back if needed.
1404   if (newResultNullabilityIdx > 0) {
1405     auto newNullability
1406       = static_cast<NullabilityKind>(newResultNullabilityIdx-1);
1407     return Context.getAttributedType(
1408              AttributedType::getNullabilityAttrKind(newNullability),
1409              resultType, resultType);
1410   }
1411
1412   return resultType;
1413 }
1414
1415 /// Look for an ObjC method whose result type exactly matches the given type.
1416 static const ObjCMethodDecl *
1417 findExplicitInstancetypeDeclarer(const ObjCMethodDecl *MD,
1418                                  QualType instancetype) {
1419   if (MD->getReturnType() == instancetype)
1420     return MD;
1421
1422   // For these purposes, a method in an @implementation overrides a
1423   // declaration in the @interface.
1424   if (const ObjCImplDecl *impl =
1425         dyn_cast<ObjCImplDecl>(MD->getDeclContext())) {
1426     const ObjCContainerDecl *iface;
1427     if (const ObjCCategoryImplDecl *catImpl =
1428           dyn_cast<ObjCCategoryImplDecl>(impl)) {
1429       iface = catImpl->getCategoryDecl();
1430     } else {
1431       iface = impl->getClassInterface();
1432     }
1433
1434     const ObjCMethodDecl *ifaceMD =
1435       iface->getMethod(MD->getSelector(), MD->isInstanceMethod());
1436     if (ifaceMD) return findExplicitInstancetypeDeclarer(ifaceMD, instancetype);
1437   }
1438
1439   SmallVector<const ObjCMethodDecl *, 4> overrides;
1440   MD->getOverriddenMethods(overrides);
1441   for (unsigned i = 0, e = overrides.size(); i != e; ++i) {
1442     if (const ObjCMethodDecl *result =
1443           findExplicitInstancetypeDeclarer(overrides[i], instancetype))
1444       return result;
1445   }
1446
1447   return nullptr;
1448 }
1449
1450 void Sema::EmitRelatedResultTypeNoteForReturn(QualType destType) {
1451   // Only complain if we're in an ObjC method and the required return
1452   // type doesn't match the method's declared return type.
1453   ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(CurContext);
1454   if (!MD || !MD->hasRelatedResultType() ||
1455       Context.hasSameUnqualifiedType(destType, MD->getReturnType()))
1456     return;
1457
1458   // Look for a method overridden by this method which explicitly uses
1459   // 'instancetype'.
1460   if (const ObjCMethodDecl *overridden =
1461         findExplicitInstancetypeDeclarer(MD, Context.getObjCInstanceType())) {
1462     SourceRange range = overridden->getReturnTypeSourceRange();
1463     SourceLocation loc = range.getBegin();
1464     if (loc.isInvalid())
1465       loc = overridden->getLocation();
1466     Diag(loc, diag::note_related_result_type_explicit)
1467       << /*current method*/ 1 << range;
1468     return;
1469   }
1470
1471   // Otherwise, if we have an interesting method family, note that.
1472   // This should always trigger if the above didn't.
1473   if (ObjCMethodFamily family = MD->getMethodFamily())
1474     Diag(MD->getLocation(), diag::note_related_result_type_family)
1475       << /*current method*/ 1
1476       << family;
1477 }
1478
1479 void Sema::EmitRelatedResultTypeNote(const Expr *E) {
1480   E = E->IgnoreParenImpCasts();
1481   const ObjCMessageExpr *MsgSend = dyn_cast<ObjCMessageExpr>(E);
1482   if (!MsgSend)
1483     return;
1484
1485   const ObjCMethodDecl *Method = MsgSend->getMethodDecl();
1486   if (!Method)
1487     return;
1488
1489   if (!Method->hasRelatedResultType())
1490     return;
1491
1492   if (Context.hasSameUnqualifiedType(
1493           Method->getReturnType().getNonReferenceType(), MsgSend->getType()))
1494     return;
1495
1496   if (!Context.hasSameUnqualifiedType(Method->getReturnType(),
1497                                       Context.getObjCInstanceType()))
1498     return;
1499
1500   Diag(Method->getLocation(), diag::note_related_result_type_inferred)
1501     << Method->isInstanceMethod() << Method->getSelector()
1502     << MsgSend->getType();
1503 }
1504
1505 bool Sema::CheckMessageArgumentTypes(QualType ReceiverType,
1506                                      MultiExprArg Args,
1507                                      Selector Sel,
1508                                      ArrayRef<SourceLocation> SelectorLocs,
1509                                      ObjCMethodDecl *Method,
1510                                      bool isClassMessage, bool isSuperMessage,
1511                                      SourceLocation lbrac, SourceLocation rbrac,
1512                                      SourceRange RecRange,
1513                                      QualType &ReturnType, ExprValueKind &VK) {
1514   SourceLocation SelLoc;
1515   if (!SelectorLocs.empty() && SelectorLocs.front().isValid())
1516     SelLoc = SelectorLocs.front();
1517   else
1518     SelLoc = lbrac;
1519
1520   if (!Method) {
1521     // Apply default argument promotion as for (C99 6.5.2.2p6).
1522     for (unsigned i = 0, e = Args.size(); i != e; i++) {
1523       if (Args[i]->isTypeDependent())
1524         continue;
1525
1526       ExprResult result;
1527       if (getLangOpts().DebuggerSupport) {
1528         QualType paramTy; // ignored
1529         result = checkUnknownAnyArg(SelLoc, Args[i], paramTy);
1530       } else {
1531         result = DefaultArgumentPromotion(Args[i]);
1532       }
1533       if (result.isInvalid())
1534         return true;
1535       Args[i] = result.get();
1536     }
1537
1538     unsigned DiagID;
1539     if (getLangOpts().ObjCAutoRefCount)
1540       DiagID = diag::err_arc_method_not_found;
1541     else
1542       DiagID = isClassMessage ? diag::warn_class_method_not_found
1543                               : diag::warn_inst_method_not_found;
1544     if (!getLangOpts().DebuggerSupport) {
1545       const ObjCMethodDecl *OMD = SelectorsForTypoCorrection(Sel, ReceiverType);
1546       if (OMD && !OMD->isInvalidDecl()) {
1547         if (getLangOpts().ObjCAutoRefCount)
1548           DiagID = diag::err_method_not_found_with_typo;
1549         else
1550           DiagID = isClassMessage ? diag::warn_class_method_not_found_with_typo
1551                                   : diag::warn_instance_method_not_found_with_typo;
1552         Selector MatchedSel = OMD->getSelector();
1553         SourceRange SelectorRange(SelectorLocs.front(), SelectorLocs.back());
1554         if (MatchedSel.isUnarySelector())
1555           Diag(SelLoc, DiagID)
1556             << Sel<< isClassMessage << MatchedSel
1557             << FixItHint::CreateReplacement(SelectorRange, MatchedSel.getAsString());
1558         else
1559           Diag(SelLoc, DiagID) << Sel<< isClassMessage << MatchedSel;
1560       }
1561       else
1562         Diag(SelLoc, DiagID)
1563           << Sel << isClassMessage << SourceRange(SelectorLocs.front(),
1564                                                 SelectorLocs.back());
1565       // Find the class to which we are sending this message.
1566       if (ReceiverType->isObjCObjectPointerType()) {
1567         if (ObjCInterfaceDecl *ThisClass =
1568             ReceiverType->getAs<ObjCObjectPointerType>()->getInterfaceDecl()) {
1569           Diag(ThisClass->getLocation(), diag::note_receiver_class_declared);
1570           if (!RecRange.isInvalid())
1571             if (ThisClass->lookupClassMethod(Sel))
1572               Diag(RecRange.getBegin(),diag::note_receiver_expr_here)
1573                 << FixItHint::CreateReplacement(RecRange,
1574                                                 ThisClass->getNameAsString());
1575         }
1576       }
1577     }
1578
1579     // In debuggers, we want to use __unknown_anytype for these
1580     // results so that clients can cast them.
1581     if (getLangOpts().DebuggerSupport) {
1582       ReturnType = Context.UnknownAnyTy;
1583     } else {
1584       ReturnType = Context.getObjCIdType();
1585     }
1586     VK = VK_RValue;
1587     return false;
1588   }
1589
1590   ReturnType = getMessageSendResultType(ReceiverType, Method, isClassMessage,
1591                                         isSuperMessage);
1592   VK = Expr::getValueKindForType(Method->getReturnType());
1593
1594   unsigned NumNamedArgs = Sel.getNumArgs();
1595   // Method might have more arguments than selector indicates. This is due
1596   // to addition of c-style arguments in method.
1597   if (Method->param_size() > Sel.getNumArgs())
1598     NumNamedArgs = Method->param_size();
1599   // FIXME. This need be cleaned up.
1600   if (Args.size() < NumNamedArgs) {
1601     Diag(SelLoc, diag::err_typecheck_call_too_few_args)
1602       << 2 << NumNamedArgs << static_cast<unsigned>(Args.size());
1603     return false;
1604   }
1605
1606   // Compute the set of type arguments to be substituted into each parameter
1607   // type.
1608   Optional<ArrayRef<QualType>> typeArgs
1609     = ReceiverType->getObjCSubstitutions(Method->getDeclContext());
1610   bool IsError = false;
1611   for (unsigned i = 0; i < NumNamedArgs; i++) {
1612     // We can't do any type-checking on a type-dependent argument.
1613     if (Args[i]->isTypeDependent())
1614       continue;
1615
1616     Expr *argExpr = Args[i];
1617
1618     ParmVarDecl *param = Method->parameters()[i];
1619     assert(argExpr && "CheckMessageArgumentTypes(): missing expression");
1620
1621     if (param->hasAttr<NoEscapeAttr>())
1622       if (auto *BE = dyn_cast<BlockExpr>(
1623               argExpr->IgnoreParenNoopCasts(Context)))
1624         BE->getBlockDecl()->setDoesNotEscape();
1625
1626     // Strip the unbridged-cast placeholder expression off unless it's
1627     // a consumed argument.
1628     if (argExpr->hasPlaceholderType(BuiltinType::ARCUnbridgedCast) &&
1629         !param->hasAttr<CFConsumedAttr>())
1630       argExpr = stripARCUnbridgedCast(argExpr);
1631
1632     // If the parameter is __unknown_anytype, infer its type
1633     // from the argument.
1634     if (param->getType() == Context.UnknownAnyTy) {
1635       QualType paramType;
1636       ExprResult argE = checkUnknownAnyArg(SelLoc, argExpr, paramType);
1637       if (argE.isInvalid()) {
1638         IsError = true;
1639       } else {
1640         Args[i] = argE.get();
1641
1642         // Update the parameter type in-place.
1643         param->setType(paramType);
1644       }
1645       continue;
1646     }
1647
1648     QualType origParamType = param->getType();
1649     QualType paramType = param->getType();
1650     if (typeArgs)
1651       paramType = paramType.substObjCTypeArgs(
1652                     Context,
1653                     *typeArgs,
1654                     ObjCSubstitutionContext::Parameter);
1655
1656     if (RequireCompleteType(argExpr->getSourceRange().getBegin(),
1657                             paramType,
1658                             diag::err_call_incomplete_argument, argExpr))
1659       return true;
1660
1661     InitializedEntity Entity
1662       = InitializedEntity::InitializeParameter(Context, param, paramType);
1663     ExprResult ArgE = PerformCopyInitialization(Entity, SourceLocation(), argExpr);
1664     if (ArgE.isInvalid())
1665       IsError = true;
1666     else {
1667       Args[i] = ArgE.getAs<Expr>();
1668
1669       // If we are type-erasing a block to a block-compatible
1670       // Objective-C pointer type, we may need to extend the lifetime
1671       // of the block object.
1672       if (typeArgs && Args[i]->isRValue() && paramType->isBlockPointerType() &&
1673           Args[i]->getType()->isBlockPointerType() &&
1674           origParamType->isObjCObjectPointerType()) {
1675         ExprResult arg = Args[i];
1676         maybeExtendBlockObject(arg);
1677         Args[i] = arg.get();
1678       }
1679     }
1680   }
1681
1682   // Promote additional arguments to variadic methods.
1683   if (Method->isVariadic()) {
1684     for (unsigned i = NumNamedArgs, e = Args.size(); i < e; ++i) {
1685       if (Args[i]->isTypeDependent())
1686         continue;
1687
1688       ExprResult Arg = DefaultVariadicArgumentPromotion(Args[i], VariadicMethod,
1689                                                         nullptr);
1690       IsError |= Arg.isInvalid();
1691       Args[i] = Arg.get();
1692     }
1693   } else {
1694     // Check for extra arguments to non-variadic methods.
1695     if (Args.size() != NumNamedArgs) {
1696       Diag(Args[NumNamedArgs]->getLocStart(),
1697            diag::err_typecheck_call_too_many_args)
1698         << 2 /*method*/ << NumNamedArgs << static_cast<unsigned>(Args.size())
1699         << Method->getSourceRange()
1700         << SourceRange(Args[NumNamedArgs]->getLocStart(),
1701                        Args.back()->getLocEnd());
1702     }
1703   }
1704
1705   DiagnoseSentinelCalls(Method, SelLoc, Args);
1706
1707   // Do additional checkings on method.
1708   IsError |= CheckObjCMethodCall(
1709       Method, SelLoc, makeArrayRef(Args.data(), Args.size()));
1710
1711   return IsError;
1712 }
1713
1714 bool Sema::isSelfExpr(Expr *RExpr) {
1715   // 'self' is objc 'self' in an objc method only.
1716   ObjCMethodDecl *Method =
1717       dyn_cast_or_null<ObjCMethodDecl>(CurContext->getNonClosureAncestor());
1718   return isSelfExpr(RExpr, Method);
1719 }
1720
1721 bool Sema::isSelfExpr(Expr *receiver, const ObjCMethodDecl *method) {
1722   if (!method) return false;
1723
1724   receiver = receiver->IgnoreParenLValueCasts();
1725   if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(receiver))
1726     if (DRE->getDecl() == method->getSelfDecl())
1727       return true;
1728   return false;
1729 }
1730
1731 /// LookupMethodInType - Look up a method in an ObjCObjectType.
1732 ObjCMethodDecl *Sema::LookupMethodInObjectType(Selector sel, QualType type,
1733                                                bool isInstance) {
1734   const ObjCObjectType *objType = type->castAs<ObjCObjectType>();
1735   if (ObjCInterfaceDecl *iface = objType->getInterface()) {
1736     // Look it up in the main interface (and categories, etc.)
1737     if (ObjCMethodDecl *method = iface->lookupMethod(sel, isInstance))
1738       return method;
1739
1740     // Okay, look for "private" methods declared in any
1741     // @implementations we've seen.
1742     if (ObjCMethodDecl *method = iface->lookupPrivateMethod(sel, isInstance))
1743       return method;
1744   }
1745
1746   // Check qualifiers.
1747   for (const auto *I : objType->quals())
1748     if (ObjCMethodDecl *method = I->lookupMethod(sel, isInstance))
1749       return method;
1750
1751   return nullptr;
1752 }
1753
1754 /// LookupMethodInQualifiedType - Lookups up a method in protocol qualifier
1755 /// list of a qualified objective pointer type.
1756 ObjCMethodDecl *Sema::LookupMethodInQualifiedType(Selector Sel,
1757                                               const ObjCObjectPointerType *OPT,
1758                                               bool Instance)
1759 {
1760   ObjCMethodDecl *MD = nullptr;
1761   for (const auto *PROTO : OPT->quals()) {
1762     if ((MD = PROTO->lookupMethod(Sel, Instance))) {
1763       return MD;
1764     }
1765   }
1766   return nullptr;
1767 }
1768
1769 /// HandleExprPropertyRefExpr - Handle foo.bar where foo is a pointer to an
1770 /// objective C interface.  This is a property reference expression.
1771 ExprResult Sema::
1772 HandleExprPropertyRefExpr(const ObjCObjectPointerType *OPT,
1773                           Expr *BaseExpr, SourceLocation OpLoc,
1774                           DeclarationName MemberName,
1775                           SourceLocation MemberLoc,
1776                           SourceLocation SuperLoc, QualType SuperType,
1777                           bool Super) {
1778   const ObjCInterfaceType *IFaceT = OPT->getInterfaceType();
1779   ObjCInterfaceDecl *IFace = IFaceT->getDecl();
1780
1781   if (!MemberName.isIdentifier()) {
1782     Diag(MemberLoc, diag::err_invalid_property_name)
1783       << MemberName << QualType(OPT, 0);
1784     return ExprError();
1785   }
1786
1787   IdentifierInfo *Member = MemberName.getAsIdentifierInfo();
1788
1789   SourceRange BaseRange = Super? SourceRange(SuperLoc)
1790                                : BaseExpr->getSourceRange();
1791   if (RequireCompleteType(MemberLoc, OPT->getPointeeType(),
1792                           diag::err_property_not_found_forward_class,
1793                           MemberName, BaseRange))
1794     return ExprError();
1795
1796   if (ObjCPropertyDecl *PD = IFace->FindPropertyDeclaration(
1797           Member, ObjCPropertyQueryKind::OBJC_PR_query_instance)) {
1798     // Check whether we can reference this property.
1799     if (DiagnoseUseOfDecl(PD, MemberLoc))
1800       return ExprError();
1801     if (Super)
1802       return new (Context)
1803           ObjCPropertyRefExpr(PD, Context.PseudoObjectTy, VK_LValue,
1804                               OK_ObjCProperty, MemberLoc, SuperLoc, SuperType);
1805     else
1806       return new (Context)
1807           ObjCPropertyRefExpr(PD, Context.PseudoObjectTy, VK_LValue,
1808                               OK_ObjCProperty, MemberLoc, BaseExpr);
1809   }
1810   // Check protocols on qualified interfaces.
