xref: /freebsd/contrib/llvm-project/clang/lib/Sema/SemaExprObjC.cpp (revision 77013d11e6483b970af25e13c9b892075742f7e5)
1 //===--- SemaExprObjC.cpp - Semantic Analysis for ObjC Expressions --------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 //  This file implements semantic analysis for Objective-C expressions.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "clang/AST/ASTContext.h"
14 #include "clang/AST/DeclObjC.h"
15 #include "clang/AST/ExprObjC.h"
16 #include "clang/AST/StmtVisitor.h"
17 #include "clang/AST/TypeLoc.h"
18 #include "clang/Analysis/DomainSpecific/CocoaConventions.h"
19 #include "clang/Basic/Builtins.h"
20 #include "clang/Edit/Commit.h"
21 #include "clang/Edit/Rewriters.h"
22 #include "clang/Lex/Preprocessor.h"
23 #include "clang/Sema/Initialization.h"
24 #include "clang/Sema/Lookup.h"
25 #include "clang/Sema/Scope.h"
26 #include "clang/Sema/ScopeInfo.h"
27 #include "clang/Sema/SemaInternal.h"
28 #include "llvm/ADT/SmallString.h"
29 #include "llvm/Support/ConvertUTF.h"
30 
31 using namespace clang;
32 using namespace sema;
33 using llvm::makeArrayRef;
34 
35 ExprResult Sema::ParseObjCStringLiteral(SourceLocation *AtLocs,
36                                         ArrayRef<Expr *> Strings) {
37   // Most ObjC strings are formed out of a single piece.  However, we *can*
38   // have strings formed out of multiple @ strings with multiple pptokens in
39   // each one, e.g. @"foo" "bar" @"baz" "qux"   which need to be turned into one
40   // StringLiteral for ObjCStringLiteral to hold onto.
41   StringLiteral *S = cast<StringLiteral>(Strings[0]);
42 
43   // If we have a multi-part string, merge it all together.
44   if (Strings.size() != 1) {
45     // Concatenate objc strings.
46     SmallString<128> StrBuf;
47     SmallVector<SourceLocation, 8> StrLocs;
48 
49     for (Expr *E : Strings) {
50       S = cast<StringLiteral>(E);
51 
52       // ObjC strings can't be wide or UTF.
53       if (!S->isAscii()) {
54         Diag(S->getBeginLoc(), diag::err_cfstring_literal_not_string_constant)
55             << S->getSourceRange();
56         return true;
57       }
58 
59       // Append the string.
60       StrBuf += S->getString();
61 
62       // Get the locations of the string tokens.
63       StrLocs.append(S->tokloc_begin(), S->tokloc_end());
64     }
65 
66     // Create the aggregate string with the appropriate content and location
67     // information.
68     const ConstantArrayType *CAT = Context.getAsConstantArrayType(S->getType());
69     assert(CAT && "String literal not of constant array type!");
70     QualType StrTy = Context.getConstantArrayType(
71         CAT->getElementType(), llvm::APInt(32, StrBuf.size() + 1), nullptr,
72         CAT->getSizeModifier(), CAT->getIndexTypeCVRQualifiers());
73     S = StringLiteral::Create(Context, StrBuf, StringLiteral::Ascii,
74                               /*Pascal=*/false, StrTy, &StrLocs[0],
75                               StrLocs.size());
76   }
77 
78   return BuildObjCStringLiteral(AtLocs[0], S);
79 }
80 
81 ExprResult Sema::BuildObjCStringLiteral(SourceLocation AtLoc, StringLiteral *S){
82   // Verify that this composite string is acceptable for ObjC strings.
83   if (CheckObjCString(S))
84     return true;
85 
86   // Initialize the constant string interface lazily. This assumes
87   // the NSString interface is seen in this translation unit. Note: We
88   // don't use NSConstantString, since the runtime team considers this
89   // interface private (even though it appears in the header files).
90   QualType Ty = Context.getObjCConstantStringInterface();
91   if (!Ty.isNull()) {
92     Ty = Context.getObjCObjectPointerType(Ty);
93   } else if (getLangOpts().NoConstantCFStrings) {
94     IdentifierInfo *NSIdent=nullptr;
95     std::string StringClass(getLangOpts().ObjCConstantStringClass);
96 
97     if (StringClass.empty())
98       NSIdent = &Context.Idents.get("NSConstantString");
99     else
100       NSIdent = &Context.Idents.get(StringClass);
101 
102     NamedDecl *IF = LookupSingleName(TUScope, NSIdent, AtLoc,
103                                      LookupOrdinaryName);
104     if (ObjCInterfaceDecl *StrIF = dyn_cast_or_null<ObjCInterfaceDecl>(IF)) {
105       Context.setObjCConstantStringInterface(StrIF);
106       Ty = Context.getObjCConstantStringInterface();
107       Ty = Context.getObjCObjectPointerType(Ty);
108     } else {
109       // If there is no NSConstantString interface defined then treat this
110       // as error and recover from it.
111       Diag(S->getBeginLoc(), diag::err_no_nsconstant_string_class)
112           << NSIdent << S->getSourceRange();
113       Ty = Context.getObjCIdType();
114     }
115   } else {
116     IdentifierInfo *NSIdent = NSAPIObj->getNSClassId(NSAPI::ClassId_NSString);
117     NamedDecl *IF = LookupSingleName(TUScope, NSIdent, AtLoc,
118                                      LookupOrdinaryName);
119     if (ObjCInterfaceDecl *StrIF = dyn_cast_or_null<ObjCInterfaceDecl>(IF)) {
120       Context.setObjCConstantStringInterface(StrIF);
121       Ty = Context.getObjCConstantStringInterface();
122       Ty = Context.getObjCObjectPointerType(Ty);
123     } else {
124       // If there is no NSString interface defined, implicitly declare
125       // a @class NSString; and use that instead. This is to make sure
126       // type of an NSString literal is represented correctly, instead of
127       // being an 'id' type.
128       Ty = Context.getObjCNSStringType();
129       if (Ty.isNull()) {
130         ObjCInterfaceDecl *NSStringIDecl =
131           ObjCInterfaceDecl::Create (Context,
132                                      Context.getTranslationUnitDecl(),
133                                      SourceLocation(), NSIdent,
134                                      nullptr, nullptr, SourceLocation());
135         Ty = Context.getObjCInterfaceType(NSStringIDecl);
136         Context.setObjCNSStringType(Ty);
137       }
138       Ty = Context.getObjCObjectPointerType(Ty);
139     }
140   }
141 
142   return new (Context) ObjCStringLiteral(S, Ty, AtLoc);
143 }
144 
145 /// Emits an error if the given method does not exist, or if the return
146 /// type is not an Objective-C object.
147 static bool validateBoxingMethod(Sema &S, SourceLocation Loc,
148                                  const ObjCInterfaceDecl *Class,
149                                  Selector Sel, const ObjCMethodDecl *Method) {
150   if (!Method) {
151     // FIXME: Is there a better way to avoid quotes than using getName()?
152     S.Diag(Loc, diag::err_undeclared_boxing_method) << Sel << Class->getName();
153     return false;
154   }
155 
156   // Make sure the return type is reasonable.
157   QualType ReturnType = Method->getReturnType();
158   if (!ReturnType->isObjCObjectPointerType()) {
159     S.Diag(Loc, diag::err_objc_literal_method_sig)
160       << Sel;
161     S.Diag(Method->getLocation(), diag::note_objc_literal_method_return)
162       << ReturnType;
163     return false;
164   }
165 
166   return true;
167 }
168 
169 /// Maps ObjCLiteralKind to NSClassIdKindKind
170 static NSAPI::NSClassIdKindKind ClassKindFromLiteralKind(
171                                             Sema::ObjCLiteralKind LiteralKind) {
172   switch (LiteralKind) {
173     case Sema::LK_Array:
174       return NSAPI::ClassId_NSArray;
175     case Sema::LK_Dictionary:
176       return NSAPI::ClassId_NSDictionary;
177     case Sema::LK_Numeric:
178       return NSAPI::ClassId_NSNumber;
179     case Sema::LK_String:
180       return NSAPI::ClassId_NSString;
181     case Sema::LK_Boxed:
182       return NSAPI::ClassId_NSValue;
183 
184     // there is no corresponding matching
185     // between LK_None/LK_Block and NSClassIdKindKind
186     case Sema::LK_Block:
187     case Sema::LK_None:
188       break;
189   }
190   llvm_unreachable("LiteralKind can't be converted into a ClassKind");
191 }
192 
193 /// Validates ObjCInterfaceDecl availability.
194 /// ObjCInterfaceDecl, used to create ObjC literals, should be defined
195 /// if clang not in a debugger mode.
196 static bool ValidateObjCLiteralInterfaceDecl(Sema &S, ObjCInterfaceDecl *Decl,
197                                             SourceLocation Loc,
198                                             Sema::ObjCLiteralKind LiteralKind) {
199   if (!Decl) {
200     NSAPI::NSClassIdKindKind Kind = ClassKindFromLiteralKind(LiteralKind);
201     IdentifierInfo *II = S.NSAPIObj->getNSClassId(Kind);
202     S.Diag(Loc, diag::err_undeclared_objc_literal_class)
203       << II->getName() << LiteralKind;
204     return false;
205   } else if (!Decl->hasDefinition() && !S.getLangOpts().DebuggerObjCLiteral) {
206     S.Diag(Loc, diag::err_undeclared_objc_literal_class)
207       << Decl->getName() << LiteralKind;
208     S.Diag(Decl->getLocation(), diag::note_forward_class);
209     return false;
210   }
211 
212   return true;
213 }
214 
215 /// Looks up ObjCInterfaceDecl of a given NSClassIdKindKind.
216 /// Used to create ObjC literals, such as NSDictionary (@{}),
217 /// NSArray (@[]) and Boxed Expressions (@())
218 static ObjCInterfaceDecl *LookupObjCInterfaceDeclForLiteral(Sema &S,
219                                             SourceLocation Loc,
220                                             Sema::ObjCLiteralKind LiteralKind) {
221   NSAPI::NSClassIdKindKind ClassKind = ClassKindFromLiteralKind(LiteralKind);
222   IdentifierInfo *II = S.NSAPIObj->getNSClassId(ClassKind);
223   NamedDecl *IF = S.LookupSingleName(S.TUScope, II, Loc,
224                                      Sema::LookupOrdinaryName);
225   ObjCInterfaceDecl *ID = dyn_cast_or_null<ObjCInterfaceDecl>(IF);
226   if (!ID && S.getLangOpts().DebuggerObjCLiteral) {
227     ASTContext &Context = S.Context;
228     TranslationUnitDecl *TU = Context.getTranslationUnitDecl();
229     ID = ObjCInterfaceDecl::Create (Context, TU, SourceLocation(), II,
230                                     nullptr, nullptr, SourceLocation());
231   }
232 
233   if (!ValidateObjCLiteralInterfaceDecl(S, ID, Loc, LiteralKind)) {
234     ID = nullptr;
235   }
236 
237   return ID;
238 }
239 
240 /// Retrieve the NSNumber factory method that should be used to create
241 /// an Objective-C literal for the given type.
242 static ObjCMethodDecl *getNSNumberFactoryMethod(Sema &S, SourceLocation Loc,
243                                                 QualType NumberType,
244                                                 bool isLiteral = false,
245                                                 SourceRange R = SourceRange()) {
246   Optional<NSAPI::NSNumberLiteralMethodKind> Kind =
247       S.NSAPIObj->getNSNumberFactoryMethodKind(NumberType);
248 
249   if (!Kind) {
250     if (isLiteral) {
251       S.Diag(Loc, diag::err_invalid_nsnumber_type)
252         << NumberType << R;
253     }
254     return nullptr;
255   }
256 
257   // If we already looked up this method, we're done.
258   if (S.NSNumberLiteralMethods[*Kind])
259     return S.NSNumberLiteralMethods[*Kind];
260 
261   Selector Sel = S.NSAPIObj->getNSNumberLiteralSelector(*Kind,
262                                                         /*Instance=*/false);
263 
264   ASTContext &CX = S.Context;
265 
266   // Look up the NSNumber class, if we haven't done so already. It's cached
267   // in the Sema instance.
268   if (!S.NSNumberDecl) {
269     S.NSNumberDecl = LookupObjCInterfaceDeclForLiteral(S, Loc,
270                                                        Sema::LK_Numeric);
271     if (!S.NSNumberDecl) {
272       return nullptr;
273     }
274   }
275 
276   if (S.NSNumberPointer.isNull()) {
277     // generate the pointer to NSNumber type.
278     QualType NSNumberObject = CX.getObjCInterfaceType(S.NSNumberDecl);
279     S.NSNumberPointer = CX.getObjCObjectPointerType(NSNumberObject);
280   }
281 
282   // Look for the appropriate method within NSNumber.
283   ObjCMethodDecl *Method = S.NSNumberDecl->lookupClassMethod(Sel);
284   if (!Method && S.getLangOpts().DebuggerObjCLiteral) {
285     // create a stub definition this NSNumber factory method.
286     TypeSourceInfo *ReturnTInfo = nullptr;
287     Method =
288         ObjCMethodDecl::Create(CX, SourceLocation(), SourceLocation(), Sel,
289                                S.NSNumberPointer, ReturnTInfo, S.NSNumberDecl,
290                                /*isInstance=*/false, /*isVariadic=*/false,
291                                /*isPropertyAccessor=*/false,
292                                /*isSynthesizedAccessorStub=*/false,
293                                /*isImplicitlyDeclared=*/true,
294                                /*isDefined=*/false, ObjCMethodDecl::Required,
295                                /*HasRelatedResultType=*/false);
296     ParmVarDecl *value = ParmVarDecl::Create(S.Context, Method,
297                                              SourceLocation(), SourceLocation(),
298                                              &CX.Idents.get("value"),
299                                              NumberType, /*TInfo=*/nullptr,
300                                              SC_None, nullptr);
301     Method->setMethodParams(S.Context, value, None);
302   }
303 
304   if (!validateBoxingMethod(S, Loc, S.NSNumberDecl, Sel, Method))
305     return nullptr;
306 
307   // Note: if the parameter type is out-of-line, we'll catch it later in the
308   // implicit conversion.
309 
310   S.NSNumberLiteralMethods[*Kind] = Method;
311   return Method;
312 }
313 
314 /// BuildObjCNumericLiteral - builds an ObjCBoxedExpr AST node for the
315 /// numeric literal expression. Type of the expression will be "NSNumber *".
316 ExprResult Sema::BuildObjCNumericLiteral(SourceLocation AtLoc, Expr *Number) {
317   // Determine the type of the literal.
318   QualType NumberType = Number->getType();
319   if (CharacterLiteral *Char = dyn_cast<CharacterLiteral>(Number)) {
320     // In C, character literals have type 'int'. That's not the type we want
321     // to use to determine the Objective-c literal kind.
322     switch (Char->getKind()) {
323     case CharacterLiteral::Ascii:
324     case CharacterLiteral::UTF8:
325       NumberType = Context.CharTy;
326       break;
327 
328     case CharacterLiteral::Wide:
329       NumberType = Context.getWideCharType();
330       break;
331 
332     case CharacterLiteral::UTF16:
333       NumberType = Context.Char16Ty;
334       break;
335 
336     case CharacterLiteral::UTF32:
337       NumberType = Context.Char32Ty;
338       break;
339     }
340   }
341 
342   // Look for the appropriate method within NSNumber.
343   // Construct the literal.
344   SourceRange NR(Number->getSourceRange());
345   ObjCMethodDecl *Method = getNSNumberFactoryMethod(*this, AtLoc, NumberType,
346                                                     true, NR);
347   if (!Method)
348     return ExprError();
349 
350   // Convert the number to the type that the parameter expects.
351   ParmVarDecl *ParamDecl = Method->parameters()[0];
352   InitializedEntity Entity = InitializedEntity::InitializeParameter(Context,
353                                                                     ParamDecl);
354   ExprResult ConvertedNumber = PerformCopyInitialization(Entity,
355                                                          SourceLocation(),
356                                                          Number);
357   if (ConvertedNumber.isInvalid())
358     return ExprError();
359   Number = ConvertedNumber.get();
360 
361   // Use the effective source range of the literal, including the leading '@'.
362   return MaybeBindToTemporary(
363            new (Context) ObjCBoxedExpr(Number, NSNumberPointer, Method,
364                                        SourceRange(AtLoc, NR.getEnd())));
365 }
366 
367 ExprResult Sema::ActOnObjCBoolLiteral(SourceLocation AtLoc,
368                                       SourceLocation ValueLoc,
369                                       bool Value) {
370   ExprResult Inner;
371   if (getLangOpts().CPlusPlus) {
372     Inner = ActOnCXXBoolLiteral(ValueLoc, Value? tok::kw_true : tok::kw_false);
373   } else {
374     // C doesn't actually have a way to represent literal values of type
375     // _Bool. So, we'll use 0/1 and implicit cast to _Bool.
376     Inner = ActOnIntegerConstant(ValueLoc, Value? 1 : 0);
377     Inner = ImpCastExprToType(Inner.get(), Context.BoolTy,
378                               CK_IntegralToBoolean);
379   }
380 
381   return BuildObjCNumericLiteral(AtLoc, Inner.get());
382 }
383 
384 /// Check that the given expression is a valid element of an Objective-C
385 /// collection literal.
386 static ExprResult CheckObjCCollectionLiteralElement(Sema &S, Expr *Element,
387                                                     QualType T,
388                                                     bool ArrayLiteral = false) {
389   // If the expression is type-dependent, there's nothing for us to do.
390   if (Element->isTypeDependent())
391     return Element;
392 
393   ExprResult Result = S.CheckPlaceholderExpr(Element);
394   if (Result.isInvalid())
395     return ExprError();
396   Element = Result.get();
397 
398   // In C++, check for an implicit conversion to an Objective-C object pointer
399   // type.
400   if (S.getLangOpts().CPlusPlus && Element->getType()->isRecordType()) {
401     InitializedEntity Entity
402       = InitializedEntity::InitializeParameter(S.Context, T,
403                                                /*Consumed=*/false);
404     InitializationKind Kind = InitializationKind::CreateCopy(
405         Element->getBeginLoc(), SourceLocation());
406     InitializationSequence Seq(S, Entity, Kind, Element);
407     if (!Seq.Failed())
408       return Seq.Perform(S, Entity, Kind, Element);
409   }
410 
411   Expr *OrigElement = Element;
412 
413   // Perform lvalue-to-rvalue conversion.
414   Result = S.DefaultLvalueConversion(Element);
415   if (Result.isInvalid())
416     return ExprError();
417   Element = Result.get();
418 
419   // Make sure that we have an Objective-C pointer type or block.
420   if (!Element->getType()->isObjCObjectPointerType() &&
421       !Element->getType()->isBlockPointerType()) {
422     bool Recovered = false;
423 
424     // If this is potentially an Objective-C numeric literal, add the '@'.
425     if (isa<IntegerLiteral>(OrigElement) ||
426         isa<CharacterLiteral>(OrigElement) ||
427         isa<FloatingLiteral>(OrigElement) ||
428         isa<ObjCBoolLiteralExpr>(OrigElement) ||
429         isa<CXXBoolLiteralExpr>(OrigElement)) {
430       if (S.NSAPIObj->getNSNumberFactoryMethodKind(OrigElement->getType())) {
431         int Which = isa<CharacterLiteral>(OrigElement) ? 1
432                   : (isa<CXXBoolLiteralExpr>(OrigElement) ||
433                      isa<ObjCBoolLiteralExpr>(OrigElement)) ? 2
434                   : 3;
435 
436         S.Diag(OrigElement->getBeginLoc(), diag::err_box_literal_collection)
437             << Which << OrigElement->getSourceRange()
438             << FixItHint::CreateInsertion(OrigElement->getBeginLoc(), "@");
439 
440         Result =
441             S.BuildObjCNumericLiteral(OrigElement->getBeginLoc(), OrigElement);
442         if (Result.isInvalid())
443           return ExprError();
444 
445         Element = Result.get();
446         Recovered = true;
447       }
448     }
449     // If this is potentially an Objective-C string literal, add the '@'.
450     else if (StringLiteral *String = dyn_cast<StringLiteral>(OrigElement)) {
451       if (String->isAscii()) {
452         S.Diag(OrigElement->getBeginLoc(), diag::err_box_literal_collection)
453             << 0 << OrigElement->getSourceRange()
454             << FixItHint::CreateInsertion(OrigElement->getBeginLoc(), "@");
455 
456         Result = S.BuildObjCStringLiteral(OrigElement->getBeginLoc(), String);
457         if (Result.isInvalid())
458           return ExprError();
459 
460         Element = Result.get();
461         Recovered = true;
462       }
463     }
464 
465     if (!Recovered) {
466       S.Diag(Element->getBeginLoc(), diag::err_invalid_collection_element)
467           << Element->getType();
468       return ExprError();
469     }
470   }
471   if (ArrayLiteral)
472     if (ObjCStringLiteral *getString =
473           dyn_cast<ObjCStringLiteral>(OrigElement)) {
474       if (StringLiteral *SL = getString->getString()) {
475         unsigned numConcat = SL->getNumConcatenated();
476         if (numConcat > 1) {
477           // Only warn if the concatenated string doesn't come from a macro.
478           bool hasMacro = false;
479           for (unsigned i = 0; i < numConcat ; ++i)
480             if (SL->getStrTokenLoc(i).isMacroID()) {
481               hasMacro = true;
482               break;
483             }
484           if (!hasMacro)
485             S.Diag(Element->getBeginLoc(),
486                    diag::warn_concatenated_nsarray_literal)
487                 << Element->getType();
488         }
489       }
490     }
491 
492   // Make sure that the element has the type that the container factory
493   // function expects.
494   return S.PerformCopyInitialization(
495       InitializedEntity::InitializeParameter(S.Context, T,
496                                              /*Consumed=*/false),
497       Element->getBeginLoc(), Element);
498 }
499 
500 ExprResult Sema::BuildObjCBoxedExpr(SourceRange SR, Expr *ValueExpr) {
501   if (ValueExpr->isTypeDependent()) {
502     ObjCBoxedExpr *BoxedExpr =
503       new (Context) ObjCBoxedExpr(ValueExpr, Context.DependentTy, nullptr, SR);
504     return BoxedExpr;
505   }
506   ObjCMethodDecl *BoxingMethod = nullptr;
507   QualType BoxedType;
508   // Convert the expression to an RValue, so we can check for pointer types...
509   ExprResult RValue = DefaultFunctionArrayLvalueConversion(ValueExpr);
510   if (RValue.isInvalid()) {
511     return ExprError();
512   }
513   SourceLocation Loc = SR.getBegin();
514   ValueExpr = RValue.get();
515   QualType ValueType(ValueExpr->getType());
516   if (const PointerType *PT = ValueType->getAs<PointerType>()) {
517     QualType PointeeType = PT->getPointeeType();
518     if (Context.hasSameUnqualifiedType(PointeeType, Context.CharTy)) {
519 
520       if (!NSStringDecl) {
521         NSStringDecl = LookupObjCInterfaceDeclForLiteral(*this, Loc,
522                                                          Sema::LK_String);
523         if (!NSStringDecl) {
524           return ExprError();
525         }
526         QualType NSStringObject = Context.getObjCInterfaceType(NSStringDecl);
527         NSStringPointer = Context.getObjCObjectPointerType(NSStringObject);
528       }
529 
530       // The boxed expression can be emitted as a compile time constant if it is
531       // a string literal whose character encoding is compatible with UTF-8.
532       if (auto *CE = dyn_cast<ImplicitCastExpr>(ValueExpr))
533         if (CE->getCastKind() == CK_ArrayToPointerDecay)
534           if (auto *SL =
535                   dyn_cast<StringLiteral>(CE->getSubExpr()->IgnoreParens())) {
536             assert((SL->isAscii() || SL->isUTF8()) &&
537                    "unexpected character encoding");
538             StringRef Str = SL->getString();
539             const llvm::UTF8 *StrBegin = Str.bytes_begin();
540             const llvm::UTF8 *StrEnd = Str.bytes_end();
541             // Check that this is a valid UTF-8 string.
542             if (llvm::isLegalUTF8String(&StrBegin, StrEnd)) {
543               BoxedType = Context.getAttributedType(
544                   AttributedType::getNullabilityAttrKind(
545                       NullabilityKind::NonNull),
546                   NSStringPointer, NSStringPointer);
547               return new (Context) ObjCBoxedExpr(CE, BoxedType, nullptr, SR);
548             }
549 
550             Diag(SL->getBeginLoc(), diag::warn_objc_boxing_invalid_utf8_string)
551                 << NSStringPointer << SL->getSourceRange();
552           }
553 
554       if (!StringWithUTF8StringMethod) {
555         IdentifierInfo *II = &Context.Idents.get("stringWithUTF8String");
556         Selector stringWithUTF8String = Context.Selectors.getUnarySelector(II);
557 
558         // Look for the appropriate method within NSString.
559         BoxingMethod = NSStringDecl->lookupClassMethod(stringWithUTF8String);
560         if (!BoxingMethod && getLangOpts().DebuggerObjCLiteral) {
561           // Debugger needs to work even if NSString hasn't been defined.
562           TypeSourceInfo *ReturnTInfo = nullptr;
563           ObjCMethodDecl *M = ObjCMethodDecl::Create(
564               Context, SourceLocation(), SourceLocation(), stringWithUTF8String,
565               NSStringPointer, ReturnTInfo, NSStringDecl,
566               /*isInstance=*/false, /*isVariadic=*/false,
567               /*isPropertyAccessor=*/false,
568               /*isSynthesizedAccessorStub=*/false,
569               /*isImplicitlyDeclared=*/true,
570               /*isDefined=*/false, ObjCMethodDecl::Required,
571               /*HasRelatedResultType=*/false);
572           QualType ConstCharType = Context.CharTy.withConst();
573           ParmVarDecl *value =
574             ParmVarDecl::Create(Context, M,
575                                 SourceLocation(), SourceLocation(),
576                                 &Context.Idents.get("value"),
577                                 Context.getPointerType(ConstCharType),
578                                 /*TInfo=*/nullptr,
579                                 SC_None, nullptr);
580           M->setMethodParams(Context, value, None);
581           BoxingMethod = M;
582         }
583 
584         if (!validateBoxingMethod(*this, Loc, NSStringDecl,
585                                   stringWithUTF8String, BoxingMethod))
586            return ExprError();
587 
588         StringWithUTF8StringMethod = BoxingMethod;
589       }
590 
591       BoxingMethod = StringWithUTF8StringMethod;
592       BoxedType = NSStringPointer;
593       // Transfer the nullability from method's return type.
594       Optional<NullabilityKind> Nullability =
595           BoxingMethod->getReturnType()->getNullability(Context);
596       if (Nullability)
597         BoxedType = Context.getAttributedType(
598             AttributedType::getNullabilityAttrKind(*Nullability), BoxedType,
599             BoxedType);
600     }
601   } else if (ValueType->isBuiltinType()) {
602     // The other types we support are numeric, char and BOOL/bool. We could also
603     // provide limited support for structure types, such as NSRange, NSRect, and
604     // NSSize. See NSValue (NSValueGeometryExtensions) in <Foundation/NSGeometry.h>
605     // for more details.
