Revert r139989 and r140031, which implemented the Objective-C type

system change in <rdar://problem/10109725> that allows conversion from
'self' in class methods to the root of the class's hierarchy. This
conversion rule is a hack that has non-trivial repurcussions
(particularly with overload resolution).

llvm-svn: 140605

clang/include/clang/Sema/Sema.h

@@ -677,9 +677,8 @@ public:
 
   GlobalMethodPool::iterator ReadMethodPool(Selector Sel);
 
-  /// Private Helper predicate to check for 'self'. Upon success, it
-  /// returns method declaration where 'self' is referenced.
-  const ObjCMethodDecl *GetMethodIfSelfExpr(Expr *RExpr);
+  /// Private Helper predicate to check for 'self'.
+  bool isSelfExpr(Expr *RExpr);
 public:
   Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
        TranslationUnitKind TUKind = TU_Complete,

clang/lib/Sema/SemaExpr.cpp

@@ -5107,25 +5107,6 @@ ExprResult Sema::ActOnConditionalOp(SourceLocation QuestionLoc,
                               OK));
 }
 
-/// ConvertObjCSelfToClassRootType - convet type of 'self' in class method
-/// to pointer to root of method's class.
-static QualType
-ConvertObjCSelfToClassRootType(Sema &S, Expr *selfExpr) {
-  QualType SelfType;
-  if (const ObjCMethodDecl *MD = S.GetMethodIfSelfExpr(selfExpr))
-    if (MD->isClassMethod()) {
-      const ObjCInterfaceDecl *Root = 0;
-      if (const ObjCInterfaceDecl * IDecl = MD->getClassInterface())
-      do {
-        Root = IDecl;
-      } while ((IDecl = IDecl->getSuperClass()));
-      if (Root)
-        SelfType =  S.Context.getObjCObjectPointerType(
-                      S.Context.getObjCInterfaceType(Root)); 
-    }
-  return SelfType;
-}
-
 // checkPointerTypesForAssignment - This is a very tricky routine (despite
 // being closely modeled after the C99 spec:-). The odd characteristic of this
 // routine is it effectively iqnores the qualifiers on the top level pointee.
@@ -5453,7 +5434,7 @@ Sema::CheckAssignmentConstraints(QualType LHSType, ExprResult &RHS,
         Kind = CK_BitCast;
         return Compatible;
       }
-      
+
       Kind = CK_BitCast;
       return IncompatiblePointer;
     }
@@ -5501,9 +5482,6 @@ Sema::CheckAssignmentConstraints(QualType LHSType, ExprResult &RHS,
 
   // Conversions to Objective-C pointers.
   if (isa<ObjCObjectPointerType>(LHSType)) {
-    QualType RHSQT = ConvertObjCSelfToClassRootType(*this, RHS.get());
-    if (!RHSQT.isNull())
-      RHSType = RHSQT;
     // A* -> B*
     if (RHSType->isObjCObjectPointerType()) {
       Kind = CK_BitCast;
@@ -9619,7 +9597,7 @@ void Sema::DiagnoseAssignmentAsCondition(Expr *E) {
       Selector Sel = ME->getSelector();
 
       // self = [<foo> init...]
-      if (GetMethodIfSelfExpr(Op->getLHS()) && Sel.getNameForSlot(0).startswith("init"))
+      if (isSelfExpr(Op->getLHS()) && Sel.getNameForSlot(0).startswith("init"))
         diagnostic = diag::warn_condition_is_idiomatic_assignment;
 
       // <foo> = [<bar> nextObject]

clang/lib/Sema/SemaExprObjC.cpp

@@ -457,20 +457,18 @@ bool Sema::CheckMessageArgumentTypes(QualType ReceiverType,
   return IsError;
 }
 
-/// GetMethodIfSelfExpr - Check if receiver is an objc 'self' expression
-/// and return its method declaration if so; else return 0.
-const ObjCMethodDecl *Sema::GetMethodIfSelfExpr(Expr *receiver) {
+bool Sema::isSelfExpr(Expr *receiver) {
   // 'self' is objc 'self' in an objc method only.
   DeclContext *DC = CurContext;
   while (isa<BlockDecl>(DC))
     DC = DC->getParent();
   if (DC && !isa<ObjCMethodDecl>(DC))
-    return 0;
+    return false;
   receiver = receiver->IgnoreParenLValueCasts();
   if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(receiver))
     if (DRE->getDecl()->getIdentifier() == &Context.Idents.get("self"))
-      return static_cast<ObjCMethodDecl*>(DC);
-  return 0;
+      return true;
+  return false;
 }
 
 // Helper method for ActOnClassMethod/ActOnInstanceMethod.
@@ -1274,7 +1272,7 @@ ExprResult Sema::BuildInstanceMessage(Expr *Receiver,
         }
         if (!Method) {
           // If not messaging 'self', look for any factory method named 'Sel'.
-          if (!Receiver || !GetMethodIfSelfExpr(Receiver)) {
+          if (!Receiver || !isSelfExpr(Receiver)) {
             Method = LookupFactoryMethodInGlobalPool(Sel, 
                                                 SourceRange(LBracLoc, RBracLoc),
                                                      true);
@@ -1338,7 +1336,7 @@ ExprResult Sema::BuildInstanceMessage(Expr *Receiver,
             return ExprError();
           }
 
-          if (!Method && (!Receiver || !GetMethodIfSelfExpr(Receiver))) {
+          if (!Method && (!Receiver || !isSelfExpr(Receiver))) {
             // If we still haven't found a method, look in the global pool. This
             // behavior isn't very desirable, however we need it for GCC
             // compatibility. FIXME: should we deviate??
@@ -1509,7 +1507,7 @@ ExprResult Sema::BuildInstanceMessage(Expr *Receiver,
   if (getLangOptions().ObjCAutoRefCount) {
     // In ARC, annotate delegate init calls.
     if (Result->getMethodFamily() == OMF_init &&
-        (SuperLoc.isValid() || GetMethodIfSelfExpr(Receiver))) {
+        (SuperLoc.isValid() || isSelfExpr(Receiver))) {
       // Only consider init calls *directly* in init implementations,
       // not within blocks.
       ObjCMethodDecl *method = dyn_cast<ObjCMethodDecl>(CurContext);

clang/test/SemaObjC/class-type-conversion.m

@@ -1,44 +0,0 @@
-// RUN: %clang_cc1 -fsyntax-only -verify %s
-// rdar://10109725
-
-@interface NSObject {
-    Class isa;
-}
-- (id)addObserver:(NSObject *)observer; // expected-note 2 {{passing argument to parameter 'observer' here}}
-@end
-
-@interface MyClass : NSObject {
-}
-@end
-
-@implementation NSObject
-+ (void)initialize
-{
-        NSObject *obj = 0;
-        [obj addObserver:self];
-}
-
-- init
-{
-        NSObject *obj = 0;
-        [obj addObserver:self];
-        return [obj addObserver:(Class)0]; // expected-warning {{incompatible pointer types sending 'Class' to parameter of type 'NSObject *'}}
-}
-- (id)addObserver:(NSObject *)observer { return 0; }
-@end
-
-@implementation MyClass
-
-+ (void)initialize
-{
-        NSObject *obj = 0;
-        [obj addObserver:self];
-}
-
-- init
-{
-        NSObject *obj = 0;
-        [obj addObserver:self];
-        return [obj addObserver:(Class)0]; // expected-warning {{incompatible pointer types sending 'Class' to parameter of type 'NSObject *'}}
-}
-@end