1811   for (const auto *I : OPT->quals())
1812     if (ObjCPropertyDecl *PD = I->FindPropertyDeclaration(
1813             Member, ObjCPropertyQueryKind::OBJC_PR_query_instance)) {
1814       // Check whether we can reference this property.
1815       if (DiagnoseUseOfDecl(PD, MemberLoc))
1816         return ExprError();
1817
1818       if (Super)
1819         return new (Context) ObjCPropertyRefExpr(
1820             PD, Context.PseudoObjectTy, VK_LValue, OK_ObjCProperty, MemberLoc,
1821             SuperLoc, SuperType);
1822       else
1823         return new (Context)
1824             ObjCPropertyRefExpr(PD, Context.PseudoObjectTy, VK_LValue,
1825                                 OK_ObjCProperty, MemberLoc, BaseExpr);
1826     }
1827   // If that failed, look for an "implicit" property by seeing if the nullary
1828   // selector is implemented.
1829
1830   // FIXME: The logic for looking up nullary and unary selectors should be
1831   // shared with the code in ActOnInstanceMessage.
1832
1833   Selector Sel = PP.getSelectorTable().getNullarySelector(Member);
1834   ObjCMethodDecl *Getter = IFace->lookupInstanceMethod(Sel);
1835
1836   // May be found in property's qualified list.
1837   if (!Getter)
1838     Getter = LookupMethodInQualifiedType(Sel, OPT, true);
1839
1840   // If this reference is in an @implementation, check for 'private' methods.
1841   if (!Getter)
1842     Getter = IFace->lookupPrivateMethod(Sel);
1843
1844   if (Getter) {
1845     // Check if we can reference this property.
1846     if (DiagnoseUseOfDecl(Getter, MemberLoc))
1847       return ExprError();
1848   }
1849   // If we found a getter then this may be a valid dot-reference, we
1850   // will look for the matching setter, in case it is needed.
1851   Selector SetterSel =
1852     SelectorTable::constructSetterSelector(PP.getIdentifierTable(),
1853                                            PP.getSelectorTable(), Member);
1854   ObjCMethodDecl *Setter = IFace->lookupInstanceMethod(SetterSel);
1855
1856   // May be found in property's qualified list.
1857   if (!Setter)
1858     Setter = LookupMethodInQualifiedType(SetterSel, OPT, true);
1859
1860   if (!Setter) {
1861     // If this reference is in an @implementation, also check for 'private'
1862     // methods.
1863     Setter = IFace->lookupPrivateMethod(SetterSel);
1864   }
1865
1866   if (Setter && DiagnoseUseOfDecl(Setter, MemberLoc))
1867     return ExprError();
1868
1869   // Special warning if member name used in a property-dot for a setter accessor
1870   // does not use a property with same name; e.g. obj.X = ... for a property with
1871   // name 'x'.
1872   if (Setter && Setter->isImplicit() && Setter->isPropertyAccessor() &&
1873       !IFace->FindPropertyDeclaration(
1874           Member, ObjCPropertyQueryKind::OBJC_PR_query_instance)) {
1875       if (const ObjCPropertyDecl *PDecl = Setter->findPropertyDecl()) {
1876         // Do not warn if user is using property-dot syntax to make call to
1877         // user named setter.
1878         if (!(PDecl->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_setter))
1879           Diag(MemberLoc,
1880                diag::warn_property_access_suggest)
1881           << MemberName << QualType(OPT, 0) << PDecl->getName()
1882           << FixItHint::CreateReplacement(MemberLoc, PDecl->getName());
1883       }
1884   }
1885
1886   if (Getter || Setter) {
1887     if (Super)
1888       return new (Context)
1889           ObjCPropertyRefExpr(Getter, Setter, Context.PseudoObjectTy, VK_LValue,
1890                               OK_ObjCProperty, MemberLoc, SuperLoc, SuperType);
1891     else
1892       return new (Context)
1893           ObjCPropertyRefExpr(Getter, Setter, Context.PseudoObjectTy, VK_LValue,
1894                               OK_ObjCProperty, MemberLoc, BaseExpr);
1895
1896   }
1897
1898   // Attempt to correct for typos in property names.
1899   if (TypoCorrection Corrected =
1900           CorrectTypo(DeclarationNameInfo(MemberName, MemberLoc),
1901                       LookupOrdinaryName, nullptr, nullptr,
1902                       llvm::make_unique<DeclFilterCCC<ObjCPropertyDecl>>(),
1903                       CTK_ErrorRecovery, IFace, false, OPT)) {
1904     DeclarationName TypoResult = Corrected.getCorrection();
1905     if (TypoResult.isIdentifier() &&
1906         TypoResult.getAsIdentifierInfo() == Member) {
1907       // There is no need to try the correction if it is the same.
1908       NamedDecl *ChosenDecl =
1909         Corrected.isKeyword() ? nullptr : Corrected.getFoundDecl();
1910       if (ChosenDecl && isa<ObjCPropertyDecl>(ChosenDecl))
1911         if (cast<ObjCPropertyDecl>(ChosenDecl)->isClassProperty()) {
1912           // This is a class property, we should not use the instance to
1913           // access it.
1914           Diag(MemberLoc, diag::err_class_property_found) << MemberName
1915           << OPT->getInterfaceDecl()->getName()
1916           << FixItHint::CreateReplacement(BaseExpr->getSourceRange(),
1917                                           OPT->getInterfaceDecl()->getName());
1918           return ExprError();
1919         }
1920     } else {
1921       diagnoseTypo(Corrected, PDiag(diag::err_property_not_found_suggest)
1922                                 << MemberName << QualType(OPT, 0));
1923       return HandleExprPropertyRefExpr(OPT, BaseExpr, OpLoc,
1924                                        TypoResult, MemberLoc,
1925                                        SuperLoc, SuperType, Super);
1926     }
1927   }
1928   ObjCInterfaceDecl *ClassDeclared;
1929   if (ObjCIvarDecl *Ivar =
1930       IFace->lookupInstanceVariable(Member, ClassDeclared)) {
1931     QualType T = Ivar->getType();
1932     if (const ObjCObjectPointerType * OBJPT =
1933         T->getAsObjCInterfacePointerType()) {
1934       if (RequireCompleteType(MemberLoc, OBJPT->getPointeeType(),
1935                               diag::err_property_not_as_forward_class,
1936                               MemberName, BaseExpr))
1937         return ExprError();
1938     }
1939     Diag(MemberLoc,
1940          diag::err_ivar_access_using_property_syntax_suggest)
1941     << MemberName << QualType(OPT, 0) << Ivar->getDeclName()
1942     << FixItHint::CreateReplacement(OpLoc, "->");
1943     return ExprError();
1944   }
1945
1946   Diag(MemberLoc, diag::err_property_not_found)
1947     << MemberName << QualType(OPT, 0);
1948   if (Setter)
1949     Diag(Setter->getLocation(), diag::note_getter_unavailable)
1950           << MemberName << BaseExpr->getSourceRange();
1951   return ExprError();
1952 }
1953
1954 ExprResult Sema::
1955 ActOnClassPropertyRefExpr(IdentifierInfo &receiverName,
1956                           IdentifierInfo &propertyName,
1957                           SourceLocation receiverNameLoc,
1958                           SourceLocation propertyNameLoc) {
1959
1960   IdentifierInfo *receiverNamePtr = &receiverName;
1961   ObjCInterfaceDecl *IFace = getObjCInterfaceDecl(receiverNamePtr,
1962                                                   receiverNameLoc);
1963
1964   QualType SuperType;
1965   if (!IFace) {
1966     // If the "receiver" is 'super' in a method, handle it as an expression-like
1967     // property reference.
1968     if (receiverNamePtr->isStr("super")) {
1969       if (ObjCMethodDecl *CurMethod = tryCaptureObjCSelf(receiverNameLoc)) {
1970         if (auto classDecl = CurMethod->getClassInterface()) {
1971           SuperType = QualType(classDecl->getSuperClassType(), 0);
1972           if (CurMethod->isInstanceMethod()) {
1973             if (SuperType.isNull()) {
1974               // The current class does not have a superclass.
1975               Diag(receiverNameLoc, diag::err_root_class_cannot_use_super)
1976                 << CurMethod->getClassInterface()->getIdentifier();
1977               return ExprError();
1978             }
1979             QualType T = Context.getObjCObjectPointerType(SuperType);
1980
1981             return HandleExprPropertyRefExpr(T->castAs<ObjCObjectPointerType>(),
1982                                              /*BaseExpr*/nullptr,
1983                                              SourceLocation()/*OpLoc*/,
1984                                              &propertyName,
1985                                              propertyNameLoc,
1986                                              receiverNameLoc, T, true);
1987           }
1988
1989           // Otherwise, if this is a class method, try dispatching to our
1990           // superclass.
1991           IFace = CurMethod->getClassInterface()->getSuperClass();
1992         }
1993       }
1994     }
1995
1996     if (!IFace) {
1997       Diag(receiverNameLoc, diag::err_expected_either) << tok::identifier
1998                                                        << tok::l_paren;
1999       return ExprError();
2000     }
2001   }
2002
2003   Selector GetterSel;
2004   Selector SetterSel;
2005   if (auto PD = IFace->FindPropertyDeclaration(
2006           &propertyName, ObjCPropertyQueryKind::OBJC_PR_query_class)) {
2007     GetterSel = PD->getGetterName();
2008     SetterSel = PD->getSetterName();
2009   } else {
2010     GetterSel = PP.getSelectorTable().getNullarySelector(&propertyName);
2011     SetterSel = SelectorTable::constructSetterSelector(
2012         PP.getIdentifierTable(), PP.getSelectorTable(), &propertyName);
2013   }
2014
2015   // Search for a declared property first.
2016   ObjCMethodDecl *Getter = IFace->lookupClassMethod(GetterSel);
2017
2018   // If this reference is in an @implementation, check for 'private' methods.
2019   if (!Getter)
2020     Getter = IFace->lookupPrivateClassMethod(GetterSel);
2021
2022   if (Getter) {
2023     // FIXME: refactor/share with ActOnMemberReference().
2024     // Check if we can reference this property.
2025     if (DiagnoseUseOfDecl(Getter, propertyNameLoc))
2026       return ExprError();
2027   }
2028
2029   // Look for the matching setter, in case it is needed.
2030   ObjCMethodDecl *Setter = IFace->lookupClassMethod(SetterSel);
2031   if (!Setter) {
2032     // If this reference is in an @implementation, also check for 'private'
2033     // methods.
2034     Setter = IFace->lookupPrivateClassMethod(SetterSel);
2035   }
2036   // Look through local category implementations associated with the class.
2037   if (!Setter)
2038     Setter = IFace->getCategoryClassMethod(SetterSel);
2039
2040   if (Setter && DiagnoseUseOfDecl(Setter, propertyNameLoc))
2041     return ExprError();
2042
2043   if (Getter || Setter) {
2044     if (!SuperType.isNull())
2045       return new (Context)
2046           ObjCPropertyRefExpr(Getter, Setter, Context.PseudoObjectTy, VK_LValue,
2047                               OK_ObjCProperty, propertyNameLoc, receiverNameLoc,
2048                               SuperType);
2049
2050     return new (Context) ObjCPropertyRefExpr(
2051         Getter, Setter, Context.PseudoObjectTy, VK_LValue, OK_ObjCProperty,
2052         propertyNameLoc, receiverNameLoc, IFace);
2053   }
2054   return ExprError(Diag(propertyNameLoc, diag::err_property_not_found)
2055                      << &propertyName << Context.getObjCInterfaceType(IFace));
2056 }
2057
2058 namespace {
2059
2060 class ObjCInterfaceOrSuperCCC : public CorrectionCandidateCallback {
2061  public:
2062   ObjCInterfaceOrSuperCCC(ObjCMethodDecl *Method) {
2063     // Determine whether "super" is acceptable in the current context.
2064     if (Method && Method->getClassInterface())
2065       WantObjCSuper = Method->getClassInterface()->getSuperClass();
2066   }
2067
2068   bool ValidateCandidate(const TypoCorrection &candidate) override {
2069     return candidate.getCorrectionDeclAs<ObjCInterfaceDecl>() ||
2070         candidate.isKeyword("super");
2071   }
2072 };
2073
2074 } // end anonymous namespace
2075
2076 Sema::ObjCMessageKind Sema::getObjCMessageKind(Scope *S,
2077                                                IdentifierInfo *Name,
2078                                                SourceLocation NameLoc,
2079                                                bool IsSuper,
2080                                                bool HasTrailingDot,
2081                                                ParsedType &ReceiverType) {
2082   ReceiverType = nullptr;
2083
2084   // If the identifier is "super" and there is no trailing dot, we're
2085   // messaging super. If the identifier is "super" and there is a
2086   // trailing dot, it's an instance message.
2087   if (IsSuper && S->isInObjcMethodScope())
2088     return HasTrailingDot? ObjCInstanceMessage : ObjCSuperMessage;
2089
2090   LookupResult Result(*this, Name, NameLoc, LookupOrdinaryName);
2091   LookupName(Result, S);
2092
2093   switch (Result.getResultKind()) {
2094   case LookupResult::NotFound:
2095     // Normal name lookup didn't find anything. If we're in an
2096     // Objective-C method, look for ivars. If we find one, we're done!
2097     // FIXME: This is a hack. Ivar lookup should be part of normal
2098     // lookup.
2099     if (ObjCMethodDecl *Method = getCurMethodDecl()) {
2100       if (!Method->getClassInterface()) {
2101         // Fall back: let the parser try to parse it as an instance message.
2102         return ObjCInstanceMessage;
2103       }
2104
2105       ObjCInterfaceDecl *ClassDeclared;
2106       if (Method->getClassInterface()->lookupInstanceVariable(Name,
2107                                                               ClassDeclared))
2108         return ObjCInstanceMessage;
2109     }
2110
2111     // Break out; we'll perform typo correction below.
2112     break;
2113
2114   case LookupResult::NotFoundInCurrentInstantiation:
2115   case LookupResult::FoundOverloaded:
2116   case LookupResult::FoundUnresolvedValue:
2117   case LookupResult::Ambiguous:
2118     Result.suppressDiagnostics();
2119     return ObjCInstanceMessage;
2120
2121   case LookupResult::Found: {
2122     // If the identifier is a class or not, and there is a trailing dot,
2123     // it's an instance message.
2124     if (HasTrailingDot)
2125       return ObjCInstanceMessage;
2126     // We found something. If it's a type, then we have a class
2127     // message. Otherwise, it's an instance message.
2128     NamedDecl *ND = Result.getFoundDecl();
2129     QualType T;
2130     if (ObjCInterfaceDecl *Class = dyn_cast<ObjCInterfaceDecl>(ND))
2131       T = Context.getObjCInterfaceType(Class);
2132     else if (TypeDecl *Type = dyn_cast<TypeDecl>(ND)) {
2133       T = Context.getTypeDeclType(Type);
2134       DiagnoseUseOfDecl(Type, NameLoc);
2135     }
2136     else
2137       return ObjCInstanceMessage;
2138
2139     //  We have a class message, and T is the type we're
2140     //  messaging. Build source-location information for it.
2141     TypeSourceInfo *TSInfo = Context.getTrivialTypeSourceInfo(T, NameLoc);
2142     ReceiverType = CreateParsedType(T, TSInfo);
2143     return ObjCClassMessage;
2144   }
2145   }
2146
2147   if (TypoCorrection Corrected = CorrectTypo(
2148           Result.getLookupNameInfo(), Result.getLookupKind(), S, nullptr,
2149           llvm::make_unique<ObjCInterfaceOrSuperCCC>(getCurMethodDecl()),
2150           CTK_ErrorRecovery, nullptr, false, nullptr, false)) {
2151     if (Corrected.isKeyword()) {
2152       // If we've found the keyword "super" (the only keyword that would be
2153       // returned by CorrectTypo), this is a send to super.
2154       diagnoseTypo(Corrected,
2155                    PDiag(diag::err_unknown_receiver_suggest) << Name);
2156       return ObjCSuperMessage;
2157     } else if (ObjCInterfaceDecl *Class =
2158                    Corrected.getCorrectionDeclAs<ObjCInterfaceDecl>()) {
2159       // If we found a declaration, correct when it refers to an Objective-C
2160       // class.
2161       diagnoseTypo(Corrected,
2162                    PDiag(diag::err_unknown_receiver_suggest) << Name);
2163       QualType T = Context.getObjCInterfaceType(Class);
2164       TypeSourceInfo *TSInfo = Context.getTrivialTypeSourceInfo(T, NameLoc);
2165       ReceiverType = CreateParsedType(T, TSInfo);
2166       return ObjCClassMessage;
2167     }
2168   }
2169
2170   // Fall back: let the parser try to parse it as an instance message.
2171   return ObjCInstanceMessage;
2172 }
2173
2174 ExprResult Sema::ActOnSuperMessage(Scope *S,
2175                                    SourceLocation SuperLoc,
2176                                    Selector Sel,
2177                                    SourceLocation LBracLoc,
2178                                    ArrayRef<SourceLocation> SelectorLocs,
2179                                    SourceLocation RBracLoc,
2180                                    MultiExprArg Args) {
2181   // Determine whether we are inside a method or not.
2182   ObjCMethodDecl *Method = tryCaptureObjCSelf(SuperLoc);
2183   if (!Method) {
2184     Diag(SuperLoc, diag::err_invalid_receiver_to_message_super);
2185     return ExprError();
2186   }
2187
2188   ObjCInterfaceDecl *Class = Method->getClassInterface();
2189   if (!Class) {
2190     Diag(SuperLoc, diag::err_no_super_class_message)
2191       << Method->getDeclName();
2192     return ExprError();
2193   }
2194
2195   QualType SuperTy(Class->getSuperClassType(), 0);
2196   if (SuperTy.isNull()) {
2197     // The current class does not have a superclass.