606 
607     // Check for a top-level character literal.
608     if (const CharacterLiteral *Char =
609         dyn_cast<CharacterLiteral>(ValueExpr->IgnoreParens())) {
610       // In C, character literals have type 'int'. That's not the type we want
611       // to use to determine the Objective-c literal kind.
612       switch (Char->getKind()) {
613       case CharacterLiteral::Ascii:
614       case CharacterLiteral::UTF8:
615         ValueType = Context.CharTy;
616         break;
617 
618       case CharacterLiteral::Wide:
619         ValueType = Context.getWideCharType();
620         break;
621 
622       case CharacterLiteral::UTF16:
623         ValueType = Context.Char16Ty;
624         break;
625 
626       case CharacterLiteral::UTF32:
627         ValueType = Context.Char32Ty;
628         break;
629       }
630     }
631     // FIXME:  Do I need to do anything special with BoolTy expressions?
632 
633     // Look for the appropriate method within NSNumber.
634     BoxingMethod = getNSNumberFactoryMethod(*this, Loc, ValueType);
635     BoxedType = NSNumberPointer;
636   } else if (const EnumType *ET = ValueType->getAs<EnumType>()) {
637     if (!ET->getDecl()->isComplete()) {
638       Diag(Loc, diag::err_objc_incomplete_boxed_expression_type)
639         << ValueType << ValueExpr->getSourceRange();
640       return ExprError();
641     }
642 
643     BoxingMethod = getNSNumberFactoryMethod(*this, Loc,
644                                             ET->getDecl()->getIntegerType());
645     BoxedType = NSNumberPointer;
646   } else if (ValueType->isObjCBoxableRecordType()) {
647     // Support for structure types, that marked as objc_boxable
648     // struct __attribute__((objc_boxable)) s { ... };
649 
650     // Look up the NSValue class, if we haven't done so already. It's cached
651     // in the Sema instance.
652     if (!NSValueDecl) {
653       NSValueDecl = LookupObjCInterfaceDeclForLiteral(*this, Loc,
654                                                       Sema::LK_Boxed);
655       if (!NSValueDecl) {
656         return ExprError();
657       }
658 
659       // generate the pointer to NSValue type.
660       QualType NSValueObject = Context.getObjCInterfaceType(NSValueDecl);
661       NSValuePointer = Context.getObjCObjectPointerType(NSValueObject);
662     }
663 
664     if (!ValueWithBytesObjCTypeMethod) {
665       IdentifierInfo *II[] = {
666         &Context.Idents.get("valueWithBytes"),
667         &Context.Idents.get("objCType")
668       };
669       Selector ValueWithBytesObjCType = Context.Selectors.getSelector(2, II);
670 
671       // Look for the appropriate method within NSValue.
672       BoxingMethod = NSValueDecl->lookupClassMethod(ValueWithBytesObjCType);
673       if (!BoxingMethod && getLangOpts().DebuggerObjCLiteral) {
674         // Debugger needs to work even if NSValue hasn't been defined.
675         TypeSourceInfo *ReturnTInfo = nullptr;
676         ObjCMethodDecl *M = ObjCMethodDecl::Create(
677             Context, SourceLocation(), SourceLocation(), ValueWithBytesObjCType,
678             NSValuePointer, ReturnTInfo, NSValueDecl,
679             /*isInstance=*/false,
680             /*isVariadic=*/false,
681             /*isPropertyAccessor=*/false,
682             /*isSynthesizedAccessorStub=*/false,
683             /*isImplicitlyDeclared=*/true,
684             /*isDefined=*/false, ObjCMethodDecl::Required,
685             /*HasRelatedResultType=*/false);
686 
687         SmallVector<ParmVarDecl *, 2> Params;
688 
689         ParmVarDecl *bytes =
690         ParmVarDecl::Create(Context, M,
691                             SourceLocation(), SourceLocation(),
692                             &Context.Idents.get("bytes"),
693                             Context.VoidPtrTy.withConst(),
694                             /*TInfo=*/nullptr,
695                             SC_None, nullptr);
696         Params.push_back(bytes);
697 
698         QualType ConstCharType = Context.CharTy.withConst();
699         ParmVarDecl *type =
700         ParmVarDecl::Create(Context, M,
701                             SourceLocation(), SourceLocation(),
702                             &Context.Idents.get("type"),
703                             Context.getPointerType(ConstCharType),
704                             /*TInfo=*/nullptr,
705                             SC_None, nullptr);
706         Params.push_back(type);
707 
708         M->setMethodParams(Context, Params, None);
709         BoxingMethod = M;
710       }
711 
712       if (!validateBoxingMethod(*this, Loc, NSValueDecl,
713                                 ValueWithBytesObjCType, BoxingMethod))
714         return ExprError();
715 
716       ValueWithBytesObjCTypeMethod = BoxingMethod;
717     }
718 
719     if (!ValueType.isTriviallyCopyableType(Context)) {
720       Diag(Loc, diag::err_objc_non_trivially_copyable_boxed_expression_type)
721         << ValueType << ValueExpr->getSourceRange();
722       return ExprError();
723     }
724 
725     BoxingMethod = ValueWithBytesObjCTypeMethod;
726     BoxedType = NSValuePointer;
727   }
728 
729   if (!BoxingMethod) {
730     Diag(Loc, diag::err_objc_illegal_boxed_expression_type)
731       << ValueType << ValueExpr->getSourceRange();
732     return ExprError();
733   }
734 
735   DiagnoseUseOfDecl(BoxingMethod, Loc);
736 
737   ExprResult ConvertedValueExpr;
738   if (ValueType->isObjCBoxableRecordType()) {
739     InitializedEntity IE = InitializedEntity::InitializeTemporary(ValueType);
740     ConvertedValueExpr = PerformCopyInitialization(IE, ValueExpr->getExprLoc(),
741                                                    ValueExpr);
742   } else {
743     // Convert the expression to the type that the parameter requires.
744     ParmVarDecl *ParamDecl = BoxingMethod->parameters()[0];
745     InitializedEntity IE = InitializedEntity::InitializeParameter(Context,
746                                                                   ParamDecl);
747     ConvertedValueExpr = PerformCopyInitialization(IE, SourceLocation(),
748                                                    ValueExpr);
749   }
750 
751   if (ConvertedValueExpr.isInvalid())
752     return ExprError();
753   ValueExpr = ConvertedValueExpr.get();
754 
755   ObjCBoxedExpr *BoxedExpr =
756     new (Context) ObjCBoxedExpr(ValueExpr, BoxedType,
757                                       BoxingMethod, SR);
758   return MaybeBindToTemporary(BoxedExpr);
759 }
760 
761 /// Build an ObjC subscript pseudo-object expression, given that
762 /// that's supported by the runtime.
763 ExprResult Sema::BuildObjCSubscriptExpression(SourceLocation RB, Expr *BaseExpr,
764                                         Expr *IndexExpr,
765                                         ObjCMethodDecl *getterMethod,
766                                         ObjCMethodDecl *setterMethod) {
767   assert(!LangOpts.isSubscriptPointerArithmetic());
768 
769   // We can't get dependent types here; our callers should have
770   // filtered them out.
771   assert((!BaseExpr->isTypeDependent() && !IndexExpr->isTypeDependent()) &&
772          "base or index cannot have dependent type here");
773 
774   // Filter out placeholders in the index.  In theory, overloads could
775   // be preserved here, although that might not actually work correctly.
776   ExprResult Result = CheckPlaceholderExpr(IndexExpr);
777   if (Result.isInvalid())
778     return ExprError();
779   IndexExpr = Result.get();
780 
781   // Perform lvalue-to-rvalue conversion on the base.
782   Result = DefaultLvalueConversion(BaseExpr);
783   if (Result.isInvalid())
784     return ExprError();
785   BaseExpr = Result.get();
786 
787   // Build the pseudo-object expression.
788   return new (Context) ObjCSubscriptRefExpr(
789       BaseExpr, IndexExpr, Context.PseudoObjectTy, VK_LValue, OK_ObjCSubscript,
790       getterMethod, setterMethod, RB);
791 }
792 
793 ExprResult Sema::BuildObjCArrayLiteral(SourceRange SR, MultiExprArg Elements) {
794   SourceLocation Loc = SR.getBegin();
795 
796   if (!NSArrayDecl) {
797     NSArrayDecl = LookupObjCInterfaceDeclForLiteral(*this, Loc,
798                                                     Sema::LK_Array);
799     if (!NSArrayDecl) {
800       return ExprError();
801     }
802   }
803 
804   // Find the arrayWithObjects:count: method, if we haven't done so already.
805   QualType IdT = Context.getObjCIdType();
806   if (!ArrayWithObjectsMethod) {
807     Selector
808       Sel = NSAPIObj->getNSArraySelector(NSAPI::NSArr_arrayWithObjectsCount);
809     ObjCMethodDecl *Method = NSArrayDecl->lookupClassMethod(Sel);
810     if (!Method && getLangOpts().DebuggerObjCLiteral) {
811       TypeSourceInfo *ReturnTInfo = nullptr;
812       Method = ObjCMethodDecl::Create(
813           Context, SourceLocation(), SourceLocation(), Sel, IdT, ReturnTInfo,
814           Context.getTranslationUnitDecl(), false /*Instance*/,
815           false /*isVariadic*/,
816           /*isPropertyAccessor=*/false, /*isSynthesizedAccessorStub=*/false,
817           /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
818           ObjCMethodDecl::Required, false);
819       SmallVector<ParmVarDecl *, 2> Params;
820       ParmVarDecl *objects = ParmVarDecl::Create(Context, Method,
821                                                  SourceLocation(),
822                                                  SourceLocation(),
823                                                  &Context.Idents.get("objects"),
824                                                  Context.getPointerType(IdT),
825                                                  /*TInfo=*/nullptr,
826                                                  SC_None, nullptr);
827       Params.push_back(objects);
828       ParmVarDecl *cnt = ParmVarDecl::Create(Context, Method,
829                                              SourceLocation(),
830                                              SourceLocation(),
831                                              &Context.Idents.get("cnt"),
832                                              Context.UnsignedLongTy,
833                                              /*TInfo=*/nullptr, SC_None,
834                                              nullptr);
835       Params.push_back(cnt);
836       Method->setMethodParams(Context, Params, None);
837     }
838 
839     if (!validateBoxingMethod(*this, Loc, NSArrayDecl, Sel, Method))
840       return ExprError();
841 
842     // Dig out the type that all elements should be converted to.
843     QualType T = Method->parameters()[0]->getType();
844     const PointerType *PtrT = T->getAs<PointerType>();
845     if (!PtrT ||
846         !Context.hasSameUnqualifiedType(PtrT->getPointeeType(), IdT)) {
847       Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
848         << Sel;
849       Diag(Method->parameters()[0]->getLocation(),
850            diag::note_objc_literal_method_param)
851         << 0 << T
852         << Context.getPointerType(IdT.withConst());
853       return ExprError();
854     }
855 
856     // Check that the 'count' parameter is integral.
857     if (!Method->parameters()[1]->getType()->isIntegerType()) {
858       Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
859         << Sel;
860       Diag(Method->parameters()[1]->getLocation(),
861            diag::note_objc_literal_method_param)
862         << 1
863         << Method->parameters()[1]->getType()
864         << "integral";
865       return ExprError();
866     }
867 
868     // We've found a good +arrayWithObjects:count: method. Save it!
869     ArrayWithObjectsMethod = Method;
870   }
871 
872   QualType ObjectsType = ArrayWithObjectsMethod->parameters()[0]->getType();
873   QualType RequiredType = ObjectsType->castAs<PointerType>()->getPointeeType();
874 
875   // Check that each of the elements provided is valid in a collection literal,
876   // performing conversions as necessary.
877   Expr **ElementsBuffer = Elements.data();
878   for (unsigned I = 0, N = Elements.size(); I != N; ++I) {
879     ExprResult Converted = CheckObjCCollectionLiteralElement(*this,
880                                                              ElementsBuffer[I],
881                                                              RequiredType, true);
882     if (Converted.isInvalid())
883       return ExprError();
884 
885     ElementsBuffer[I] = Converted.get();
886   }
887 
888   QualType Ty
889     = Context.getObjCObjectPointerType(
890                                     Context.getObjCInterfaceType(NSArrayDecl));
891 
892   return MaybeBindToTemporary(
893            ObjCArrayLiteral::Create(Context, Elements, Ty,
894                                     ArrayWithObjectsMethod, SR));
895 }
896 
897 /// Check for duplicate keys in an ObjC dictionary literal. For instance:
898 ///   NSDictionary *nd = @{ @"foo" : @"bar", @"foo" : @"baz" };
899 static void
900 CheckObjCDictionaryLiteralDuplicateKeys(Sema &S,
901                                         ObjCDictionaryLiteral *Literal) {
902   if (Literal->isValueDependent() || Literal->isTypeDependent())
903     return;
904 
905   // NSNumber has quite relaxed equality semantics (for instance, @YES is
906   // considered equal to @1.0). For now, ignore floating points and just do a
907   // bit-width and sign agnostic integer compare.
908   struct APSIntCompare {
909     bool operator()(const llvm::APSInt &LHS, const llvm::APSInt &RHS) const {
910       return llvm::APSInt::compareValues(LHS, RHS) < 0;
911     }
912   };
913 
914   llvm::DenseMap<StringRef, SourceLocation> StringKeys;
915   std::map<llvm::APSInt, SourceLocation, APSIntCompare> IntegralKeys;
916 
917   auto checkOneKey = [&](auto &Map, const auto &Key, SourceLocation Loc) {
918     auto Pair = Map.insert({Key, Loc});
919     if (!Pair.second) {
920       S.Diag(Loc, diag::warn_nsdictionary_duplicate_key);
921       S.Diag(Pair.first->second, diag::note_nsdictionary_duplicate_key_here);
922     }
923   };
924 
925   for (unsigned Idx = 0, End = Literal->getNumElements(); Idx != End; ++Idx) {
926     Expr *Key = Literal->getKeyValueElement(Idx).Key->IgnoreParenImpCasts();
927 
928     if (auto *StrLit = dyn_cast<ObjCStringLiteral>(Key)) {
929       StringRef Bytes = StrLit->getString()->getBytes();
930       SourceLocation Loc = StrLit->getExprLoc();
931       checkOneKey(StringKeys, Bytes, Loc);
932     }
933 
934     if (auto *BE = dyn_cast<ObjCBoxedExpr>(Key)) {
935       Expr *Boxed = BE->getSubExpr();
936       SourceLocation Loc = BE->getExprLoc();
937 
938       // Check for @("foo").
939       if (auto *Str = dyn_cast<StringLiteral>(Boxed->IgnoreParenImpCasts())) {
940         checkOneKey(StringKeys, Str->getBytes(), Loc);
941         continue;
942       }
943 
944       Expr::EvalResult Result;
945       if (Boxed->EvaluateAsInt(Result, S.getASTContext(),
946                                Expr::SE_AllowSideEffects)) {
947         checkOneKey(IntegralKeys, Result.Val.getInt(), Loc);
948       }
949     }
950   }
951 }
952 
953 ExprResult Sema::BuildObjCDictionaryLiteral(SourceRange SR,
954                               MutableArrayRef<ObjCDictionaryElement> Elements) {
955   SourceLocation Loc = SR.getBegin();
956 
957   if (!NSDictionaryDecl) {
958     NSDictionaryDecl = LookupObjCInterfaceDeclForLiteral(*this, Loc,
959                                                          Sema::LK_Dictionary);
960     if (!NSDictionaryDecl) {
961       return ExprError();
962     }
963   }
964 
965   // Find the dictionaryWithObjects:forKeys:count: method, if we haven't done
966   // so already.
967   QualType IdT = Context.getObjCIdType();
968   if (!DictionaryWithObjectsMethod) {
969     Selector Sel = NSAPIObj->getNSDictionarySelector(
970                                NSAPI::NSDict_dictionaryWithObjectsForKeysCount);
971     ObjCMethodDecl *Method = NSDictionaryDecl->lookupClassMethod(Sel);
972     if (!Method && getLangOpts().DebuggerObjCLiteral) {
973       Method = ObjCMethodDecl::Create(
974           Context, SourceLocation(), SourceLocation(), Sel, IdT,
975           nullptr /*TypeSourceInfo */, Context.getTranslationUnitDecl(),
976           false /*Instance*/, false /*isVariadic*/,
977           /*isPropertyAccessor=*/false,
978           /*isSynthesizedAccessorStub=*/false,
979           /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
980           ObjCMethodDecl::Required, false);
981       SmallVector<ParmVarDecl *, 3> Params;
982       ParmVarDecl *objects = ParmVarDecl::Create(Context, Method,
983                                                  SourceLocation(),
984                                                  SourceLocation(),
985                                                  &Context.Idents.get("objects"),
986                                                  Context.getPointerType(IdT),
987                                                  /*TInfo=*/nullptr, SC_None,
988                                                  nullptr);
989       Params.push_back(objects);
990       ParmVarDecl *keys = ParmVarDecl::Create(Context, Method,
991                                               SourceLocation(),
992                                               SourceLocation(),
993                                               &Context.Idents.get("keys"),
994                                               Context.getPointerType(IdT),
995                                               /*TInfo=*/nullptr, SC_None,
996                                               nullptr);
997       Params.push_back(keys);
998       ParmVarDecl *cnt = ParmVarDecl::Create(Context, Method,
999                                              SourceLocation(),
1000                                              SourceLocation(),
1001                                              &Context.Idents.get("cnt"),
1002                                              Context.UnsignedLongTy,
1003                                              /*TInfo=*/nullptr, SC_None,
1004                                              nullptr);
1005       Params.push_back(cnt);
1006       Method->setMethodParams(Context, Params, None);
1007     }
1008 
1009     if (!validateBoxingMethod(*this, SR.getBegin(), NSDictionaryDecl, Sel,
1010                               Method))
1011        return ExprError();
1012 
1013     // Dig out the type that all values should be converted to.
1014     QualType ValueT = Method->parameters()[0]->getType();
1015     const PointerType *PtrValue = ValueT->getAs<PointerType>();
1016     if (!PtrValue ||
1017         !Context.hasSameUnqualifiedType(PtrValue->getPointeeType(), IdT)) {
1018       Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
1019         << Sel;
1020       Diag(Method->parameters()[0]->getLocation(),
1021            diag::note_objc_literal_method_param)
1022         << 0 << ValueT
1023         << Context.getPointerType(IdT.withConst());
1024       return ExprError();
1025     }
1026 
1027     // Dig out the type that all keys should be converted to.
1028     QualType KeyT = Method->parameters()[1]->getType();
1029     const PointerType *PtrKey = KeyT->getAs<PointerType>();
1030     if (!PtrKey ||
1031         !Context.hasSameUnqualifiedType(PtrKey->getPointeeType(),
1032                                         IdT)) {
1033       bool err = true;
1034       if (PtrKey) {
1035         if (QIDNSCopying.isNull()) {
1036           // key argument of selector is id<NSCopying>?
1037           if (ObjCProtocolDecl *NSCopyingPDecl =
1038               LookupProtocol(&Context.Idents.get("NSCopying"), SR.getBegin())) {
1039             ObjCProtocolDecl *PQ[] = {NSCopyingPDecl};
1040             QIDNSCopying =
1041               Context.getObjCObjectType(Context.ObjCBuiltinIdTy, { },
1042                                         llvm::makeArrayRef(
1043                                           (ObjCProtocolDecl**) PQ,
1044                                           1),
1045                                         false);
1046             QIDNSCopying = Context.getObjCObjectPointerType(QIDNSCopying);
1047           }
1048         }
1049         if (!QIDNSCopying.isNull())
1050           err = !Context.hasSameUnqualifiedType(PtrKey->getPointeeType(),
1051                                                 QIDNSCopying);
1052       }
1053 
1054       if (err) {
1055         Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
1056           << Sel;
1057         Diag(Method->parameters()[1]->getLocation(),
1058              diag::note_objc_literal_method_param)
1059           << 1 << KeyT
1060           << Context.getPointerType(IdT.withConst());
1061         return ExprError();
1062       }
1063     }
1064 
1065     // Check that the 'count' parameter is integral.
1066     QualType CountType = Method->parameters()[2]->getType();
1067     if (!CountType->isIntegerType()) {
1068       Diag(SR.getBegin(), diag::err_objc_literal_method_sig)
1069         << Sel;
1070       Diag(Method->parameters()[2]->getLocation(),
1071            diag::note_objc_literal_method_param)
1072         << 2 << CountType
1073         << "integral";
1074       return ExprError();
1075     }
1076 
1077     // We've found a good +dictionaryWithObjects:keys:count: method; save it!
1078     DictionaryWithObjectsMethod = Method;
1079   }
1080 
1081   QualType ValuesT = DictionaryWithObjectsMethod->parameters()[0]->getType();
1082   QualType ValueT = ValuesT->castAs<PointerType>()->getPointeeType();
1083   QualType KeysT = DictionaryWithObjectsMethod->parameters()[1]->getType();
1084   QualType KeyT = KeysT->castAs<PointerType>()->getPointeeType();
1085 
1086   // Check that each of the keys and values provided is valid in a collection
1087   // literal, performing conversions as necessary.
1088   bool HasPackExpansions = false;
1089   for (ObjCDictionaryElement &Element : Elements) {
1090     // Check the key.
1091     ExprResult Key = CheckObjCCollectionLiteralElement(*this, Element.Key,
1092                                                        KeyT);
1093     if (Key.isInvalid())
1094       return ExprError();
1095 
1096     // Check the value.
1097     ExprResult Value
1098       = CheckObjCCollectionLiteralElement(*this, Element.Value, ValueT);
1099     if (Value.isInvalid())
1100       return ExprError();
1101 
1102     Element.Key = Key.get();
1103     Element.Value = Value.get();
1104 
1105     if (Element.EllipsisLoc.isInvalid())
1106       continue;
1107 
1108     if (!Element.Key->containsUnexpandedParameterPack() &&
1109         !Element.Value->containsUnexpandedParameterPack()) {
1110       Diag(Element.EllipsisLoc,
1111            diag::err_pack_expansion_without_parameter_packs)
1112           << SourceRange(Element.Key->getBeginLoc(),
1113                          Element.Value->getEndLoc());
1114       return ExprError();
1115     }
1116 
1117     HasPackExpansions = true;
1118   }
1119 
1120   QualType Ty = Context.getObjCObjectPointerType(
1121       Context.getObjCInterfaceType(NSDictionaryDecl));
1122 
1123   auto *Literal =
1124       ObjCDictionaryLiteral::Create(Context, Elements, HasPackExpansions, Ty,
1125                                     DictionaryWithObjectsMethod, SR);
1126   CheckObjCDictionaryLiteralDuplicateKeys(*this, Literal);
1127   return MaybeBindToTemporary(Literal);
1128 }
1129 
1130 ExprResult Sema::BuildObjCEncodeExpression(SourceLocation AtLoc,
1131                                       TypeSourceInfo *EncodedTypeInfo,
1132                                       SourceLocation RParenLoc) {
1133   QualType EncodedType = EncodedTypeInfo->getType();
1134   QualType StrTy;
1135   if (EncodedType->isDependentType())
1136     StrTy = Context.DependentTy;
1137   else {
1138     if (!EncodedType->getAsArrayTypeUnsafe() && //// Incomplete array is handled.
1139         !EncodedType->isVoidType()) // void is handled too.
1140       if (RequireCompleteType(AtLoc, EncodedType,
1141                               diag::err_incomplete_type_objc_at_encode,
1142                               EncodedTypeInfo->getTypeLoc()))
1143         return ExprError();
1144 
1145     std::string Str;
1146     QualType NotEncodedT;
1147     Context.getObjCEncodingForType(EncodedType, Str, nullptr, &NotEncodedT);
1148     if (!NotEncodedT.isNull())
1149       Diag(AtLoc, diag::warn_incomplete_encoded_type)
1150         << EncodedType << NotEncodedT;
1151 
1152     // The type of @encode is the same as the type of the corresponding string,
1153     // which is an array type.
1154     StrTy = Context.getStringLiteralArrayType(Context.CharTy, Str.size());
1155   }
1156 
1157   return new (Context) ObjCEncodeExpr(StrTy, EncodedTypeInfo, AtLoc, RParenLoc);
1158 }
1159 
1160 ExprResult Sema::ParseObjCEncodeExpression(SourceLocation AtLoc,
1161                                            SourceLocation EncodeLoc,
1162                                            SourceLocation LParenLoc,
1163                                            ParsedType ty,
1164                                            SourceLocation RParenLoc) {
1165   // FIXME: Preserve type source info ?
1166   TypeSourceInfo *TInfo;
1167   QualType EncodedType = GetTypeFromParser(ty, &TInfo);
1168   if (!TInfo)
1169     TInfo = Context.getTrivialTypeSourceInfo(EncodedType,
1170                                              getLocForEndOfToken(LParenLoc));
1171 
1172   return BuildObjCEncodeExpression(AtLoc, TInfo, RParenLoc);
1173 }
1174 
1175 static bool HelperToDiagnoseMismatchedMethodsInGlobalPool(Sema &S,
1176                                                SourceLocation AtLoc,
1177                                                SourceLocation LParenLoc,
1178                                                SourceLocation RParenLoc,
1179                                                ObjCMethodDecl *Method,
1180                                                ObjCMethodList &MethList) {
1181   ObjCMethodList *M = &MethList;
1182   bool Warned = false;
1183   for (M = M->getNext(); M; M=M->getNext()) {
1184     ObjCMethodDecl *MatchingMethodDecl = M->getMethod();
1185     if (MatchingMethodDecl == Method ||
1186         isa<ObjCImplDecl>(MatchingMethodDecl->getDeclContext()) ||
1187         MatchingMethodDecl->getSelector() != Method->getSelector())
1188       continue;
1189     if (!S.MatchTwoMethodDeclarations(Method,
1190                                       MatchingMethodDecl, Sema::MMS_loose)) {
1191       if (!Warned) {
1192         Warned = true;
1193         S.Diag(AtLoc, diag::warn_multiple_selectors)
1194           << Method->getSelector() << FixItHint::CreateInsertion(LParenLoc, "(")
1195           << FixItHint::CreateInsertion(RParenLoc, ")");
1196         S.Diag(Method->getLocation(), diag::note_method_declared_at)
1197           << Method->getDeclName();
1198       }
1199       S.Diag(MatchingMethodDecl->getLocation(), diag::note_method_declared_at)
1200         << MatchingMethodDecl->getDeclName();
1201     }
1202   }
1203   return Warned;
1204 }
1205 
1206 static void DiagnoseMismatchedSelectors(Sema &S, SourceLocation AtLoc,
1207                                         ObjCMethodDecl *Method,
1208                                         SourceLocation LParenLoc,
1209                                         SourceLocation RParenLoc,
1210                                         bool WarnMultipleSelectors) {
1211   if (!WarnMultipleSelectors ||
1212       S.Diags.isIgnored(diag::warn_multiple_selectors, SourceLocation()))
1213     return;
1214   bool Warned = false;
1215   for (Sema::GlobalMethodPool::iterator b = S.MethodPool.begin(),
1216        e = S.MethodPool.end(); b != e; b++) {
1217     // first, instance methods
1218     ObjCMethodList &InstMethList = b->second.first;
1219     if (HelperToDiagnoseMismatchedMethodsInGlobalPool(S, AtLoc, LParenLoc, RParenLoc,
1220                                                       Method, InstMethList))
1221       Warned = true;
1222 
1223     // second, class methods
1224     ObjCMethodList &ClsMethList = b->second.second;
1225     if (HelperToDiagnoseMismatchedMethodsInGlobalPool(S, AtLoc, LParenLoc, RParenLoc,
1226                                                       Method, ClsMethList) || Warned)
1227       return;
1228   }
1229 }
1230 
1231 static ObjCMethodDecl *LookupDirectMethodInMethodList(Sema &S, Selector Sel,
1232                                                       ObjCMethodList &MethList,
1233                                                       bool &onlyDirect,
1234                                                       bool &anyDirect) {
1235   (void)Sel;
1236   ObjCMethodList *M = &MethList;
1237   ObjCMethodDecl *DirectMethod = nullptr;
1238   for (; M; M = M->getNext()) {
1239     ObjCMethodDecl *Method = M->getMethod();
1240     if (!Method)
1241       continue;
1242     assert(Method->getSelector() == Sel && "Method with wrong selector in method list");
1243     if (Method->isDirectMethod()) {
1244       anyDirect = true;
1245       DirectMethod = Method;
1246     } else
1247       onlyDirect = false;
1248   }
1249 
1250   return DirectMethod;
1251 }
1252 
1253 // Search the global pool for (potentially) direct methods matching the given
1254 // selector. If a non-direct method is found, set \param onlyDirect to false. If
1255 // a direct method is found, set \param anyDirect to true. Returns a direct
1256 // method, if any.
