objc-arc/mrc: Allow ns_returns_not_retained attribute on properties

to turn off warning on those properties which follow Cocoa naming
convention for retaining objects and yet they were not meant for
such purposes. Also, perform consistancy checking for declared
getters of such methods. // rdar://9636091

llvm-svn: 133849

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -441,6 +441,9 @@ def warn_atomic_property_rule : Warning<
 def warn_ownin_getter_rule : Warning<
   "property's synthesized getter follows Cocoa naming"
   " convention for returning 'owned' objects">;
+def warn_property_getter_owning_mismatch : Warning<
+  "property declared as returning non-retained objects"
+  "; getter returning retained objects">;
 def err_ownin_getter_rule : Error<
   "property's synthesized getter follows Cocoa naming"
   " convention for returning 'owned' objects">;

clang/lib/Sema/SemaDeclAttr.cpp

@@ -2716,6 +2716,8 @@ static void HandleNSReturnsRetainedAttr(Decl *d, const AttributeList &attr,
 
   if (ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(d))
     returnType = MD->getResultType();
+  else if (ObjCPropertyDecl *PD = dyn_cast<ObjCPropertyDecl>(d))
+    returnType = PD->getType();
   else if (S.getLangOptions().ObjCAutoRefCount && hasDeclarator(d) &&
            (attr.getKind() == AttributeList::AT_ns_returns_retained))
     return; // ignore: was handled as a type attribute

clang/lib/Sema/SemaObjCProperty.cpp

@@ -737,6 +737,12 @@ Decl *Sema::ActOnPropertyImplDecl(Scope *S,
         PIDecl->setGetterCXXConstructor(ResExpr);
       }
     }
+    if (property->hasAttr<NSReturnsNotRetainedAttr>() &&
+        !getterMethod->hasAttr<NSReturnsNotRetainedAttr>()) {
+      Diag(getterMethod->getLocation(), 
+           diag::warn_property_getter_owning_mismatch);
+      Diag(property->getLocation(), diag::note_property_declare);
+    }
   }
   if (ObjCMethodDecl *setterMethod = property->getSetterMethodDecl()) {
     setterMethod->createImplicitParams(Context, IDecl);
@@ -1369,7 +1375,8 @@ void Sema::DiagnoseOwningPropertyGetterSynthesis(const ObjCImplementationDecl *D
       continue;
     
     const ObjCPropertyDecl *PD = PID->getPropertyDecl();
-    if (PD && !D->getInstanceMethod(PD->getGetterName())) {
+    if (PD && !PD->hasAttr<NSReturnsNotRetainedAttr>() &&
+        !D->getInstanceMethod(PD->getGetterName())) {
       ObjCMethodDecl *method = PD->getGetterMethodDecl();
       if (!method)
         continue;
@@ -1465,6 +1472,9 @@ void Sema::ProcessPropertyDecl(ObjCPropertyDecl *property,
     // and the real context should be the same.
     if (lexicalDC)
       GetterMethod->setLexicalDeclContext(lexicalDC);
+    if (property->hasAttr<NSReturnsNotRetainedAttr>())
+      GetterMethod->addAttr(
+        ::new (Context) NSReturnsNotRetainedAttr(Loc, Context));
   } else
     // A user declared getter will be synthesize when @synthesize of
     // the property with the same name is seen in the @implementation

clang/test/SemaObjC/arc.m

@@ -572,3 +572,23 @@ int Test33(id someid) {
   return (int)someid;
 }
 
+// rdar://9636091
+@interface I34
+@property (nonatomic, retain) id newName __attribute__((ns_returns_not_retained)) ;
+
+@property (nonatomic, retain) id newName1 __attribute__((ns_returns_not_retained)) ;
+- (id) newName1 __attribute__((ns_returns_not_retained));
+
+@property (nonatomic, retain) id newName2 __attribute__((ns_returns_not_retained)); // expected-note {{roperty declared here}}
+- (id) newName2;   // expected-warning {{property declared as returning non-retained objects; getter returning retained objects}}
+@end
+
+@implementation I34
+@synthesize newName;
+
+@synthesize newName1;
+- (id) newName1 { return 0; }
+
+@synthesize newName2;
+@end
+

clang/test/SemaObjC/property-ns-returns-not-retained-attr.m

@@ -0,0 +1,21 @@
+// RUN: %clang_cc1 -triple x86_64-apple-darwin11 -fobjc-nonfragile-abi -fsyntax-only -verify %s
+// rdar://9636091
+
+@interface I
+@property (nonatomic, retain) id newName __attribute__((ns_returns_not_retained)) ;
+
+@property (nonatomic, retain) id newName1 __attribute__((ns_returns_not_retained)) ;
+- (id) newName1 __attribute__((ns_returns_not_retained));
+
+@property (nonatomic, retain) id newName2 __attribute__((ns_returns_not_retained)); // expected-note {{roperty declared here}}
+- (id) newName2;   // expected-warning {{property declared as returning non-retained objects; getter returning retained objects}}
+@end
+
+@implementation I
+@synthesize newName;
+
+@synthesize newName1;
+- (id) newName1 { return 0; }
+
+@synthesize newName2;
+@end