2198     Diag(SuperLoc, diag::err_root_class_cannot_use_super)
2199       << Class->getIdentifier();
2200     return ExprError();
2201   }
2202
2203   // We are in a method whose class has a superclass, so 'super'
2204   // is acting as a keyword.
2205   if (Method->getSelector() == Sel)
2206     getCurFunction()->ObjCShouldCallSuper = false;
2207
2208   if (Method->isInstanceMethod()) {
2209     // Since we are in an instance method, this is an instance
2210     // message to the superclass instance.
2211     SuperTy = Context.getObjCObjectPointerType(SuperTy);
2212     return BuildInstanceMessage(nullptr, SuperTy, SuperLoc,
2213                                 Sel, /*Method=*/nullptr,
2214                                 LBracLoc, SelectorLocs, RBracLoc, Args);
2215   }
2216
2217   // Since we are in a class method, this is a class message to
2218   // the superclass.
2219   return BuildClassMessage(/*ReceiverTypeInfo=*/nullptr,
2220                            SuperTy,
2221                            SuperLoc, Sel, /*Method=*/nullptr,
2222                            LBracLoc, SelectorLocs, RBracLoc, Args);
2223 }
2224
2225 ExprResult Sema::BuildClassMessageImplicit(QualType ReceiverType,
2226                                            bool isSuperReceiver,
2227                                            SourceLocation Loc,
2228                                            Selector Sel,
2229                                            ObjCMethodDecl *Method,
2230                                            MultiExprArg Args) {
2231   TypeSourceInfo *receiverTypeInfo = nullptr;
2232   if (!ReceiverType.isNull())
2233     receiverTypeInfo = Context.getTrivialTypeSourceInfo(ReceiverType);
2234
2235   return BuildClassMessage(receiverTypeInfo, ReceiverType,
2236                           /*SuperLoc=*/isSuperReceiver ? Loc : SourceLocation(),
2237                            Sel, Method, Loc, Loc, Loc, Args,
2238                            /*isImplicit=*/true);
2239 }
2240
2241 static void applyCocoaAPICheck(Sema &S, const ObjCMessageExpr *Msg,
2242                                unsigned DiagID,
2243                                bool (*refactor)(const ObjCMessageExpr *,
2244                                               const NSAPI &, edit::Commit &)) {
2245   SourceLocation MsgLoc = Msg->getExprLoc();
2246   if (S.Diags.isIgnored(DiagID, MsgLoc))
2247     return;
2248
2249   SourceManager &SM = S.SourceMgr;
2250   edit::Commit ECommit(SM, S.LangOpts);
2251   if (refactor(Msg,*S.NSAPIObj, ECommit)) {
2252     DiagnosticBuilder Builder = S.Diag(MsgLoc, DiagID)
2253                         << Msg->getSelector() << Msg->getSourceRange();
2254     // FIXME: Don't emit diagnostic at all if fixits are non-commitable.
2255     if (!ECommit.isCommitable())
2256       return;
2257     for (edit::Commit::edit_iterator
2258            I = ECommit.edit_begin(), E = ECommit.edit_end(); I != E; ++I) {
2259       const edit::Commit::Edit &Edit = *I;
2260       switch (Edit.Kind) {
2261       case edit::Commit::Act_Insert:
2262         Builder.AddFixItHint(FixItHint::CreateInsertion(Edit.OrigLoc,
2263                                                         Edit.Text,
2264                                                         Edit.BeforePrev));
2265         break;
2266       case edit::Commit::Act_InsertFromRange:
2267         Builder.AddFixItHint(
2268             FixItHint::CreateInsertionFromRange(Edit.OrigLoc,
2269                                                 Edit.getInsertFromRange(SM),
2270                                                 Edit.BeforePrev));
2271         break;
2272       case edit::Commit::Act_Remove:
2273         Builder.AddFixItHint(FixItHint::CreateRemoval(Edit.getFileRange(SM)));
2274         break;
2275       }
2276     }
2277   }
2278 }
2279
2280 static void checkCocoaAPI(Sema &S, const ObjCMessageExpr *Msg) {
2281   applyCocoaAPICheck(S, Msg, diag::warn_objc_redundant_literal_use,
2282                      edit::rewriteObjCRedundantCallWithLiteral);
2283 }
2284
2285 static void checkFoundationAPI(Sema &S, SourceLocation Loc,
2286                                const ObjCMethodDecl *Method,
2287                                ArrayRef<Expr *> Args, QualType ReceiverType,
2288                                bool IsClassObjectCall) {
2289   // Check if this is a performSelector method that uses a selector that returns
2290   // a record or a vector type.
2291   if (Method->getSelector().getMethodFamily() != OMF_performSelector ||
2292       Args.empty())
2293     return;
2294   const auto *SE = dyn_cast<ObjCSelectorExpr>(Args[0]->IgnoreParens());
2295   if (!SE)
2296     return;
2297   ObjCMethodDecl *ImpliedMethod;
2298   if (!IsClassObjectCall) {
2299     const auto *OPT = ReceiverType->getAs<ObjCObjectPointerType>();
2300     if (!OPT || !OPT->getInterfaceDecl())
2301       return;
2302     ImpliedMethod =
2303         OPT->getInterfaceDecl()->lookupInstanceMethod(SE->getSelector());
2304     if (!ImpliedMethod)
2305       ImpliedMethod =
2306           OPT->getInterfaceDecl()->lookupPrivateMethod(SE->getSelector());
2307   } else {
2308     const auto *IT = ReceiverType->getAs<ObjCInterfaceType>();
2309     if (!IT)
2310       return;
2311     ImpliedMethod = IT->getDecl()->lookupClassMethod(SE->getSelector());
2312     if (!ImpliedMethod)
2313       ImpliedMethod =
2314           IT->getDecl()->lookupPrivateClassMethod(SE->getSelector());
2315   }
2316   if (!ImpliedMethod)
2317     return;
2318   QualType Ret = ImpliedMethod->getReturnType();
2319   if (Ret->isRecordType() || Ret->isVectorType() || Ret->isExtVectorType()) {
2320     QualType Ret = ImpliedMethod->getReturnType();
2321     S.Diag(Loc, diag::warn_objc_unsafe_perform_selector)
2322         << Method->getSelector()
2323         << (!Ret->isRecordType()
2324                 ? /*Vector*/ 2
2325                 : Ret->isUnionType() ? /*Union*/ 1 : /*Struct*/ 0);
2326     S.Diag(ImpliedMethod->getLocStart(),
2327            diag::note_objc_unsafe_perform_selector_method_declared_here)
2328         << ImpliedMethod->getSelector() << Ret;
2329   }
2330 }
2331
2332 /// Diagnose use of %s directive in an NSString which is being passed
2333 /// as formatting string to formatting method.
2334 static void
2335 DiagnoseCStringFormatDirectiveInObjCAPI(Sema &S,
2336                                         ObjCMethodDecl *Method,
2337                                         Selector Sel,
2338                                         Expr **Args, unsigned NumArgs) {
2339   unsigned Idx = 0;
2340   bool Format = false;
2341   ObjCStringFormatFamily SFFamily = Sel.getStringFormatFamily();
2342   if (SFFamily == ObjCStringFormatFamily::SFF_NSString) {
2343     Idx = 0;
2344     Format = true;
2345   }
2346   else if (Method) {
2347     for (const auto *I : Method->specific_attrs<FormatAttr>()) {
2348       if (S.GetFormatNSStringIdx(I, Idx)) {
2349         Format = true;
2350         break;
2351       }
2352     }
2353   }
2354   if (!Format || NumArgs <= Idx)
2355     return;
2356
2357   Expr *FormatExpr = Args[Idx];
2358   if (ObjCStringLiteral *OSL =
2359       dyn_cast<ObjCStringLiteral>(FormatExpr->IgnoreParenImpCasts())) {
2360     StringLiteral *FormatString = OSL->getString();
2361     if (S.FormatStringHasSArg(FormatString)) {
2362       S.Diag(FormatExpr->getExprLoc(), diag::warn_objc_cdirective_format_string)
2363         << "%s" << 0 << 0;
2364       if (Method)
2365         S.Diag(Method->getLocation(), diag::note_method_declared_at)
2366           << Method->getDeclName();
2367     }
2368   }
2369 }
2370
2371 /// Build an Objective-C class message expression.
2372 ///
2373 /// This routine takes care of both normal class messages and
2374 /// class messages to the superclass.
2375 ///
2376 /// \param ReceiverTypeInfo Type source information that describes the
2377 /// receiver of this message. This may be NULL, in which case we are
2378 /// sending to the superclass and \p SuperLoc must be a valid source
2379 /// location.
2380
2381 /// \param ReceiverType The type of the object receiving the
2382 /// message. When \p ReceiverTypeInfo is non-NULL, this is the same
2383 /// type as that refers to. For a superclass send, this is the type of
2384 /// the superclass.
2385 ///
2386 /// \param SuperLoc The location of the "super" keyword in a
2387 /// superclass message.
2388 ///
2389 /// \param Sel The selector to which the message is being sent.
2390 ///
2391 /// \param Method The method that this class message is invoking, if
2392 /// already known.
2393 ///
2394 /// \param LBracLoc The location of the opening square bracket ']'.
2395 ///
2396 /// \param RBracLoc The location of the closing square bracket ']'.
2397 ///
2398 /// \param ArgsIn The message arguments.
2399 ExprResult Sema::BuildClassMessage(TypeSourceInfo *ReceiverTypeInfo,
2400                                    QualType ReceiverType,
2401                                    SourceLocation SuperLoc,
2402                                    Selector Sel,
2403                                    ObjCMethodDecl *Method,
2404                                    SourceLocation LBracLoc,
2405                                    ArrayRef<SourceLocation> SelectorLocs,
2406                                    SourceLocation RBracLoc,
2407                                    MultiExprArg ArgsIn,
2408                                    bool isImplicit) {
2409   SourceLocation Loc = SuperLoc.isValid()? SuperLoc
2410     : ReceiverTypeInfo->getTypeLoc().getSourceRange().getBegin();
2411   if (LBracLoc.isInvalid()) {
2412     Diag(Loc, diag::err_missing_open_square_message_send)
2413       << FixItHint::CreateInsertion(Loc, "[");
2414     LBracLoc = Loc;
2415   }
2416   ArrayRef<SourceLocation> SelectorSlotLocs;
2417   if (!SelectorLocs.empty() && SelectorLocs.front().isValid())
2418     SelectorSlotLocs = SelectorLocs;
2419   else
2420     SelectorSlotLocs = Loc;
2421   SourceLocation SelLoc = SelectorSlotLocs.front();
2422
2423   if (ReceiverType->isDependentType()) {
2424     // If the receiver type is dependent, we can't type-check anything
2425     // at this point. Build a dependent expression.
2426     unsigned NumArgs = ArgsIn.size();
2427     Expr **Args = ArgsIn.data();
2428     assert(SuperLoc.isInvalid() && "Message to super with dependent type");
2429     return ObjCMessageExpr::Create(
2430         Context, ReceiverType, VK_RValue, LBracLoc, ReceiverTypeInfo, Sel,
2431         SelectorLocs, /*Method=*/nullptr, makeArrayRef(Args, NumArgs), RBracLoc,
2432         isImplicit);
2433   }
2434
2435   // Find the class to which we are sending this message.
2436   ObjCInterfaceDecl *Class = nullptr;
2437   const ObjCObjectType *ClassType = ReceiverType->getAs<ObjCObjectType>();
2438   if (!ClassType || !(Class = ClassType->getInterface())) {
2439     Diag(Loc, diag::err_invalid_receiver_class_message)
2440       << ReceiverType;
2441     return ExprError();
2442   }
2443   assert(Class && "We don't know which class we're messaging?");
2444   // objc++ diagnoses during typename annotation.
2445   if (!getLangOpts().CPlusPlus)
2446     (void)DiagnoseUseOfDecl(Class, SelectorSlotLocs);
2447   // Find the method we are messaging.
2448   if (!Method) {
2449     SourceRange TypeRange
2450       = SuperLoc.isValid()? SourceRange(SuperLoc)
2451                           : ReceiverTypeInfo->getTypeLoc().getSourceRange();
2452     if (RequireCompleteType(Loc, Context.getObjCInterfaceType(Class),
2453                             (getLangOpts().ObjCAutoRefCount
2454                                ? diag::err_arc_receiver_forward_class
2455                                : diag::warn_receiver_forward_class),
2456                             TypeRange)) {
2457       // A forward class used in messaging is treated as a 'Class'
2458       Method = LookupFactoryMethodInGlobalPool(Sel,
2459                                                SourceRange(LBracLoc, RBracLoc));
2460       if (Method && !getLangOpts().ObjCAutoRefCount)
2461         Diag(Method->getLocation(), diag::note_method_sent_forward_class)
2462           << Method->getDeclName();
2463     }
2464     if (!Method)
2465       Method = Class->lookupClassMethod(Sel);
2466
2467     // If we have an implementation in scope, check "private" methods.
2468     if (!Method)
2469       Method = Class->lookupPrivateClassMethod(Sel);
2470
2471     if (Method && DiagnoseUseOfDecl(Method, SelectorSlotLocs))
2472       return ExprError();
2473   }
2474
2475   // Check the argument types and determine the result type.
2476   QualType ReturnType;
2477   ExprValueKind VK = VK_RValue;
2478
2479   unsigned NumArgs = ArgsIn.size();
2480   Expr **Args = ArgsIn.data();
2481   if (CheckMessageArgumentTypes(ReceiverType, MultiExprArg(Args, NumArgs),
2482                                 Sel, SelectorLocs,
2483                                 Method, true,
2484                                 SuperLoc.isValid(), LBracLoc, RBracLoc,
2485                                 SourceRange(),
2486                                 ReturnType, VK))
2487     return ExprError();
2488
2489   if (Method && !Method->getReturnType()->isVoidType() &&
2490       RequireCompleteType(LBracLoc, Method->getReturnType(),
2491                           diag::err_illegal_message_expr_incomplete_type))
2492     return ExprError();
2493
2494   // Warn about explicit call of +initialize on its own class. But not on 'super'.
2495   if (Method && Method->getMethodFamily() == OMF_initialize) {
2496     if (!SuperLoc.isValid()) {
2497       const ObjCInterfaceDecl *ID =
2498         dyn_cast<ObjCInterfaceDecl>(Method->getDeclContext());
2499       if (ID == Class) {
2500         Diag(Loc, diag::warn_direct_initialize_call);
2501         Diag(Method->getLocation(), diag::note_method_declared_at)
2502           << Method->getDeclName();
2503       }
2504     }
2505     else if (ObjCMethodDecl *CurMeth = getCurMethodDecl()) {
2506       // [super initialize] is allowed only within an +initialize implementation
2507       if (CurMeth->getMethodFamily() != OMF_initialize) {
2508         Diag(Loc, diag::warn_direct_super_initialize_call);
2509         Diag(Method->getLocation(), diag::note_method_declared_at)
2510           << Method->getDeclName();
2511         Diag(CurMeth->getLocation(), diag::note_method_declared_at)
2512         << CurMeth->getDeclName();
2513       }
2514     }
2515   }
2516
2517   DiagnoseCStringFormatDirectiveInObjCAPI(*this, Method, Sel, Args, NumArgs);
2518
2519   // Construct the appropriate ObjCMessageExpr.
2520   ObjCMessageExpr *Result;
2521   if (SuperLoc.isValid())
2522     Result = ObjCMessageExpr::Create(Context, ReturnType, VK, LBracLoc,
2523                                      SuperLoc, /*IsInstanceSuper=*/false,
2524                                      ReceiverType, Sel, SelectorLocs,
2525                                      Method, makeArrayRef(Args, NumArgs),
2526                                      RBracLoc, isImplicit);
2527   else {
2528     Result = ObjCMessageExpr::Create(Context, ReturnType, VK, LBracLoc,
2529                                      ReceiverTypeInfo, Sel, SelectorLocs,
2530                                      Method, makeArrayRef(Args, NumArgs),
2531                                      RBracLoc, isImplicit);
2532     if (!isImplicit)
2533       checkCocoaAPI(*this, Result);
2534   }
2535   if (Method)
2536     checkFoundationAPI(*this, SelLoc, Method, makeArrayRef(Args, NumArgs),
2537                        ReceiverType, /*IsClassObjectCall=*/true);
2538   return MaybeBindToTemporary(Result);
2539 }
2540
2541 // ActOnClassMessage - used for both unary and keyword messages.
2542 // ArgExprs is optional - if it is present, the number of expressions
2543 // is obtained from Sel.getNumArgs().