1257 static ObjCMethodDecl *LookupDirectMethodInGlobalPool(Sema &S, Selector Sel,
1258                                                       bool &onlyDirect,
1259                                                       bool &anyDirect) {
1260   auto Iter = S.MethodPool.find(Sel);
1261   if (Iter == S.MethodPool.end())
1262     return nullptr;
1263 
1264   ObjCMethodDecl *DirectInstance = LookupDirectMethodInMethodList(
1265       S, Sel, Iter->second.first, onlyDirect, anyDirect);
1266   ObjCMethodDecl *DirectClass = LookupDirectMethodInMethodList(
1267       S, Sel, Iter->second.second, onlyDirect, anyDirect);
1268 
1269   return DirectInstance ? DirectInstance : DirectClass;
1270 }
1271 
1272 static ObjCMethodDecl *findMethodInCurrentClass(Sema &S, Selector Sel) {
1273   auto *CurMD = S.getCurMethodDecl();
1274   if (!CurMD)
1275     return nullptr;
1276   ObjCInterfaceDecl *IFace = CurMD->getClassInterface();
1277 
1278   // The language enforce that only one direct method is present in a given
1279   // class, so we just need to find one method in the current class to know
1280   // whether Sel is potentially direct in this context.
1281   if (ObjCMethodDecl *MD = IFace->lookupMethod(Sel, /*isInstance=*/true))
1282     return MD;
1283   if (ObjCMethodDecl *MD = IFace->lookupPrivateMethod(Sel, /*isInstance=*/true))
1284     return MD;
1285   if (ObjCMethodDecl *MD = IFace->lookupMethod(Sel, /*isInstance=*/false))
1286     return MD;
1287   if (ObjCMethodDecl *MD = IFace->lookupPrivateMethod(Sel, /*isInstance=*/false))
1288     return MD;
1289 
1290   return nullptr;
1291 }
1292 
1293 ExprResult Sema::ParseObjCSelectorExpression(Selector Sel,
1294                                              SourceLocation AtLoc,
1295                                              SourceLocation SelLoc,
1296                                              SourceLocation LParenLoc,
1297                                              SourceLocation RParenLoc,
1298                                              bool WarnMultipleSelectors) {
1299   ObjCMethodDecl *Method = LookupInstanceMethodInGlobalPool(Sel,
1300                              SourceRange(LParenLoc, RParenLoc));
1301   if (!Method)
1302     Method = LookupFactoryMethodInGlobalPool(Sel,
1303                                           SourceRange(LParenLoc, RParenLoc));
1304   if (!Method) {
1305     if (const ObjCMethodDecl *OM = SelectorsForTypoCorrection(Sel)) {
1306       Selector MatchedSel = OM->getSelector();
1307       SourceRange SelectorRange(LParenLoc.getLocWithOffset(1),
1308                                 RParenLoc.getLocWithOffset(-1));
1309       Diag(SelLoc, diag::warn_undeclared_selector_with_typo)
1310         << Sel << MatchedSel
1311         << FixItHint::CreateReplacement(SelectorRange, MatchedSel.getAsString());
1312 
1313     } else
1314         Diag(SelLoc, diag::warn_undeclared_selector) << Sel;
1315   } else {
1316     DiagnoseMismatchedSelectors(*this, AtLoc, Method, LParenLoc, RParenLoc,
1317                                 WarnMultipleSelectors);
1318 
1319     bool onlyDirect = true;
1320     bool anyDirect = false;
1321     ObjCMethodDecl *GlobalDirectMethod =
1322         LookupDirectMethodInGlobalPool(*this, Sel, onlyDirect, anyDirect);
1323 
1324     if (onlyDirect) {
1325       Diag(AtLoc, diag::err_direct_selector_expression)
1326           << Method->getSelector();
1327       Diag(Method->getLocation(), diag::note_direct_method_declared_at)
1328           << Method->getDeclName();
1329     } else if (anyDirect) {
1330       // If we saw any direct methods, see if we see a direct member of the
1331       // current class. If so, the @selector will likely be used to refer to
1332       // this direct method.
1333       ObjCMethodDecl *LikelyTargetMethod = findMethodInCurrentClass(*this, Sel);
1334       if (LikelyTargetMethod && LikelyTargetMethod->isDirectMethod()) {
1335         Diag(AtLoc, diag::warn_potentially_direct_selector_expression) << Sel;
1336         Diag(LikelyTargetMethod->getLocation(),
1337              diag::note_direct_method_declared_at)
1338             << LikelyTargetMethod->getDeclName();
1339       } else if (!LikelyTargetMethod) {
1340         // Otherwise, emit the "strict" variant of this diagnostic, unless
1341         // LikelyTargetMethod is non-direct.
1342         Diag(AtLoc, diag::warn_strict_potentially_direct_selector_expression)
1343             << Sel;
1344         Diag(GlobalDirectMethod->getLocation(),
1345              diag::note_direct_method_declared_at)
1346             << GlobalDirectMethod->getDeclName();
1347       }
1348     }
1349   }
1350 
1351   if (Method &&
1352       Method->getImplementationControl() != ObjCMethodDecl::Optional &&
1353       !getSourceManager().isInSystemHeader(Method->getLocation()))
1354     ReferencedSelectors.insert(std::make_pair(Sel, AtLoc));
1355 
1356   // In ARC, forbid the user from using @selector for
1357   // retain/release/autorelease/dealloc/retainCount.
1358   if (getLangOpts().ObjCAutoRefCount) {
1359     switch (Sel.getMethodFamily()) {
1360     case OMF_retain:
1361     case OMF_release:
1362     case OMF_autorelease:
1363     case OMF_retainCount:
1364     case OMF_dealloc:
1365       Diag(AtLoc, diag::err_arc_illegal_selector) <<
1366         Sel << SourceRange(LParenLoc, RParenLoc);
1367       break;
1368 
1369     case OMF_None:
1370     case OMF_alloc:
1371     case OMF_copy:
1372     case OMF_finalize:
1373     case OMF_init:
1374     case OMF_mutableCopy:
1375     case OMF_new:
1376     case OMF_self:
1377     case OMF_initialize:
1378     case OMF_performSelector:
1379       break;
1380     }
1381   }
1382   QualType Ty = Context.getObjCSelType();
1383   return new (Context) ObjCSelectorExpr(Ty, Sel, AtLoc, RParenLoc);
1384 }
1385 
1386 ExprResult Sema::ParseObjCProtocolExpression(IdentifierInfo *ProtocolId,
1387                                              SourceLocation AtLoc,
1388                                              SourceLocation ProtoLoc,
1389                                              SourceLocation LParenLoc,
1390                                              SourceLocation ProtoIdLoc,
1391                                              SourceLocation RParenLoc) {
1392   ObjCProtocolDecl* PDecl = LookupProtocol(ProtocolId, ProtoIdLoc);
1393   if (!PDecl) {
1394     Diag(ProtoLoc, diag::err_undeclared_protocol) << ProtocolId;
1395     return true;
1396   }
1397   if (PDecl->isNonRuntimeProtocol())
1398     Diag(ProtoLoc, diag::err_objc_non_runtime_protocol_in_protocol_expr)
1399         << PDecl;
1400   if (!PDecl->hasDefinition()) {
1401     Diag(ProtoLoc, diag::err_atprotocol_protocol) << PDecl;
1402     Diag(PDecl->getLocation(), diag::note_entity_declared_at) << PDecl;
1403   } else {
1404     PDecl = PDecl->getDefinition();
1405   }
1406 
1407   QualType Ty = Context.getObjCProtoType();
1408   if (Ty.isNull())
1409     return true;
1410   Ty = Context.getObjCObjectPointerType(Ty);
1411   return new (Context) ObjCProtocolExpr(Ty, PDecl, AtLoc, ProtoIdLoc, RParenLoc);
1412 }
1413 
1414 /// Try to capture an implicit reference to 'self'.
1415 ObjCMethodDecl *Sema::tryCaptureObjCSelf(SourceLocation Loc) {
1416   DeclContext *DC = getFunctionLevelDeclContext();
1417 
1418   // If we're not in an ObjC method, error out.  Note that, unlike the
1419   // C++ case, we don't require an instance method --- class methods
1420   // still have a 'self', and we really do still need to capture it!
1421   ObjCMethodDecl *method = dyn_cast<ObjCMethodDecl>(DC);
1422   if (!method)
1423     return nullptr;
1424 
1425   tryCaptureVariable(method->getSelfDecl(), Loc);
1426 
1427   return method;
1428 }
1429 
1430 static QualType stripObjCInstanceType(ASTContext &Context, QualType T) {
1431   QualType origType = T;
1432   if (auto nullability = AttributedType::stripOuterNullability(T)) {
1433     if (T == Context.getObjCInstanceType()) {
1434       return Context.getAttributedType(
1435                AttributedType::getNullabilityAttrKind(*nullability),
1436                Context.getObjCIdType(),
1437                Context.getObjCIdType());
1438     }
1439 
1440     return origType;
1441   }
1442 
1443   if (T == Context.getObjCInstanceType())
1444     return Context.getObjCIdType();
1445 
1446   return origType;
1447 }
1448 
1449 /// Determine the result type of a message send based on the receiver type,
1450 /// method, and the kind of message send.
1451 ///
1452 /// This is the "base" result type, which will still need to be adjusted
1453 /// to account for nullability.
1454 static QualType getBaseMessageSendResultType(Sema &S,
1455                                              QualType ReceiverType,
1456                                              ObjCMethodDecl *Method,
1457                                              bool isClassMessage,
1458                                              bool isSuperMessage) {
1459   assert(Method && "Must have a method");
1460   if (!Method->hasRelatedResultType())
1461     return Method->getSendResultType(ReceiverType);
1462 
1463   ASTContext &Context = S.Context;
1464 
1465   // Local function that transfers the nullability of the method's
1466   // result type to the returned result.
1467   auto transferNullability = [&](QualType type) -> QualType {
1468     // If the method's result type has nullability, extract it.
1469     if (auto nullability = Method->getSendResultType(ReceiverType)
1470                              ->getNullability(Context)){
1471       // Strip off any outer nullability sugar from the provided type.
1472       (void)AttributedType::stripOuterNullability(type);
1473 
1474       // Form a new attributed type using the method result type's nullability.
1475       return Context.getAttributedType(
1476                AttributedType::getNullabilityAttrKind(*nullability),
1477                type,
1478                type);
1479     }
1480 
1481     return type;
1482   };
1483 
1484   // If a method has a related return type:
1485   //   - if the method found is an instance method, but the message send
1486   //     was a class message send, T is the declared return type of the method
1487   //     found
1488   if (Method->isInstanceMethod() && isClassMessage)
1489     return stripObjCInstanceType(Context,
1490                                  Method->getSendResultType(ReceiverType));
1491 
1492   //   - if the receiver is super, T is a pointer to the class of the
1493   //     enclosing method definition
1494   if (isSuperMessage) {
1495     if (ObjCMethodDecl *CurMethod = S.getCurMethodDecl())
1496       if (ObjCInterfaceDecl *Class = CurMethod->getClassInterface()) {
1497         return transferNullability(
1498                  Context.getObjCObjectPointerType(
1499                    Context.getObjCInterfaceType(Class)));
1500       }
1501   }
1502 
1503   //   - if the receiver is the name of a class U, T is a pointer to U
1504   if (ReceiverType->getAsObjCInterfaceType())
1505     return transferNullability(Context.getObjCObjectPointerType(ReceiverType));
1506   //   - if the receiver is of type Class or qualified Class type,
1507   //     T is the declared return type of the method.
1508   if (ReceiverType->isObjCClassType() ||
1509       ReceiverType->isObjCQualifiedClassType())
1510     return stripObjCInstanceType(Context,
1511                                  Method->getSendResultType(ReceiverType));
1512 
1513   //   - if the receiver is id, qualified id, Class, or qualified Class, T
1514   //     is the receiver type, otherwise
1515   //   - T is the type of the receiver expression.
1516   return transferNullability(ReceiverType);
1517 }
1518 
1519 QualType Sema::getMessageSendResultType(const Expr *Receiver,
1520                                         QualType ReceiverType,
1521                                         ObjCMethodDecl *Method,
1522                                         bool isClassMessage,
1523                                         bool isSuperMessage) {
1524   // Produce the result type.
1525   QualType resultType = getBaseMessageSendResultType(*this, ReceiverType,
1526                                                      Method,
1527                                                      isClassMessage,
1528                                                      isSuperMessage);
1529 
1530   // If this is a class message, ignore the nullability of the receiver.
1531   if (isClassMessage) {
1532     // In a class method, class messages to 'self' that return instancetype can
1533     // be typed as the current class.  We can safely do this in ARC because self
1534     // can't be reassigned, and we do it unsafely outside of ARC because in
1535     // practice people never reassign self in class methods and there's some
1536     // virtue in not being aggressively pedantic.
1537     if (Receiver && Receiver->isObjCSelfExpr()) {
1538       assert(ReceiverType->isObjCClassType() && "expected a Class self");
1539       QualType T = Method->getSendResultType(ReceiverType);
1540       AttributedType::stripOuterNullability(T);
1541       if (T == Context.getObjCInstanceType()) {
1542         const ObjCMethodDecl *MD = cast<ObjCMethodDecl>(
1543             cast<ImplicitParamDecl>(
1544                 cast<DeclRefExpr>(Receiver->IgnoreParenImpCasts())->getDecl())
1545                 ->getDeclContext());
1546         assert(MD->isClassMethod() && "expected a class method");
1547         QualType NewResultType = Context.getObjCObjectPointerType(
1548             Context.getObjCInterfaceType(MD->getClassInterface()));
1549         if (auto Nullability = resultType->getNullability(Context))
1550           NewResultType = Context.getAttributedType(
1551               AttributedType::getNullabilityAttrKind(*Nullability),
1552               NewResultType, NewResultType);
1553         return NewResultType;
1554       }
1555     }
1556     return resultType;
1557   }
1558 
1559   // There is nothing left to do if the result type cannot have a nullability
1560   // specifier.
1561   if (!resultType->canHaveNullability())
1562     return resultType;
1563 
1564   // Map the nullability of the result into a table index.
1565   unsigned receiverNullabilityIdx = 0;
1566   if (Optional<NullabilityKind> nullability =
1567           ReceiverType->getNullability(Context)) {
1568     if (*nullability == NullabilityKind::NullableResult)
1569       nullability = NullabilityKind::Nullable;
1570     receiverNullabilityIdx = 1 + static_cast<unsigned>(*nullability);
1571   }
1572 
1573   unsigned resultNullabilityIdx = 0;
1574   if (Optional<NullabilityKind> nullability =
1575           resultType->getNullability(Context)) {
1576     if (*nullability == NullabilityKind::NullableResult)
1577       nullability = NullabilityKind::Nullable;
1578     resultNullabilityIdx = 1 + static_cast<unsigned>(*nullability);
1579   }
1580 
1581   // The table of nullability mappings, indexed by the receiver's nullability
1582   // and then the result type's nullability.
1583   static const uint8_t None = 0;
1584   static const uint8_t NonNull = 1;
1585   static const uint8_t Nullable = 2;
1586   static const uint8_t Unspecified = 3;
1587   static const uint8_t nullabilityMap[4][4] = {
1588     //                  None        NonNull       Nullable    Unspecified
1589     /* None */        { None,       None,         Nullable,   None },
1590     /* NonNull */     { None,       NonNull,      Nullable,   Unspecified },
1591     /* Nullable */    { Nullable,   Nullable,     Nullable,   Nullable },
1592     /* Unspecified */ { None,       Unspecified,  Nullable,   Unspecified }
1593   };
1594 
1595   unsigned newResultNullabilityIdx
1596     = nullabilityMap[receiverNullabilityIdx][resultNullabilityIdx];
1597   if (newResultNullabilityIdx == resultNullabilityIdx)
1598     return resultType;
1599 
1600   // Strip off the existing nullability. This removes as little type sugar as
1601   // possible.
1602   do {
1603     if (auto attributed = dyn_cast<AttributedType>(resultType.getTypePtr())) {
1604       resultType = attributed->getModifiedType();
1605     } else {
1606       resultType = resultType.getDesugaredType(Context);
1607     }
1608   } while (resultType->getNullability(Context));
1609 
1610   // Add nullability back if needed.
1611   if (newResultNullabilityIdx > 0) {
1612     auto newNullability
1613       = static_cast<NullabilityKind>(newResultNullabilityIdx-1);
1614     return Context.getAttributedType(
1615              AttributedType::getNullabilityAttrKind(newNullability),
1616              resultType, resultType);
1617   }
1618 
1619   return resultType;
1620 }
1621 
1622 /// Look for an ObjC method whose result type exactly matches the given type.
1623 static const ObjCMethodDecl *
1624 findExplicitInstancetypeDeclarer(const ObjCMethodDecl *MD,
1625                                  QualType instancetype) {
1626   if (MD->getReturnType() == instancetype)
1627     return MD;
1628 
1629   // For these purposes, a method in an @implementation overrides a
1630   // declaration in the @interface.
1631   if (const ObjCImplDecl *impl =
1632         dyn_cast<ObjCImplDecl>(MD->getDeclContext())) {
1633     const ObjCContainerDecl *iface;
1634     if (const ObjCCategoryImplDecl *catImpl =
1635           dyn_cast<ObjCCategoryImplDecl>(impl)) {
1636       iface = catImpl->getCategoryDecl();
1637     } else {
1638       iface = impl->getClassInterface();
1639     }
1640 
1641     const ObjCMethodDecl *ifaceMD =
1642       iface->getMethod(MD->getSelector(), MD->isInstanceMethod());
1643     if (ifaceMD) return findExplicitInstancetypeDeclarer(ifaceMD, instancetype);
1644   }
1645 
1646   SmallVector<const ObjCMethodDecl *, 4> overrides;
1647   MD->getOverriddenMethods(overrides);
1648   for (unsigned i = 0, e = overrides.size(); i != e; ++i) {
1649     if (const ObjCMethodDecl *result =
1650           findExplicitInstancetypeDeclarer(overrides[i], instancetype))
1651       return result;
1652   }
1653 
1654   return nullptr;
1655 }
1656 
1657 void Sema::EmitRelatedResultTypeNoteForReturn(QualType destType) {
1658   // Only complain if we're in an ObjC method and the required return
1659   // type doesn't match the method's declared return type.
1660   ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(CurContext);
1661   if (!MD || !MD->hasRelatedResultType() ||
1662       Context.hasSameUnqualifiedType(destType, MD->getReturnType()))
1663     return;
1664 
1665   // Look for a method overridden by this method which explicitly uses
1666   // 'instancetype'.
1667   if (const ObjCMethodDecl *overridden =
1668         findExplicitInstancetypeDeclarer(MD, Context.getObjCInstanceType())) {
1669     SourceRange range = overridden->getReturnTypeSourceRange();
1670     SourceLocation loc = range.getBegin();
1671     if (loc.isInvalid())
1672       loc = overridden->getLocation();
1673     Diag(loc, diag::note_related_result_type_explicit)
1674       << /*current method*/ 1 << range;
1675     return;
1676   }
1677 
1678   // Otherwise, if we have an interesting method family, note that.
1679   // This should always trigger if the above didn't.
1680   if (ObjCMethodFamily family = MD->getMethodFamily())
1681     Diag(MD->getLocation(), diag::note_related_result_type_family)
1682       << /*current method*/ 1
1683       << family;
1684 }
1685 
1686 void Sema::EmitRelatedResultTypeNote(const Expr *E) {
1687   E = E->IgnoreParenImpCasts();
1688   const ObjCMessageExpr *MsgSend = dyn_cast<ObjCMessageExpr>(E);
1689   if (!MsgSend)
1690     return;
1691 
1692   const ObjCMethodDecl *Method = MsgSend->getMethodDecl();
1693   if (!Method)
1694     return;
1695 
1696   if (!Method->hasRelatedResultType())
1697     return;
1698 
1699   if (Context.hasSameUnqualifiedType(
1700           Method->getReturnType().getNonReferenceType(), MsgSend->getType()))
1701     return;
1702 
1703   if (!Context.hasSameUnqualifiedType(Method->getReturnType(),
1704                                       Context.getObjCInstanceType()))
1705     return;
1706 
1707   Diag(Method->getLocation(), diag::note_related_result_type_inferred)
1708     << Method->isInstanceMethod() << Method->getSelector()
1709     << MsgSend->getType();
1710 }
1711 
1712 bool Sema::CheckMessageArgumentTypes(
1713     const Expr *Receiver, QualType ReceiverType, MultiExprArg Args,
1714     Selector Sel, ArrayRef<SourceLocation> SelectorLocs, ObjCMethodDecl *Method,
1715     bool isClassMessage, bool isSuperMessage, SourceLocation lbrac,
1716     SourceLocation rbrac, SourceRange RecRange, QualType &ReturnType,
1717     ExprValueKind &VK) {
1718   SourceLocation SelLoc;
1719   if (!SelectorLocs.empty() && SelectorLocs.front().isValid())
1720     SelLoc = SelectorLocs.front();
1721   else
1722     SelLoc = lbrac;
1723 
1724   if (!Method) {
1725     // Apply default argument promotion as for (C99 6.5.2.2p6).
1726     for (unsigned i = 0, e = Args.size(); i != e; i++) {
1727       if (Args[i]->isTypeDependent())
1728         continue;
1729 
1730       ExprResult result;
1731       if (getLangOpts().DebuggerSupport) {
1732         QualType paramTy; // ignored
1733         result = checkUnknownAnyArg(SelLoc, Args[i], paramTy);
1734       } else {
1735         result = DefaultArgumentPromotion(Args[i]);
1736       }
1737       if (result.isInvalid())
1738         return true;
1739       Args[i] = result.get();
1740     }
1741 
1742     unsigned DiagID;
1743     if (getLangOpts().ObjCAutoRefCount)
1744       DiagID = diag::err_arc_method_not_found;
1745     else
1746       DiagID = isClassMessage ? diag::warn_class_method_not_found
1747                               : diag::warn_inst_method_not_found;
1748     if (!getLangOpts().DebuggerSupport) {
1749       const ObjCMethodDecl *OMD = SelectorsForTypoCorrection(Sel, ReceiverType);
1750       if (OMD && !OMD->isInvalidDecl()) {
1751         if (getLangOpts().ObjCAutoRefCount)
1752           DiagID = diag::err_method_not_found_with_typo;
1753         else
1754           DiagID = isClassMessage ? diag::warn_class_method_not_found_with_typo
1755                                   : diag::warn_instance_method_not_found_with_typo;
1756         Selector MatchedSel = OMD->getSelector();
1757         SourceRange SelectorRange(SelectorLocs.front(), SelectorLocs.back());
1758         if (MatchedSel.isUnarySelector())
1759           Diag(SelLoc, DiagID)
1760             << Sel<< isClassMessage << MatchedSel
1761             << FixItHint::CreateReplacement(SelectorRange, MatchedSel.getAsString());
1762         else
1763           Diag(SelLoc, DiagID) << Sel<< isClassMessage << MatchedSel;
1764       }
1765       else
1766         Diag(SelLoc, DiagID)
1767           << Sel << isClassMessage << SourceRange(SelectorLocs.front(),
1768                                                 SelectorLocs.back());
1769       // Find the class to which we are sending this message.
1770       if (auto *ObjPT = ReceiverType->getAs<ObjCObjectPointerType>()) {
1771         if (ObjCInterfaceDecl *ThisClass = ObjPT->getInterfaceDecl()) {
1772           Diag(ThisClass->getLocation(), diag::note_receiver_class_declared);
1773           if (!RecRange.isInvalid())
1774             if (ThisClass->lookupClassMethod(Sel))
1775               Diag(RecRange.getBegin(), diag::note_receiver_expr_here)
1776                   << FixItHint::CreateReplacement(RecRange,
1777                                                   ThisClass->getNameAsString());
1778         }
1779       }
1780     }
1781 
1782     // In debuggers, we want to use __unknown_anytype for these
1783     // results so that clients can cast them.
1784     if (getLangOpts().DebuggerSupport) {
1785       ReturnType = Context.UnknownAnyTy;
1786     } else {
1787       ReturnType = Context.getObjCIdType();
1788     }
1789     VK = VK_RValue;
1790     return false;
1791   }
1792 
1793   ReturnType = getMessageSendResultType(Receiver, ReceiverType, Method,
1794                                         isClassMessage, isSuperMessage);
1795   VK = Expr::getValueKindForType(Method->getReturnType());
1796 
1797   unsigned NumNamedArgs = Sel.getNumArgs();
1798   // Method might have more arguments than selector indicates. This is due
1799   // to addition of c-style arguments in method.
1800   if (Method->param_size() > Sel.getNumArgs())
1801     NumNamedArgs = Method->param_size();
1802   // FIXME. This need be cleaned up.
1803   if (Args.size() < NumNamedArgs) {
1804     Diag(SelLoc, diag::err_typecheck_call_too_few_args)
1805       << 2 << NumNamedArgs << static_cast<unsigned>(Args.size());
1806     return false;
1807   }
1808 
1809   // Compute the set of type arguments to be substituted into each parameter
1810   // type.
1811   Optional<ArrayRef<QualType>> typeArgs
1812     = ReceiverType->getObjCSubstitutions(Method->getDeclContext());
1813   bool IsError = false;
1814   for (unsigned i = 0; i < NumNamedArgs; i++) {
1815     // We can't do any type-checking on a type-dependent argument.
