objective-arc: Retune my previous patch so warning

is issued on weak property as receiver and not on
any other use of a weak property. // rdar://10225276


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@155169 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Sema/Sema.h

@@ -5901,9 +5901,6 @@ public:
                                            bool IsInstance);
 
   bool inferObjCARCLifetime(ValueDecl *decl);
-  
-  void DiagnoseARCUseOfWeakReceiver(NamedDecl *PDecl,
-                                    QualType T, SourceLocation Loc);
 
   ExprResult
   HandleExprPropertyRefExpr(const ObjCObjectPointerType *OPT,

lib/Sema/SemaExprObjC.cpp

@@ -1323,30 +1323,48 @@ ObjCMethodDecl *Sema::LookupMethodInQualifiedType(Selector Sel,
   return 0;
 }
 
-void 
-Sema::DiagnoseARCUseOfWeakReceiver(NamedDecl *PDecl,
-                                   QualType T, SourceLocation Loc) {
-  if (!getLangOpts().ObjCAutoRefCount)
+static void DiagnoseARCUseOfWeakReceiver(Sema &S, Expr *Receiver) {
+  if (!Receiver)
     return;
   
-  if (T.getObjCLifetime() == Qualifiers::OCL_Weak) {
-    Diag(Loc, diag::warn_receiver_is_weak) 
-      << (!PDecl ? 0 : (isa<ObjCPropertyDecl>(PDecl) ? 1 : 2));
-    if (PDecl) {
-      if (isa<ObjCPropertyDecl>(PDecl))
-        Diag(PDecl->getLocation(), diag::note_property_declare);
-      else
-        Diag(PDecl->getLocation(), diag::note_method_declared_at) << PDecl;
+  Expr *RExpr = Receiver->IgnoreParenImpCasts();
+  SourceLocation Loc = RExpr->getLocStart();
+  QualType T = RExpr->getType();
+  ObjCPropertyDecl *PDecl = 0;
+  ObjCMethodDecl *GDecl = 0;
+  if (PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(RExpr)) {
+    RExpr = POE->getSyntacticForm();
+    if (ObjCPropertyRefExpr *PRE = dyn_cast<ObjCPropertyRefExpr>(RExpr)) {
+      if (PRE->isImplicitProperty()) {
+        GDecl = PRE->getImplicitPropertyGetter();
+        if (GDecl) {
+          T = GDecl->getResultType();
+        }
+      }
+      else {
+        PDecl = PRE->getExplicitProperty();
+        if (PDecl) {
+          T = PDecl->getType();
+        }
+      }
     }
+  }
+  
+  if (T.getObjCLifetime() == Qualifiers::OCL_Weak) {
+    S.Diag(Loc, diag::warn_receiver_is_weak) 
+      << ((!PDecl && !GDecl) ? 0 : (PDecl ? 1 : 2));
+    if (PDecl)
+      S.Diag(PDecl->getLocation(), diag::note_property_declare);
+    else if (GDecl)
+      S.Diag(GDecl->getLocation(), diag::note_method_declared_at) << GDecl;
     return;
   }
   
-  if (PDecl)
-    if (ObjCPropertyDecl *Prop = dyn_cast<ObjCPropertyDecl>(PDecl))
-      if (Prop->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_weak) {
-        Diag(Loc, diag::warn_receiver_is_weak) << 1;
-        Diag(Prop->getLocation(), diag::note_property_declare);
-      }
+  if (PDecl && 
+      (PDecl->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_weak)) {
+    S.Diag(Loc, diag::warn_receiver_is_weak) << 1;
+    S.Diag(PDecl->getLocation(), diag::note_property_declare);
+  }
 }
 
 /// HandleExprPropertyRefExpr - Handle foo.bar where foo is a pointer to an
@@ -2404,10 +2422,7 @@ ExprResult Sema::BuildInstanceMessage(Expr *Receiver,
   }
 
   if (getLangOpts().ObjCAutoRefCount) {
-    if (Receiver)
-      DiagnoseARCUseOfWeakReceiver(0 /* PDecl */,
-                                   Receiver->IgnoreParenImpCasts()->getType(),
-                                   Receiver->getLocStart());
+    DiagnoseARCUseOfWeakReceiver(*this, Receiver);
     
     // In ARC, annotate delegate init calls.
     if (Result->getMethodFamily() == OMF_init &&

lib/Sema/SemaPseudoObject.cpp

@@ -478,8 +478,6 @@ bool ObjCPropertyOpBuilder::findGetter() {
   if (RefExpr->isImplicitProperty()) {
     if ((Getter = RefExpr->getImplicitPropertyGetter())) {
       GetterSelector = Getter->getSelector();
-      S.DiagnoseARCUseOfWeakReceiver(Getter, Getter->getResultType(),
-                                     RefExpr->getLocation());
       return true;
     }
     else {
@@ -499,8 +497,6 @@ bool ObjCPropertyOpBuilder::findGetter() {
   }
 
   ObjCPropertyDecl *prop = RefExpr->getExplicitProperty();
-  S.DiagnoseARCUseOfWeakReceiver(prop, prop->getType(),
-                                 RefExpr->getLocation());
   Getter = LookupMethodInReceiverType(S, prop->getGetterName(), RefExpr);
   return (Getter != 0);
 }

test/SemaObjC/weak-receiver-warn.m

@@ -23,21 +23,21 @@ void test0(Test0 *x) {
   __weak Test* weak_prop;
 }
 - (void) Meth;
-@property  __weak Test* weak_prop; // expected-note 2 {{property declared here}}
-@property (weak, atomic) id weak_atomic_prop; // expected-note 2 {{property declared here}}
-- (__weak id) P; // expected-note 2 {{method 'P' declared here}}
+@property  __weak Test* weak_prop; // expected-note {{property declared here}}
+@property (weak, atomic) id weak_atomic_prop; // expected-note {{property declared here}}
+- (__weak id) P; // expected-note {{method 'P' declared here}}
 @end
 
 @implementation Test
 - (void) Meth {
-    if (self.weak_prop) { // expected-warning {{weak property may be unpredictably null in ARC mode}}
+    if (self.weak_prop) {
       self.weak_prop = 0;
     }
-    if (self.weak_atomic_prop) { // expected-warning {{weak property may be unpredictably null in ARC mode}}
+    if (self.weak_atomic_prop) {
       self.weak_atomic_prop = 0;
     }
     [self.weak_prop Meth]; // expected-warning {{weak property may be unpredictably null in ARC mode}}
-    id pi = self.P; // expected-warning {{weak implicit property may be unpredictably null in ARC mode}}
+    id pi = self.P;
 
     [self.weak_atomic_prop Meth];  // expected-warning {{weak property may be unpredictably null in ARC mode}}