2544 ExprResult Sema::ActOnClassMessage(Scope *S,
2545                                    ParsedType Receiver,
2546                                    Selector Sel,
2547                                    SourceLocation LBracLoc,
2548                                    ArrayRef<SourceLocation> SelectorLocs,
2549                                    SourceLocation RBracLoc,
2550                                    MultiExprArg Args) {
2551   TypeSourceInfo *ReceiverTypeInfo;
2552   QualType ReceiverType = GetTypeFromParser(Receiver, &ReceiverTypeInfo);
2553   if (ReceiverType.isNull())
2554     return ExprError();
2555
2556   if (!ReceiverTypeInfo)
2557     ReceiverTypeInfo = Context.getTrivialTypeSourceInfo(ReceiverType, LBracLoc);
2558
2559   return BuildClassMessage(ReceiverTypeInfo, ReceiverType,
2560                            /*SuperLoc=*/SourceLocation(), Sel,
2561                            /*Method=*/nullptr, LBracLoc, SelectorLocs, RBracLoc,
2562                            Args);
2563 }
2564
2565 ExprResult Sema::BuildInstanceMessageImplicit(Expr *Receiver,
2566                                               QualType ReceiverType,
2567                                               SourceLocation Loc,
2568                                               Selector Sel,
2569                                               ObjCMethodDecl *Method,
2570                                               MultiExprArg Args) {
2571   return BuildInstanceMessage(Receiver, ReceiverType,
2572                               /*SuperLoc=*/!Receiver ? Loc : SourceLocation(),
2573                               Sel, Method, Loc, Loc, Loc, Args,
2574                               /*isImplicit=*/true);
2575 }
2576
2577 static bool isMethodDeclaredInRootProtocol(Sema &S, const ObjCMethodDecl *M) {
2578   if (!S.NSAPIObj)
2579     return false;
2580   const auto *Protocol = dyn_cast<ObjCProtocolDecl>(M->getDeclContext());
2581   if (!Protocol)
2582     return false;
2583   const IdentifierInfo *II = S.NSAPIObj->getNSClassId(NSAPI::ClassId_NSObject);
2584   if (const auto *RootClass = dyn_cast_or_null<ObjCInterfaceDecl>(
2585           S.LookupSingleName(S.TUScope, II, Protocol->getLocStart(),
2586                              Sema::LookupOrdinaryName))) {
2587     for (const ObjCProtocolDecl *P : RootClass->all_referenced_protocols()) {
2588       if (P->getCanonicalDecl() == Protocol->getCanonicalDecl())
2589         return true;
2590     }
2591   }
2592   return false;
2593 }
2594
2595 /// Build an Objective-C instance message expression.
2596 ///
2597 /// This routine takes care of both normal instance messages and
2598 /// instance messages to the superclass instance.
2599 ///
2600 /// \param Receiver The expression that computes the object that will
2601 /// receive this message. This may be empty, in which case we are
2602 /// sending to the superclass instance and \p SuperLoc must be a valid
2603 /// source location.
2604 ///
2605 /// \param ReceiverType The (static) type of the object receiving the
2606 /// message. When a \p Receiver expression is provided, this is the
2607 /// same type as that expression. For a superclass instance send, this
2608 /// is a pointer to the type of the superclass.
2609 ///
2610 /// \param SuperLoc The location of the "super" keyword in a
2611 /// superclass instance message.
2612 ///
2613 /// \param Sel The selector to which the message is being sent.
2614 ///
2615 /// \param Method The method that this instance message is invoking, if
2616 /// already known.
2617 ///
2618 /// \param LBracLoc The location of the opening square bracket ']'.
2619 ///
2620 /// \param RBracLoc The location of the closing square bracket ']'.
2621 ///
2622 /// \param ArgsIn The message arguments.
2623 ExprResult Sema::BuildInstanceMessage(Expr *Receiver,
2624                                       QualType ReceiverType,
2625                                       SourceLocation SuperLoc,
2626                                       Selector Sel,
2627                                       ObjCMethodDecl *Method,
2628                                       SourceLocation LBracLoc,
2629                                       ArrayRef<SourceLocation> SelectorLocs,
2630                                       SourceLocation RBracLoc,
2631                                       MultiExprArg ArgsIn,
2632                                       bool isImplicit) {
2633   assert((Receiver || SuperLoc.isValid()) && "If the Receiver is null, the "
2634                                              "SuperLoc must be valid so we can "
2635                                              "use it instead.");
2636
2637   // The location of the receiver.
2638   SourceLocation Loc = SuperLoc.isValid()? SuperLoc : Receiver->getLocStart();
2639   SourceRange RecRange =
2640       SuperLoc.isValid()? SuperLoc : Receiver->getSourceRange();
2641   ArrayRef<SourceLocation> SelectorSlotLocs;
2642   if (!SelectorLocs.empty() && SelectorLocs.front().isValid())
2643     SelectorSlotLocs = SelectorLocs;
2644   else
2645     SelectorSlotLocs = Loc;
2646   SourceLocation SelLoc = SelectorSlotLocs.front();
2647
2648   if (LBracLoc.isInvalid()) {
2649     Diag(Loc, diag::err_missing_open_square_message_send)
2650       << FixItHint::CreateInsertion(Loc, "[");
2651     LBracLoc = Loc;
2652   }
2653
2654   // If we have a receiver expression, perform appropriate promotions
2655   // and determine receiver type.
2656   if (Receiver) {
2657     if (Receiver->hasPlaceholderType()) {
2658       ExprResult Result;
2659       if (Receiver->getType() == Context.UnknownAnyTy)
2660         Result = forceUnknownAnyToType(Receiver, Context.getObjCIdType());
2661       else
2662         Result = CheckPlaceholderExpr(Receiver);
2663       if (Result.isInvalid()) return ExprError();
2664       Receiver = Result.get();
2665     }
2666
2667     if (Receiver->isTypeDependent()) {
2668       // If the receiver is type-dependent, we can't type-check anything
2669       // at this point. Build a dependent expression.
2670       unsigned NumArgs = ArgsIn.size();
2671       Expr **Args = ArgsIn.data();
2672       assert(SuperLoc.isInvalid() && "Message to super with dependent type");
2673       return ObjCMessageExpr::Create(
2674           Context, Context.DependentTy, VK_RValue, LBracLoc, Receiver, Sel,
2675           SelectorLocs, /*Method=*/nullptr, makeArrayRef(Args, NumArgs),
2676           RBracLoc, isImplicit);
2677     }
2678
2679     // If necessary, apply function/array conversion to the receiver.
2680     // C99 6.7.5.3p[7,8].
2681     ExprResult Result = DefaultFunctionArrayLvalueConversion(Receiver);
2682     if (Result.isInvalid())
2683       return ExprError();
2684     Receiver = Result.get();
2685     ReceiverType = Receiver->getType();
2686
2687     // If the receiver is an ObjC pointer, a block pointer, or an
2688     // __attribute__((NSObject)) pointer, we don't need to do any
2689     // special conversion in order to look up a receiver.
2690     if (ReceiverType->isObjCRetainableType()) {
2691       // do nothing
2692     } else if (!getLangOpts().ObjCAutoRefCount &&
2693                !Context.getObjCIdType().isNull() &&
2694                (ReceiverType->isPointerType() ||
2695                 ReceiverType->isIntegerType())) {
2696       // Implicitly convert integers and pointers to 'id' but emit a warning.
2697       // But not in ARC.
2698       Diag(Loc, diag::warn_bad_receiver_type)
2699         << ReceiverType
2700         << Receiver->getSourceRange();
2701       if (ReceiverType->isPointerType()) {
2702         Receiver = ImpCastExprToType(Receiver, Context.getObjCIdType(),
2703                                      CK_CPointerToObjCPointerCast).get();
2704       } else {
2705         // TODO: specialized warning on null receivers?
2706         bool IsNull = Receiver->isNullPointerConstant(Context,
2707                                               Expr::NPC_ValueDependentIsNull);
2708         CastKind Kind = IsNull ? CK_NullToPointer : CK_IntegralToPointer;
2709         Receiver = ImpCastExprToType(Receiver, Context.getObjCIdType(),
2710                                      Kind).get();
2711       }
2712       ReceiverType = Receiver->getType();
2713     } else if (getLangOpts().CPlusPlus) {
2714       // The receiver must be a complete type.
2715       if (RequireCompleteType(Loc, Receiver->getType(),
2716                               diag::err_incomplete_receiver_type))
2717         return ExprError();
2718
2719       ExprResult result = PerformContextuallyConvertToObjCPointer(Receiver);
2720       if (result.isUsable()) {
2721         Receiver = result.get();
2722         ReceiverType = Receiver->getType();
2723       }
2724     }
2725   }
2726
2727   if (ReceiverType->isObjCIdType() && !isImplicit)
2728     Diag(Receiver->getExprLoc(), diag::warn_messaging_unqualified_id);
2729
2730   // There's a somewhat weird interaction here where we assume that we
2731   // won't actually have a method unless we also don't need to do some
2732   // of the more detailed type-checking on the receiver.
2733
2734   if (!Method) {
2735     // Handle messages to id and __kindof types (where we use the
2736     // global method pool).
2737     const ObjCObjectType *typeBound = nullptr;
2738     bool receiverIsIdLike = ReceiverType->isObjCIdOrObjectKindOfType(Context,
2739                                                                      typeBound);
2740     if (receiverIsIdLike || ReceiverType->isBlockPointerType() ||
2741         (Receiver && Context.isObjCNSObjectType(Receiver->getType()))) {
2742       SmallVector<ObjCMethodDecl*, 4> Methods;
2743       // If we have a type bound, further filter the methods.
2744       CollectMultipleMethodsInGlobalPool(Sel, Methods, true/*InstanceFirst*/,
2745                                          true/*CheckTheOther*/, typeBound);
2746       if (!Methods.empty()) {
2747         // We choose the first method as the initial candidate, then try to
2748         // select a better one.
2749         Method = Methods[0];
2750
2751         if (ObjCMethodDecl *BestMethod =
2752             SelectBestMethod(Sel, ArgsIn, Method->isInstanceMethod(), Methods))
2753           Method = BestMethod;
2754
2755         if (!AreMultipleMethodsInGlobalPool(Sel, Method,
2756                                             SourceRange(LBracLoc, RBracLoc),
2757                                             receiverIsIdLike, Methods))
2758           DiagnoseUseOfDecl(Method, SelectorSlotLocs);
2759       }
2760     } else if (ReceiverType->isObjCClassOrClassKindOfType() ||
2761                ReceiverType->isObjCQualifiedClassType()) {
2762       // Handle messages to Class.
2763       // We allow sending a message to a qualified Class ("Class<foo>"), which
2764       // is ok as long as one of the protocols implements the selector (if not,
2765       // warn).
2766       if (!ReceiverType->isObjCClassOrClassKindOfType()) {
2767         const ObjCObjectPointerType *QClassTy
2768           = ReceiverType->getAsObjCQualifiedClassType();
2769         // Search protocols for class methods.
2770         Method = LookupMethodInQualifiedType(Sel, QClassTy, false);
2771         if (!Method) {
2772           Method = LookupMethodInQualifiedType(Sel, QClassTy, true);
2773           // warn if instance method found for a Class message.
2774           if (Method && !isMethodDeclaredInRootProtocol(*this, Method)) {
2775             Diag(SelLoc, diag::warn_instance_method_on_class_found)
2776               << Method->getSelector() << Sel;
2777             Diag(Method->getLocation(), diag::note_method_declared_at)
2778               << Method->getDeclName();
2779           }
2780         }
2781       } else {
2782         if (ObjCMethodDecl *CurMeth = getCurMethodDecl()) {
2783           if (ObjCInterfaceDecl *ClassDecl = CurMeth->getClassInterface()) {
2784             // First check the public methods in the class interface.
2785             Method = ClassDecl->lookupClassMethod(Sel);
2786
2787             if (!Method)
2788               Method = ClassDecl->lookupPrivateClassMethod(Sel);
2789           }
2790           if (Method && DiagnoseUseOfDecl(Method, SelectorSlotLocs))
2791             return ExprError();
2792         }
2793         if (!Method) {
2794           // If not messaging 'self', look for any factory method named 'Sel'.
2795           if (!Receiver || !isSelfExpr(Receiver)) {
2796             // If no class (factory) method was found, check if an _instance_
2797             // method of the same name exists in the root class only.
2798             SmallVector<ObjCMethodDecl*, 4> Methods;
2799             CollectMultipleMethodsInGlobalPool(Sel, Methods,
2800                                                false/*InstanceFirst*/,
2801                                                true/*CheckTheOther*/);
2802             if (!Methods.empty()) {
2803               // We choose the first method as the initial candidate, then try
2804               // to select a better one.
2805               Method = Methods[0];
2806
2807               // If we find an instance method, emit warning.
2808               if (Method->isInstanceMethod()) {
2809                 if (const ObjCInterfaceDecl *ID =
2810                     dyn_cast<ObjCInterfaceDecl>(Method->getDeclContext())) {
2811                   if (ID->getSuperClass())
2812                     Diag(SelLoc, diag::warn_root_inst_method_not_found)
2813                         << Sel << SourceRange(LBracLoc, RBracLoc);
2814                 }
2815               }
2816
2817              if (ObjCMethodDecl *BestMethod =
2818                  SelectBestMethod(Sel, ArgsIn, Method->isInstanceMethod(),
2819                                   Methods))
2820                Method = BestMethod;
2821             }
2822           }
2823         }
2824       }
2825     } else {
2826       ObjCInterfaceDecl *ClassDecl = nullptr;
2827
2828       // We allow sending a message to a qualified ID ("id<foo>"), which is ok as
2829       // long as one of the protocols implements the selector (if not, warn).
2830       // And as long as message is not deprecated/unavailable (warn if it is).
2831       if (const ObjCObjectPointerType *QIdTy
2832                                    = ReceiverType->getAsObjCQualifiedIdType()) {
2833         // Search protocols for instance methods.
2834         Method = LookupMethodInQualifiedType(Sel, QIdTy, true);
2835         if (!Method)
2836           Method = LookupMethodInQualifiedType(Sel, QIdTy, false);
2837         if (Method && DiagnoseUseOfDecl(Method, SelectorSlotLocs))
2838           return ExprError();
2839       } else if (const ObjCObjectPointerType *OCIType
2840                    = ReceiverType->getAsObjCInterfacePointerType()) {
2841         // We allow sending a message to a pointer to an interface (an object).
2842         ClassDecl = OCIType->getInterfaceDecl();
2843
2844         // Try to complete the type. Under ARC, this is a hard error from which
2845         // we don't try to recover.
2846         // FIXME: In the non-ARC case, this will still be a hard error if the
2847         // definition is found in a module that's not visible.
2848         const ObjCInterfaceDecl *forwardClass = nullptr;
2849         if (RequireCompleteType(Loc, OCIType->getPointeeType(),
2850               getLangOpts().ObjCAutoRefCount
2851                 ? diag::err_arc_receiver_forward_instance
2852                 : diag::warn_receiver_forward_instance,
2853                                 Receiver? Receiver->getSourceRange()
2854                                         : SourceRange(SuperLoc))) {
2855           if (getLangOpts().ObjCAutoRefCount)
2856             return ExprError();
2857
2858           forwardClass = OCIType->getInterfaceDecl();
2859           Diag(Receiver ? Receiver->getLocStart()
2860                         : SuperLoc, diag::note_receiver_is_id);
2861           Method = nullptr;
2862         } else {
2863           Method = ClassDecl->lookupInstanceMethod(Sel);
2864         }
2865
2866         if (!Method)
2867           // Search protocol qualifiers.
2868           Method = LookupMethodInQualifiedType(Sel, OCIType, true);
2869
2870         if (!Method) {
2871           // If we have implementations in scope, check "private" methods.
2872           Method = ClassDecl->lookupPrivateMethod(Sel);
2873
2874           if (!Method && getLangOpts().ObjCAutoRefCount) {
2875             Diag(SelLoc, diag::err_arc_may_not_respond)
2876               << OCIType->getPointeeType() << Sel << RecRange
2877               << SourceRange(SelectorLocs.front(), SelectorLocs.back());
2878             return ExprError();
2879           }
2880
2881           if (!Method && (!Receiver || !isSelfExpr(Receiver))) {
2882             // If we still haven't found a method, look in the global pool. This
2883             // behavior isn't very desirable, however we need it for GCC
2884             // compatibility. FIXME: should we deviate??
2885             if (OCIType->qual_empty()) {
2886               SmallVector<ObjCMethodDecl*, 4> Methods;
2887               CollectMultipleMethodsInGlobalPool(Sel, Methods,
2888                                                  true/*InstanceFirst*/,
2889                                                  false/*CheckTheOther*/);
2890               if (!Methods.empty()) {
2891                 // We choose the first method as the initial candidate, then try
2892                 // to select a better one.
2893                 Method = Methods[0];
2894
2895                 if (ObjCMethodDecl *BestMethod =
2896                     SelectBestMethod(Sel, ArgsIn, Method->isInstanceMethod(),
2897                                      Methods))
2898                   Method = BestMethod;
2899
2900                 AreMultipleMethodsInGlobalPool(Sel, Method,
2901                                                SourceRange(LBracLoc, RBracLoc),
2902                                                true/*receiverIdOrClass*/,
2903                                                Methods);
2904               }
2905               if (Method && !forwardClass)
2906                 Diag(SelLoc, diag::warn_maynot_respond)
2907                   << OCIType->getInterfaceDecl()->getIdentifier()
2908                   << Sel << RecRange;
2909             }
2910           }
2911         }
2912         if (Method && DiagnoseUseOfDecl(Method, SelectorSlotLocs, forwardClass))
2913           return ExprError();
2914       } else {
2915         // Reject other random receiver types (e.g. structs).
2916         Diag(Loc, diag::err_bad_receiver_type)
2917           << ReceiverType << Receiver->getSourceRange();
2918         return ExprError();
2919       }
2920     }
2921   }
2922
2923   FunctionScopeInfo *DIFunctionScopeInfo =
2924     (Method && Method->getMethodFamily() == OMF_init)
2925       ? getEnclosingFunction() : nullptr;
2926
2927   if (DIFunctionScopeInfo &&
2928       DIFunctionScopeInfo->ObjCIsDesignatedInit &&
2929       (SuperLoc.isValid() || isSelfExpr(Receiver))) {
2930     bool isDesignatedInitChain = false;
2931     if (SuperLoc.isValid()) {
2932       if (const ObjCObjectPointerType *
2933             OCIType = ReceiverType->getAsObjCInterfacePointerType()) {
2934         if (const ObjCInterfaceDecl *ID = OCIType->getInterfaceDecl()) {
2935           // Either we know this is a designated initializer or we
2936           // conservatively assume it because we don't know for sure.