1816     if (Args[i]->isTypeDependent())
1817       continue;
1818 
1819     Expr *argExpr = Args[i];
1820 
1821     ParmVarDecl *param = Method->parameters()[i];
1822     assert(argExpr && "CheckMessageArgumentTypes(): missing expression");
1823 
1824     if (param->hasAttr<NoEscapeAttr>())
1825       if (auto *BE = dyn_cast<BlockExpr>(
1826               argExpr->IgnoreParenNoopCasts(Context)))
1827         BE->getBlockDecl()->setDoesNotEscape();
1828 
1829     // Strip the unbridged-cast placeholder expression off unless it's
1830     // a consumed argument.
1831     if (argExpr->hasPlaceholderType(BuiltinType::ARCUnbridgedCast) &&
1832         !param->hasAttr<CFConsumedAttr>())
1833       argExpr = stripARCUnbridgedCast(argExpr);
1834 
1835     // If the parameter is __unknown_anytype, infer its type
1836     // from the argument.
1837     if (param->getType() == Context.UnknownAnyTy) {
1838       QualType paramType;
1839       ExprResult argE = checkUnknownAnyArg(SelLoc, argExpr, paramType);
1840       if (argE.isInvalid()) {
1841         IsError = true;
1842       } else {
1843         Args[i] = argE.get();
1844 
1845         // Update the parameter type in-place.
1846         param->setType(paramType);
1847       }
1848       continue;
1849     }
1850 
1851     QualType origParamType = param->getType();
1852     QualType paramType = param->getType();
1853     if (typeArgs)
1854       paramType = paramType.substObjCTypeArgs(
1855                     Context,
1856                     *typeArgs,
1857                     ObjCSubstitutionContext::Parameter);
1858 
1859     if (RequireCompleteType(argExpr->getSourceRange().getBegin(),
1860                             paramType,
1861                             diag::err_call_incomplete_argument, argExpr))
1862       return true;
1863 
1864     InitializedEntity Entity
1865       = InitializedEntity::InitializeParameter(Context, param, paramType);
1866     ExprResult ArgE = PerformCopyInitialization(Entity, SourceLocation(), argExpr);
1867     if (ArgE.isInvalid())
1868       IsError = true;
1869     else {
1870       Args[i] = ArgE.getAs<Expr>();
1871 
1872       // If we are type-erasing a block to a block-compatible
1873       // Objective-C pointer type, we may need to extend the lifetime
1874       // of the block object.
1875       if (typeArgs && Args[i]->isRValue() && paramType->isBlockPointerType() &&
1876           Args[i]->getType()->isBlockPointerType() &&
1877           origParamType->isObjCObjectPointerType()) {
1878         ExprResult arg = Args[i];
1879         maybeExtendBlockObject(arg);
1880         Args[i] = arg.get();
1881       }
1882     }
1883   }
1884 
1885   // Promote additional arguments to variadic methods.
1886   if (Method->isVariadic()) {
1887     for (unsigned i = NumNamedArgs, e = Args.size(); i < e; ++i) {
1888       if (Args[i]->isTypeDependent())
1889         continue;
1890 
1891       ExprResult Arg = DefaultVariadicArgumentPromotion(Args[i], VariadicMethod,
1892                                                         nullptr);
1893       IsError |= Arg.isInvalid();
1894       Args[i] = Arg.get();
1895     }
1896   } else {
1897     // Check for extra arguments to non-variadic methods.
1898     if (Args.size() != NumNamedArgs) {
1899       Diag(Args[NumNamedArgs]->getBeginLoc(),
1900            diag::err_typecheck_call_too_many_args)
1901           << 2 /*method*/ << NumNamedArgs << static_cast<unsigned>(Args.size())
1902           << Method->getSourceRange()
1903           << SourceRange(Args[NumNamedArgs]->getBeginLoc(),
1904                          Args.back()->getEndLoc());
1905     }
1906   }
1907 
1908   DiagnoseSentinelCalls(Method, SelLoc, Args);
1909 
1910   // Do additional checkings on method.
1911   IsError |= CheckObjCMethodCall(
1912       Method, SelLoc, makeArrayRef(Args.data(), Args.size()));
1913 
1914   return IsError;
1915 }
1916 
1917 bool Sema::isSelfExpr(Expr *RExpr) {
1918   // 'self' is objc 'self' in an objc method only.
1919   ObjCMethodDecl *Method =
1920       dyn_cast_or_null<ObjCMethodDecl>(CurContext->getNonClosureAncestor());
1921   return isSelfExpr(RExpr, Method);
1922 }
1923 
1924 bool Sema::isSelfExpr(Expr *receiver, const ObjCMethodDecl *method) {
1925   if (!method) return false;
1926 
1927   receiver = receiver->IgnoreParenLValueCasts();
1928   if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(receiver))
1929     if (DRE->getDecl() == method->getSelfDecl())
1930       return true;
1931   return false;
1932 }
1933 
1934 /// LookupMethodInType - Look up a method in an ObjCObjectType.
1935 ObjCMethodDecl *Sema::LookupMethodInObjectType(Selector sel, QualType type,
1936                                                bool isInstance) {
1937   const ObjCObjectType *objType = type->castAs<ObjCObjectType>();
1938   if (ObjCInterfaceDecl *iface = objType->getInterface()) {
1939     // Look it up in the main interface (and categories, etc.)
1940     if (ObjCMethodDecl *method = iface->lookupMethod(sel, isInstance))
1941       return method;
1942 
1943     // Okay, look for "private" methods declared in any
1944     // @implementations we've seen.
1945     if (ObjCMethodDecl *method = iface->lookupPrivateMethod(sel, isInstance))
1946       return method;
1947   }
1948 
1949   // Check qualifiers.
1950   for (const auto *I : objType->quals())
1951     if (ObjCMethodDecl *method = I->lookupMethod(sel, isInstance))
1952       return method;
1953 
1954   return nullptr;
1955 }
1956 
1957 /// LookupMethodInQualifiedType - Lookups up a method in protocol qualifier
1958 /// list of a qualified objective pointer type.
1959 ObjCMethodDecl *Sema::LookupMethodInQualifiedType(Selector Sel,
1960                                               const ObjCObjectPointerType *OPT,
1961                                               bool Instance)
1962 {
1963   ObjCMethodDecl *MD = nullptr;
1964   for (const auto *PROTO : OPT->quals()) {
1965     if ((MD = PROTO->lookupMethod(Sel, Instance))) {
1966       return MD;
1967     }
1968   }
1969   return nullptr;
1970 }
1971 
1972 /// HandleExprPropertyRefExpr - Handle foo.bar where foo is a pointer to an
1973 /// objective C interface.  This is a property reference expression.
1974 ExprResult Sema::
1975 HandleExprPropertyRefExpr(const ObjCObjectPointerType *OPT,
1976                           Expr *BaseExpr, SourceLocation OpLoc,
1977                           DeclarationName MemberName,
1978                           SourceLocation MemberLoc,
1979                           SourceLocation SuperLoc, QualType SuperType,
1980                           bool Super) {
1981   const ObjCInterfaceType *IFaceT = OPT->getInterfaceType();
1982   ObjCInterfaceDecl *IFace = IFaceT->getDecl();
1983 
1984   if (!MemberName.isIdentifier()) {
1985     Diag(MemberLoc, diag::err_invalid_property_name)
1986       << MemberName << QualType(OPT, 0);
1987     return ExprError();
1988   }
1989 
1990   IdentifierInfo *Member = MemberName.getAsIdentifierInfo();
1991 
1992   SourceRange BaseRange = Super? SourceRange(SuperLoc)
1993                                : BaseExpr->getSourceRange();
1994   if (RequireCompleteType(MemberLoc, OPT->getPointeeType(),
1995                           diag::err_property_not_found_forward_class,
1996                           MemberName, BaseRange))
1997     return ExprError();
1998 
1999   if (ObjCPropertyDecl *PD = IFace->FindPropertyDeclaration(
2000           Member, ObjCPropertyQueryKind::OBJC_PR_query_instance)) {
2001     // Check whether we can reference this property.
2002     if (DiagnoseUseOfDecl(PD, MemberLoc))
2003       return ExprError();
2004     if (Super)
2005       return new (Context)
2006           ObjCPropertyRefExpr(PD, Context.PseudoObjectTy, VK_LValue,
2007                               OK_ObjCProperty, MemberLoc, SuperLoc, SuperType);
2008     else
2009       return new (Context)
2010           ObjCPropertyRefExpr(PD, Context.PseudoObjectTy, VK_LValue,
2011                               OK_ObjCProperty, MemberLoc, BaseExpr);
2012   }
2013   // Check protocols on qualified interfaces.
2014   for (const auto *I : OPT->quals())
2015     if (ObjCPropertyDecl *PD = I->FindPropertyDeclaration(
2016             Member, ObjCPropertyQueryKind::OBJC_PR_query_instance)) {
2017       // Check whether we can reference this property.
2018       if (DiagnoseUseOfDecl(PD, MemberLoc))
2019         return ExprError();
2020 
2021       if (Super)
2022         return new (Context) ObjCPropertyRefExpr(
2023             PD, Context.PseudoObjectTy, VK_LValue, OK_ObjCProperty, MemberLoc,
2024             SuperLoc, SuperType);
2025       else
2026         return new (Context)
2027             ObjCPropertyRefExpr(PD, Context.PseudoObjectTy, VK_LValue,
2028                                 OK_ObjCProperty, MemberLoc, BaseExpr);
2029     }
2030   // If that failed, look for an "implicit" property by seeing if the nullary
2031   // selector is implemented.
2032 
2033   // FIXME: The logic for looking up nullary and unary selectors should be
2034   // shared with the code in ActOnInstanceMessage.
2035 
2036   Selector Sel = PP.getSelectorTable().getNullarySelector(Member);
2037   ObjCMethodDecl *Getter = IFace->lookupInstanceMethod(Sel);
2038 
2039   // May be found in property's qualified list.
2040   if (!Getter)
2041     Getter = LookupMethodInQualifiedType(Sel, OPT, true);
2042 
2043   // If this reference is in an @implementation, check for 'private' methods.
2044   if (!Getter)
2045     Getter = IFace->lookupPrivateMethod(Sel);
2046 
2047   if (Getter) {
2048     // Check if we can reference this property.
2049     if (DiagnoseUseOfDecl(Getter, MemberLoc))
2050       return ExprError();
2051   }
2052   // If we found a getter then this may be a valid dot-reference, we
2053   // will look for the matching setter, in case it is needed.
2054   Selector SetterSel =
2055     SelectorTable::constructSetterSelector(PP.getIdentifierTable(),
2056                                            PP.getSelectorTable(), Member);
2057   ObjCMethodDecl *Setter = IFace->lookupInstanceMethod(SetterSel);
2058 
2059   // May be found in property's qualified list.
2060   if (!Setter)
2061     Setter = LookupMethodInQualifiedType(SetterSel, OPT, true);
2062 
2063   if (!Setter) {
2064     // If this reference is in an @implementation, also check for 'private'
2065     // methods.
2066     Setter = IFace->lookupPrivateMethod(SetterSel);
2067   }
2068 
2069   if (Setter && DiagnoseUseOfDecl(Setter, MemberLoc))
2070     return ExprError();
2071 
2072   // Special warning if member name used in a property-dot for a setter accessor
2073   // does not use a property with same name; e.g. obj.X = ... for a property with
2074   // name 'x'.
2075   if (Setter && Setter->isImplicit() && Setter->isPropertyAccessor() &&
2076       !IFace->FindPropertyDeclaration(
2077           Member, ObjCPropertyQueryKind::OBJC_PR_query_instance)) {
2078       if (const ObjCPropertyDecl *PDecl = Setter->findPropertyDecl()) {
2079         // Do not warn if user is using property-dot syntax to make call to
2080         // user named setter.
2081         if (!(PDecl->getPropertyAttributes() &
2082               ObjCPropertyAttribute::kind_setter))
2083           Diag(MemberLoc,
2084                diag::warn_property_access_suggest)
2085           << MemberName << QualType(OPT, 0) << PDecl->getName()
2086           << FixItHint::CreateReplacement(MemberLoc, PDecl->getName());
2087       }
2088   }
2089 
2090   if (Getter || Setter) {
2091     if (Super)
2092       return new (Context)
2093           ObjCPropertyRefExpr(Getter, Setter, Context.PseudoObjectTy, VK_LValue,
2094                               OK_ObjCProperty, MemberLoc, SuperLoc, SuperType);
2095     else
2096       return new (Context)
2097           ObjCPropertyRefExpr(Getter, Setter, Context.PseudoObjectTy, VK_LValue,
2098                               OK_ObjCProperty, MemberLoc, BaseExpr);
2099 
2100   }
2101 
2102   // Attempt to correct for typos in property names.
2103   DeclFilterCCC<ObjCPropertyDecl> CCC{};
2104   if (TypoCorrection Corrected = CorrectTypo(
2105           DeclarationNameInfo(MemberName, MemberLoc), LookupOrdinaryName,
2106           nullptr, nullptr, CCC, CTK_ErrorRecovery, IFace, false, OPT)) {
2107     DeclarationName TypoResult = Corrected.getCorrection();
2108     if (TypoResult.isIdentifier() &&
2109         TypoResult.getAsIdentifierInfo() == Member) {
2110       // There is no need to try the correction if it is the same.
2111       NamedDecl *ChosenDecl =
2112         Corrected.isKeyword() ? nullptr : Corrected.getFoundDecl();
2113       if (ChosenDecl && isa<ObjCPropertyDecl>(ChosenDecl))
2114         if (cast<ObjCPropertyDecl>(ChosenDecl)->isClassProperty()) {
2115           // This is a class property, we should not use the instance to
2116           // access it.
2117           Diag(MemberLoc, diag::err_class_property_found) << MemberName
2118           << OPT->getInterfaceDecl()->getName()
2119           << FixItHint::CreateReplacement(BaseExpr->getSourceRange(),
2120                                           OPT->getInterfaceDecl()->getName());
2121           return ExprError();
2122         }
2123     } else {
2124       diagnoseTypo(Corrected, PDiag(diag::err_property_not_found_suggest)
2125                                 << MemberName << QualType(OPT, 0));
2126       return HandleExprPropertyRefExpr(OPT, BaseExpr, OpLoc,
2127                                        TypoResult, MemberLoc,
2128                                        SuperLoc, SuperType, Super);
2129     }
2130   }
2131   ObjCInterfaceDecl *ClassDeclared;
2132   if (ObjCIvarDecl *Ivar =
2133       IFace->lookupInstanceVariable(Member, ClassDeclared)) {
2134     QualType T = Ivar->getType();
2135     if (const ObjCObjectPointerType * OBJPT =
2136         T->getAsObjCInterfacePointerType()) {
2137       if (RequireCompleteType(MemberLoc, OBJPT->getPointeeType(),
2138                               diag::err_property_not_as_forward_class,
2139                               MemberName, BaseExpr))
2140         return ExprError();
2141     }
2142     Diag(MemberLoc,
2143          diag::err_ivar_access_using_property_syntax_suggest)
2144     << MemberName << QualType(OPT, 0) << Ivar->getDeclName()
2145     << FixItHint::CreateReplacement(OpLoc, "->");
2146     return ExprError();
2147   }
2148 
2149   Diag(MemberLoc, diag::err_property_not_found)
2150     << MemberName << QualType(OPT, 0);
2151   if (Setter)
2152     Diag(Setter->getLocation(), diag::note_getter_unavailable)
2153           << MemberName << BaseExpr->getSourceRange();
2154   return ExprError();
2155 }
2156 
2157 ExprResult Sema::
2158 ActOnClassPropertyRefExpr(IdentifierInfo &receiverName,
2159                           IdentifierInfo &propertyName,
2160                           SourceLocation receiverNameLoc,
2161                           SourceLocation propertyNameLoc) {
2162 
2163   IdentifierInfo *receiverNamePtr = &receiverName;
2164   ObjCInterfaceDecl *IFace = getObjCInterfaceDecl(receiverNamePtr,
2165                                                   receiverNameLoc);
2166 
2167   QualType SuperType;
2168   if (!IFace) {
2169     // If the "receiver" is 'super' in a method, handle it as an expression-like
2170     // property reference.
2171     if (receiverNamePtr->isStr("super")) {
2172       if (ObjCMethodDecl *CurMethod = tryCaptureObjCSelf(receiverNameLoc)) {
2173         if (auto classDecl = CurMethod->getClassInterface()) {
2174           SuperType = QualType(classDecl->getSuperClassType(), 0);
2175           if (CurMethod->isInstanceMethod()) {
2176             if (SuperType.isNull()) {
2177               // The current class does not have a superclass.
2178               Diag(receiverNameLoc, diag::err_root_class_cannot_use_super)
2179                 << CurMethod->getClassInterface()->getIdentifier();
2180               return ExprError();
2181             }
2182             QualType T = Context.getObjCObjectPointerType(SuperType);
2183 
2184             return HandleExprPropertyRefExpr(T->castAs<ObjCObjectPointerType>(),
2185                                              /*BaseExpr*/nullptr,
2186                                              SourceLocation()/*OpLoc*/,
2187                                              &propertyName,
2188                                              propertyNameLoc,
2189                                              receiverNameLoc, T, true);
2190           }
2191 
2192           // Otherwise, if this is a class method, try dispatching to our
2193           // superclass.
2194           IFace = CurMethod->getClassInterface()->getSuperClass();
2195         }
2196       }
2197     }
2198 
2199     if (!IFace) {
2200       Diag(receiverNameLoc, diag::err_expected_either) << tok::identifier
2201                                                        << tok::l_paren;
2202       return ExprError();
2203     }
2204   }
2205 
2206   Selector GetterSel;
2207   Selector SetterSel;
2208   if (auto PD = IFace->FindPropertyDeclaration(
2209           &propertyName, ObjCPropertyQueryKind::OBJC_PR_query_class)) {
2210     GetterSel = PD->getGetterName();
2211     SetterSel = PD->getSetterName();
2212   } else {
2213     GetterSel = PP.getSelectorTable().getNullarySelector(&propertyName);
2214     SetterSel = SelectorTable::constructSetterSelector(
2215         PP.getIdentifierTable(), PP.getSelectorTable(), &propertyName);
2216   }
2217 
2218   // Search for a declared property first.
2219   ObjCMethodDecl *Getter = IFace->lookupClassMethod(GetterSel);
2220 
2221   // If this reference is in an @implementation, check for 'private' methods.
2222   if (!Getter)
2223     Getter = IFace->lookupPrivateClassMethod(GetterSel);
2224 
2225   if (Getter) {
2226     // FIXME: refactor/share with ActOnMemberReference().
2227     // Check if we can reference this property.
2228     if (DiagnoseUseOfDecl(Getter, propertyNameLoc))
2229       return ExprError();
2230   }
2231 
2232   // Look for the matching setter, in case it is needed.
2233   ObjCMethodDecl *Setter = IFace->lookupClassMethod(SetterSel);
2234   if (!Setter) {
2235     // If this reference is in an @implementation, also check for 'private'
2236     // methods.
2237     Setter = IFace->lookupPrivateClassMethod(SetterSel);
2238   }
2239   // Look through local category implementations associated with the class.
2240   if (!Setter)
2241     Setter = IFace->getCategoryClassMethod(SetterSel);
2242 
2243   if (Setter && DiagnoseUseOfDecl(Setter, propertyNameLoc))
2244     return ExprError();
2245 
2246   if (Getter || Setter) {
2247     if (!SuperType.isNull())
2248       return new (Context)
2249           ObjCPropertyRefExpr(Getter, Setter, Context.PseudoObjectTy, VK_LValue,
2250                               OK_ObjCProperty, propertyNameLoc, receiverNameLoc,
2251                               SuperType);
2252 
2253     return new (Context) ObjCPropertyRefExpr(
2254         Getter, Setter, Context.PseudoObjectTy, VK_LValue, OK_ObjCProperty,
2255         propertyNameLoc, receiverNameLoc, IFace);
2256   }
2257   return ExprError(Diag(propertyNameLoc, diag::err_property_not_found)
2258                      << &propertyName << Context.getObjCInterfaceType(IFace));
2259 }
2260 
2261 namespace {
2262 
2263 class ObjCInterfaceOrSuperCCC final : public CorrectionCandidateCallback {
2264  public:
2265   ObjCInterfaceOrSuperCCC(ObjCMethodDecl *Method) {
2266     // Determine whether "super" is acceptable in the current context.
2267     if (Method && Method->getClassInterface())
2268       WantObjCSuper = Method->getClassInterface()->getSuperClass();
2269   }
2270 
2271   bool ValidateCandidate(const TypoCorrection &candidate) override {
2272     return candidate.getCorrectionDeclAs<ObjCInterfaceDecl>() ||
2273         candidate.isKeyword("super");
2274   }
2275 
2276   std::unique_ptr<CorrectionCandidateCallback> clone() override {
2277     return std::make_unique<ObjCInterfaceOrSuperCCC>(*this);
2278   }
2279 };
2280 
2281 } // end anonymous namespace
2282 
2283 Sema::ObjCMessageKind Sema::getObjCMessageKind(Scope *S,
2284                                                IdentifierInfo *Name,
2285                                                SourceLocation NameLoc,
2286                                                bool IsSuper,
2287                                                bool HasTrailingDot,
2288                                                ParsedType &ReceiverType) {
2289   ReceiverType = nullptr;
2290 
2291   // If the identifier is "super" and there is no trailing dot, we're
2292   // messaging super. If the identifier is "super" and there is a
2293   // trailing dot, it's an instance message.
2294   if (IsSuper && S->isInObjcMethodScope())
2295     return HasTrailingDot? ObjCInstanceMessage : ObjCSuperMessage;
2296 
2297   LookupResult Result(*this, Name, NameLoc, LookupOrdinaryName);
2298   LookupName(Result, S);
2299 
2300   switch (Result.getResultKind()) {
2301   case LookupResult::NotFound:
2302     // Normal name lookup didn't find anything. If we're in an
2303     // Objective-C method, look for ivars. If we find one, we're done!
2304     // FIXME: This is a hack. Ivar lookup should be part of normal
2305     // lookup.
2306     if (ObjCMethodDecl *Method = getCurMethodDecl()) {
2307       if (!Method->getClassInterface()) {
2308         // Fall back: let the parser try to parse it as an instance message.
2309         return ObjCInstanceMessage;
2310       }
2311 
2312       ObjCInterfaceDecl *ClassDeclared;
2313       if (Method->getClassInterface()->lookupInstanceVariable(Name,
2314                                                               ClassDeclared))
2315         return ObjCInstanceMessage;
2316     }
2317 
2318     // Break out; we'll perform typo correction below.
2319     break;
2320 
2321   case LookupResult::NotFoundInCurrentInstantiation:
2322   case LookupResult::FoundOverloaded:
2323   case LookupResult::FoundUnresolvedValue:
2324   case LookupResult::Ambiguous:
2325     Result.suppressDiagnostics();
2326     return ObjCInstanceMessage;
2327 
2328   case LookupResult::Found: {
2329     // If the identifier is a class or not, and there is a trailing dot,
2330     // it's an instance message.
2331     if (HasTrailingDot)
2332       return ObjCInstanceMessage;
2333     // We found something. If it's a type, then we have a class
2334     // message. Otherwise, it's an instance message.
2335     NamedDecl *ND = Result.getFoundDecl();
2336     QualType T;
2337     if (ObjCInterfaceDecl *Class = dyn_cast<ObjCInterfaceDecl>(ND))
2338       T = Context.getObjCInterfaceType(Class);
2339     else if (TypeDecl *Type = dyn_cast<TypeDecl>(ND)) {
2340       T = Context.getTypeDeclType(Type);
2341       DiagnoseUseOfDecl(Type, NameLoc);
2342     }
2343     else
2344       return ObjCInstanceMessage;
2345 
2346     //  We have a class message, and T is the type we're
2347     //  messaging. Build source-location information for it.
2348     TypeSourceInfo *TSInfo = Context.getTrivialTypeSourceInfo(T, NameLoc);
2349     ReceiverType = CreateParsedType(T, TSInfo);
2350     return ObjCClassMessage;
2351   }
2352   }
2353 
2354   ObjCInterfaceOrSuperCCC CCC(getCurMethodDecl());
2355   if (TypoCorrection Corrected = CorrectTypo(
2356           Result.getLookupNameInfo(), Result.getLookupKind(), S, nullptr, CCC,
2357           CTK_ErrorRecovery, nullptr, false, nullptr, false)) {
2358     if (Corrected.isKeyword()) {
2359       // If we've found the keyword "super" (the only keyword that would be
2360       // returned by CorrectTypo), this is a send to super.
2361       diagnoseTypo(Corrected,
2362                    PDiag(diag::err_unknown_receiver_suggest) << Name);
2363       return ObjCSuperMessage;
2364     } else if (ObjCInterfaceDecl *Class =
2365                    Corrected.getCorrectionDeclAs<ObjCInterfaceDecl>()) {
2366       // If we found a declaration, correct when it refers to an Objective-C
2367       // class.
2368       diagnoseTypo(Corrected,
2369                    PDiag(diag::err_unknown_receiver_suggest) << Name);
2370       QualType T = Context.getObjCInterfaceType(Class);
2371       TypeSourceInfo *TSInfo = Context.getTrivialTypeSourceInfo(T, NameLoc);
2372       ReceiverType = CreateParsedType(T, TSInfo);
2373       return ObjCClassMessage;
2374     }
2375   }
2376 
2377   // Fall back: let the parser try to parse it as an instance message.
2378   return ObjCInstanceMessage;
2379 }
2380 
2381 ExprResult Sema::ActOnSuperMessage(Scope *S,
2382                                    SourceLocation SuperLoc,
2383                                    Selector Sel,
2384                                    SourceLocation LBracLoc,
2385                                    ArrayRef<SourceLocation> SelectorLocs,
2386                                    SourceLocation RBracLoc,
2387                                    MultiExprArg Args) {
2388   // Determine whether we are inside a method or not.
2389   ObjCMethodDecl *Method = tryCaptureObjCSelf(SuperLoc);
2390   if (!Method) {
2391     Diag(SuperLoc, diag::err_invalid_receiver_to_message_super);
2392     return ExprError();
2393   }
2394 
2395   ObjCInterfaceDecl *Class = Method->getClassInterface();
2396   if (!Class) {
2397     Diag(SuperLoc, diag::err_no_super_class_message)
2398       << Method->getDeclName();
2399     return ExprError();
2400   }
2401 
2402   QualType SuperTy(Class->getSuperClassType(), 0);
2403   if (SuperTy.isNull()) {
2404     // The current class does not have a superclass.
2405     Diag(SuperLoc, diag::err_root_class_cannot_use_super)
2406       << Class->getIdentifier();
2407     return ExprError();
2408   }
2409 
2410   // We are in a method whose class has a superclass, so 'super'
2411   // is acting as a keyword.
2412   if (Method->getSelector() == Sel)
2413     getCurFunction()->ObjCShouldCallSuper = false;
2414 
2415   if (Method->isInstanceMethod()) {
2416     // Since we are in an instance method, this is an instance
2417     // message to the superclass instance.