2937           if (!ID->declaresOrInheritsDesignatedInitializers() ||
2938               ID->isDesignatedInitializer(Sel)) {
2939             isDesignatedInitChain = true;
2940             DIFunctionScopeInfo->ObjCWarnForNoDesignatedInitChain = false;
2941           }
2942         }
2943       }
2944     }
2945     if (!isDesignatedInitChain) {
2946       const ObjCMethodDecl *InitMethod = nullptr;
2947       bool isDesignated =
2948         getCurMethodDecl()->isDesignatedInitializerForTheInterface(&InitMethod);
2949       assert(isDesignated && InitMethod);
2950       (void)isDesignated;
2951       Diag(SelLoc, SuperLoc.isValid() ?
2952              diag::warn_objc_designated_init_non_designated_init_call :
2953              diag::warn_objc_designated_init_non_super_designated_init_call);
2954       Diag(InitMethod->getLocation(),
2955            diag::note_objc_designated_init_marked_here);
2956     }
2957   }
2958
2959   if (DIFunctionScopeInfo &&
2960       DIFunctionScopeInfo->ObjCIsSecondaryInit &&
2961       (SuperLoc.isValid() || isSelfExpr(Receiver))) {
2962     if (SuperLoc.isValid()) {
2963       Diag(SelLoc, diag::warn_objc_secondary_init_super_init_call);
2964     } else {
2965       DIFunctionScopeInfo->ObjCWarnForNoInitDelegation = false;
2966     }
2967   }
2968
2969   // Check the message arguments.
2970   unsigned NumArgs = ArgsIn.size();
2971   Expr **Args = ArgsIn.data();
2972   QualType ReturnType;
2973   ExprValueKind VK = VK_RValue;
2974   bool ClassMessage = (ReceiverType->isObjCClassType() ||
2975                        ReceiverType->isObjCQualifiedClassType());
2976   if (CheckMessageArgumentTypes(ReceiverType, MultiExprArg(Args, NumArgs),
2977                                 Sel, SelectorLocs, Method,
2978                                 ClassMessage, SuperLoc.isValid(),
2979                                 LBracLoc, RBracLoc, RecRange, ReturnType, VK))
2980     return ExprError();
2981
2982   if (Method && !Method->getReturnType()->isVoidType() &&
2983       RequireCompleteType(LBracLoc, Method->getReturnType(),
2984                           diag::err_illegal_message_expr_incomplete_type))
2985     return ExprError();
2986
2987   // In ARC, forbid the user from sending messages to
2988   // retain/release/autorelease/dealloc/retainCount explicitly.
2989   if (getLangOpts().ObjCAutoRefCount) {
2990     ObjCMethodFamily family =
2991       (Method ? Method->getMethodFamily() : Sel.getMethodFamily());
2992     switch (family) {
2993     case OMF_init:
2994       if (Method)
2995         checkInitMethod(Method, ReceiverType);
2996       break;
2997
2998     case OMF_None:
2999     case OMF_alloc:
3000     case OMF_copy:
3001     case OMF_finalize:
3002     case OMF_mutableCopy:
3003     case OMF_new:
3004     case OMF_self:
3005     case OMF_initialize:
3006       break;
3007
3008     case OMF_dealloc:
3009     case OMF_retain:
3010     case OMF_release:
3011     case OMF_autorelease:
3012     case OMF_retainCount:
3013       Diag(SelLoc, diag::err_arc_illegal_explicit_message)
3014         << Sel << RecRange;
3015       break;
3016
3017     case OMF_performSelector:
3018       if (Method && NumArgs >= 1) {
3019         if (const auto *SelExp =
3020                 dyn_cast<ObjCSelectorExpr>(Args[0]->IgnoreParens())) {
3021           Selector ArgSel = SelExp->getSelector();
3022           ObjCMethodDecl *SelMethod =
3023             LookupInstanceMethodInGlobalPool(ArgSel,
3024                                              SelExp->getSourceRange());
3025           if (!SelMethod)
3026             SelMethod =
3027               LookupFactoryMethodInGlobalPool(ArgSel,
3028                                               SelExp->getSourceRange());
3029           if (SelMethod) {
3030             ObjCMethodFamily SelFamily = SelMethod->getMethodFamily();
3031             switch (SelFamily) {
3032               case OMF_alloc:
3033               case OMF_copy:
3034               case OMF_mutableCopy:
3035               case OMF_new:
3036               case OMF_init:
3037                 // Issue error, unless ns_returns_not_retained.
3038                 if (!SelMethod->hasAttr<NSReturnsNotRetainedAttr>()) {
3039                   // selector names a +1 method
3040                   Diag(SelLoc,
3041                        diag::err_arc_perform_selector_retains);
3042                   Diag(SelMethod->getLocation(), diag::note_method_declared_at)
3043                     << SelMethod->getDeclName();
3044                 }
3045                 break;
3046               default:
3047                 // +0 call. OK. unless ns_returns_retained.
3048                 if (SelMethod->hasAttr<NSReturnsRetainedAttr>()) {
3049                   // selector names a +1 method
3050                   Diag(SelLoc,
3051                        diag::err_arc_perform_selector_retains);
3052                   Diag(SelMethod->getLocation(), diag::note_method_declared_at)
3053                     << SelMethod->getDeclName();
3054                 }
3055                 break;
3056             }
3057           }
3058         } else {
3059           // error (may leak).
3060           Diag(SelLoc, diag::warn_arc_perform_selector_leaks);
3061           Diag(Args[0]->getExprLoc(), diag::note_used_here);
3062         }
3063       }
3064       break;
3065     }
3066   }
3067
3068   DiagnoseCStringFormatDirectiveInObjCAPI(*this, Method, Sel, Args, NumArgs);
3069
3070   // Construct the appropriate ObjCMessageExpr instance.
3071   ObjCMessageExpr *Result;
3072   if (SuperLoc.isValid())
3073     Result = ObjCMessageExpr::Create(Context, ReturnType, VK, LBracLoc,
3074                                      SuperLoc,  /*IsInstanceSuper=*/true,
3075                                      ReceiverType, Sel, SelectorLocs, Method,
3076                                      makeArrayRef(Args, NumArgs), RBracLoc,
3077                                      isImplicit);
3078   else {
3079     Result = ObjCMessageExpr::Create(Context, ReturnType, VK, LBracLoc,
3080                                      Receiver, Sel, SelectorLocs, Method,
3081                                      makeArrayRef(Args, NumArgs), RBracLoc,
3082                                      isImplicit);
3083     if (!isImplicit)
3084       checkCocoaAPI(*this, Result);
3085   }
3086   if (Method) {
3087     bool IsClassObjectCall = ClassMessage;
3088     // 'self' message receivers in class methods should be treated as message
3089     // sends to the class object in order for the semantic checks to be
3090     // performed correctly. Messages to 'super' already count as class messages,
3091     // so they don't need to be handled here.
3092     if (Receiver && isSelfExpr(Receiver)) {
3093       if (const auto *OPT = ReceiverType->getAs<ObjCObjectPointerType>()) {
3094         if (OPT->getObjectType()->isObjCClass()) {
3095           if (const auto *CurMeth = getCurMethodDecl()) {
3096             IsClassObjectCall = true;
3097             ReceiverType =
3098                 Context.getObjCInterfaceType(CurMeth->getClassInterface());
3099           }
3100         }
3101       }
3102     }
3103     checkFoundationAPI(*this, SelLoc, Method, makeArrayRef(Args, NumArgs),
3104                        ReceiverType, IsClassObjectCall);
3105   }
3106
3107   if (getLangOpts().ObjCAutoRefCount) {
3108     // In ARC, annotate delegate init calls.
3109     if (Result->getMethodFamily() == OMF_init &&
3110         (SuperLoc.isValid() || isSelfExpr(Receiver))) {
3111       // Only consider init calls *directly* in init implementations,
3112       // not within blocks.
3113       ObjCMethodDecl *method = dyn_cast<ObjCMethodDecl>(CurContext);
3114       if (method && method->getMethodFamily() == OMF_init) {
3115         // The implicit assignment to self means we also don't want to
3116         // consume the result.
3117         Result->setDelegateInitCall(true);
3118         return Result;
3119       }
3120     }
3121
3122     // In ARC, check for message sends which are likely to introduce
3123     // retain cycles.
3124     checkRetainCycles(Result);
3125   }
3126
3127   if (getLangOpts().ObjCWeak) {
3128     if (!isImplicit && Method) {
3129       if (const ObjCPropertyDecl *Prop = Method->findPropertyDecl()) {
3130         bool IsWeak =
3131           Prop->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_weak;
3132         if (!IsWeak && Sel.isUnarySelector())
3133           IsWeak = ReturnType.getObjCLifetime() & Qualifiers::OCL_Weak;
3134         if (IsWeak &&
3135             !Diags.isIgnored(diag::warn_arc_repeated_use_of_weak, LBracLoc))
3136           getCurFunction()->recordUseOfWeak(Result, Prop);
3137       }
3138     }
3139   }
3140
3141   CheckObjCCircularContainer(Result);
3142
3143   return MaybeBindToTemporary(Result);
3144 }
3145
3146 static void RemoveSelectorFromWarningCache(Sema &S, Expr* Arg) {
3147   if (ObjCSelectorExpr *OSE =
3148       dyn_cast<ObjCSelectorExpr>(Arg->IgnoreParenCasts())) {
3149     Selector Sel = OSE->getSelector();
3150     SourceLocation Loc = OSE->getAtLoc();
3151     auto Pos = S.ReferencedSelectors.find(Sel);
3152     if (Pos != S.ReferencedSelectors.end() && Pos->second == Loc)
3153       S.ReferencedSelectors.erase(Pos);
3154   }
3155 }
3156
3157 // ActOnInstanceMessage - used for both unary and keyword messages.
3158 // ArgExprs is optional - if it is present, the number of expressions
3159 // is obtained from Sel.getNumArgs().
3160 ExprResult Sema::ActOnInstanceMessage(Scope *S,
3161                                       Expr *Receiver,
3162                                       Selector Sel,
3163                                       SourceLocation LBracLoc,
3164                                       ArrayRef<SourceLocation> SelectorLocs,
3165                                       SourceLocation RBracLoc,
3166                                       MultiExprArg Args) {
3167   if (!Receiver)
3168     return ExprError();
3169
3170   // A ParenListExpr can show up while doing error recovery with invalid code.
3171   if (isa<ParenListExpr>(Receiver)) {
3172     ExprResult Result = MaybeConvertParenListExprToParenExpr(S, Receiver);
3173     if (Result.isInvalid()) return ExprError();
3174     Receiver = Result.get();
3175   }
3176
3177   if (RespondsToSelectorSel.isNull()) {
3178     IdentifierInfo *SelectorId = &Context.Idents.get("respondsToSelector");
3179     RespondsToSelectorSel = Context.Selectors.getUnarySelector(SelectorId);
3180   }
3181   if (Sel == RespondsToSelectorSel)
3182     RemoveSelectorFromWarningCache(*this, Args[0]);
3183
3184   return BuildInstanceMessage(Receiver, Receiver->getType(),
3185                               /*SuperLoc=*/SourceLocation(), Sel,
3186                               /*Method=*/nullptr, LBracLoc, SelectorLocs,
3187                               RBracLoc, Args);
3188 }
3189
3190 enum ARCConversionTypeClass {
3191   /// int, void, struct A
3192   ACTC_none,
3193
3194   /// id, void (^)()
3195   ACTC_retainable,
3196
3197   /// id*, id***, void (^*)(),
3198   ACTC_indirectRetainable,
3199
3200   /// void* might be a normal C type, or it might a CF type.
3201   ACTC_voidPtr,
3202
3203   /// struct A*
3204   ACTC_coreFoundation
3205 };
3206
3207 static bool isAnyRetainable(ARCConversionTypeClass ACTC) {
3208   return (ACTC == ACTC_retainable ||
3209           ACTC == ACTC_coreFoundation ||
3210           ACTC == ACTC_voidPtr);
3211 }
3212
3213 static bool isAnyCLike(ARCConversionTypeClass ACTC) {
3214   return ACTC == ACTC_none ||
3215          ACTC == ACTC_voidPtr ||
3216          ACTC == ACTC_coreFoundation;
3217 }
3218
3219 static ARCConversionTypeClass classifyTypeForARCConversion(QualType type) {
3220   bool isIndirect = false;
3221
3222   // Ignore an outermost reference type.
3223   if (const ReferenceType *ref = type->getAs<ReferenceType>()) {
3224     type = ref->getPointeeType();
3225     isIndirect = true;
3226   }
3227
3228   // Drill through pointers and arrays recursively.
3229   while (true) {
3230     if (const PointerType *ptr = type->getAs<PointerType>()) {
3231       type = ptr->getPointeeType();
3232
3233       // The first level of pointer may be the innermost pointer on a CF type.
3234       if (!isIndirect) {
3235         if (type->isVoidType()) return ACTC_voidPtr;
3236         if (type->isRecordType()) return ACTC_coreFoundation;
3237       }
3238     } else if (const ArrayType *array = type->getAsArrayTypeUnsafe()) {
3239       type = QualType(array->getElementType()->getBaseElementTypeUnsafe(), 0);
3240     } else {
3241       break;
3242     }
3243     isIndirect = true;
3244   }
3245
3246   if (isIndirect) {
3247     if (type->isObjCARCBridgableType())
3248       return ACTC_indirectRetainable;
3249     return ACTC_none;
3250   }
3251
3252   if (type->isObjCARCBridgableType())
3253     return ACTC_retainable;
3254
3255   return ACTC_none;
3256 }
3257
3258 namespace {
3259   /// A result from the cast checker.
3260   enum ACCResult {
3261     /// Cannot be casted.
3262     ACC_invalid,
3263
3264     /// Can be safely retained or not retained.
3265     ACC_bottom,
3266
3267     /// Can be casted at +0.
3268     ACC_plusZero,
3269
3270     /// Can be casted at +1.
3271     ACC_plusOne
3272   };
3273   ACCResult merge(ACCResult left, ACCResult right) {
3274     if (left == right) return left;
3275     if (left == ACC_bottom) return right;
3276     if (right == ACC_bottom) return left;
3277     return ACC_invalid;
3278   }
3279
3280   /// A checker which white-lists certain expressions whose conversion
3281   /// to or from retainable type would otherwise be forbidden in ARC.
3282   class ARCCastChecker : public StmtVisitor<ARCCastChecker, ACCResult> {
3283     typedef StmtVisitor<ARCCastChecker, ACCResult> super;
3284
3285     ASTContext &Context;
3286     ARCConversionTypeClass SourceClass;
3287     ARCConversionTypeClass TargetClass;
3288     bool Diagnose;
3289
3290     static bool isCFType(QualType type) {
3291       // Someday this can use ns_bridged.  For now, it has to do this.
3292       return type->isCARCBridgableType();
3293     }
3294
3295   public:
3296     ARCCastChecker(ASTContext &Context, ARCConversionTypeClass source,
3297                    ARCConversionTypeClass target, bool diagnose)
3298       : Context(Context), SourceClass(source), TargetClass(target),
3299         Diagnose(diagnose) {}
3300
3301     using super::Visit;
3302     ACCResult Visit(Expr *e) {
3303       return super::Visit(e->IgnoreParens());
3304     }
3305
3306     ACCResult VisitStmt(Stmt *s) {
3307       return ACC_invalid;
3308     }
3309
3310     /// Null pointer constants can be casted however you please.
3311     ACCResult VisitExpr(Expr *e) {
3312       if (e->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNotNull))
3313         return ACC_bottom;
3314       return ACC_invalid;
3315     }
3316
3317     /// Objective-C string literals can be safely casted.
3318     ACCResult VisitObjCStringLiteral(ObjCStringLiteral *e) {
3319       // If we're casting to any retainable type, go ahead.  Global
3320       // strings are immune to retains, so this is bottom.
3321       if (isAnyRetainable(TargetClass)) return ACC_bottom;
3322
3323       return ACC_invalid;
3324     }
3325
3326     /// Look through certain implicit and explicit casts.
3327     ACCResult VisitCastExpr(CastExpr *e) {
3328       switch (e->getCastKind()) {
3329         case CK_NullToPointer:
3330           return ACC_bottom;
3331
3332         case CK_NoOp:
3333         case CK_LValueToRValue:
3334         case CK_BitCast:
3335         case CK_CPointerToObjCPointerCast:
3336         case CK_BlockPointerToObjCPointerCast:
3337         case CK_AnyPointerToBlockPointerCast:
3338           return Visit(e->getSubExpr());
3339
3340         default:
3341           return ACC_invalid;
3342       }
3343     }
3344
3345     /// Look through unary extension.
3346     ACCResult VisitUnaryExtension(UnaryOperator *e) {
3347       return Visit(e->getSubExpr());
3348     }
3349
3350     /// Ignore the LHS of a comma operator.
3351     ACCResult VisitBinComma(BinaryOperator *e) {
3352       return Visit(e->getRHS());
3353     }
3354
3355     /// Conditional operators are okay if both sides are okay.
3356     ACCResult VisitConditionalOperator(ConditionalOperator *e) {
3357       ACCResult left = Visit(e->getTrueExpr());
3358       if (left == ACC_invalid) return ACC_invalid;
3359       return merge(left, Visit(e->getFalseExpr()));
3360     }
3361
3362     /// Look through pseudo-objects.
3363     ACCResult VisitPseudoObjectExpr(PseudoObjectExpr *e) {
3364       // If we're getting here, we should always have a result.
3365       return Visit(e->getResultExpr());
3366     }
3367
3368     /// Statement expressions are okay if their result expression is okay.
3369     ACCResult VisitStmtExpr(StmtExpr *e) {
3370       return Visit(e->getSubStmt()->body_back());
3371     }
3372
3373     /// Some declaration references are okay.