2418     SuperTy = Context.getObjCObjectPointerType(SuperTy);
2419     return BuildInstanceMessage(nullptr, SuperTy, SuperLoc,
2420                                 Sel, /*Method=*/nullptr,
2421                                 LBracLoc, SelectorLocs, RBracLoc, Args);
2422   }
2423 
2424   // Since we are in a class method, this is a class message to
2425   // the superclass.
2426   return BuildClassMessage(/*ReceiverTypeInfo=*/nullptr,
2427                            SuperTy,
2428                            SuperLoc, Sel, /*Method=*/nullptr,
2429                            LBracLoc, SelectorLocs, RBracLoc, Args);
2430 }
2431 
2432 ExprResult Sema::BuildClassMessageImplicit(QualType ReceiverType,
2433                                            bool isSuperReceiver,
2434                                            SourceLocation Loc,
2435                                            Selector Sel,
2436                                            ObjCMethodDecl *Method,
2437                                            MultiExprArg Args) {
2438   TypeSourceInfo *receiverTypeInfo = nullptr;
2439   if (!ReceiverType.isNull())
2440     receiverTypeInfo = Context.getTrivialTypeSourceInfo(ReceiverType);
2441 
2442   return BuildClassMessage(receiverTypeInfo, ReceiverType,
2443                           /*SuperLoc=*/isSuperReceiver ? Loc : SourceLocation(),
2444                            Sel, Method, Loc, Loc, Loc, Args,
2445                            /*isImplicit=*/true);
2446 }
2447 
2448 static void applyCocoaAPICheck(Sema &S, const ObjCMessageExpr *Msg,
2449                                unsigned DiagID,
2450                                bool (*refactor)(const ObjCMessageExpr *,
2451                                               const NSAPI &, edit::Commit &)) {
2452   SourceLocation MsgLoc = Msg->getExprLoc();
2453   if (S.Diags.isIgnored(DiagID, MsgLoc))
2454     return;
2455 
2456   SourceManager &SM = S.SourceMgr;
2457   edit::Commit ECommit(SM, S.LangOpts);
2458   if (refactor(Msg,*S.NSAPIObj, ECommit)) {
2459     auto Builder = S.Diag(MsgLoc, DiagID)
2460                    << Msg->getSelector() << Msg->getSourceRange();
2461     // FIXME: Don't emit diagnostic at all if fixits are non-commitable.
2462     if (!ECommit.isCommitable())
2463       return;
2464     for (edit::Commit::edit_iterator
2465            I = ECommit.edit_begin(), E = ECommit.edit_end(); I != E; ++I) {
2466       const edit::Commit::Edit &Edit = *I;
2467       switch (Edit.Kind) {
2468       case edit::Commit::Act_Insert:
2469         Builder.AddFixItHint(FixItHint::CreateInsertion(Edit.OrigLoc,
2470                                                         Edit.Text,
2471                                                         Edit.BeforePrev));
2472         break;
2473       case edit::Commit::Act_InsertFromRange:
2474         Builder.AddFixItHint(
2475             FixItHint::CreateInsertionFromRange(Edit.OrigLoc,
2476                                                 Edit.getInsertFromRange(SM),
2477                                                 Edit.BeforePrev));
2478         break;
2479       case edit::Commit::Act_Remove:
2480         Builder.AddFixItHint(FixItHint::CreateRemoval(Edit.getFileRange(SM)));
2481         break;
2482       }
2483     }
2484   }
2485 }
2486 
2487 static void checkCocoaAPI(Sema &S, const ObjCMessageExpr *Msg) {
2488   applyCocoaAPICheck(S, Msg, diag::warn_objc_redundant_literal_use,
2489                      edit::rewriteObjCRedundantCallWithLiteral);
2490 }
2491 
2492 static void checkFoundationAPI(Sema &S, SourceLocation Loc,
2493                                const ObjCMethodDecl *Method,
2494                                ArrayRef<Expr *> Args, QualType ReceiverType,
2495                                bool IsClassObjectCall) {
2496   // Check if this is a performSelector method that uses a selector that returns
2497   // a record or a vector type.
2498   if (Method->getSelector().getMethodFamily() != OMF_performSelector ||
2499       Args.empty())
2500     return;
2501   const auto *SE = dyn_cast<ObjCSelectorExpr>(Args[0]->IgnoreParens());
2502   if (!SE)
2503     return;
2504   ObjCMethodDecl *ImpliedMethod;
2505   if (!IsClassObjectCall) {
2506     const auto *OPT = ReceiverType->getAs<ObjCObjectPointerType>();
2507     if (!OPT || !OPT->getInterfaceDecl())
2508       return;
2509     ImpliedMethod =
2510         OPT->getInterfaceDecl()->lookupInstanceMethod(SE->getSelector());
2511     if (!ImpliedMethod)
2512       ImpliedMethod =
2513           OPT->getInterfaceDecl()->lookupPrivateMethod(SE->getSelector());
2514   } else {
2515     const auto *IT = ReceiverType->getAs<ObjCInterfaceType>();
2516     if (!IT)
2517       return;
2518     ImpliedMethod = IT->getDecl()->lookupClassMethod(SE->getSelector());
2519     if (!ImpliedMethod)
2520       ImpliedMethod =
2521           IT->getDecl()->lookupPrivateClassMethod(SE->getSelector());
2522   }
2523   if (!ImpliedMethod)
2524     return;
2525   QualType Ret = ImpliedMethod->getReturnType();
2526   if (Ret->isRecordType() || Ret->isVectorType() || Ret->isExtVectorType()) {
2527     S.Diag(Loc, diag::warn_objc_unsafe_perform_selector)
2528         << Method->getSelector()
2529         << (!Ret->isRecordType()
2530                 ? /*Vector*/ 2
2531                 : Ret->isUnionType() ? /*Union*/ 1 : /*Struct*/ 0);
2532     S.Diag(ImpliedMethod->getBeginLoc(),
2533            diag::note_objc_unsafe_perform_selector_method_declared_here)
2534         << ImpliedMethod->getSelector() << Ret;
2535   }
2536 }
2537 
2538 /// Diagnose use of %s directive in an NSString which is being passed
2539 /// as formatting string to formatting method.
2540 static void
2541 DiagnoseCStringFormatDirectiveInObjCAPI(Sema &S,
2542                                         ObjCMethodDecl *Method,
2543                                         Selector Sel,
2544                                         Expr **Args, unsigned NumArgs) {
2545   unsigned Idx = 0;
2546   bool Format = false;
2547   ObjCStringFormatFamily SFFamily = Sel.getStringFormatFamily();
2548   if (SFFamily == ObjCStringFormatFamily::SFF_NSString) {
2549     Idx = 0;
2550     Format = true;
2551   }
2552   else if (Method) {
2553     for (const auto *I : Method->specific_attrs<FormatAttr>()) {
2554       if (S.GetFormatNSStringIdx(I, Idx)) {
2555         Format = true;
2556         break;
2557       }
2558     }
2559   }
2560   if (!Format || NumArgs <= Idx)
2561     return;
2562 
2563   Expr *FormatExpr = Args[Idx];
2564   if (ObjCStringLiteral *OSL =
2565       dyn_cast<ObjCStringLiteral>(FormatExpr->IgnoreParenImpCasts())) {
2566     StringLiteral *FormatString = OSL->getString();
2567     if (S.FormatStringHasSArg(FormatString)) {
2568       S.Diag(FormatExpr->getExprLoc(), diag::warn_objc_cdirective_format_string)
2569         << "%s" << 0 << 0;
2570       if (Method)
2571         S.Diag(Method->getLocation(), diag::note_method_declared_at)
2572           << Method->getDeclName();
2573     }
2574   }
2575 }
2576 
2577 /// Build an Objective-C class message expression.
2578 ///
2579 /// This routine takes care of both normal class messages and
2580 /// class messages to the superclass.
2581 ///
2582 /// \param ReceiverTypeInfo Type source information that describes the
2583 /// receiver of this message. This may be NULL, in which case we are
2584 /// sending to the superclass and \p SuperLoc must be a valid source
2585 /// location.
2586 
2587 /// \param ReceiverType The type of the object receiving the
2588 /// message. When \p ReceiverTypeInfo is non-NULL, this is the same
2589 /// type as that refers to. For a superclass send, this is the type of
2590 /// the superclass.
2591 ///
2592 /// \param SuperLoc The location of the "super" keyword in a
2593 /// superclass message.
2594 ///
2595 /// \param Sel The selector to which the message is being sent.
2596 ///
2597 /// \param Method The method that this class message is invoking, if
2598 /// already known.
2599 ///
2600 /// \param LBracLoc The location of the opening square bracket ']'.
2601 ///
2602 /// \param RBracLoc The location of the closing square bracket ']'.
2603 ///
2604 /// \param ArgsIn The message arguments.
2605 ExprResult Sema::BuildClassMessage(TypeSourceInfo *ReceiverTypeInfo,
2606                                    QualType ReceiverType,
2607                                    SourceLocation SuperLoc,
2608                                    Selector Sel,
2609                                    ObjCMethodDecl *Method,
2610                                    SourceLocation LBracLoc,
2611                                    ArrayRef<SourceLocation> SelectorLocs,
2612                                    SourceLocation RBracLoc,
2613                                    MultiExprArg ArgsIn,
2614                                    bool isImplicit) {
2615   SourceLocation Loc = SuperLoc.isValid()? SuperLoc
2616     : ReceiverTypeInfo->getTypeLoc().getSourceRange().getBegin();
2617   if (LBracLoc.isInvalid()) {
2618     Diag(Loc, diag::err_missing_open_square_message_send)
2619       << FixItHint::CreateInsertion(Loc, "[");
2620     LBracLoc = Loc;
2621   }
2622   ArrayRef<SourceLocation> SelectorSlotLocs;
2623   if (!SelectorLocs.empty() && SelectorLocs.front().isValid())
2624     SelectorSlotLocs = SelectorLocs;
2625   else
2626     SelectorSlotLocs = Loc;
2627   SourceLocation SelLoc = SelectorSlotLocs.front();
2628 
2629   if (ReceiverType->isDependentType()) {
2630     // If the receiver type is dependent, we can't type-check anything
2631     // at this point. Build a dependent expression.
2632     unsigned NumArgs = ArgsIn.size();
2633     Expr **Args = ArgsIn.data();
2634     assert(SuperLoc.isInvalid() && "Message to super with dependent type");
2635     return ObjCMessageExpr::Create(
2636         Context, ReceiverType, VK_RValue, LBracLoc, ReceiverTypeInfo, Sel,
2637         SelectorLocs, /*Method=*/nullptr, makeArrayRef(Args, NumArgs), RBracLoc,
2638         isImplicit);
2639   }
2640 
2641   // Find the class to which we are sending this message.
2642   ObjCInterfaceDecl *Class = nullptr;
2643   const ObjCObjectType *ClassType = ReceiverType->getAs<ObjCObjectType>();
2644   if (!ClassType || !(Class = ClassType->getInterface())) {
2645     Diag(Loc, diag::err_invalid_receiver_class_message)
2646       << ReceiverType;
2647     return ExprError();
2648   }
2649   assert(Class && "We don't know which class we're messaging?");
2650   // objc++ diagnoses during typename annotation.
2651   if (!getLangOpts().CPlusPlus)
2652     (void)DiagnoseUseOfDecl(Class, SelectorSlotLocs);
2653   // Find the method we are messaging.
2654   if (!Method) {
2655     SourceRange TypeRange
2656       = SuperLoc.isValid()? SourceRange(SuperLoc)
2657                           : ReceiverTypeInfo->getTypeLoc().getSourceRange();
2658     if (RequireCompleteType(Loc, Context.getObjCInterfaceType(Class),
2659                             (getLangOpts().ObjCAutoRefCount
2660                                ? diag::err_arc_receiver_forward_class
2661                                : diag::warn_receiver_forward_class),
2662                             TypeRange)) {
2663       // A forward class used in messaging is treated as a 'Class'
2664       Method = LookupFactoryMethodInGlobalPool(Sel,
2665                                                SourceRange(LBracLoc, RBracLoc));
2666       if (Method && !getLangOpts().ObjCAutoRefCount)
2667         Diag(Method->getLocation(), diag::note_method_sent_forward_class)
2668           << Method->getDeclName();
2669     }
2670     if (!Method)
2671       Method = Class->lookupClassMethod(Sel);
2672 
2673     // If we have an implementation in scope, check "private" methods.
2674     if (!Method)
2675       Method = Class->lookupPrivateClassMethod(Sel);
2676 
2677     if (Method && DiagnoseUseOfDecl(Method, SelectorSlotLocs,
2678                                     nullptr, false, false, Class))
2679       return ExprError();
2680   }
2681 
2682   // Check the argument types and determine the result type.
2683   QualType ReturnType;
2684   ExprValueKind VK = VK_RValue;
2685 
2686   unsigned NumArgs = ArgsIn.size();
2687   Expr **Args = ArgsIn.data();
2688   if (CheckMessageArgumentTypes(/*Receiver=*/nullptr, ReceiverType,
2689                                 MultiExprArg(Args, NumArgs), Sel, SelectorLocs,
2690                                 Method, true, SuperLoc.isValid(), LBracLoc,
2691                                 RBracLoc, SourceRange(), ReturnType, VK))
2692     return ExprError();
2693 
2694   if (Method && !Method->getReturnType()->isVoidType() &&
2695       RequireCompleteType(LBracLoc, Method->getReturnType(),
2696                           diag::err_illegal_message_expr_incomplete_type))
2697     return ExprError();
2698 
2699   if (Method && Method->isDirectMethod() && SuperLoc.isValid()) {
2700     Diag(SuperLoc, diag::err_messaging_super_with_direct_method)
2701         << FixItHint::CreateReplacement(
2702                SuperLoc, getLangOpts().ObjCAutoRefCount
2703                              ? "self"
2704                              : Method->getClassInterface()->getName());
2705     Diag(Method->getLocation(), diag::note_direct_method_declared_at)
2706         << Method->getDeclName();
2707   }
2708 
2709   // Warn about explicit call of +initialize on its own class. But not on 'super'.
2710   if (Method && Method->getMethodFamily() == OMF_initialize) {
2711     if (!SuperLoc.isValid()) {
2712       const ObjCInterfaceDecl *ID =
2713         dyn_cast<ObjCInterfaceDecl>(Method->getDeclContext());
2714       if (ID == Class) {
2715         Diag(Loc, diag::warn_direct_initialize_call);
2716         Diag(Method->getLocation(), diag::note_method_declared_at)
2717           << Method->getDeclName();
2718       }
2719     }
2720     else if (ObjCMethodDecl *CurMeth = getCurMethodDecl()) {
2721       // [super initialize] is allowed only within an +initialize implementation
2722       if (CurMeth->getMethodFamily() != OMF_initialize) {
2723         Diag(Loc, diag::warn_direct_super_initialize_call);
2724         Diag(Method->getLocation(), diag::note_method_declared_at)
2725           << Method->getDeclName();
2726         Diag(CurMeth->getLocation(), diag::note_method_declared_at)
2727         << CurMeth->getDeclName();
2728       }
2729     }
2730   }
2731 
2732   DiagnoseCStringFormatDirectiveInObjCAPI(*this, Method, Sel, Args, NumArgs);
2733 
2734   // Construct the appropriate ObjCMessageExpr.
2735   ObjCMessageExpr *Result;
2736   if (SuperLoc.isValid())
2737     Result = ObjCMessageExpr::Create(Context, ReturnType, VK, LBracLoc,
2738                                      SuperLoc, /*IsInstanceSuper=*/false,
2739                                      ReceiverType, Sel, SelectorLocs,
2740                                      Method, makeArrayRef(Args, NumArgs),
2741                                      RBracLoc, isImplicit);
2742   else {
2743     Result = ObjCMessageExpr::Create(Context, ReturnType, VK, LBracLoc,
2744                                      ReceiverTypeInfo, Sel, SelectorLocs,
2745                                      Method, makeArrayRef(Args, NumArgs),
2746                                      RBracLoc, isImplicit);
2747     if (!isImplicit)
2748       checkCocoaAPI(*this, Result);
2749   }
2750   if (Method)
2751     checkFoundationAPI(*this, SelLoc, Method, makeArrayRef(Args, NumArgs),
2752                        ReceiverType, /*IsClassObjectCall=*/true);
2753   return MaybeBindToTemporary(Result);
2754 }
2755 
2756 // ActOnClassMessage - used for both unary and keyword messages.
2757 // ArgExprs is optional - if it is present, the number of expressions
2758 // is obtained from Sel.getNumArgs().
2759 ExprResult Sema::ActOnClassMessage(Scope *S,
2760                                    ParsedType Receiver,
2761                                    Selector Sel,
2762                                    SourceLocation LBracLoc,
2763                                    ArrayRef<SourceLocation> SelectorLocs,
2764                                    SourceLocation RBracLoc,
2765                                    MultiExprArg Args) {
2766   TypeSourceInfo *ReceiverTypeInfo;
2767   QualType ReceiverType = GetTypeFromParser(Receiver, &ReceiverTypeInfo);
2768   if (ReceiverType.isNull())
2769     return ExprError();
2770 
2771   if (!ReceiverTypeInfo)
2772     ReceiverTypeInfo = Context.getTrivialTypeSourceInfo(ReceiverType, LBracLoc);
2773 
2774   return BuildClassMessage(ReceiverTypeInfo, ReceiverType,
2775                            /*SuperLoc=*/SourceLocation(), Sel,
2776                            /*Method=*/nullptr, LBracLoc, SelectorLocs, RBracLoc,
2777                            Args);
2778 }
2779 
2780 ExprResult Sema::BuildInstanceMessageImplicit(Expr *Receiver,
2781                                               QualType ReceiverType,
2782                                               SourceLocation Loc,
2783                                               Selector Sel,
2784                                               ObjCMethodDecl *Method,
2785                                               MultiExprArg Args) {
2786   return BuildInstanceMessage(Receiver, ReceiverType,
2787                               /*SuperLoc=*/!Receiver ? Loc : SourceLocation(),
2788                               Sel, Method, Loc, Loc, Loc, Args,
2789                               /*isImplicit=*/true);
2790 }
2791 
2792 static bool isMethodDeclaredInRootProtocol(Sema &S, const ObjCMethodDecl *M) {
2793   if (!S.NSAPIObj)
2794     return false;
2795   const auto *Protocol = dyn_cast<ObjCProtocolDecl>(M->getDeclContext());
2796   if (!Protocol)
2797     return false;
2798   const IdentifierInfo *II = S.NSAPIObj->getNSClassId(NSAPI::ClassId_NSObject);
2799   if (const auto *RootClass = dyn_cast_or_null<ObjCInterfaceDecl>(
2800           S.LookupSingleName(S.TUScope, II, Protocol->getBeginLoc(),
2801                              Sema::LookupOrdinaryName))) {
2802     for (const ObjCProtocolDecl *P : RootClass->all_referenced_protocols()) {
2803       if (P->getCanonicalDecl() == Protocol->getCanonicalDecl())
2804         return true;
2805     }
2806   }
2807   return false;
2808 }
2809 
2810 /// Build an Objective-C instance message expression.
2811 ///
2812 /// This routine takes care of both normal instance messages and
2813 /// instance messages to the superclass instance.
2814 ///
2815 /// \param Receiver The expression that computes the object that will
2816 /// receive this message. This may be empty, in which case we are
2817 /// sending to the superclass instance and \p SuperLoc must be a valid
2818 /// source location.
2819 ///
2820 /// \param ReceiverType The (static) type of the object receiving the
2821 /// message. When a \p Receiver expression is provided, this is the
2822 /// same type as that expression. For a superclass instance send, this
2823 /// is a pointer to the type of the superclass.
2824 ///
2825 /// \param SuperLoc The location of the "super" keyword in a
2826 /// superclass instance message.
2827 ///
2828 /// \param Sel The selector to which the message is being sent.
2829 ///
2830 /// \param Method The method that this instance message is invoking, if
2831 /// already known.
2832 ///
2833 /// \param LBracLoc The location of the opening square bracket ']'.
2834 ///
2835 /// \param RBracLoc The location of the closing square bracket ']'.
2836 ///
2837 /// \param ArgsIn The message arguments.
2838 ExprResult Sema::BuildInstanceMessage(Expr *Receiver,
2839                                       QualType ReceiverType,
2840                                       SourceLocation SuperLoc,
2841                                       Selector Sel,
2842                                       ObjCMethodDecl *Method,
2843                                       SourceLocation LBracLoc,
2844                                       ArrayRef<SourceLocation> SelectorLocs,
2845                                       SourceLocation RBracLoc,
2846                                       MultiExprArg ArgsIn,
2847                                       bool isImplicit) {
2848   assert((Receiver || SuperLoc.isValid()) && "If the Receiver is null, the "
2849                                              "SuperLoc must be valid so we can "
2850                                              "use it instead.");
2851 
2852   // The location of the receiver.
2853   SourceLocation Loc = SuperLoc.isValid() ? SuperLoc : Receiver->getBeginLoc();
2854   SourceRange RecRange =
2855       SuperLoc.isValid()? SuperLoc : Receiver->getSourceRange();
2856   ArrayRef<SourceLocation> SelectorSlotLocs;
2857   if (!SelectorLocs.empty() && SelectorLocs.front().isValid())
2858     SelectorSlotLocs = SelectorLocs;
2859   else
2860     SelectorSlotLocs = Loc;
2861   SourceLocation SelLoc = SelectorSlotLocs.front();
2862 
2863   if (LBracLoc.isInvalid()) {
2864     Diag(Loc, diag::err_missing_open_square_message_send)
2865       << FixItHint::CreateInsertion(Loc, "[");
2866     LBracLoc = Loc;
2867   }
2868 
2869   // If we have a receiver expression, perform appropriate promotions
2870   // and determine receiver type.
2871   if (Receiver) {
2872     if (Receiver->hasPlaceholderType()) {
2873       ExprResult Result;
2874       if (Receiver->getType() == Context.UnknownAnyTy)
2875         Result = forceUnknownAnyToType(Receiver, Context.getObjCIdType());
2876       else
2877         Result = CheckPlaceholderExpr(Receiver);
2878       if (Result.isInvalid()) return ExprError();
2879       Receiver = Result.get();
2880     }
2881 
2882     if (Receiver->isTypeDependent()) {
2883       // If the receiver is type-dependent, we can't type-check anything
2884       // at this point. Build a dependent expression.
2885       unsigned NumArgs = ArgsIn.size();
2886       Expr **Args = ArgsIn.data();
2887       assert(SuperLoc.isInvalid() && "Message to super with dependent type");
2888       return ObjCMessageExpr::Create(
2889           Context, Context.DependentTy, VK_RValue, LBracLoc, Receiver, Sel,
2890           SelectorLocs, /*Method=*/nullptr, makeArrayRef(Args, NumArgs),
2891           RBracLoc, isImplicit);
2892     }
2893 
2894     // If necessary, apply function/array conversion to the receiver.
2895     // C99 6.7.5.3p[7,8].
2896     ExprResult Result = DefaultFunctionArrayLvalueConversion(Receiver);
2897     if (Result.isInvalid())
2898       return ExprError();
2899     Receiver = Result.get();
2900     ReceiverType = Receiver->getType();
2901 
2902     // If the receiver is an ObjC pointer, a block pointer, or an
2903     // __attribute__((NSObject)) pointer, we don't need to do any
2904     // special conversion in order to look up a receiver.
2905     if (ReceiverType->isObjCRetainableType()) {
2906       // do nothing
2907     } else if (!getLangOpts().ObjCAutoRefCount &&
2908                !Context.getObjCIdType().isNull() &&
2909                (ReceiverType->isPointerType() ||
2910                 ReceiverType->isIntegerType())) {
2911       // Implicitly convert integers and pointers to 'id' but emit a warning.
2912       // But not in ARC.
2913       Diag(Loc, diag::warn_bad_receiver_type) << ReceiverType << RecRange;
2914       if (ReceiverType->isPointerType()) {
2915         Receiver = ImpCastExprToType(Receiver, Context.getObjCIdType(),
2916                                      CK_CPointerToObjCPointerCast).get();
2917       } else {
2918         // TODO: specialized warning on null receivers?
2919         bool IsNull = Receiver->isNullPointerConstant(Context,
2920                                               Expr::NPC_ValueDependentIsNull);
2921         CastKind Kind = IsNull ? CK_NullToPointer : CK_IntegralToPointer;
2922         Receiver = ImpCastExprToType(Receiver, Context.getObjCIdType(),
2923                                      Kind).get();
2924       }
2925       ReceiverType = Receiver->getType();
2926     } else if (getLangOpts().CPlusPlus) {
2927       // The receiver must be a complete type.
2928       if (RequireCompleteType(Loc, Receiver->getType(),
2929                               diag::err_incomplete_receiver_type))
2930         return ExprError();
2931 
2932       ExprResult result = PerformContextuallyConvertToObjCPointer(Receiver);
2933       if (result.isUsable()) {
2934         Receiver = result.get();
2935         ReceiverType = Receiver->getType();
2936       }
2937     }
2938   }
2939 
2940   // There's a somewhat weird interaction here where we assume that we
2941   // won't actually have a method unless we also don't need to do some
2942   // of the more detailed type-checking on the receiver.
2943 
2944   if (!Method) {
2945     // Handle messages to id and __kindof types (where we use the
2946     // global method pool).
2947     const ObjCObjectType *typeBound = nullptr;
2948     bool receiverIsIdLike = ReceiverType->isObjCIdOrObjectKindOfType(Context,
2949                                                                      typeBound);
2950     if (receiverIsIdLike || ReceiverType->isBlockPointerType() ||
2951         (Receiver && Context.isObjCNSObjectType(Receiver->getType()))) {
2952       SmallVector<ObjCMethodDecl*, 4> Methods;
2953       // If we have a type bound, further filter the methods.
2954       CollectMultipleMethodsInGlobalPool(Sel, Methods, true/*InstanceFirst*/,
2955                                          true/*CheckTheOther*/, typeBound);
2956       if (!Methods.empty()) {
2957         // We choose the first method as the initial candidate, then try to
2958         // select a better one.
2959         Method = Methods[0];
2960 
2961         if (ObjCMethodDecl *BestMethod =
2962             SelectBestMethod(Sel, ArgsIn, Method->isInstanceMethod(), Methods))
2963           Method = BestMethod;
2964 
2965         if (!AreMultipleMethodsInGlobalPool(Sel, Method,
2966                                             SourceRange(LBracLoc, RBracLoc),
2967                                             receiverIsIdLike, Methods))
2968           DiagnoseUseOfDecl(Method, SelectorSlotLocs);
2969       }
2970     } else if (ReceiverType->isObjCClassOrClassKindOfType() ||
2971                ReceiverType->isObjCQualifiedClassType()) {
2972       // Handle messages to Class.
2973       // We allow sending a message to a qualified Class ("Class<foo>"), which
2974       // is ok as long as one of the protocols implements the selector (if not,
2975       // warn).
2976       if (!ReceiverType->isObjCClassOrClassKindOfType()) {
2977         const ObjCObjectPointerType *QClassTy
2978           = ReceiverType->getAsObjCQualifiedClassType();
2979         // Search protocols for class methods.
2980         Method = LookupMethodInQualifiedType(Sel, QClassTy, false);
2981         if (!Method) {
2982           Method = LookupMethodInQualifiedType(Sel, QClassTy, true);
2983           // warn if instance method found for a Class message.