3374     ACCResult VisitDeclRefExpr(DeclRefExpr *e) {
3375       VarDecl *var = dyn_cast<VarDecl>(e->getDecl());
3376       // References to global constants are okay.
3377       if (isAnyRetainable(TargetClass) &&
3378           isAnyRetainable(SourceClass) &&
3379           var &&
3380           !var->hasDefinition(Context) &&
3381           var->getType().isConstQualified()) {
3382
3383         // In system headers, they can also be assumed to be immune to retains.
3384         // These are things like 'kCFStringTransformToLatin'.
3385         if (Context.getSourceManager().isInSystemHeader(var->getLocation()))
3386           return ACC_bottom;
3387
3388         return ACC_plusZero;
3389       }
3390
3391       // Nothing else.
3392       return ACC_invalid;
3393     }
3394
3395     /// Some calls are okay.
3396     ACCResult VisitCallExpr(CallExpr *e) {
3397       if (FunctionDecl *fn = e->getDirectCallee())
3398         if (ACCResult result = checkCallToFunction(fn))
3399           return result;
3400
3401       return super::VisitCallExpr(e);
3402     }
3403
3404     ACCResult checkCallToFunction(FunctionDecl *fn) {
3405       // Require a CF*Ref return type.
3406       if (!isCFType(fn->getReturnType()))
3407         return ACC_invalid;
3408
3409       if (!isAnyRetainable(TargetClass))
3410         return ACC_invalid;
3411
3412       // Honor an explicit 'not retained' attribute.
3413       if (fn->hasAttr<CFReturnsNotRetainedAttr>())
3414         return ACC_plusZero;
3415
3416       // Honor an explicit 'retained' attribute, except that for
3417       // now we're not going to permit implicit handling of +1 results,
3418       // because it's a bit frightening.
3419       if (fn->hasAttr<CFReturnsRetainedAttr>())
3420         return Diagnose ? ACC_plusOne
3421                         : ACC_invalid; // ACC_plusOne if we start accepting this
3422
3423       // Recognize this specific builtin function, which is used by CFSTR.
3424       unsigned builtinID = fn->getBuiltinID();
3425       if (builtinID == Builtin::BI__builtin___CFStringMakeConstantString)
3426         return ACC_bottom;
3427
3428       // Otherwise, don't do anything implicit with an unaudited function.
3429       if (!fn->hasAttr<CFAuditedTransferAttr>())
3430         return ACC_invalid;
3431
3432       // Otherwise, it's +0 unless it follows the create convention.
3433       if (ento::coreFoundation::followsCreateRule(fn))
3434         return Diagnose ? ACC_plusOne
3435                         : ACC_invalid; // ACC_plusOne if we start accepting this
3436
3437       return ACC_plusZero;
3438     }
3439
3440     ACCResult VisitObjCMessageExpr(ObjCMessageExpr *e) {
3441       return checkCallToMethod(e->getMethodDecl());
3442     }
3443
3444     ACCResult VisitObjCPropertyRefExpr(ObjCPropertyRefExpr *e) {
3445       ObjCMethodDecl *method;
3446       if (e->isExplicitProperty())
3447         method = e->getExplicitProperty()->getGetterMethodDecl();
3448       else
3449         method = e->getImplicitPropertyGetter();
3450       return checkCallToMethod(method);
3451     }
3452
3453     ACCResult checkCallToMethod(ObjCMethodDecl *method) {
3454       if (!method) return ACC_invalid;
3455
3456       // Check for message sends to functions returning CF types.  We
3457       // just obey the Cocoa conventions with these, even though the
3458       // return type is CF.
3459       if (!isAnyRetainable(TargetClass) || !isCFType(method->getReturnType()))
3460         return ACC_invalid;
3461
3462       // If the method is explicitly marked not-retained, it's +0.
3463       if (method->hasAttr<CFReturnsNotRetainedAttr>())
3464         return ACC_plusZero;
3465
3466       // If the method is explicitly marked as returning retained, or its
3467       // selector follows a +1 Cocoa convention, treat it as +1.
3468       if (method->hasAttr<CFReturnsRetainedAttr>())
3469         return ACC_plusOne;
3470
3471       switch (method->getSelector().getMethodFamily()) {
3472       case OMF_alloc:
3473       case OMF_copy:
3474       case OMF_mutableCopy:
3475       case OMF_new:
3476         return ACC_plusOne;
3477
3478       default:
3479         // Otherwise, treat it as +0.
3480         return ACC_plusZero;
3481       }
3482     }
3483   };
3484 } // end anonymous namespace
3485
3486 bool Sema::isKnownName(StringRef name) {
3487   if (name.empty())
3488     return false;
3489   LookupResult R(*this, &Context.Idents.get(name), SourceLocation(),
3490                  Sema::LookupOrdinaryName);
3491   return LookupName(R, TUScope, false);
3492 }
3493
3494 static void addFixitForObjCARCConversion(Sema &S,
3495                                          DiagnosticBuilder &DiagB,
3496                                          Sema::CheckedConversionKind CCK,
3497                                          SourceLocation afterLParen,
3498                                          QualType castType,
3499                                          Expr *castExpr,
3500                                          Expr *realCast,
3501                                          const char *bridgeKeyword,
3502                                          const char *CFBridgeName) {
3503   // We handle C-style and implicit casts here.
3504   switch (CCK) {
3505   case Sema::CCK_ImplicitConversion:
3506   case Sema::CCK_ForBuiltinOverloadedOp:
3507   case Sema::CCK_CStyleCast:
3508   case Sema::CCK_OtherCast:
3509     break;
3510   case Sema::CCK_FunctionalCast:
3511     return;
3512   }
3513
3514   if (CFBridgeName) {
3515     if (CCK == Sema::CCK_OtherCast) {
3516       if (const CXXNamedCastExpr *NCE = dyn_cast<CXXNamedCastExpr>(realCast)) {
3517         SourceRange range(NCE->getOperatorLoc(),
3518                           NCE->getAngleBrackets().getEnd());
3519         SmallString<32> BridgeCall;
3520
3521         SourceManager &SM = S.getSourceManager();
3522         char PrevChar = *SM.getCharacterData(range.getBegin().getLocWithOffset(-1));
3523         if (Lexer::isIdentifierBodyChar(PrevChar, S.getLangOpts()))
3524           BridgeCall += ' ';
3525
3526         BridgeCall += CFBridgeName;
3527         DiagB.AddFixItHint(FixItHint::CreateReplacement(range, BridgeCall));
3528       }
3529       return;
3530     }
3531     Expr *castedE = castExpr;
3532     if (CStyleCastExpr *CCE = dyn_cast<CStyleCastExpr>(castedE))
3533       castedE = CCE->getSubExpr();
3534     castedE = castedE->IgnoreImpCasts();
3535     SourceRange range = castedE->getSourceRange();
3536
3537     SmallString<32> BridgeCall;
3538
3539     SourceManager &SM = S.getSourceManager();
3540     char PrevChar = *SM.getCharacterData(range.getBegin().getLocWithOffset(-1));
3541     if (Lexer::isIdentifierBodyChar(PrevChar, S.getLangOpts()))
3542       BridgeCall += ' ';
3543
3544     BridgeCall += CFBridgeName;
3545
3546     if (isa<ParenExpr>(castedE)) {
3547       DiagB.AddFixItHint(FixItHint::CreateInsertion(range.getBegin(),
3548                          BridgeCall));
3549     } else {
3550       BridgeCall += '(';
3551       DiagB.AddFixItHint(FixItHint::CreateInsertion(range.getBegin(),
3552                                                     BridgeCall));
3553       DiagB.AddFixItHint(FixItHint::CreateInsertion(
3554                                        S.getLocForEndOfToken(range.getEnd()),
3555                                        ")"));
3556     }
3557     return;
3558   }
3559
3560   if (CCK == Sema::CCK_CStyleCast) {
3561     DiagB.AddFixItHint(FixItHint::CreateInsertion(afterLParen, bridgeKeyword));
3562   } else if (CCK == Sema::CCK_OtherCast) {
3563     if (const CXXNamedCastExpr *NCE = dyn_cast<CXXNamedCastExpr>(realCast)) {
3564       std::string castCode = "(";
3565       castCode += bridgeKeyword;
3566       castCode += castType.getAsString();
3567       castCode += ")";
3568       SourceRange Range(NCE->getOperatorLoc(),
3569                         NCE->getAngleBrackets().getEnd());
3570       DiagB.AddFixItHint(FixItHint::CreateReplacement(Range, castCode));
3571     }
3572   } else {
3573     std::string castCode = "(";
3574     castCode += bridgeKeyword;
3575     castCode += castType.getAsString();
3576     castCode += ")";
3577     Expr *castedE = castExpr->IgnoreImpCasts();
3578     SourceRange range = castedE->getSourceRange();
3579     if (isa<ParenExpr>(castedE)) {
3580       DiagB.AddFixItHint(FixItHint::CreateInsertion(range.getBegin(),
3581                          castCode));
3582     } else {
3583       castCode += "(";
3584       DiagB.AddFixItHint(FixItHint::CreateInsertion(range.getBegin(),
3585                                                     castCode));
3586       DiagB.AddFixItHint(FixItHint::CreateInsertion(
3587                                        S.getLocForEndOfToken(range.getEnd()),
3588                                        ")"));
3589     }
3590   }
3591 }
3592
3593 template <typename T>
3594 static inline T *getObjCBridgeAttr(const TypedefType *TD) {
3595   TypedefNameDecl *TDNDecl = TD->getDecl();
3596   QualType QT = TDNDecl->getUnderlyingType();
3597   if (QT->isPointerType()) {
3598     QT = QT->getPointeeType();
3599     if (const RecordType *RT = QT->getAs<RecordType>())
3600       if (RecordDecl *RD = RT->getDecl()->getMostRecentDecl())
3601         return RD->getAttr<T>();
3602   }
3603   return nullptr;
3604 }
3605
3606 static ObjCBridgeRelatedAttr *ObjCBridgeRelatedAttrFromType(QualType T,
3607                                                             TypedefNameDecl *&TDNDecl) {
3608   while (const TypedefType *TD = dyn_cast<TypedefType>(T.getTypePtr())) {
3609     TDNDecl = TD->getDecl();
3610     if (ObjCBridgeRelatedAttr *ObjCBAttr =
3611         getObjCBridgeAttr<ObjCBridgeRelatedAttr>(TD))
3612       return ObjCBAttr;
3613     T = TDNDecl->getUnderlyingType();
3614   }
3615   return nullptr;
3616 }
3617
3618 static void
3619 diagnoseObjCARCConversion(Sema &S, SourceRange castRange,
3620                           QualType castType, ARCConversionTypeClass castACTC,
3621                           Expr *castExpr, Expr *realCast,
3622                           ARCConversionTypeClass exprACTC,
3623                           Sema::CheckedConversionKind CCK) {
3624   SourceLocation loc =
3625     (castRange.isValid() ? castRange.getBegin() : castExpr->getExprLoc());
3626
3627   if (S.makeUnavailableInSystemHeader(loc,
3628                                  UnavailableAttr::IR_ARCForbiddenConversion))
3629     return;
3630
3631   QualType castExprType = castExpr->getType();
3632   // Defer emitting a diagnostic for bridge-related casts; that will be
3633   // handled by CheckObjCBridgeRelatedConversions.
3634   TypedefNameDecl *TDNDecl = nullptr;
3635   if ((castACTC == ACTC_coreFoundation &&  exprACTC == ACTC_retainable &&
3636        ObjCBridgeRelatedAttrFromType(castType, TDNDecl)) ||
3637       (exprACTC == ACTC_coreFoundation && castACTC == ACTC_retainable &&
3638        ObjCBridgeRelatedAttrFromType(castExprType, TDNDecl)))
3639     return;
3640
3641   unsigned srcKind = 0;
3642   switch (exprACTC) {
3643   case ACTC_none:
3644   case ACTC_coreFoundation:
3645   case ACTC_voidPtr:
3646     srcKind = (castExprType->isPointerType() ? 1 : 0);
3647     break;
3648   case ACTC_retainable:
3649     srcKind = (castExprType->isBlockPointerType() ? 2 : 3);
3650     break;
3651   case ACTC_indirectRetainable:
3652     srcKind = 4;
3653     break;
3654   }
3655
3656   // Check whether this could be fixed with a bridge cast.
3657   SourceLocation afterLParen = S.getLocForEndOfToken(castRange.getBegin());
3658   SourceLocation noteLoc = afterLParen.isValid() ? afterLParen : loc;
3659
3660   unsigned convKindForDiag = Sema::isCast(CCK) ? 0 : 1;
3661
3662   // Bridge from an ARC type to a CF type.
3663   if (castACTC == ACTC_retainable && isAnyRetainable(exprACTC)) {
3664
3665     S.Diag(loc, diag::err_arc_cast_requires_bridge)
3666       << convKindForDiag
3667       << 2 // of C pointer type
3668       << castExprType
3669       << unsigned(castType->isBlockPointerType()) // to ObjC|block type
3670       << castType
3671       << castRange
3672       << castExpr->getSourceRange();
3673     bool br = S.isKnownName("CFBridgingRelease");
3674     ACCResult CreateRule =
3675       ARCCastChecker(S.Context, exprACTC, castACTC, true).Visit(castExpr);
3676     assert(CreateRule != ACC_bottom && "This cast should already be accepted.");
3677     if (CreateRule != ACC_plusOne)
3678     {
3679       DiagnosticBuilder DiagB =
3680         (CCK != Sema::CCK_OtherCast) ? S.Diag(noteLoc, diag::note_arc_bridge)
3681                               : S.Diag(noteLoc, diag::note_arc_cstyle_bridge);
3682
3683       addFixitForObjCARCConversion(S, DiagB, CCK, afterLParen,
3684                                    castType, castExpr, realCast, "__bridge ",
3685                                    nullptr);
3686     }
3687     if (CreateRule != ACC_plusZero)
3688     {
3689       DiagnosticBuilder DiagB =
3690         (CCK == Sema::CCK_OtherCast && !br) ?
3691           S.Diag(noteLoc, diag::note_arc_cstyle_bridge_transfer) << castExprType :
3692           S.Diag(br ? castExpr->getExprLoc() : noteLoc,
3693                  diag::note_arc_bridge_transfer)
3694             << castExprType << br;
3695
3696       addFixitForObjCARCConversion(S, DiagB, CCK, afterLParen,
3697                                    castType, castExpr, realCast, "__bridge_transfer ",
3698                                    br ? "CFBridgingRelease" : nullptr);
3699     }
3700
3701     return;
3702   }
3703
3704   // Bridge from a CF type to an ARC type.
3705   if (exprACTC == ACTC_retainable && isAnyRetainable(castACTC)) {
3706     bool br = S.isKnownName("CFBridgingRetain");
3707     S.Diag(loc, diag::err_arc_cast_requires_bridge)
3708       << convKindForDiag
3709       << unsigned(castExprType->isBlockPointerType()) // of ObjC|block type
3710       << castExprType
3711       << 2 // to C pointer type
3712       << castType
3713       << castRange
3714       << castExpr->getSourceRange();
3715     ACCResult CreateRule =
3716       ARCCastChecker(S.Context, exprACTC, castACTC, true).Visit(castExpr);
3717     assert(CreateRule != ACC_bottom && "This cast should already be accepted.");
3718     if (CreateRule != ACC_plusOne)
3719     {
3720       DiagnosticBuilder DiagB =
3721       (CCK != Sema::CCK_OtherCast) ? S.Diag(noteLoc, diag::note_arc_bridge)
3722                                : S.Diag(noteLoc, diag::note_arc_cstyle_bridge);
3723       addFixitForObjCARCConversion(S, DiagB, CCK, afterLParen,
3724                                    castType, castExpr, realCast, "__bridge ",
3725                                    nullptr);
3726     }
3727     if (CreateRule != ACC_plusZero)
3728     {
3729       DiagnosticBuilder DiagB =
3730         (CCK == Sema::CCK_OtherCast && !br) ?
3731           S.Diag(noteLoc, diag::note_arc_cstyle_bridge_retained) << castType :
3732           S.Diag(br ? castExpr->getExprLoc() : noteLoc,
3733                  diag::note_arc_bridge_retained)
3734             << castType << br;
3735
3736       addFixitForObjCARCConversion(S, DiagB, CCK, afterLParen,
3737                                    castType, castExpr, realCast, "__bridge_retained ",
3738                                    br ? "CFBridgingRetain" : nullptr);
3739     }
3740
3741     return;
3742   }
3743
3744   S.Diag(loc, diag::err_arc_mismatched_cast)
3745     << !convKindForDiag
3746     << srcKind << castExprType << castType
3747     << castRange << castExpr->getSourceRange();
3748 }
3749
3750 template <typename TB>
3751 static bool CheckObjCBridgeNSCast(Sema &S, QualType castType, Expr *castExpr,
3752                                   bool &HadTheAttribute, bool warn) {
3753   QualType T = castExpr->getType();
3754   HadTheAttribute = false;
3755   while (const TypedefType *TD = dyn_cast<TypedefType>(T.getTypePtr())) {
3756     TypedefNameDecl *TDNDecl = TD->getDecl();
3757     if (TB *ObjCBAttr = getObjCBridgeAttr<TB>(TD)) {
3758       if (IdentifierInfo *Parm = ObjCBAttr->getBridgedType()) {
3759         HadTheAttribute = true;
3760         if (Parm->isStr("id"))
3761           return true;
3762
3763         NamedDecl *Target = nullptr;
3764         // Check for an existing type with this name.