2984           if (Method && !isMethodDeclaredInRootProtocol(*this, Method)) {
2985             Diag(SelLoc, diag::warn_instance_method_on_class_found)
2986               << Method->getSelector() << Sel;
2987             Diag(Method->getLocation(), diag::note_method_declared_at)
2988               << Method->getDeclName();
2989           }
2990         }
2991       } else {
2992         if (ObjCMethodDecl *CurMeth = getCurMethodDecl()) {
2993           if (ObjCInterfaceDecl *ClassDecl = CurMeth->getClassInterface()) {
2994             // As a guess, try looking for the method in the current interface.
2995             // This very well may not produce the "right" method.
2996 
2997             // First check the public methods in the class interface.
2998             Method = ClassDecl->lookupClassMethod(Sel);
2999 
3000             if (!Method)
3001               Method = ClassDecl->lookupPrivateClassMethod(Sel);
3002 
3003             if (Method && DiagnoseUseOfDecl(Method, SelectorSlotLocs))
3004               return ExprError();
3005           }
3006         }
3007         if (!Method) {
3008           // If not messaging 'self', look for any factory method named 'Sel'.
3009           if (!Receiver || !isSelfExpr(Receiver)) {
3010             // If no class (factory) method was found, check if an _instance_
3011             // method of the same name exists in the root class only.
3012             SmallVector<ObjCMethodDecl*, 4> Methods;
3013             CollectMultipleMethodsInGlobalPool(Sel, Methods,
3014                                                false/*InstanceFirst*/,
3015                                                true/*CheckTheOther*/);
3016             if (!Methods.empty()) {
3017               // We choose the first method as the initial candidate, then try
3018               // to select a better one.
3019               Method = Methods[0];
3020 
3021               // If we find an instance method, emit warning.
3022               if (Method->isInstanceMethod()) {
3023                 if (const ObjCInterfaceDecl *ID =
3024                     dyn_cast<ObjCInterfaceDecl>(Method->getDeclContext())) {
3025                   if (ID->getSuperClass())
3026                     Diag(SelLoc, diag::warn_root_inst_method_not_found)
3027                         << Sel << SourceRange(LBracLoc, RBracLoc);
3028                 }
3029               }
3030 
3031              if (ObjCMethodDecl *BestMethod =
3032                  SelectBestMethod(Sel, ArgsIn, Method->isInstanceMethod(),
3033                                   Methods))
3034                Method = BestMethod;
3035             }
3036           }
3037         }
3038       }
3039     } else {
3040       ObjCInterfaceDecl *ClassDecl = nullptr;
3041 
3042       // We allow sending a message to a qualified ID ("id<foo>"), which is ok as
3043       // long as one of the protocols implements the selector (if not, warn).
3044       // And as long as message is not deprecated/unavailable (warn if it is).
3045       if (const ObjCObjectPointerType *QIdTy
3046                                    = ReceiverType->getAsObjCQualifiedIdType()) {
3047         // Search protocols for instance methods.
3048         Method = LookupMethodInQualifiedType(Sel, QIdTy, true);
3049         if (!Method)
3050           Method = LookupMethodInQualifiedType(Sel, QIdTy, false);
3051         if (Method && DiagnoseUseOfDecl(Method, SelectorSlotLocs))
3052           return ExprError();
3053       } else if (const ObjCObjectPointerType *OCIType
3054                    = ReceiverType->getAsObjCInterfacePointerType()) {
3055         // We allow sending a message to a pointer to an interface (an object).
3056         ClassDecl = OCIType->getInterfaceDecl();
3057 
3058         // Try to complete the type. Under ARC, this is a hard error from which
3059         // we don't try to recover.
3060         // FIXME: In the non-ARC case, this will still be a hard error if the
3061         // definition is found in a module that's not visible.
3062         const ObjCInterfaceDecl *forwardClass = nullptr;
3063         if (RequireCompleteType(Loc, OCIType->getPointeeType(),
3064                                 getLangOpts().ObjCAutoRefCount
3065                                     ? diag::err_arc_receiver_forward_instance
3066                                     : diag::warn_receiver_forward_instance,
3067                                 RecRange)) {
3068           if (getLangOpts().ObjCAutoRefCount)
3069             return ExprError();
3070 
3071           forwardClass = OCIType->getInterfaceDecl();
3072           Diag(Receiver ? Receiver->getBeginLoc() : SuperLoc,
3073                diag::note_receiver_is_id);
3074           Method = nullptr;
3075         } else {
3076           Method = ClassDecl->lookupInstanceMethod(Sel);
3077         }
3078 
3079         if (!Method)
3080           // Search protocol qualifiers.
3081           Method = LookupMethodInQualifiedType(Sel, OCIType, true);
3082 
3083         if (!Method) {
3084           // If we have implementations in scope, check "private" methods.
3085           Method = ClassDecl->lookupPrivateMethod(Sel);
3086 
3087           if (!Method && getLangOpts().ObjCAutoRefCount) {
3088             Diag(SelLoc, diag::err_arc_may_not_respond)
3089               << OCIType->getPointeeType() << Sel << RecRange
3090               << SourceRange(SelectorLocs.front(), SelectorLocs.back());
3091             return ExprError();
3092           }
3093 
3094           if (!Method && (!Receiver || !isSelfExpr(Receiver))) {
3095             // If we still haven't found a method, look in the global pool. This
3096             // behavior isn't very desirable, however we need it for GCC
3097             // compatibility. FIXME: should we deviate??
3098             if (OCIType->qual_empty()) {
3099               SmallVector<ObjCMethodDecl*, 4> Methods;
3100               CollectMultipleMethodsInGlobalPool(Sel, Methods,
3101                                                  true/*InstanceFirst*/,
3102                                                  false/*CheckTheOther*/);
3103               if (!Methods.empty()) {
3104                 // We choose the first method as the initial candidate, then try
3105                 // to select a better one.
3106                 Method = Methods[0];
3107 
3108                 if (ObjCMethodDecl *BestMethod =
3109                     SelectBestMethod(Sel, ArgsIn, Method->isInstanceMethod(),
3110                                      Methods))
3111                   Method = BestMethod;
3112 
3113                 AreMultipleMethodsInGlobalPool(Sel, Method,
3114                                                SourceRange(LBracLoc, RBracLoc),
3115                                                true/*receiverIdOrClass*/,
3116                                                Methods);
3117               }
3118               if (Method && !forwardClass)
3119                 Diag(SelLoc, diag::warn_maynot_respond)
3120                   << OCIType->getInterfaceDecl()->getIdentifier()
3121                   << Sel << RecRange;
3122             }
3123           }
3124         }
3125         if (Method && DiagnoseUseOfDecl(Method, SelectorSlotLocs, forwardClass))
3126           return ExprError();
3127       } else {
3128         // Reject other random receiver types (e.g. structs).
3129         Diag(Loc, diag::err_bad_receiver_type) << ReceiverType << RecRange;
3130         return ExprError();
3131       }
3132     }
3133   }
3134 
3135   FunctionScopeInfo *DIFunctionScopeInfo =
3136     (Method && Method->getMethodFamily() == OMF_init)
3137       ? getEnclosingFunction() : nullptr;
3138 
3139   if (Method && Method->isDirectMethod()) {
3140     if (ReceiverType->isObjCIdType() && !isImplicit) {
3141       Diag(Receiver->getExprLoc(),
3142            diag::err_messaging_unqualified_id_with_direct_method);
3143       Diag(Method->getLocation(), diag::note_direct_method_declared_at)
3144           << Method->getDeclName();
3145     }
3146 
3147     // Under ARC, self can't be assigned, and doing a direct call to `self`
3148     // when it's a Class is hence safe.  For other cases, we can't trust `self`
3149     // is what we think it is, so we reject it.
3150     if (ReceiverType->isObjCClassType() && !isImplicit &&
3151         !(Receiver->isObjCSelfExpr() && getLangOpts().ObjCAutoRefCount)) {
3152       {
3153         auto Builder = Diag(Receiver->getExprLoc(),
3154                             diag::err_messaging_class_with_direct_method);
3155         if (Receiver->isObjCSelfExpr()) {
3156           Builder.AddFixItHint(FixItHint::CreateReplacement(
3157               RecRange, Method->getClassInterface()->getName()));
3158         }
3159       }
3160       Diag(Method->getLocation(), diag::note_direct_method_declared_at)
3161           << Method->getDeclName();
3162     }
3163 
3164     if (SuperLoc.isValid()) {
3165       {
3166         auto Builder =
3167             Diag(SuperLoc, diag::err_messaging_super_with_direct_method);
3168         if (ReceiverType->isObjCClassType()) {
3169           Builder.AddFixItHint(FixItHint::CreateReplacement(
3170               SuperLoc, Method->getClassInterface()->getName()));
3171         } else {
3172           Builder.AddFixItHint(FixItHint::CreateReplacement(SuperLoc, "self"));
3173         }
3174       }
3175       Diag(Method->getLocation(), diag::note_direct_method_declared_at)
3176           << Method->getDeclName();
3177     }
3178   } else if (ReceiverType->isObjCIdType() && !isImplicit) {
3179     Diag(Receiver->getExprLoc(), diag::warn_messaging_unqualified_id);
3180   }
3181 
3182   if (DIFunctionScopeInfo &&
3183       DIFunctionScopeInfo->ObjCIsDesignatedInit &&
3184       (SuperLoc.isValid() || isSelfExpr(Receiver))) {
3185     bool isDesignatedInitChain = false;
3186     if (SuperLoc.isValid()) {
3187       if (const ObjCObjectPointerType *
3188             OCIType = ReceiverType->getAsObjCInterfacePointerType()) {
3189         if (const ObjCInterfaceDecl *ID = OCIType->getInterfaceDecl()) {
3190           // Either we know this is a designated initializer or we
3191           // conservatively assume it because we don't know for sure.
3192           if (!ID->declaresOrInheritsDesignatedInitializers() ||
3193               ID->isDesignatedInitializer(Sel)) {
3194             isDesignatedInitChain = true;
3195             DIFunctionScopeInfo->ObjCWarnForNoDesignatedInitChain = false;
3196           }
3197         }
3198       }
3199     }
3200     if (!isDesignatedInitChain) {
3201       const ObjCMethodDecl *InitMethod = nullptr;
3202       bool isDesignated =
3203         getCurMethodDecl()->isDesignatedInitializerForTheInterface(&InitMethod);
3204       assert(isDesignated && InitMethod);
3205       (void)isDesignated;
3206       Diag(SelLoc, SuperLoc.isValid() ?
3207              diag::warn_objc_designated_init_non_designated_init_call :
3208              diag::warn_objc_designated_init_non_super_designated_init_call);
3209       Diag(InitMethod->getLocation(),
3210            diag::note_objc_designated_init_marked_here);
3211     }
3212   }
3213 
3214   if (DIFunctionScopeInfo &&
3215       DIFunctionScopeInfo->ObjCIsSecondaryInit &&
3216       (SuperLoc.isValid() || isSelfExpr(Receiver))) {
3217     if (SuperLoc.isValid()) {
3218       Diag(SelLoc, diag::warn_objc_secondary_init_super_init_call);
3219     } else {
3220       DIFunctionScopeInfo->ObjCWarnForNoInitDelegation = false;
3221     }
3222   }
3223 
3224   // Check the message arguments.
3225   unsigned NumArgs = ArgsIn.size();
3226   Expr **Args = ArgsIn.data();
3227   QualType ReturnType;
3228   ExprValueKind VK = VK_RValue;
3229   bool ClassMessage = (ReceiverType->isObjCClassType() ||
3230                        ReceiverType->isObjCQualifiedClassType());
3231   if (CheckMessageArgumentTypes(Receiver, ReceiverType,
3232                                 MultiExprArg(Args, NumArgs), Sel, SelectorLocs,
3233                                 Method, ClassMessage, SuperLoc.isValid(),
3234                                 LBracLoc, RBracLoc, RecRange, ReturnType, VK))
3235     return ExprError();
3236 
3237   if (Method && !Method->getReturnType()->isVoidType() &&
3238       RequireCompleteType(LBracLoc, Method->getReturnType(),
3239                           diag::err_illegal_message_expr_incomplete_type))
3240     return ExprError();
3241 
3242   // In ARC, forbid the user from sending messages to
3243   // retain/release/autorelease/dealloc/retainCount explicitly.
3244   if (getLangOpts().ObjCAutoRefCount) {
3245     ObjCMethodFamily family =
3246       (Method ? Method->getMethodFamily() : Sel.getMethodFamily());
3247     switch (family) {
3248     case OMF_init:
3249       if (Method)
3250         checkInitMethod(Method, ReceiverType);
3251       break;
3252 
3253     case OMF_None:
3254     case OMF_alloc:
3255     case OMF_copy:
3256     case OMF_finalize:
3257     case OMF_mutableCopy:
3258     case OMF_new:
3259     case OMF_self:
3260     case OMF_initialize:
3261       break;
3262 
3263     case OMF_dealloc:
3264     case OMF_retain:
3265     case OMF_release:
3266     case OMF_autorelease:
3267     case OMF_retainCount:
3268       Diag(SelLoc, diag::err_arc_illegal_explicit_message)
3269         << Sel << RecRange;
3270       break;
3271 
3272     case OMF_performSelector:
3273       if (Method && NumArgs >= 1) {
3274         if (const auto *SelExp =
3275                 dyn_cast<ObjCSelectorExpr>(Args[0]->IgnoreParens())) {
3276           Selector ArgSel = SelExp->getSelector();
3277           ObjCMethodDecl *SelMethod =
3278             LookupInstanceMethodInGlobalPool(ArgSel,
3279                                              SelExp->getSourceRange());
3280           if (!SelMethod)
3281             SelMethod =
3282               LookupFactoryMethodInGlobalPool(ArgSel,
3283                                               SelExp->getSourceRange());
3284           if (SelMethod) {
3285             ObjCMethodFamily SelFamily = SelMethod->getMethodFamily();
3286             switch (SelFamily) {
3287               case OMF_alloc:
3288               case OMF_copy:
3289               case OMF_mutableCopy:
3290               case OMF_new:
3291               case OMF_init:
3292                 // Issue error, unless ns_returns_not_retained.
3293                 if (!SelMethod->hasAttr<NSReturnsNotRetainedAttr>()) {
3294                   // selector names a +1 method
3295                   Diag(SelLoc,
3296                        diag::err_arc_perform_selector_retains);
3297                   Diag(SelMethod->getLocation(), diag::note_method_declared_at)
3298                     << SelMethod->getDeclName();
3299                 }
3300                 break;
3301               default:
3302                 // +0 call. OK. unless ns_returns_retained.
3303                 if (SelMethod->hasAttr<NSReturnsRetainedAttr>()) {
3304                   // selector names a +1 method
3305                   Diag(SelLoc,
3306                        diag::err_arc_perform_selector_retains);
3307                   Diag(SelMethod->getLocation(), diag::note_method_declared_at)
3308                     << SelMethod->getDeclName();
3309                 }
3310                 break;
3311             }
3312           }
3313         } else {
3314           // error (may leak).
3315           Diag(SelLoc, diag::warn_arc_perform_selector_leaks);
3316           Diag(Args[0]->getExprLoc(), diag::note_used_here);
3317         }
3318       }
3319       break;
3320     }
3321   }
3322 
3323   DiagnoseCStringFormatDirectiveInObjCAPI(*this, Method, Sel, Args, NumArgs);
3324 
3325   // Construct the appropriate ObjCMessageExpr instance.
3326   ObjCMessageExpr *Result;
3327   if (SuperLoc.isValid())
3328     Result = ObjCMessageExpr::Create(Context, ReturnType, VK, LBracLoc,
3329                                      SuperLoc,  /*IsInstanceSuper=*/true,
3330                                      ReceiverType, Sel, SelectorLocs, Method,
3331                                      makeArrayRef(Args, NumArgs), RBracLoc,
3332                                      isImplicit);
3333   else {
3334     Result = ObjCMessageExpr::Create(Context, ReturnType, VK, LBracLoc,
3335                                      Receiver, Sel, SelectorLocs, Method,
3336                                      makeArrayRef(Args, NumArgs), RBracLoc,
3337                                      isImplicit);
3338     if (!isImplicit)
3339       checkCocoaAPI(*this, Result);
3340   }
3341   if (Method) {
3342     bool IsClassObjectCall = ClassMessage;
3343     // 'self' message receivers in class methods should be treated as message
3344     // sends to the class object in order for the semantic checks to be
3345     // performed correctly. Messages to 'super' already count as class messages,
3346     // so they don't need to be handled here.
3347     if (Receiver && isSelfExpr(Receiver)) {
3348       if (const auto *OPT = ReceiverType->getAs<ObjCObjectPointerType>()) {
3349         if (OPT->getObjectType()->isObjCClass()) {
3350           if (const auto *CurMeth = getCurMethodDecl()) {
3351             IsClassObjectCall = true;
3352             ReceiverType =
3353                 Context.getObjCInterfaceType(CurMeth->getClassInterface());
3354           }
3355         }
3356       }
3357     }
3358     checkFoundationAPI(*this, SelLoc, Method, makeArrayRef(Args, NumArgs),
3359                        ReceiverType, IsClassObjectCall);
3360   }
3361 
3362   if (getLangOpts().ObjCAutoRefCount) {
3363     // In ARC, annotate delegate init calls.
3364     if (Result->getMethodFamily() == OMF_init &&
3365         (SuperLoc.isValid() || isSelfExpr(Receiver))) {
3366       // Only consider init calls *directly* in init implementations,
3367       // not within blocks.
3368       ObjCMethodDecl *method = dyn_cast<ObjCMethodDecl>(CurContext);
3369       if (method && method->getMethodFamily() == OMF_init) {
3370         // The implicit assignment to self means we also don't want to
3371         // consume the result.
3372         Result->setDelegateInitCall(true);
3373         return Result;
3374       }
3375     }
3376 
3377     // In ARC, check for message sends which are likely to introduce
3378     // retain cycles.
3379     checkRetainCycles(Result);
3380   }
3381 
3382   if (getLangOpts().ObjCWeak) {
3383     if (!isImplicit && Method) {
3384       if (const ObjCPropertyDecl *Prop = Method->findPropertyDecl()) {
3385         bool IsWeak =
3386             Prop->getPropertyAttributes() & ObjCPropertyAttribute::kind_weak;
3387         if (!IsWeak && Sel.isUnarySelector())
3388           IsWeak = ReturnType.getObjCLifetime() & Qualifiers::OCL_Weak;
3389         if (IsWeak && !isUnevaluatedContext() &&
3390             !Diags.isIgnored(diag::warn_arc_repeated_use_of_weak, LBracLoc))
3391           getCurFunction()->recordUseOfWeak(Result, Prop);
3392       }
3393     }
3394   }
3395 
3396   CheckObjCCircularContainer(Result);
3397 
3398   return MaybeBindToTemporary(Result);
3399 }
3400 
3401 static void RemoveSelectorFromWarningCache(Sema &S, Expr* Arg) {
3402   if (ObjCSelectorExpr *OSE =
3403       dyn_cast<ObjCSelectorExpr>(Arg->IgnoreParenCasts())) {
3404     Selector Sel = OSE->getSelector();
3405     SourceLocation Loc = OSE->getAtLoc();
3406     auto Pos = S.ReferencedSelectors.find(Sel);
3407     if (Pos != S.ReferencedSelectors.end() && Pos->second == Loc)
3408       S.ReferencedSelectors.erase(Pos);
3409   }
3410 }
3411 
3412 // ActOnInstanceMessage - used for both unary and keyword messages.
3413 // ArgExprs is optional - if it is present, the number of expressions
3414 // is obtained from Sel.getNumArgs().
3415 ExprResult Sema::ActOnInstanceMessage(Scope *S,
3416                                       Expr *Receiver,
3417                                       Selector Sel,
3418                                       SourceLocation LBracLoc,
3419                                       ArrayRef<SourceLocation> SelectorLocs,
3420                                       SourceLocation RBracLoc,
3421                                       MultiExprArg Args) {
3422   if (!Receiver)
3423     return ExprError();
3424 
3425   // A ParenListExpr can show up while doing error recovery with invalid code.
3426   if (isa<ParenListExpr>(Receiver)) {
3427     ExprResult Result = MaybeConvertParenListExprToParenExpr(S, Receiver);
3428     if (Result.isInvalid()) return ExprError();
3429     Receiver = Result.get();
3430   }
3431 
3432   if (RespondsToSelectorSel.isNull()) {
3433     IdentifierInfo *SelectorId = &Context.Idents.get("respondsToSelector");
3434     RespondsToSelectorSel = Context.Selectors.getUnarySelector(SelectorId);
3435   }
3436   if (Sel == RespondsToSelectorSel)
3437     RemoveSelectorFromWarningCache(*this, Args[0]);
3438 
3439   return BuildInstanceMessage(Receiver, Receiver->getType(),
3440                               /*SuperLoc=*/SourceLocation(), Sel,
3441                               /*Method=*/nullptr, LBracLoc, SelectorLocs,
3442                               RBracLoc, Args);
3443 }
3444 
3445 enum ARCConversionTypeClass {
3446   /// int, void, struct A
3447   ACTC_none,
3448 
3449   /// id, void (^)()
3450   ACTC_retainable,
3451 
3452   /// id*, id***, void (^*)(),
3453   ACTC_indirectRetainable,
3454 
3455   /// void* might be a normal C type, or it might a CF type.
3456   ACTC_voidPtr,
3457 
3458   /// struct A*
3459   ACTC_coreFoundation
3460 };
3461 
3462 static bool isAnyRetainable(ARCConversionTypeClass ACTC) {
3463   return (ACTC == ACTC_retainable ||
3464           ACTC == ACTC_coreFoundation ||
3465           ACTC == ACTC_voidPtr);
3466 }
3467 
3468 static bool isAnyCLike(ARCConversionTypeClass ACTC) {
3469   return ACTC == ACTC_none ||
3470          ACTC == ACTC_voidPtr ||
3471          ACTC == ACTC_coreFoundation;
3472 }
3473 
3474 static ARCConversionTypeClass classifyTypeForARCConversion(QualType type) {
3475   bool isIndirect = false;
3476 
3477   // Ignore an outermost reference type.
3478   if (const ReferenceType *ref = type->getAs<ReferenceType>()) {
3479     type = ref->getPointeeType();
3480     isIndirect = true;
3481   }
3482 
3483   // Drill through pointers and arrays recursively.
3484   while (true) {
3485     if (const PointerType *ptr = type->getAs<PointerType>()) {
3486       type = ptr->getPointeeType();
3487 
3488       // The first level of pointer may be the innermost pointer on a CF type.
3489       if (!isIndirect) {
3490         if (type->isVoidType()) return ACTC_voidPtr;
3491         if (type->isRecordType()) return ACTC_coreFoundation;
3492       }
3493     } else if (const ArrayType *array = type->getAsArrayTypeUnsafe()) {
3494       type = QualType(array->getElementType()->getBaseElementTypeUnsafe(), 0);
3495     } else {
3496       break;
3497     }
3498     isIndirect = true;
3499   }
3500 
3501   if (isIndirect) {
3502     if (type->isObjCARCBridgableType())
3503       return ACTC_indirectRetainable;
3504     return ACTC_none;
3505   }
3506 
3507   if (type->isObjCARCBridgableType())
3508     return ACTC_retainable;
3509 
3510   return ACTC_none;
3511 }
3512 
3513 namespace {
3514   /// A result from the cast checker.
3515   enum ACCResult {
3516     /// Cannot be casted.
3517     ACC_invalid,
3518 
3519     /// Can be safely retained or not retained.
3520     ACC_bottom,
3521 
3522     /// Can be casted at +0.
3523     ACC_plusZero,
3524 
3525     /// Can be casted at +1.
3526     ACC_plusOne
3527   };
3528   ACCResult merge(ACCResult left, ACCResult right) {
3529     if (left == right) return left;
3530     if (left == ACC_bottom) return right;
3531     if (right == ACC_bottom) return left;
3532     return ACC_invalid;
3533   }
3534 
3535   /// A checker which white-lists certain expressions whose conversion
3536   /// to or from retainable type would otherwise be forbidden in ARC.
3537   class ARCCastChecker : public StmtVisitor<ARCCastChecker, ACCResult> {
3538     typedef StmtVisitor<ARCCastChecker, ACCResult> super;
3539 
3540     ASTContext &Context;
3541     ARCConversionTypeClass SourceClass;
3542     ARCConversionTypeClass TargetClass;
3543     bool Diagnose;
3544 
3545     static bool isCFType(QualType type) {
3546       // Someday this can use ns_bridged.  For now, it has to do this.
3547       return type->isCARCBridgableType();
3548     }
3549 
3550   public:
3551     ARCCastChecker(ASTContext &Context, ARCConversionTypeClass source,
3552                    ARCConversionTypeClass target, bool diagnose)
3553       : Context(Context), SourceClass(source), TargetClass(target),
3554         Diagnose(diagnose) {}
3555 
3556     using super::Visit;
3557     ACCResult Visit(Expr *e) {
3558       return super::Visit(e->IgnoreParens());
3559     }
3560 
3561     ACCResult VisitStmt(Stmt *s) {
3562       return ACC_invalid;
3563     }
3564 
3565     /// Null pointer constants can be casted however you please.
3566     ACCResult VisitExpr(Expr *e) {
3567       if (e->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNotNull))
3568         return ACC_bottom;
3569       return ACC_invalid;
3570     }
3571 
3572     /// Objective-C string literals can be safely casted.
3573     ACCResult VisitObjCStringLiteral(ObjCStringLiteral *e) {
3574       // If we're casting to any retainable type, go ahead.  Global
3575       // strings are immune to retains, so this is bottom.
3576       if (isAnyRetainable(TargetClass)) return ACC_bottom;
3577 
3578       return ACC_invalid;
3579     }
3580 
3581     /// Look through certain implicit and explicit casts.
3582     ACCResult VisitCastExpr(CastExpr *e) {
3583       switch (e->getCastKind()) {
3584         case CK_NullToPointer:
3585           return ACC_bottom;
3586 
3587         case CK_NoOp:
3588         case CK_LValueToRValue:
3589         case CK_BitCast:
3590         case CK_CPointerToObjCPointerCast:
3591         case CK_BlockPointerToObjCPointerCast:
3592         case CK_AnyPointerToBlockPointerCast:
3593           return Visit(e->getSubExpr());
3594 
3595         default:
3596           return ACC_invalid;
3597       }
3598     }
3599 
3600     /// Look through unary extension.
3601     ACCResult VisitUnaryExtension(UnaryOperator *e) {
3602       return Visit(e->getSubExpr());
3603     }
3604 
3605     /// Ignore the LHS of a comma operator.
3606     ACCResult VisitBinComma(BinaryOperator *e) {
3607       return Visit(e->getRHS());
3608     }
3609 
3610     /// Conditional operators are okay if both sides are okay.
3611     ACCResult VisitConditionalOperator(ConditionalOperator *e) {
3612       ACCResult left = Visit(e->getTrueExpr());
3613       if (left == ACC_invalid) return ACC_invalid;
3614       return merge(left, Visit(e->getFalseExpr()));
3615     }
3616 
3617     /// Look through pseudo-objects.
3618     ACCResult VisitPseudoObjectExpr(PseudoObjectExpr *e) {
3619       // If we're getting here, we should always have a result.
3620       return Visit(e->getResultExpr());
3621     }
3622 
3623     /// Statement expressions are okay if their result expression is okay.
3624     ACCResult VisitStmtExpr(StmtExpr *e) {
3625       return Visit(e->getSubStmt()->body_back());
3626     }
3627 
3628     /// Some declaration references are okay.
3629     ACCResult VisitDeclRefExpr(DeclRefExpr *e) {
3630       VarDecl *var = dyn_cast<VarDecl>(e->getDecl());
3631       // References to global constants are okay.
3632       if (isAnyRetainable(TargetClass) &&
3633           isAnyRetainable(SourceClass) &&
3634           var &&
3635           !var->hasDefinition(Context) &&
3636           var->getType().isConstQualified()) {
3637 
3638         // In system headers, they can also be assumed to be immune to retains.
3639         // These are things like 'kCFStringTransformToLatin'.
3640         if (Context.getSourceManager().isInSystemHeader(var->getLocation()))
3641           return ACC_bottom;
3642 
3643         return ACC_plusZero;
3644       }
3645 
3646       // Nothing else.
3647       return ACC_invalid;
3648     }
3649 
3650     /// Some calls are okay.
3651     ACCResult VisitCallExpr(CallExpr *e) {
3652       if (FunctionDecl *fn = e->getDirectCallee())
3653         if (ACCResult result = checkCallToFunction(fn))
3654           return result;
3655 
3656       return super::VisitCallExpr(e);
3657     }
3658 
3659     ACCResult checkCallToFunction(FunctionDecl *fn) {
3660       // Require a CF*Ref return type.
3661       if (!isCFType(fn->getReturnType()))
3662         return ACC_invalid;
3663 
3664       if (!isAnyRetainable(TargetClass))
3665         return ACC_invalid;
3666 
3667       // Honor an explicit 'not retained' attribute.
3668       if (fn->hasAttr<CFReturnsNotRetainedAttr>())
3669         return ACC_plusZero;
3670 
3671       // Honor an explicit 'retained' attribute, except that for
3672       // now we're not going to permit implicit handling of +1 results,
3673       // because it's a bit frightening.
3674       if (fn->hasAttr<CFReturnsRetainedAttr>())
3675         return Diagnose ? ACC_plusOne
3676                         : ACC_invalid; // ACC_plusOne if we start accepting this
3677 
3678       // Recognize this specific builtin function, which is used by CFSTR.
3679       unsigned builtinID = fn->getBuiltinID();
3680       if (builtinID == Builtin::BI__builtin___CFStringMakeConstantString)
3681         return ACC_bottom;
3682 
3683       // Otherwise, don't do anything implicit with an unaudited function.
3684       if (!fn->hasAttr<CFAuditedTransferAttr>())
3685         return ACC_invalid;
3686 
3687       // Otherwise, it's +0 unless it follows the create convention.
3688       if (ento::coreFoundation::followsCreateRule(fn))
3689         return Diagnose ? ACC_plusOne
3690                         : ACC_invalid; // ACC_plusOne if we start accepting this
3691 
3692       return ACC_plusZero;
3693     }
3694 
3695     ACCResult VisitObjCMessageExpr(ObjCMessageExpr *e) {
3696       return checkCallToMethod(e->getMethodDecl());
3697     }
3698 
3699     ACCResult VisitObjCPropertyRefExpr(ObjCPropertyRefExpr *e) {
3700       ObjCMethodDecl *method;
3701       if (e->isExplicitProperty())
3702         method = e->getExplicitProperty()->getGetterMethodDecl();
3703       else
3704         method = e->getImplicitPropertyGetter();
3705       return checkCallToMethod(method);
3706     }
3707 
3708     ACCResult checkCallToMethod(ObjCMethodDecl *method) {
3709       if (!method) return ACC_invalid;
3710 
3711       // Check for message sends to functions returning CF types.  We
3712       // just obey the Cocoa conventions with these, even though the
3713       // return type is CF.
3714       if (!isAnyRetainable(TargetClass) || !isCFType(method->getReturnType()))
3715         return ACC_invalid;
3716 
3717       // If the method is explicitly marked not-retained, it's +0.
3718       if (method->hasAttr<CFReturnsNotRetainedAttr>())
3719         return ACC_plusZero;
3720 
3721       // If the method is explicitly marked as returning retained, or its
3722       // selector follows a +1 Cocoa convention, treat it as +1.
3723       if (method->hasAttr<CFReturnsRetainedAttr>())
3724         return ACC_plusOne;
3725 
3726       switch (method->getSelector().getMethodFamily()) {
3727       case OMF_alloc:
3728       case OMF_copy:
3729       case OMF_mutableCopy:
3730       case OMF_new:
3731         return ACC_plusOne;
3732 
3733       default:
3734         // Otherwise, treat it as +0.
3735         return ACC_plusZero;
3736       }
3737     }
3738   };
3739 } // end anonymous namespace
3740 
3741 bool Sema::isKnownName(StringRef name) {
3742   if (name.empty())
3743     return false;
3744   LookupResult R(*this, &Context.Idents.get(name), SourceLocation(),
3745                  Sema::LookupOrdinaryName);
3746   return LookupName(R, TUScope, false);
3747 }
3748 
3749 template <typename DiagBuilderT>
3750 static void addFixitForObjCARCConversion(
3751     Sema &S, DiagBuilderT &DiagB, Sema::CheckedConversionKind CCK,
3752     SourceLocation afterLParen, QualType castType, Expr *castExpr,
3753     Expr *realCast, const char *bridgeKeyword, const char *CFBridgeName) {
3754   // We handle C-style and implicit casts here.
3755   switch (CCK) {
3756   case Sema::CCK_ImplicitConversion:
3757   case Sema::CCK_ForBuiltinOverloadedOp:
3758   case Sema::CCK_CStyleCast:
3759   case Sema::CCK_OtherCast:
3760     break;
3761   case Sema::CCK_FunctionalCast:
3762     return;
3763   }
3764 
3765   if (CFBridgeName) {
3766     if (CCK == Sema::CCK_OtherCast) {
3767       if (const CXXNamedCastExpr *NCE = dyn_cast<CXXNamedCastExpr>(realCast)) {
3768         SourceRange range(NCE->getOperatorLoc(),
3769                           NCE->getAngleBrackets().getEnd());
3770         SmallString<32> BridgeCall;
3771 
3772         SourceManager &SM = S.getSourceManager();
3773         char PrevChar = *SM.getCharacterData(range.getBegin().getLocWithOffset(-1));
3774         if (Lexer::isIdentifierBodyChar(PrevChar, S.getLangOpts()))
3775           BridgeCall += ' ';
3776 
3777         BridgeCall += CFBridgeName;
3778         DiagB.AddFixItHint(FixItHint::CreateReplacement(range, BridgeCall));
3779       }
3780       return;
3781     }
3782     Expr *castedE = castExpr;
3783     if (CStyleCastExpr *CCE = dyn_cast<CStyleCastExpr>(castedE))
3784       castedE = CCE->getSubExpr();
3785     castedE = castedE->IgnoreImpCasts();
3786     SourceRange range = castedE->getSourceRange();
3787 
3788     SmallString<32> BridgeCall;
3789 
3790     SourceManager &SM = S.getSourceManager();
3791     char PrevChar = *SM.getCharacterData(range.getBegin().getLocWithOffset(-1));
3792     if (Lexer::isIdentifierBodyChar(PrevChar, S.getLangOpts()))
3793       BridgeCall += ' ';
3794 
3795     BridgeCall += CFBridgeName;
3796 
3797     if (isa<ParenExpr>(castedE)) {
3798       DiagB.AddFixItHint(FixItHint::CreateInsertion(range.getBegin(),
3799                          BridgeCall));
3800     } else {
3801       BridgeCall += '(';
3802       DiagB.AddFixItHint(FixItHint::CreateInsertion(range.getBegin(),
3803                                                     BridgeCall));
3804       DiagB.AddFixItHint(FixItHint::CreateInsertion(
3805                                        S.getLocForEndOfToken(range.getEnd()),
3806                                        ")"));
3807     }
3808     return;
3809   }
3810 
3811   if (CCK == Sema::CCK_CStyleCast) {
3812     DiagB.AddFixItHint(FixItHint::CreateInsertion(afterLParen, bridgeKeyword));
3813   } else if (CCK == Sema::CCK_OtherCast) {
3814     if (const CXXNamedCastExpr *NCE = dyn_cast<CXXNamedCastExpr>(realCast)) {
3815       std::string castCode = "(";
3816       castCode += bridgeKeyword;
3817       castCode += castType.getAsString();
3818       castCode += ")";
3819       SourceRange Range(NCE->getOperatorLoc(),
3820                         NCE->getAngleBrackets().getEnd());
3821       DiagB.AddFixItHint(FixItHint::CreateReplacement(Range, castCode));
3822     }
3823   } else {
3824     std::string castCode = "(";
3825     castCode += bridgeKeyword;
3826     castCode += castType.getAsString();
3827     castCode += ")";
3828     Expr *castedE = castExpr->IgnoreImpCasts();
3829     SourceRange range = castedE->getSourceRange();
3830     if (isa<ParenExpr>(castedE)) {
3831       DiagB.AddFixItHint(FixItHint::CreateInsertion(range.getBegin(),
3832                          castCode));
3833     } else {
3834       castCode += "(";
3835       DiagB.AddFixItHint(FixItHint::CreateInsertion(range.getBegin(),
3836                                                     castCode));
3837       DiagB.AddFixItHint(FixItHint::CreateInsertion(
3838                                        S.getLocForEndOfToken(range.getEnd()),
3839                                        ")"));
3840     }
3841   }
3842 }
3843 
3844 template <typename T>
3845 static inline T *getObjCBridgeAttr(const TypedefType *TD) {
3846   TypedefNameDecl *TDNDecl = TD->getDecl();
3847   QualType QT = TDNDecl->getUnderlyingType();
3848   if (QT->isPointerType()) {
3849     QT = QT->getPointeeType();
3850     if (const RecordType *RT = QT->getAs<RecordType>())
3851       if (RecordDecl *RD = RT->getDecl()->getMostRecentDecl())
3852         return RD->getAttr<T>();
3853   }
3854   return nullptr;
3855 }
3856 
3857 static ObjCBridgeRelatedAttr *ObjCBridgeRelatedAttrFromType(QualType T,
3858                                                             TypedefNameDecl *&TDNDecl) {
3859   while (const TypedefType *TD = dyn_cast<TypedefType>(T.getTypePtr())) {
3860     TDNDecl = TD->getDecl();
3861     if (ObjCBridgeRelatedAttr *ObjCBAttr =
3862         getObjCBridgeAttr<ObjCBridgeRelatedAttr>(TD))
3863       return ObjCBAttr;
3864     T = TDNDecl->getUnderlyingType();
3865   }
3866   return nullptr;
3867 }
3868 
3869 static void
3870 diagnoseObjCARCConversion(Sema &S, SourceRange castRange,
3871                           QualType castType, ARCConversionTypeClass castACTC,
3872                           Expr *castExpr, Expr *realCast,
3873                           ARCConversionTypeClass exprACTC,
3874                           Sema::CheckedConversionKind CCK) {
3875   SourceLocation loc =
3876     (castRange.isValid() ? castRange.getBegin() : castExpr->getExprLoc());
3877 
3878   if (S.makeUnavailableInSystemHeader(loc,
3879                                  UnavailableAttr::IR_ARCForbiddenConversion))
3880     return;
3881 
3882   QualType castExprType = castExpr->getType();
3883   // Defer emitting a diagnostic for bridge-related casts; that will be
3884   // handled by CheckObjCBridgeRelatedConversions.
3885   TypedefNameDecl *TDNDecl = nullptr;
3886   if ((castACTC == ACTC_coreFoundation &&  exprACTC == ACTC_retainable &&
3887        ObjCBridgeRelatedAttrFromType(castType, TDNDecl)) ||
3888       (exprACTC == ACTC_coreFoundation && castACTC == ACTC_retainable &&
3889        ObjCBridgeRelatedAttrFromType(castExprType, TDNDecl)))
3890     return;
3891 
3892   unsigned srcKind = 0;
3893   switch (exprACTC) {
3894   case ACTC_none:
3895   case ACTC_coreFoundation:
3896   case ACTC_voidPtr:
3897     srcKind = (castExprType->isPointerType() ? 1 : 0);
3898     break;
3899   case ACTC_retainable:
3900     srcKind = (castExprType->isBlockPointerType() ? 2 : 3);
3901     break;
3902   case ACTC_indirectRetainable:
3903     srcKind = 4;
3904     break;
3905   }
3906 
3907   // Check whether this could be fixed with a bridge cast.
3908   SourceLocation afterLParen = S.getLocForEndOfToken(castRange.getBegin());
3909   SourceLocation noteLoc = afterLParen.isValid() ? afterLParen : loc;
3910 
3911   unsigned convKindForDiag = Sema::isCast(CCK) ? 0 : 1;
3912 
3913   // Bridge from an ARC type to a CF type.
3914   if (castACTC == ACTC_retainable && isAnyRetainable(exprACTC)) {
3915 
3916     S.Diag(loc, diag::err_arc_cast_requires_bridge)
3917       << convKindForDiag
3918       << 2 // of C pointer type
3919       << castExprType
3920       << unsigned(castType->isBlockPointerType()) // to ObjC|block type
3921       << castType
3922       << castRange
3923       << castExpr->getSourceRange();
3924     bool br = S.isKnownName("CFBridgingRelease");
3925     ACCResult CreateRule =
3926       ARCCastChecker(S.Context, exprACTC, castACTC, true).Visit(castExpr);
3927     assert(CreateRule != ACC_bottom && "This cast should already be accepted.");
3928     if (CreateRule != ACC_plusOne)
3929     {
3930       auto DiagB = (CCK != Sema::CCK_OtherCast)
3931                        ? S.Diag(noteLoc, diag::note_arc_bridge)
3932                        : S.Diag(noteLoc, diag::note_arc_cstyle_bridge);
3933 
3934       addFixitForObjCARCConversion(S, DiagB, CCK, afterLParen,
3935                                    castType, castExpr, realCast, "__bridge ",
3936                                    nullptr);
3937     }
3938     if (CreateRule != ACC_plusZero)
3939     {
3940       auto DiagB = (CCK == Sema::CCK_OtherCast && !br)
3941                        ? S.Diag(noteLoc, diag::note_arc_cstyle_bridge_transfer)
3942                              << castExprType
3943                        : S.Diag(br ? castExpr->getExprLoc() : noteLoc,
3944                                 diag::note_arc_bridge_transfer)
3945                              << castExprType << br;
3946 
3947       addFixitForObjCARCConversion(S, DiagB, CCK, afterLParen,
3948                                    castType, castExpr, realCast, "__bridge_transfer ",
3949                                    br ? "CFBridgingRelease" : nullptr);
3950     }
3951 
3952     return;
3953   }
3954 
3955   // Bridge from a CF type to an ARC type.
3956   if (exprACTC == ACTC_retainable && isAnyRetainable(castACTC)) {
3957     bool br = S.isKnownName("CFBridgingRetain");
3958     S.Diag(loc, diag::err_arc_cast_requires_bridge)
3959       << convKindForDiag
3960       << unsigned(castExprType->isBlockPointerType()) // of ObjC|block type
3961       << castExprType
3962       << 2 // to C pointer type
3963       << castType
3964       << castRange
3965       << castExpr->getSourceRange();
3966     ACCResult CreateRule =
3967       ARCCastChecker(S.Context, exprACTC, castACTC, true).Visit(castExpr);
3968     assert(CreateRule != ACC_bottom && "This cast should already be accepted.");
3969     if (CreateRule != ACC_plusOne)
3970     {
3971       auto DiagB = (CCK != Sema::CCK_OtherCast)
3972                        ? S.Diag(noteLoc, diag::note_arc_bridge)
3973                        : S.Diag(noteLoc, diag::note_arc_cstyle_bridge);
3974       addFixitForObjCARCConversion(S, DiagB, CCK, afterLParen,
3975                                    castType, castExpr, realCast, "__bridge ",
3976                                    nullptr);
3977     }
3978     if (CreateRule != ACC_plusZero)
3979     {
3980       auto DiagB = (CCK == Sema::CCK_OtherCast && !br)
3981                        ? S.Diag(noteLoc, diag::note_arc_cstyle_bridge_retained)
3982                              << castType
3983                        : S.Diag(br ? castExpr->getExprLoc() : noteLoc,
3984                                 diag::note_arc_bridge_retained)
3985                              << castType << br;
3986 
3987       addFixitForObjCARCConversion(S, DiagB, CCK, afterLParen,
3988                                    castType, castExpr, realCast, "__bridge_retained ",
3989                                    br ? "CFBridgingRetain" : nullptr);
3990     }
3991 
3992     return;
3993   }
3994 
3995   S.Diag(loc, diag::err_arc_mismatched_cast)
3996     << !convKindForDiag
3997     << srcKind << castExprType << castType
3998     << castRange << castExpr->getSourceRange();
3999 }
4000 
4001 template <typename TB>
4002 static bool CheckObjCBridgeNSCast(Sema &S, QualType castType, Expr *castExpr,
4003                                   bool &HadTheAttribute, bool warn) {
4004   QualType T = castExpr->getType();
4005   HadTheAttribute = false;
4006   while (const TypedefType *TD = dyn_cast<TypedefType>(T.getTypePtr())) {
4007     TypedefNameDecl *TDNDecl = TD->getDecl();
4008     if (TB *ObjCBAttr = getObjCBridgeAttr<TB>(TD)) {
4009       if (IdentifierInfo *Parm = ObjCBAttr->getBridgedType()) {
4010         HadTheAttribute = true;
4011         if (Parm->isStr("id"))
4012           return true;
4013 
4014         NamedDecl *Target = nullptr;
4015         // Check for an existing type with this name.
4016         LookupResult R(S, DeclarationName(Parm), SourceLocation(),
4017                        Sema::LookupOrdinaryName);
4018         if (S.LookupName(R, S.TUScope)) {
4019           Target = R.getFoundDecl();
4020           if (Target && isa<ObjCInterfaceDecl>(Target)) {
4021             ObjCInterfaceDecl *ExprClass = cast<ObjCInterfaceDecl>(Target);
4022             if (const ObjCObjectPointerType *InterfacePointerType =
4023                   castType->getAsObjCInterfacePointerType()) {
4024               ObjCInterfaceDecl *CastClass
4025                 = InterfacePointerType->getObjectType()->getInterface();
4026               if ((CastClass == ExprClass) ||
4027                   (CastClass && CastClass->isSuperClassOf(ExprClass)))
4028                 return true;
4029               if (warn)
4030                 S.Diag(castExpr->getBeginLoc(), diag::warn_objc_invalid_bridge)
4031                     << T << Target->getName() << castType->getPointeeType();
4032               return false;
4033             } else if (castType->isObjCIdType() ||
4034                        (S.Context.ObjCObjectAdoptsQTypeProtocols(
4035                           castType, ExprClass)))
4036               // ok to cast to 'id'.
4037               // casting to id<p-list> is ok if bridge type adopts all of
4038               // p-list protocols.
4039               return true;
4040             else {
4041               if (warn) {
4042                 S.Diag(castExpr->getBeginLoc(), diag::warn_objc_invalid_bridge)
4043                     << T << Target->getName() << castType;
4044                 S.Diag(TDNDecl->getBeginLoc(), diag::note_declared_at);
4045                 S.Diag(Target->getBeginLoc(), diag::note_declared_at);
4046               }
4047               return false;
4048            }
4049           }
4050         } else if (!castType->isObjCIdType()) {
4051           S.Diag(castExpr->getBeginLoc(),
4052                  diag::err_objc_cf_bridged_not_interface)
4053               << castExpr->getType() << Parm;
4054           S.Diag(TDNDecl->getBeginLoc(), diag::note_declared_at);
4055           if (Target)
4056             S.Diag(Target->getBeginLoc(), diag::note_declared_at);
4057         }
4058         return true;
4059       }
4060       return false;
4061     }
4062     T = TDNDecl->getUnderlyingType();
4063   }
4064   return true;
4065 }
4066 
4067 template <typename TB>
4068 static bool CheckObjCBridgeCFCast(Sema &S, QualType castType, Expr *castExpr,
4069                                   bool &HadTheAttribute, bool warn) {
4070   QualType T = castType;
4071   HadTheAttribute = false;
4072   while (const TypedefType *TD = dyn_cast<TypedefType>(T.getTypePtr())) {
4073     TypedefNameDecl *TDNDecl = TD->getDecl();
4074     if (TB *ObjCBAttr = getObjCBridgeAttr<TB>(TD)) {
4075       if (IdentifierInfo *Parm = ObjCBAttr->getBridgedType()) {
4076         HadTheAttribute = true;
4077         if (Parm->isStr("id"))
4078           return true;
4079 
4080         NamedDecl *Target = nullptr;
4081         // Check for an existing type with this name.
4082         LookupResult R(S, DeclarationName(Parm), SourceLocation(),
4083                        Sema::LookupOrdinaryName);
4084         if (S.LookupName(R, S.TUScope)) {
4085           Target = R.getFoundDecl();
4086           if (Target && isa<ObjCInterfaceDecl>(Target)) {
4087             ObjCInterfaceDecl *CastClass = cast<ObjCInterfaceDecl>(Target);
4088             if (const ObjCObjectPointerType *InterfacePointerType =
4089                   castExpr->getType()->getAsObjCInterfacePointerType()) {
4090               ObjCInterfaceDecl *ExprClass
4091                 = InterfacePointerType->getObjectType()->getInterface();
4092               if ((CastClass == ExprClass) ||
4093                   (ExprClass && CastClass->isSuperClassOf(ExprClass)))
4094                 return true;
4095               if (warn) {
4096                 S.Diag(castExpr->getBeginLoc(),
4097                        diag::warn_objc_invalid_bridge_to_cf)
4098                     << castExpr->getType()->getPointeeType() << T;
4099                 S.Diag(TDNDecl->getBeginLoc(), diag::note_declared_at);
4100               }
4101               return false;
4102             } else if (castExpr->getType()->isObjCIdType() ||
4103                        (S.Context.QIdProtocolsAdoptObjCObjectProtocols(
4104                           castExpr->getType(), CastClass)))
4105               // ok to cast an 'id' expression to a CFtype.
4106               // ok to cast an 'id<plist>' expression to CFtype provided plist
4107               // adopts all of CFtype's ObjetiveC's class plist.
4108               return true;
4109             else {
4110               if (warn) {
4111                 S.Diag(castExpr->getBeginLoc(),
4112                        diag::warn_objc_invalid_bridge_to_cf)
4113                     << castExpr->getType() << castType;
4114                 S.Diag(TDNDecl->getBeginLoc(), diag::note_declared_at);
4115                 S.Diag(Target->getBeginLoc(), diag::note_declared_at);
4116               }
4117               return false;
4118             }
4119           }
4120         }
4121         S.Diag(castExpr->getBeginLoc(),
4122                diag::err_objc_ns_bridged_invalid_cfobject)
4123             << castExpr->getType() << castType;
4124         S.Diag(TDNDecl->getBeginLoc(), diag::note_declared_at);
4125         if (Target)
4126           S.Diag(Target->getBeginLoc(), diag::note_declared_at);
4127         return true;
4128       }
4129       return false;
4130     }
4131     T = TDNDecl->getUnderlyingType();
4132   }
4133   return true;
4134 }
4135 
4136 void Sema::CheckTollFreeBridgeCast(QualType castType, Expr *castExpr) {
4137   if (!getLangOpts().ObjC)
4138     return;
4139   // warn in presence of __bridge casting to or from a toll free bridge cast.
4140   ARCConversionTypeClass exprACTC = classifyTypeForARCConversion(castExpr->getType());
4141   ARCConversionTypeClass castACTC = classifyTypeForARCConversion(castType);
4142   if (castACTC == ACTC_retainable && exprACTC == ACTC_coreFoundation) {
4143     bool HasObjCBridgeAttr;
4144     bool ObjCBridgeAttrWillNotWarn =
4145       CheckObjCBridgeNSCast<ObjCBridgeAttr>(*this, castType, castExpr, HasObjCBridgeAttr,
4146                                             false);
4147     if (ObjCBridgeAttrWillNotWarn && HasObjCBridgeAttr)
4148       return;
4149     bool HasObjCBridgeMutableAttr;
4150     bool ObjCBridgeMutableAttrWillNotWarn =
4151       CheckObjCBridgeNSCast<ObjCBridgeMutableAttr>(*this, castType, castExpr,
4152                                                    HasObjCBridgeMutableAttr, false);
4153     if (ObjCBridgeMutableAttrWillNotWarn && HasObjCBridgeMutableAttr)
4154       return;
4155 
4156     if (HasObjCBridgeAttr)
4157       CheckObjCBridgeNSCast<ObjCBridgeAttr>(*this, castType, castExpr, HasObjCBridgeAttr,
4158                                             true);
4159     else if (HasObjCBridgeMutableAttr)
4160       CheckObjCBridgeNSCast<ObjCBridgeMutableAttr>(*this, castType, castExpr,
4161                                                    HasObjCBridgeMutableAttr, true);
4162   }
4163   else if (castACTC == ACTC_coreFoundation && exprACTC == ACTC_retainable) {
4164     bool HasObjCBridgeAttr;
4165     bool ObjCBridgeAttrWillNotWarn =
4166       CheckObjCBridgeCFCast<ObjCBridgeAttr>(*this, castType, castExpr, HasObjCBridgeAttr,
4167                                             false);
4168     if (ObjCBridgeAttrWillNotWarn && HasObjCBridgeAttr)
4169       return;
4170     bool HasObjCBridgeMutableAttr;
4171     bool ObjCBridgeMutableAttrWillNotWarn =
4172       CheckObjCBridgeCFCast<ObjCBridgeMutableAttr>(*this, castType, castExpr,
4173                                                    HasObjCBridgeMutableAttr, false);
4174     if (ObjCBridgeMutableAttrWillNotWarn && HasObjCBridgeMutableAttr)
4175       return;
4176 
4177     if (HasObjCBridgeAttr)
4178       CheckObjCBridgeCFCast<ObjCBridgeAttr>(*this, castType, castExpr, HasObjCBridgeAttr,
4179                                             true);
4180     else if (HasObjCBridgeMutableAttr)
4181       CheckObjCBridgeCFCast<ObjCBridgeMutableAttr>(*this, castType, castExpr,
4182                                                    HasObjCBridgeMutableAttr, true);
4183   }
4184 }
4185 
4186 void Sema::CheckObjCBridgeRelatedCast(QualType castType, Expr *castExpr) {
4187   QualType SrcType = castExpr->getType();
4188   if (ObjCPropertyRefExpr *PRE = dyn_cast<ObjCPropertyRefExpr>(castExpr)) {
4189     if (PRE->isExplicitProperty()) {
4190       if (ObjCPropertyDecl *PDecl = PRE->getExplicitProperty())
4191         SrcType = PDecl->getType();
4192     }
4193     else if (PRE->isImplicitProperty()) {
4194       if (ObjCMethodDecl *Getter = PRE->getImplicitPropertyGetter())
4195         SrcType = Getter->getReturnType();
4196     }
4197   }
4198 
4199   ARCConversionTypeClass srcExprACTC = classifyTypeForARCConversion(SrcType);
4200   ARCConversionTypeClass castExprACTC = classifyTypeForARCConversion(castType);
4201   if (srcExprACTC != ACTC_retainable || castExprACTC != ACTC_coreFoundation)
4202     return;
4203   CheckObjCBridgeRelatedConversions(castExpr->getBeginLoc(), castType, SrcType,
4204                                     castExpr);
4205 }
4206 
4207 bool Sema::CheckTollFreeBridgeStaticCast(QualType castType, Expr *castExpr,
4208                                          CastKind &Kind) {
4209   if (!getLangOpts().ObjC)
4210     return false;
4211   ARCConversionTypeClass exprACTC =
4212     classifyTypeForARCConversion(castExpr->getType());
4213   ARCConversionTypeClass castACTC = classifyTypeForARCConversion(castType);
4214   if ((castACTC == ACTC_retainable && exprACTC == ACTC_coreFoundation) ||
4215       (castACTC == ACTC_coreFoundation && exprACTC == ACTC_retainable)) {
4216     CheckTollFreeBridgeCast(castType, castExpr);
4217     Kind = (castACTC == ACTC_coreFoundation) ? CK_BitCast
4218                                              : CK_CPointerToObjCPointerCast;
4219     return true;
4220   }
4221   return false;
4222 }
4223 
4224 bool Sema::checkObjCBridgeRelatedComponents(SourceLocation Loc,
4225                                             QualType DestType, QualType SrcType,
4226                                             ObjCInterfaceDecl *&RelatedClass,
4227                                             ObjCMethodDecl *&ClassMethod,
4228                                             ObjCMethodDecl *&InstanceMethod,
4229                                             TypedefNameDecl *&TDNDecl,
4230                                             bool CfToNs, bool Diagnose) {
4231   QualType T = CfToNs ? SrcType : DestType;
4232   ObjCBridgeRelatedAttr *ObjCBAttr = ObjCBridgeRelatedAttrFromType(T, TDNDecl);
4233   if (!ObjCBAttr)
4234     return false;
4235 
4236   IdentifierInfo *RCId = ObjCBAttr->getRelatedClass();
4237   IdentifierInfo *CMId = ObjCBAttr->getClassMethod();
4238   IdentifierInfo *IMId = ObjCBAttr->getInstanceMethod();
4239   if (!RCId)
4240     return false;
4241   NamedDecl *Target = nullptr;
4242   // Check for an existing type with this name.