3765         LookupResult R(S, DeclarationName(Parm), SourceLocation(),
3766                        Sema::LookupOrdinaryName);
3767         if (S.LookupName(R, S.TUScope)) {
3768           Target = R.getFoundDecl();
3769           if (Target && isa<ObjCInterfaceDecl>(Target)) {
3770             ObjCInterfaceDecl *ExprClass = cast<ObjCInterfaceDecl>(Target);
3771             if (const ObjCObjectPointerType *InterfacePointerType =
3772                   castType->getAsObjCInterfacePointerType()) {
3773               ObjCInterfaceDecl *CastClass
3774                 = InterfacePointerType->getObjectType()->getInterface();
3775               if ((CastClass == ExprClass) ||
3776                   (CastClass && CastClass->isSuperClassOf(ExprClass)))
3777                 return true;
3778               if (warn)
3779                 S.Diag(castExpr->getLocStart(), diag::warn_objc_invalid_bridge)
3780                   << T << Target->getName() << castType->getPointeeType();
3781               return false;
3782             } else if (castType->isObjCIdType() ||
3783                        (S.Context.ObjCObjectAdoptsQTypeProtocols(
3784                           castType, ExprClass)))
3785               // ok to cast to 'id'.
3786               // casting to id<p-list> is ok if bridge type adopts all of
3787               // p-list protocols.
3788               return true;
3789             else {
3790               if (warn) {
3791                 S.Diag(castExpr->getLocStart(), diag::warn_objc_invalid_bridge)
3792                   << T << Target->getName() << castType;
3793                 S.Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3794                 S.Diag(Target->getLocStart(), diag::note_declared_at);
3795               }
3796               return false;
3797            }
3798           }
3799         } else if (!castType->isObjCIdType()) {
3800           S.Diag(castExpr->getLocStart(), diag::err_objc_cf_bridged_not_interface)
3801             << castExpr->getType() << Parm;
3802           S.Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3803           if (Target)
3804             S.Diag(Target->getLocStart(), diag::note_declared_at);
3805         }
3806         return true;
3807       }
3808       return false;
3809     }
3810     T = TDNDecl->getUnderlyingType();
3811   }
3812   return true;
3813 }
3814
3815 template <typename TB>
3816 static bool CheckObjCBridgeCFCast(Sema &S, QualType castType, Expr *castExpr,
3817                                   bool &HadTheAttribute, bool warn) {
3818   QualType T = castType;
3819   HadTheAttribute = false;
3820   while (const TypedefType *TD = dyn_cast<TypedefType>(T.getTypePtr())) {
3821     TypedefNameDecl *TDNDecl = TD->getDecl();
3822     if (TB *ObjCBAttr = getObjCBridgeAttr<TB>(TD)) {
3823       if (IdentifierInfo *Parm = ObjCBAttr->getBridgedType()) {
3824         HadTheAttribute = true;
3825         if (Parm->isStr("id"))
3826           return true;
3827
3828         NamedDecl *Target = nullptr;
3829         // Check for an existing type with this name.
3830         LookupResult R(S, DeclarationName(Parm), SourceLocation(),
3831                        Sema::LookupOrdinaryName);
3832         if (S.LookupName(R, S.TUScope)) {
3833           Target = R.getFoundDecl();
3834           if (Target && isa<ObjCInterfaceDecl>(Target)) {
3835             ObjCInterfaceDecl *CastClass = cast<ObjCInterfaceDecl>(Target);
3836             if (const ObjCObjectPointerType *InterfacePointerType =
3837                   castExpr->getType()->getAsObjCInterfacePointerType()) {
3838               ObjCInterfaceDecl *ExprClass
3839                 = InterfacePointerType->getObjectType()->getInterface();
3840               if ((CastClass == ExprClass) ||
3841                   (ExprClass && CastClass->isSuperClassOf(ExprClass)))
3842                 return true;
3843               if (warn) {
3844                 S.Diag(castExpr->getLocStart(), diag::warn_objc_invalid_bridge_to_cf)
3845                   << castExpr->getType()->getPointeeType() << T;
3846                 S.Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3847               }
3848               return false;
3849             } else if (castExpr->getType()->isObjCIdType() ||
3850                        (S.Context.QIdProtocolsAdoptObjCObjectProtocols(
3851                           castExpr->getType(), CastClass)))
3852               // ok to cast an 'id' expression to a CFtype.
3853               // ok to cast an 'id<plist>' expression to CFtype provided plist
3854               // adopts all of CFtype's ObjetiveC's class plist.
3855               return true;
3856             else {
3857               if (warn) {
3858                 S.Diag(castExpr->getLocStart(), diag::warn_objc_invalid_bridge_to_cf)
3859                   << castExpr->getType() << castType;
3860                 S.Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3861                 S.Diag(Target->getLocStart(), diag::note_declared_at);
3862               }
3863               return false;
3864             }
3865           }
3866         }
3867         S.Diag(castExpr->getLocStart(), diag::err_objc_ns_bridged_invalid_cfobject)
3868         << castExpr->getType() << castType;
3869         S.Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3870         if (Target)
3871           S.Diag(Target->getLocStart(), diag::note_declared_at);
3872         return true;
3873       }
3874       return false;
3875     }
3876     T = TDNDecl->getUnderlyingType();
3877   }
3878   return true;
3879 }
3880
3881 void Sema::CheckTollFreeBridgeCast(QualType castType, Expr *castExpr) {
3882   if (!getLangOpts().ObjC1)
3883     return;
3884   // warn in presence of __bridge casting to or from a toll free bridge cast.
3885   ARCConversionTypeClass exprACTC = classifyTypeForARCConversion(castExpr->getType());
3886   ARCConversionTypeClass castACTC = classifyTypeForARCConversion(castType);
3887   if (castACTC == ACTC_retainable && exprACTC == ACTC_coreFoundation) {
3888     bool HasObjCBridgeAttr;
3889     bool ObjCBridgeAttrWillNotWarn =
3890       CheckObjCBridgeNSCast<ObjCBridgeAttr>(*this, castType, castExpr, HasObjCBridgeAttr,
3891                                             false);
3892     if (ObjCBridgeAttrWillNotWarn && HasObjCBridgeAttr)
3893       return;
3894     bool HasObjCBridgeMutableAttr;
3895     bool ObjCBridgeMutableAttrWillNotWarn =
3896       CheckObjCBridgeNSCast<ObjCBridgeMutableAttr>(*this, castType, castExpr,
3897                                                    HasObjCBridgeMutableAttr, false);
3898     if (ObjCBridgeMutableAttrWillNotWarn && HasObjCBridgeMutableAttr)
3899       return;
3900
3901     if (HasObjCBridgeAttr)
3902       CheckObjCBridgeNSCast<ObjCBridgeAttr>(*this, castType, castExpr, HasObjCBridgeAttr,
3903                                             true);
3904     else if (HasObjCBridgeMutableAttr)
3905       CheckObjCBridgeNSCast<ObjCBridgeMutableAttr>(*this, castType, castExpr,
3906                                                    HasObjCBridgeMutableAttr, true);
3907   }
3908   else if (castACTC == ACTC_coreFoundation && exprACTC == ACTC_retainable) {
3909     bool HasObjCBridgeAttr;
3910     bool ObjCBridgeAttrWillNotWarn =
3911       CheckObjCBridgeCFCast<ObjCBridgeAttr>(*this, castType, castExpr, HasObjCBridgeAttr,
3912                                             false);
3913     if (ObjCBridgeAttrWillNotWarn && HasObjCBridgeAttr)
3914       return;
3915     bool HasObjCBridgeMutableAttr;
3916     bool ObjCBridgeMutableAttrWillNotWarn =
3917       CheckObjCBridgeCFCast<ObjCBridgeMutableAttr>(*this, castType, castExpr,
3918                                                    HasObjCBridgeMutableAttr, false);
3919     if (ObjCBridgeMutableAttrWillNotWarn && HasObjCBridgeMutableAttr)
3920       return;
3921
3922     if (HasObjCBridgeAttr)
3923       CheckObjCBridgeCFCast<ObjCBridgeAttr>(*this, castType, castExpr, HasObjCBridgeAttr,
3924                                             true);
3925     else if (HasObjCBridgeMutableAttr)
3926       CheckObjCBridgeCFCast<ObjCBridgeMutableAttr>(*this, castType, castExpr,
3927                                                    HasObjCBridgeMutableAttr, true);
3928   }
3929 }
3930
3931 void Sema::CheckObjCBridgeRelatedCast(QualType castType, Expr *castExpr) {
3932   QualType SrcType = castExpr->getType();
3933   if (ObjCPropertyRefExpr *PRE = dyn_cast<ObjCPropertyRefExpr>(castExpr)) {
3934     if (PRE->isExplicitProperty()) {
3935       if (ObjCPropertyDecl *PDecl = PRE->getExplicitProperty())
3936         SrcType = PDecl->getType();
3937     }
3938     else if (PRE->isImplicitProperty()) {
3939       if (ObjCMethodDecl *Getter = PRE->getImplicitPropertyGetter())
3940         SrcType = Getter->getReturnType();
3941     }
3942   }
3943
3944   ARCConversionTypeClass srcExprACTC = classifyTypeForARCConversion(SrcType);
3945   ARCConversionTypeClass castExprACTC = classifyTypeForARCConversion(castType);
3946   if (srcExprACTC != ACTC_retainable || castExprACTC != ACTC_coreFoundation)
3947     return;
3948   CheckObjCBridgeRelatedConversions(castExpr->getLocStart(),
3949                                     castType, SrcType, castExpr);
3950 }
3951
3952 bool Sema::CheckTollFreeBridgeStaticCast(QualType castType, Expr *castExpr,
3953                                          CastKind &Kind) {
3954   if (!getLangOpts().ObjC1)
3955     return false;
3956   ARCConversionTypeClass exprACTC =
3957     classifyTypeForARCConversion(castExpr->getType());
3958   ARCConversionTypeClass castACTC = classifyTypeForARCConversion(castType);
3959   if ((castACTC == ACTC_retainable && exprACTC == ACTC_coreFoundation) ||
3960       (castACTC == ACTC_coreFoundation && exprACTC == ACTC_retainable)) {
3961     CheckTollFreeBridgeCast(castType, castExpr);
3962     Kind = (castACTC == ACTC_coreFoundation) ? CK_BitCast
3963                                              : CK_CPointerToObjCPointerCast;
3964     return true;
3965   }
3966   return false;
3967 }
3968
3969 bool Sema::checkObjCBridgeRelatedComponents(SourceLocation Loc,
3970                                             QualType DestType, QualType SrcType,
3971                                             ObjCInterfaceDecl *&RelatedClass,
3972                                             ObjCMethodDecl *&ClassMethod,
3973                                             ObjCMethodDecl *&InstanceMethod,
3974                                             TypedefNameDecl *&TDNDecl,
3975                                             bool CfToNs, bool Diagnose) {
3976   QualType T = CfToNs ? SrcType : DestType;
3977   ObjCBridgeRelatedAttr *ObjCBAttr = ObjCBridgeRelatedAttrFromType(T, TDNDecl);
3978   if (!ObjCBAttr)
3979     return false;
3980
3981   IdentifierInfo *RCId = ObjCBAttr->getRelatedClass();
3982   IdentifierInfo *CMId = ObjCBAttr->getClassMethod();
3983   IdentifierInfo *IMId = ObjCBAttr->getInstanceMethod();
3984   if (!RCId)
3985     return false;
3986   NamedDecl *Target = nullptr;
3987   // Check for an existing type with this name.
3988   LookupResult R(*this, DeclarationName(RCId), SourceLocation(),
3989                  Sema::LookupOrdinaryName);
3990   if (!LookupName(R, TUScope)) {
3991     if (Diagnose) {
3992       Diag(Loc, diag::err_objc_bridged_related_invalid_class) << RCId
3993             << SrcType << DestType;
3994       Diag(TDNDecl->getLocStart(), diag::note_declared_at);
3995     }
3996     return false;
3997   }
3998   Target = R.getFoundDecl();
3999   if (Target && isa<ObjCInterfaceDecl>(Target))
4000     RelatedClass = cast<ObjCInterfaceDecl>(Target);
4001   else {
4002     if (Diagnose) {
4003       Diag(Loc, diag::err_objc_bridged_related_invalid_class_name) << RCId
4004             << SrcType << DestType;
4005       Diag(TDNDecl->getLocStart(), diag::note_declared_at);
4006       if (Target)
4007         Diag(Target->getLocStart(), diag::note_declared_at);
4008     }
4009     return false;
4010   }
4011
4012   // Check for an existing class method with the given selector name.
4013   if (CfToNs && CMId) {
4014     Selector Sel = Context.Selectors.getUnarySelector(CMId);
4015     ClassMethod = RelatedClass->lookupMethod(Sel, false);
4016     if (!ClassMethod) {
4017       if (Diagnose) {
4018         Diag(Loc, diag::err_objc_bridged_related_known_method)
4019               << SrcType << DestType << Sel << false;
4020         Diag(TDNDecl->getLocStart(), diag::note_declared_at);
4021       }
4022       return false;
4023     }
4024   }
4025
4026   // Check for an existing instance method with the given selector name.
4027   if (!CfToNs && IMId) {
4028     Selector Sel = Context.Selectors.getNullarySelector(IMId);
4029     InstanceMethod = RelatedClass->lookupMethod(Sel, true);
4030     if (!InstanceMethod) {
4031       if (Diagnose) {
4032         Diag(Loc, diag::err_objc_bridged_related_known_method)
4033               << SrcType << DestType << Sel << true;
4034         Diag(TDNDecl->getLocStart(), diag::note_declared_at);
4035       }
4036       return false;
4037     }
4038   }
4039   return true;
4040 }
4041
4042 bool
4043 Sema::CheckObjCBridgeRelatedConversions(SourceLocation Loc,
4044                                         QualType DestType, QualType SrcType,
4045                                         Expr *&SrcExpr, bool Diagnose) {
4046   ARCConversionTypeClass rhsExprACTC = classifyTypeForARCConversion(SrcType);
4047   ARCConversionTypeClass lhsExprACTC = classifyTypeForARCConversion(DestType);
4048   bool CfToNs = (rhsExprACTC == ACTC_coreFoundation && lhsExprACTC == ACTC_retainable);
4049   bool NsToCf = (rhsExprACTC == ACTC_retainable && lhsExprACTC == ACTC_coreFoundation);
4050   if (!CfToNs && !NsToCf)
4051     return false;
4052
4053   ObjCInterfaceDecl *RelatedClass;
4054   ObjCMethodDecl *ClassMethod = nullptr;
4055   ObjCMethodDecl *InstanceMethod = nullptr;
4056   TypedefNameDecl *TDNDecl = nullptr;
4057   if (!checkObjCBridgeRelatedComponents(Loc, DestType, SrcType, RelatedClass,
4058                                         ClassMethod, InstanceMethod, TDNDecl,
4059                                         CfToNs, Diagnose))
4060     return false;
4061
4062   if (CfToNs) {
4063     // Implicit conversion from CF to ObjC object is needed.
4064     if (ClassMethod) {
4065       if (Diagnose) {
4066         std::string ExpressionString = "[";
4067         ExpressionString += RelatedClass->getNameAsString();
4068         ExpressionString += " ";
4069         ExpressionString += ClassMethod->getSelector().getAsString();
4070         SourceLocation SrcExprEndLoc = getLocForEndOfToken(SrcExpr->getLocEnd());
4071         // Provide a fixit: [RelatedClass ClassMethod SrcExpr]
4072         Diag(Loc, diag::err_objc_bridged_related_known_method)
4073           << SrcType << DestType << ClassMethod->getSelector() << false
4074           << FixItHint::CreateInsertion(SrcExpr->getLocStart(), ExpressionString)
4075           << FixItHint::CreateInsertion(SrcExprEndLoc, "]");
4076         Diag(RelatedClass->getLocStart(), diag::note_declared_at);
4077         Diag(TDNDecl->getLocStart(), diag::note_declared_at);
4078
4079         QualType receiverType = Context.getObjCInterfaceType(RelatedClass);
4080         // Argument.
4081         Expr *args[] = { SrcExpr };
4082         ExprResult msg = BuildClassMessageImplicit(receiverType, false,
4083                                       ClassMethod->getLocation(),
4084                                       ClassMethod->getSelector(), ClassMethod,
4085                                       MultiExprArg(args, 1));
4086         SrcExpr = msg.get();
4087       }
4088       return true;
4089     }
4090   }
4091   else {
4092     // Implicit conversion from ObjC type to CF object is needed.
4093     if (InstanceMethod) {
4094       if (Diagnose) {
4095         std::string ExpressionString;
4096         SourceLocation SrcExprEndLoc =
4097             getLocForEndOfToken(SrcExpr->getLocEnd());
4098         if (InstanceMethod->isPropertyAccessor())
4099           if (const ObjCPropertyDecl *PDecl =
4100                   InstanceMethod->findPropertyDecl()) {
4101             // fixit: ObjectExpr.propertyname when it is  aproperty accessor.
4102             ExpressionString = ".";
4103             ExpressionString += PDecl->getNameAsString();
4104             Diag(Loc, diag::err_objc_bridged_related_known_method)
4105                 << SrcType << DestType << InstanceMethod->getSelector() << true
4106                 << FixItHint::CreateInsertion(SrcExprEndLoc, ExpressionString);
4107           }
4108         if (ExpressionString.empty()) {
4109           // Provide a fixit: [ObjectExpr InstanceMethod]
4110           ExpressionString = " ";
4111           ExpressionString += InstanceMethod->getSelector().getAsString();
4112           ExpressionString += "]";
4113
4114           Diag(Loc, diag::err_objc_bridged_related_known_method)
4115               << SrcType << DestType << InstanceMethod->getSelector() << true
4116               << FixItHint::CreateInsertion(SrcExpr->getLocStart(), "[")
4117               << FixItHint::CreateInsertion(SrcExprEndLoc, ExpressionString);
4118         }
4119         Diag(RelatedClass->getLocStart(), diag::note_declared_at);
4120         Diag(TDNDecl->getLocStart(), diag::note_declared_at);
4121
4122         ExprResult msg =
4123           BuildInstanceMessageImplicit(SrcExpr, SrcType,
4124                                        InstanceMethod->getLocation(),
4125                                        InstanceMethod->getSelector(),
4126                                        InstanceMethod, None);
4127         SrcExpr = msg.get();
4128       }
4129       return true;
4130     }
4131   }
4132   return false;
4133 }
4134
4135 Sema::ARCConversionResult
4136 Sema::CheckObjCConversion(SourceRange castRange, QualType castType,
4137                           Expr *&castExpr, CheckedConversionKind CCK,
4138                           bool Diagnose, bool DiagnoseCFAudited,
4139                           BinaryOperatorKind Opc) {
4140   QualType castExprType = castExpr->getType();
4141
4142   // For the purposes of the classification, we assume reference types
4143   // will bind to temporaries.
4144   QualType effCastType = castType;
4145   if (const ReferenceType *ref = castType->getAs<ReferenceType>())
4146     effCastType = ref->getPointeeType();
4147
4148   ARCConversionTypeClass exprACTC = classifyTypeForARCConversion(castExprType);
4149   ARCConversionTypeClass castACTC = classifyTypeForARCConversion(effCastType);
4150   if (exprACTC == castACTC) {
4151     // Check for viability and report error if casting an rvalue to a
4152     // life-time qualifier.
4153     if (castACTC == ACTC_retainable &&
4154         (CCK == CCK_CStyleCast || CCK == CCK_OtherCast) &&
4155         castType != castExprType) {
4156       const Type *DT = castType.getTypePtr();
4157       QualType QDT = castType;
4158       // We desugar some types but not others. We ignore those
4159       // that cannot happen in a cast; i.e. auto, and those which
4160       // should not be de-sugared; i.e typedef.
4161       if (const ParenType *PT = dyn_cast<ParenType>(DT))
4162         QDT = PT->desugar();
4163       else if (const TypeOfType *TP = dyn_cast<TypeOfType>(DT))
4164         QDT = TP->desugar();
4165       else if (const AttributedType *AT = dyn_cast<AttributedType>(DT))
4166         QDT = AT->desugar();
4167       if (QDT != castType &&
4168           QDT.getObjCLifetime() !=  Qualifiers::OCL_None) {
4169         if (Diagnose) {
4170           SourceLocation loc = (castRange.isValid() ? castRange.getBegin()
4171                                                     : castExpr->getExprLoc());
4172           Diag(loc, diag::err_arc_nolifetime_behavior);
4173         }
4174         return ACR_error;
4175       }
4176     }
4177     return ACR_okay;
4178   }
4179
4180   // The life-time qualifier cast check above is all we need for ObjCWeak.
4181   // ObjCAutoRefCount has more restrictions on what is legal.
4182   if (!getLangOpts().ObjCAutoRefCount)
4183     return ACR_okay;
4184
4185   if (isAnyCLike(exprACTC) && isAnyCLike(castACTC)) return ACR_okay;
4186
4187   // Allow all of these types to be cast to integer types (but not
4188   // vice-versa).
4189   if (castACTC == ACTC_none && castType->isIntegralType(Context))
4190     return ACR_okay;
4191
4192   // Allow casts between pointers to lifetime types (e.g., __strong id*)
4193   // and pointers to void (e.g., cv void *). Casting from void* to lifetime*
4194   // must be explicit.
4195   if (exprACTC == ACTC_indirectRetainable && castACTC == ACTC_voidPtr)
4196     return ACR_okay;
4197   if (castACTC == ACTC_indirectRetainable && exprACTC == ACTC_voidPtr &&
4198       isCast(CCK))
4199     return ACR_okay;
4200
4201   switch (ARCCastChecker(Context, exprACTC, castACTC, false).Visit(castExpr)) {
4202   // For invalid casts, fall through.
4203   case ACC_invalid:
4204     break;
4205
4206   // Do nothing for both bottom and +0.
4207   case ACC_bottom:
4208   case ACC_plusZero:
4209     return ACR_okay;
4210
4211   // If the result is +1, consume it here.
4212   case ACC_plusOne:
4213     castExpr = ImplicitCastExpr::Create(Context, castExpr->getType(),
4214                                         CK_ARCConsumeObject, castExpr,
4215                                         nullptr, VK_RValue);
4216     Cleanup.setExprNeedsCleanups(true);
4217     return ACR_okay;
4218   }
4219
4220   // If this is a non-implicit cast from id or block type to a
4221   // CoreFoundation type, delay complaining in case the cast is used
4222   // in an acceptable context.
4223   if (exprACTC == ACTC_retainable && isAnyRetainable(castACTC) && isCast(CCK))
4224     return ACR_unbridged;
4225
4226   // Issue a diagnostic about a missing @-sign when implicit casting a cstring
4227   // to 'NSString *', instead of falling through to report a "bridge cast"
4228   // diagnostic.
4229   if (castACTC == ACTC_retainable && exprACTC == ACTC_none &&
4230       ConversionToObjCStringLiteralCheck(castType, castExpr, Diagnose))
4231     return ACR_error;
4232
4233   // Do not issue "bridge cast" diagnostic when implicit casting
4234   // a retainable object to a CF type parameter belonging to an audited
4235   // CF API function. Let caller issue a normal type mismatched diagnostic
4236   // instead.
4237   if ((!DiagnoseCFAudited || exprACTC != ACTC_retainable ||
4238        castACTC != ACTC_coreFoundation) &&
4239       !(exprACTC == ACTC_voidPtr && castACTC == ACTC_retainable &&
4240         (Opc == BO_NE || Opc == BO_EQ))) {
4241     if (Diagnose)
4242       diagnoseObjCARCConversion(*this, castRange, castType, castACTC, castExpr,
4243                                 castExpr, exprACTC, CCK);
4244     return ACR_error;
4245   }
4246   return ACR_okay;
4247 }
4248
4249 /// Given that we saw an expression with the ARCUnbridgedCastTy
4250 /// placeholder type, complain bitterly.
4251 void Sema::diagnoseARCUnbridgedCast(Expr *e) {
4252   // We expect the spurious ImplicitCastExpr to already have been stripped.
4253   assert(!e->hasPlaceholderType(BuiltinType::ARCUnbridgedCast));
4254   CastExpr *realCast = cast<CastExpr>(e->IgnoreParens());
4255
4256   SourceRange castRange;
4257   QualType castType;
4258   CheckedConversionKind CCK;
4259
4260   if (CStyleCastExpr *cast = dyn_cast<CStyleCastExpr>(realCast)) {
4261     castRange = SourceRange(cast->getLParenLoc(), cast->getRParenLoc());
4262     castType = cast->getTypeAsWritten();
4263     CCK = CCK_CStyleCast;
4264   } else if (ExplicitCastExpr *cast = dyn_cast<ExplicitCastExpr>(realCast)) {
4265     castRange = cast->getTypeInfoAsWritten()->getTypeLoc().getSourceRange();
4266     castType = cast->getTypeAsWritten();
4267     CCK = CCK_OtherCast;
4268   } else {
4269     llvm_unreachable("Unexpected ImplicitCastExpr");
4270   }
4271
4272   ARCConversionTypeClass castACTC =
4273     classifyTypeForARCConversion(castType.getNonReferenceType());
4274
4275   Expr *castExpr = realCast->getSubExpr();
4276   assert(classifyTypeForARCConversion(castExpr->getType()) == ACTC_retainable);
4277
4278   diagnoseObjCARCConversion(*this, castRange, castType, castACTC,
4279                             castExpr, realCast, ACTC_retainable, CCK);
4280 }
4281
4282 /// stripARCUnbridgedCast - Given an expression of ARCUnbridgedCast
4283 /// type, remove the placeholder cast.
4284 Expr *Sema::stripARCUnbridgedCast(Expr *e) {
4285   assert(e->hasPlaceholderType(BuiltinType::ARCUnbridgedCast));
4286
4287   if (ParenExpr *pe = dyn_cast<ParenExpr>(e)) {
4288     Expr *sub = stripARCUnbridgedCast(pe->getSubExpr());
4289     return new (Context) ParenExpr(pe->getLParen(), pe->getRParen(), sub);
4290   } else if (UnaryOperator *uo = dyn_cast<UnaryOperator>(e)) {
4291     assert(uo->getOpcode() == UO_Extension);
4292     Expr *sub = stripARCUnbridgedCast(uo->getSubExpr());
4293     return new (Context)
4294         UnaryOperator(sub, UO_Extension, sub->getType(), sub->getValueKind(),
4295                       sub->getObjectKind(), uo->getOperatorLoc(), false);
4296   } else if (GenericSelectionExpr *gse = dyn_cast<GenericSelectionExpr>(e)) {
4297     assert(!gse->isResultDependent());
4298
4299     unsigned n = gse->getNumAssocs();
4300     SmallVector<Expr*, 4> subExprs(n);
4301     SmallVector<TypeSourceInfo*, 4> subTypes(n);
4302     for (unsigned i = 0; i != n; ++i) {
4303       subTypes[i] = gse->getAssocTypeSourceInfo(i);
4304       Expr *sub = gse->getAssocExpr(i);
4305       if (i == gse->getResultIndex())
4306         sub = stripARCUnbridgedCast(sub);
4307       subExprs[i] = sub;
4308     }
4309
4310     return new (Context) GenericSelectionExpr(Context, gse->getGenericLoc(),
4311                                               gse->getControllingExpr(),
4312                                               subTypes, subExprs,
4313                                               gse->getDefaultLoc(),
4314                                               gse->getRParenLoc(),
4315                                        gse->containsUnexpandedParameterPack(),
4316                                               gse->getResultIndex());
4317   } else {
4318     assert(isa<ImplicitCastExpr>(e) && "bad form of unbridged cast!");
4319     return cast<ImplicitCastExpr>(e)->getSubExpr();
4320   }
4321 }
4322
4323 bool Sema::CheckObjCARCUnavailableWeakConversion(QualType castType,
4324                                                  QualType exprType) {
4325   QualType canCastType =
4326     Context.getCanonicalType(castType).getUnqualifiedType();
4327   QualType canExprType =
4328     Context.getCanonicalType(exprType).getUnqualifiedType();
4329   if (isa<ObjCObjectPointerType>(canCastType) &&
4330       castType.getObjCLifetime() == Qualifiers::OCL_Weak &&
4331       canExprType->isObjCObjectPointerType()) {
4332     if (const ObjCObjectPointerType *ObjT =
4333         canExprType->getAs<ObjCObjectPointerType>())
4334       if (const ObjCInterfaceDecl *ObjI = ObjT->getInterfaceDecl())
4335         return !ObjI->isArcWeakrefUnavailable();
4336   }
4337   return true;
4338 }
4339
4340 /// Look for an ObjCReclaimReturnedObject cast and destroy it.
4341 static Expr *maybeUndoReclaimObject(Expr *e) {
4342   Expr *curExpr = e, *prevExpr = nullptr;
4343
4344   // Walk down the expression until we hit an implicit cast of kind
4345   // ARCReclaimReturnedObject or an Expr that is neither a Paren nor a Cast.
4346   while (true) {
4347     if (auto *pe = dyn_cast<ParenExpr>(curExpr)) {
4348       prevExpr = curExpr;
4349       curExpr = pe->getSubExpr();
4350       continue;
4351     }
4352
4353     if (auto *ce = dyn_cast<CastExpr>(curExpr)) {
4354       if (auto *ice = dyn_cast<ImplicitCastExpr>(ce))
4355         if (ice->getCastKind() == CK_ARCReclaimReturnedObject) {
4356           if (!prevExpr)
4357             return ice->getSubExpr();
4358           if (auto *pe = dyn_cast<ParenExpr>(prevExpr))
4359             pe->setSubExpr(ice->getSubExpr());
4360           else
4361             cast<CastExpr>(prevExpr)->setSubExpr(ice->getSubExpr());
4362           return e;
4363         }
4364
4365       prevExpr = curExpr;
4366       curExpr = ce->getSubExpr();
4367       continue;
4368     }
4369
4370     // Break out of the loop if curExpr is neither a Paren nor a Cast.
4371     break;
4372   }
4373
4374   return e;
4375 }
4376
4377 ExprResult Sema::BuildObjCBridgedCast(SourceLocation LParenLoc,
4378                                       ObjCBridgeCastKind Kind,
4379                                       SourceLocation BridgeKeywordLoc,
4380                                       TypeSourceInfo *TSInfo,
4381                                       Expr *SubExpr) {
4382   ExprResult SubResult = UsualUnaryConversions(SubExpr);
4383   if (SubResult.isInvalid()) return ExprError();
4384   SubExpr = SubResult.get();
4385
4386   QualType T = TSInfo->getType();
4387   QualType FromType = SubExpr->getType();
4388
4389   CastKind CK;
4390
4391   bool MustConsume = false;
4392   if (T->isDependentType() || SubExpr->isTypeDependent()) {
4393     // Okay: we'll build a dependent expression type.
4394     CK = CK_Dependent;
4395   } else if (T->isObjCARCBridgableType() && FromType->isCARCBridgableType()) {
4396     // Casting CF -> id
4397     CK = (T->isBlockPointerType() ? CK_AnyPointerToBlockPointerCast
4398                                   : CK_CPointerToObjCPointerCast);
4399     switch (Kind) {
4400     case OBC_Bridge:
4401       break;
4402
4403     case OBC_BridgeRetained: {
4404       bool br = isKnownName("CFBridgingRelease");
4405       Diag(BridgeKeywordLoc, diag::err_arc_bridge_cast_wrong_kind)
4406         << 2
4407         << FromType
4408         << (T->isBlockPointerType()? 1 : 0)
4409         << T
4410         << SubExpr->getSourceRange()
4411         << Kind;
4412       Diag(BridgeKeywordLoc, diag::note_arc_bridge)
4413         << FixItHint::CreateReplacement(BridgeKeywordLoc, "__bridge");
4414       Diag(BridgeKeywordLoc, diag::note_arc_bridge_transfer)
4415         << FromType << br
4416         << FixItHint::CreateReplacement(BridgeKeywordLoc,
4417                                         br ? "CFBridgingRelease "
4418                                            : "__bridge_transfer ");
4419
4420       Kind = OBC_Bridge;
4421       break;
4422     }
4423
4424     case OBC_BridgeTransfer:
4425       // We must consume the Objective-C object produced by the cast.
4426       MustConsume = true;
4427       break;
4428     }
4429   } else if (T->isCARCBridgableType() && FromType->isObjCARCBridgableType()) {
4430     // Okay: id -> CF
4431     CK = CK_BitCast;
4432     switch (Kind) {
4433     case OBC_Bridge:
4434       // Reclaiming a value that's going to be __bridge-casted to CF
4435       // is very dangerous, so we don't do it.
4436       SubExpr = maybeUndoReclaimObject(SubExpr);
4437       break;
4438
4439     case OBC_BridgeRetained:
4440       // Produce the object before casting it.
4441       SubExpr = ImplicitCastExpr::Create(Context, FromType,
4442                                          CK_ARCProduceObject,
4443                                          SubExpr, nullptr, VK_RValue);
4444       break;
4445
4446     case OBC_BridgeTransfer: {
4447       bool br = isKnownName("CFBridgingRetain");
4448       Diag(BridgeKeywordLoc, diag::err_arc_bridge_cast_wrong_kind)
4449         << (FromType->isBlockPointerType()? 1 : 0)
4450         << FromType
4451         << 2
4452         << T
4453         << SubExpr->getSourceRange()
4454         << Kind;
4455
4456       Diag(BridgeKeywordLoc, diag::note_arc_bridge)
4457         << FixItHint::CreateReplacement(BridgeKeywordLoc, "__bridge ");
4458       Diag(BridgeKeywordLoc, diag::note_arc_bridge_retained)
4459         << T << br
4460         << FixItHint::CreateReplacement(BridgeKeywordLoc,
4461                           br ? "CFBridgingRetain " : "__bridge_retained");
4462
4463       Kind = OBC_Bridge;
4464       break;
4465     }
4466     }
4467   } else {
4468     Diag(LParenLoc, diag::err_arc_bridge_cast_incompatible)
4469       << FromType << T << Kind
4470       << SubExpr->getSourceRange()
4471       << TSInfo->getTypeLoc().getSourceRange();
4472     return ExprError();
4473   }
4474
4475   Expr *Result = new (Context) ObjCBridgedCastExpr(LParenLoc, Kind, CK,
4476                                                    BridgeKeywordLoc,
4477                                                    TSInfo, SubExpr);
4478
4479   if (MustConsume) {
4480     Cleanup.setExprNeedsCleanups(true);
4481     Result = ImplicitCastExpr::Create(Context, T, CK_ARCConsumeObject, Result,
4482                                       nullptr, VK_RValue);
4483   }
4484
4485   return Result;
4486 }
4487
4488 ExprResult Sema::ActOnObjCBridgedCast(Scope *S,
4489                                       SourceLocation LParenLoc,
4490                                       ObjCBridgeCastKind Kind,
4491                                       SourceLocation BridgeKeywordLoc,
4492                                       ParsedType Type,
4493                                       SourceLocation RParenLoc,
4494                                       Expr *SubExpr) {
4495   TypeSourceInfo *TSInfo = nullptr;
4496   QualType T = GetTypeFromParser(Type, &TSInfo);
4497   if (Kind == OBC_Bridge)
4498     CheckTollFreeBridgeCast(T, SubExpr);
4499   if (!TSInfo)
4500     TSInfo = Context.getTrivialTypeSourceInfo(T, LParenLoc);
4501   return BuildObjCBridgedCast(LParenLoc, Kind, BridgeKeywordLoc, TSInfo,
4502                               SubExpr);
4503 }