4243   LookupResult R(*this, DeclarationName(RCId), SourceLocation(),
4244                  Sema::LookupOrdinaryName);
4245   if (!LookupName(R, TUScope)) {
4246     if (Diagnose) {
4247       Diag(Loc, diag::err_objc_bridged_related_invalid_class) << RCId
4248             << SrcType << DestType;
4249       Diag(TDNDecl->getBeginLoc(), diag::note_declared_at);
4250     }
4251     return false;
4252   }
4253   Target = R.getFoundDecl();
4254   if (Target && isa<ObjCInterfaceDecl>(Target))
4255     RelatedClass = cast<ObjCInterfaceDecl>(Target);
4256   else {
4257     if (Diagnose) {
4258       Diag(Loc, diag::err_objc_bridged_related_invalid_class_name) << RCId
4259             << SrcType << DestType;
4260       Diag(TDNDecl->getBeginLoc(), diag::note_declared_at);
4261       if (Target)
4262         Diag(Target->getBeginLoc(), diag::note_declared_at);
4263     }
4264     return false;
4265   }
4266 
4267   // Check for an existing class method with the given selector name.
4268   if (CfToNs && CMId) {
4269     Selector Sel = Context.Selectors.getUnarySelector(CMId);
4270     ClassMethod = RelatedClass->lookupMethod(Sel, false);
4271     if (!ClassMethod) {
4272       if (Diagnose) {
4273         Diag(Loc, diag::err_objc_bridged_related_known_method)
4274               << SrcType << DestType << Sel << false;
4275         Diag(TDNDecl->getBeginLoc(), diag::note_declared_at);
4276       }
4277       return false;
4278     }
4279   }
4280 
4281   // Check for an existing instance method with the given selector name.
4282   if (!CfToNs && IMId) {
4283     Selector Sel = Context.Selectors.getNullarySelector(IMId);
4284     InstanceMethod = RelatedClass->lookupMethod(Sel, true);
4285     if (!InstanceMethod) {
4286       if (Diagnose) {
4287         Diag(Loc, diag::err_objc_bridged_related_known_method)
4288               << SrcType << DestType << Sel << true;
4289         Diag(TDNDecl->getBeginLoc(), diag::note_declared_at);
4290       }
4291       return false;
4292     }
4293   }
4294   return true;
4295 }
4296 
4297 bool
4298 Sema::CheckObjCBridgeRelatedConversions(SourceLocation Loc,
4299                                         QualType DestType, QualType SrcType,
4300                                         Expr *&SrcExpr, bool Diagnose) {
4301   ARCConversionTypeClass rhsExprACTC = classifyTypeForARCConversion(SrcType);
4302   ARCConversionTypeClass lhsExprACTC = classifyTypeForARCConversion(DestType);
4303   bool CfToNs = (rhsExprACTC == ACTC_coreFoundation && lhsExprACTC == ACTC_retainable);
4304   bool NsToCf = (rhsExprACTC == ACTC_retainable && lhsExprACTC == ACTC_coreFoundation);
4305   if (!CfToNs && !NsToCf)
4306     return false;
4307 
4308   ObjCInterfaceDecl *RelatedClass;
4309   ObjCMethodDecl *ClassMethod = nullptr;
4310   ObjCMethodDecl *InstanceMethod = nullptr;
4311   TypedefNameDecl *TDNDecl = nullptr;
4312   if (!checkObjCBridgeRelatedComponents(Loc, DestType, SrcType, RelatedClass,
4313                                         ClassMethod, InstanceMethod, TDNDecl,
4314                                         CfToNs, Diagnose))
4315     return false;
4316 
4317   if (CfToNs) {
4318     // Implicit conversion from CF to ObjC object is needed.
4319     if (ClassMethod) {
4320       if (Diagnose) {
4321         std::string ExpressionString = "[";
4322         ExpressionString += RelatedClass->getNameAsString();
4323         ExpressionString += " ";
4324         ExpressionString += ClassMethod->getSelector().getAsString();
4325         SourceLocation SrcExprEndLoc =
4326             getLocForEndOfToken(SrcExpr->getEndLoc());
4327         // Provide a fixit: [RelatedClass ClassMethod SrcExpr]
4328         Diag(Loc, diag::err_objc_bridged_related_known_method)
4329             << SrcType << DestType << ClassMethod->getSelector() << false
4330             << FixItHint::CreateInsertion(SrcExpr->getBeginLoc(),
4331                                           ExpressionString)
4332             << FixItHint::CreateInsertion(SrcExprEndLoc, "]");
4333         Diag(RelatedClass->getBeginLoc(), diag::note_declared_at);
4334         Diag(TDNDecl->getBeginLoc(), diag::note_declared_at);
4335 
4336         QualType receiverType = Context.getObjCInterfaceType(RelatedClass);
4337         // Argument.
4338         Expr *args[] = { SrcExpr };
4339         ExprResult msg = BuildClassMessageImplicit(receiverType, false,
4340                                       ClassMethod->getLocation(),
4341                                       ClassMethod->getSelector(), ClassMethod,
4342                                       MultiExprArg(args, 1));
4343         SrcExpr = msg.get();
4344       }
4345       return true;
4346     }
4347   }
4348   else {
4349     // Implicit conversion from ObjC type to CF object is needed.
4350     if (InstanceMethod) {
4351       if (Diagnose) {
4352         std::string ExpressionString;
4353         SourceLocation SrcExprEndLoc =
4354             getLocForEndOfToken(SrcExpr->getEndLoc());
4355         if (InstanceMethod->isPropertyAccessor())
4356           if (const ObjCPropertyDecl *PDecl =
4357                   InstanceMethod->findPropertyDecl()) {
4358             // fixit: ObjectExpr.propertyname when it is  aproperty accessor.
4359             ExpressionString = ".";
4360             ExpressionString += PDecl->getNameAsString();
4361             Diag(Loc, diag::err_objc_bridged_related_known_method)
4362                 << SrcType << DestType << InstanceMethod->getSelector() << true
4363                 << FixItHint::CreateInsertion(SrcExprEndLoc, ExpressionString);
4364           }
4365         if (ExpressionString.empty()) {
4366           // Provide a fixit: [ObjectExpr InstanceMethod]
4367           ExpressionString = " ";
4368           ExpressionString += InstanceMethod->getSelector().getAsString();
4369           ExpressionString += "]";
4370 
4371           Diag(Loc, diag::err_objc_bridged_related_known_method)
4372               << SrcType << DestType << InstanceMethod->getSelector() << true
4373               << FixItHint::CreateInsertion(SrcExpr->getBeginLoc(), "[")
4374               << FixItHint::CreateInsertion(SrcExprEndLoc, ExpressionString);
4375         }
4376         Diag(RelatedClass->getBeginLoc(), diag::note_declared_at);
4377         Diag(TDNDecl->getBeginLoc(), diag::note_declared_at);
4378 
4379         ExprResult msg =
4380           BuildInstanceMessageImplicit(SrcExpr, SrcType,
4381                                        InstanceMethod->getLocation(),
4382                                        InstanceMethod->getSelector(),
4383                                        InstanceMethod, None);
4384         SrcExpr = msg.get();
4385       }
4386       return true;
4387     }
4388   }
4389   return false;
4390 }
4391 
4392 Sema::ARCConversionResult
4393 Sema::CheckObjCConversion(SourceRange castRange, QualType castType,
4394                           Expr *&castExpr, CheckedConversionKind CCK,
4395                           bool Diagnose, bool DiagnoseCFAudited,
4396                           BinaryOperatorKind Opc) {
4397   QualType castExprType = castExpr->getType();
4398 
4399   // For the purposes of the classification, we assume reference types
4400   // will bind to temporaries.
4401   QualType effCastType = castType;
4402   if (const ReferenceType *ref = castType->getAs<ReferenceType>())
4403     effCastType = ref->getPointeeType();
4404 
4405   ARCConversionTypeClass exprACTC = classifyTypeForARCConversion(castExprType);
4406   ARCConversionTypeClass castACTC = classifyTypeForARCConversion(effCastType);
4407   if (exprACTC == castACTC) {
4408     // Check for viability and report error if casting an rvalue to a
4409     // life-time qualifier.
4410     if (castACTC == ACTC_retainable &&
4411         (CCK == CCK_CStyleCast || CCK == CCK_OtherCast) &&
4412         castType != castExprType) {
4413       const Type *DT = castType.getTypePtr();
4414       QualType QDT = castType;
4415       // We desugar some types but not others. We ignore those
4416       // that cannot happen in a cast; i.e. auto, and those which
4417       // should not be de-sugared; i.e typedef.
4418       if (const ParenType *PT = dyn_cast<ParenType>(DT))
4419         QDT = PT->desugar();
4420       else if (const TypeOfType *TP = dyn_cast<TypeOfType>(DT))
4421         QDT = TP->desugar();
4422       else if (const AttributedType *AT = dyn_cast<AttributedType>(DT))
4423         QDT = AT->desugar();
4424       if (QDT != castType &&
4425           QDT.getObjCLifetime() !=  Qualifiers::OCL_None) {
4426         if (Diagnose) {
4427           SourceLocation loc = (castRange.isValid() ? castRange.getBegin()
4428                                                     : castExpr->getExprLoc());
4429           Diag(loc, diag::err_arc_nolifetime_behavior);
4430         }
4431         return ACR_error;
4432       }
4433     }
4434     return ACR_okay;
4435   }
4436 
4437   // The life-time qualifier cast check above is all we need for ObjCWeak.
4438   // ObjCAutoRefCount has more restrictions on what is legal.
4439   if (!getLangOpts().ObjCAutoRefCount)
4440     return ACR_okay;
4441 
4442   if (isAnyCLike(exprACTC) && isAnyCLike(castACTC)) return ACR_okay;
4443 
4444   // Allow all of these types to be cast to integer types (but not
4445   // vice-versa).
4446   if (castACTC == ACTC_none && castType->isIntegralType(Context))
4447     return ACR_okay;
4448 
4449   // Allow casts between pointers to lifetime types (e.g., __strong id*)
4450   // and pointers to void (e.g., cv void *). Casting from void* to lifetime*
4451   // must be explicit.
4452   if (exprACTC == ACTC_indirectRetainable && castACTC == ACTC_voidPtr)
4453     return ACR_okay;
4454   if (castACTC == ACTC_indirectRetainable && exprACTC == ACTC_voidPtr &&
4455       isCast(CCK))
4456     return ACR_okay;
4457 
4458   switch (ARCCastChecker(Context, exprACTC, castACTC, false).Visit(castExpr)) {
4459   // For invalid casts, fall through.
4460   case ACC_invalid:
4461     break;
4462 
4463   // Do nothing for both bottom and +0.
4464   case ACC_bottom:
4465   case ACC_plusZero:
4466     return ACR_okay;
4467 
4468   // If the result is +1, consume it here.
4469   case ACC_plusOne:
4470     castExpr = ImplicitCastExpr::Create(Context, castExpr->getType(),
4471                                         CK_ARCConsumeObject, castExpr, nullptr,
4472                                         VK_RValue, FPOptionsOverride());
4473     Cleanup.setExprNeedsCleanups(true);
4474     return ACR_okay;
4475   }
4476 
4477   // If this is a non-implicit cast from id or block type to a
4478   // CoreFoundation type, delay complaining in case the cast is used
4479   // in an acceptable context.
4480   if (exprACTC == ACTC_retainable && isAnyRetainable(castACTC) && isCast(CCK))
4481     return ACR_unbridged;
4482 
4483   // Issue a diagnostic about a missing @-sign when implicit casting a cstring
4484   // to 'NSString *', instead of falling through to report a "bridge cast"
4485   // diagnostic.
4486   if (castACTC == ACTC_retainable && exprACTC == ACTC_none &&
4487       CheckConversionToObjCLiteral(castType, castExpr, Diagnose))
4488     return ACR_error;
4489 
4490   // Do not issue "bridge cast" diagnostic when implicit casting
4491   // a retainable object to a CF type parameter belonging to an audited
4492   // CF API function. Let caller issue a normal type mismatched diagnostic
4493   // instead.
4494   if ((!DiagnoseCFAudited || exprACTC != ACTC_retainable ||
4495        castACTC != ACTC_coreFoundation) &&
4496       !(exprACTC == ACTC_voidPtr && castACTC == ACTC_retainable &&
4497         (Opc == BO_NE || Opc == BO_EQ))) {
4498     if (Diagnose)
4499       diagnoseObjCARCConversion(*this, castRange, castType, castACTC, castExpr,
4500                                 castExpr, exprACTC, CCK);
4501     return ACR_error;
4502   }
4503   return ACR_okay;
4504 }
4505 
4506 /// Given that we saw an expression with the ARCUnbridgedCastTy
4507 /// placeholder type, complain bitterly.
4508 void Sema::diagnoseARCUnbridgedCast(Expr *e) {
4509   // We expect the spurious ImplicitCastExpr to already have been stripped.
4510   assert(!e->hasPlaceholderType(BuiltinType::ARCUnbridgedCast));
4511   CastExpr *realCast = cast<CastExpr>(e->IgnoreParens());
4512 
4513   SourceRange castRange;
4514   QualType castType;
4515   CheckedConversionKind CCK;
4516 
4517   if (CStyleCastExpr *cast = dyn_cast<CStyleCastExpr>(realCast)) {
4518     castRange = SourceRange(cast->getLParenLoc(), cast->getRParenLoc());
4519     castType = cast->getTypeAsWritten();
4520     CCK = CCK_CStyleCast;
4521   } else if (ExplicitCastExpr *cast = dyn_cast<ExplicitCastExpr>(realCast)) {
4522     castRange = cast->getTypeInfoAsWritten()->getTypeLoc().getSourceRange();
4523     castType = cast->getTypeAsWritten();
4524     CCK = CCK_OtherCast;
4525   } else {
4526     llvm_unreachable("Unexpected ImplicitCastExpr");
4527   }
4528 
4529   ARCConversionTypeClass castACTC =
4530     classifyTypeForARCConversion(castType.getNonReferenceType());
4531 
4532   Expr *castExpr = realCast->getSubExpr();
4533   assert(classifyTypeForARCConversion(castExpr->getType()) == ACTC_retainable);
4534 
4535   diagnoseObjCARCConversion(*this, castRange, castType, castACTC,
4536                             castExpr, realCast, ACTC_retainable, CCK);
4537 }
4538 
4539 /// stripARCUnbridgedCast - Given an expression of ARCUnbridgedCast
4540 /// type, remove the placeholder cast.
4541 Expr *Sema::stripARCUnbridgedCast(Expr *e) {
4542   assert(e->hasPlaceholderType(BuiltinType::ARCUnbridgedCast));
4543 
4544   if (ParenExpr *pe = dyn_cast<ParenExpr>(e)) {
4545     Expr *sub = stripARCUnbridgedCast(pe->getSubExpr());
4546     return new (Context) ParenExpr(pe->getLParen(), pe->getRParen(), sub);
4547   } else if (UnaryOperator *uo = dyn_cast<UnaryOperator>(e)) {
4548     assert(uo->getOpcode() == UO_Extension);
4549     Expr *sub = stripARCUnbridgedCast(uo->getSubExpr());
4550     return UnaryOperator::Create(Context, sub, UO_Extension, sub->getType(),
4551                                  sub->getValueKind(), sub->getObjectKind(),
4552                                  uo->getOperatorLoc(), false,
4553                                  CurFPFeatureOverrides());
4554   } else if (GenericSelectionExpr *gse = dyn_cast<GenericSelectionExpr>(e)) {
4555     assert(!gse->isResultDependent());
4556 
4557     unsigned n = gse->getNumAssocs();
4558     SmallVector<Expr *, 4> subExprs;
4559     SmallVector<TypeSourceInfo *, 4> subTypes;
4560     subExprs.reserve(n);
4561     subTypes.reserve(n);
4562     for (const GenericSelectionExpr::Association assoc : gse->associations()) {
4563       subTypes.push_back(assoc.getTypeSourceInfo());
4564       Expr *sub = assoc.getAssociationExpr();
4565       if (assoc.isSelected())
4566         sub = stripARCUnbridgedCast(sub);
4567       subExprs.push_back(sub);
4568     }
4569 
4570     return GenericSelectionExpr::Create(
4571         Context, gse->getGenericLoc(), gse->getControllingExpr(), subTypes,
4572         subExprs, gse->getDefaultLoc(), gse->getRParenLoc(),
4573         gse->containsUnexpandedParameterPack(), gse->getResultIndex());
4574   } else {
4575     assert(isa<ImplicitCastExpr>(e) && "bad form of unbridged cast!");
4576     return cast<ImplicitCastExpr>(e)->getSubExpr();
4577   }
4578 }
4579 
4580 bool Sema::CheckObjCARCUnavailableWeakConversion(QualType castType,
4581                                                  QualType exprType) {
4582   QualType canCastType =
4583     Context.getCanonicalType(castType).getUnqualifiedType();
4584   QualType canExprType =
4585     Context.getCanonicalType(exprType).getUnqualifiedType();
4586   if (isa<ObjCObjectPointerType>(canCastType) &&
4587       castType.getObjCLifetime() == Qualifiers::OCL_Weak &&
4588       canExprType->isObjCObjectPointerType()) {
4589     if (const ObjCObjectPointerType *ObjT =
4590         canExprType->getAs<ObjCObjectPointerType>())
4591       if (const ObjCInterfaceDecl *ObjI = ObjT->getInterfaceDecl())
4592         return !ObjI->isArcWeakrefUnavailable();
4593   }
4594   return true;
4595 }
4596 
4597 /// Look for an ObjCReclaimReturnedObject cast and destroy it.
4598 static Expr *maybeUndoReclaimObject(Expr *e) {
4599   Expr *curExpr = e, *prevExpr = nullptr;
4600 
4601   // Walk down the expression until we hit an implicit cast of kind
4602   // ARCReclaimReturnedObject or an Expr that is neither a Paren nor a Cast.
4603   while (true) {
4604     if (auto *pe = dyn_cast<ParenExpr>(curExpr)) {
4605       prevExpr = curExpr;
4606       curExpr = pe->getSubExpr();
4607       continue;
4608     }
4609 
4610     if (auto *ce = dyn_cast<CastExpr>(curExpr)) {
4611       if (auto *ice = dyn_cast<ImplicitCastExpr>(ce))
4612         if (ice->getCastKind() == CK_ARCReclaimReturnedObject) {
4613           if (!prevExpr)
4614             return ice->getSubExpr();
4615           if (auto *pe = dyn_cast<ParenExpr>(prevExpr))
4616             pe->setSubExpr(ice->getSubExpr());
4617           else
4618             cast<CastExpr>(prevExpr)->setSubExpr(ice->getSubExpr());
4619           return e;
4620         }
4621 
4622       prevExpr = curExpr;
4623       curExpr = ce->getSubExpr();
4624       continue;
4625     }
4626 
4627     // Break out of the loop if curExpr is neither a Paren nor a Cast.
4628     break;
4629   }
4630 
4631   return e;
4632 }
4633 
4634 ExprResult Sema::BuildObjCBridgedCast(SourceLocation LParenLoc,
4635                                       ObjCBridgeCastKind Kind,
4636                                       SourceLocation BridgeKeywordLoc,
4637                                       TypeSourceInfo *TSInfo,
4638                                       Expr *SubExpr) {
4639   ExprResult SubResult = UsualUnaryConversions(SubExpr);
4640   if (SubResult.isInvalid()) return ExprError();
4641   SubExpr = SubResult.get();
4642 
4643   QualType T = TSInfo->getType();
4644   QualType FromType = SubExpr->getType();
4645 
4646   CastKind CK;
4647 
4648   bool MustConsume = false;
4649   if (T->isDependentType() || SubExpr->isTypeDependent()) {
4650     // Okay: we'll build a dependent expression type.
4651     CK = CK_Dependent;
4652   } else if (T->isObjCARCBridgableType() && FromType->isCARCBridgableType()) {
4653     // Casting CF -> id
4654     CK = (T->isBlockPointerType() ? CK_AnyPointerToBlockPointerCast
4655                                   : CK_CPointerToObjCPointerCast);
4656     switch (Kind) {
4657     case OBC_Bridge:
4658       break;
4659 
4660     case OBC_BridgeRetained: {
4661       bool br = isKnownName("CFBridgingRelease");
4662       Diag(BridgeKeywordLoc, diag::err_arc_bridge_cast_wrong_kind)
4663         << 2
4664         << FromType
4665         << (T->isBlockPointerType()? 1 : 0)
4666         << T
4667         << SubExpr->getSourceRange()
4668         << Kind;
4669       Diag(BridgeKeywordLoc, diag::note_arc_bridge)
4670         << FixItHint::CreateReplacement(BridgeKeywordLoc, "__bridge");
4671       Diag(BridgeKeywordLoc, diag::note_arc_bridge_transfer)
4672         << FromType << br
4673         << FixItHint::CreateReplacement(BridgeKeywordLoc,
4674                                         br ? "CFBridgingRelease "
4675                                            : "__bridge_transfer ");
4676 
4677       Kind = OBC_Bridge;
4678       break;
4679     }
4680 
4681     case OBC_BridgeTransfer:
4682       // We must consume the Objective-C object produced by the cast.
4683       MustConsume = true;
4684       break;
4685     }
4686   } else if (T->isCARCBridgableType() && FromType->isObjCARCBridgableType()) {
4687     // Okay: id -> CF
4688     CK = CK_BitCast;
4689     switch (Kind) {
4690     case OBC_Bridge:
4691       // Reclaiming a value that's going to be __bridge-casted to CF
4692       // is very dangerous, so we don't do it.
4693       SubExpr = maybeUndoReclaimObject(SubExpr);
4694       break;
4695 
4696     case OBC_BridgeRetained:
4697       // Produce the object before casting it.
4698       SubExpr = ImplicitCastExpr::Create(Context, FromType, CK_ARCProduceObject,
4699                                          SubExpr, nullptr, VK_RValue,
4700                                          FPOptionsOverride());
4701       break;
4702 
4703     case OBC_BridgeTransfer: {
4704       bool br = isKnownName("CFBridgingRetain");
4705       Diag(BridgeKeywordLoc, diag::err_arc_bridge_cast_wrong_kind)
4706         << (FromType->isBlockPointerType()? 1 : 0)
4707         << FromType
4708         << 2
4709         << T
4710         << SubExpr->getSourceRange()
4711         << Kind;
4712 
4713       Diag(BridgeKeywordLoc, diag::note_arc_bridge)
4714         << FixItHint::CreateReplacement(BridgeKeywordLoc, "__bridge ");
4715       Diag(BridgeKeywordLoc, diag::note_arc_bridge_retained)
4716         << T << br
4717         << FixItHint::CreateReplacement(BridgeKeywordLoc,
4718                           br ? "CFBridgingRetain " : "__bridge_retained");
4719 
4720       Kind = OBC_Bridge;
4721       break;
4722     }
4723     }
4724   } else {
4725     Diag(LParenLoc, diag::err_arc_bridge_cast_incompatible)
4726       << FromType << T << Kind
4727       << SubExpr->getSourceRange()
4728       << TSInfo->getTypeLoc().getSourceRange();
4729     return ExprError();
4730   }
4731 
4732   Expr *Result = new (Context) ObjCBridgedCastExpr(LParenLoc, Kind, CK,
4733                                                    BridgeKeywordLoc,
4734                                                    TSInfo, SubExpr);
4735 
4736   if (MustConsume) {
4737     Cleanup.setExprNeedsCleanups(true);
4738     Result = ImplicitCastExpr::Create(Context, T, CK_ARCConsumeObject, Result,
4739                                       nullptr, VK_RValue, FPOptionsOverride());
4740   }
4741 
4742   return Result;
4743 }
4744 
4745 ExprResult Sema::ActOnObjCBridgedCast(Scope *S,
4746                                       SourceLocation LParenLoc,
4747                                       ObjCBridgeCastKind Kind,
4748                                       SourceLocation BridgeKeywordLoc,
4749                                       ParsedType Type,
4750                                       SourceLocation RParenLoc,
4751                                       Expr *SubExpr) {
4752   TypeSourceInfo *TSInfo = nullptr;
4753   QualType T = GetTypeFromParser(Type, &TSInfo);
4754   if (Kind == OBC_Bridge)
4755     CheckTollFreeBridgeCast(T, SubExpr);
4756   if (!TSInfo)
4757     TSInfo = Context.getTrivialTypeSourceInfo(T, LParenLoc);
4758   return BuildObjCBridgedCast(LParenLoc, Kind, BridgeKeywordLoc, TSInfo,
4759                               SubExpr);
4760 }
4761