r299992 - [Sema][ObjC] Check whether a variable has a definition, rather than

[Akira Hatanaka via cfe-commits]

Author: ahatanak
Date: Tue Apr 11 17:01:33 2017
New Revision: 299992

URL: http://llvm.org/viewvc/llvm-project?rev=299992&view=rev
Log:
[Sema][ObjC] Check whether a variable has a definition, rather than
checking its storage class, when determining whether casting a C pointer
to an ObjC pointer is allowed.

This change allows casting variables whose declarations are directly
contained in a linkage specification to an ObjC pointer type. Those
variables are treated as if they contain the extern specifier for the
purpose of determining whether they are definitions or not.

rdar://problem/29249853

Differential Revision: https://reviews.llvm.org/D31673

Modified:
    cfe/trunk/lib/Sema/SemaExprObjC.cpp
    cfe/trunk/test/SemaObjCXX/arc-bridged-cast.mm

Modified: cfe/trunk/lib/Sema/SemaExprObjC.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExprObjC.cpp?rev=299992&r1=299991&r2=299992&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaExprObjC.cpp (original)
+++ cfe/trunk/lib/Sema/SemaExprObjC.cpp Tue Apr 11 17:01:33 2017
@@ -3355,7 +3355,7 @@ namespace {
       if (isAnyRetainable(TargetClass) &&
           isAnyRetainable(SourceClass) &&
           var &&
-          var->getStorageClass() == SC_Extern &&
+          !var->hasDefinition(Context) &&
           var->getType().isConstQualified()) {
 
         // In system headers, they can also be assumed to be immune to retains.

Modified: cfe/trunk/test/SemaObjCXX/arc-bridged-cast.mm
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaObjCXX/arc-bridged-cast.mm?rev=299992&r1=299991&r2=299992&view=diff
==============================================================================
--- cfe/trunk/test/SemaObjCXX/arc-bridged-cast.mm (original)
+++ cfe/trunk/test/SemaObjCXX/arc-bridged-cast.mm Tue Apr 11 17:01:33 2017
@@ -52,3 +52,19 @@ void testObjCBridgeId() {
   ref = (__bridge_retained CFAnnotatedObjectRef) CreateSomething();
   ref = (__bridge_retained CFAnnotatedObjectRef) CreateNSString();
 }
+
+struct __CFAnnotatedObject {
+} cf0;
+
+extern const CFAnnotatedObjectRef r0;
+extern const CFAnnotatedObjectRef r1 = &cf0;
+extern "C" const CFAnnotatedObjectRef r2;
+extern "C" const CFAnnotatedObjectRef r3 = &cf0;
+
+void testExternC() {
+  id obj;
+  obj = (id)r0;
+  obj = (id)r1; // expected-error{{cast of C pointer type 'CFAnnotatedObjectRef' (aka 'const __CFAnnotatedObject *') to Objective-C pointer type 'id' requires a bridged cast}} expected-note{{use __bridge to convert directly}} expected-note{{use __bridge_transfer to transfer ownership of a +1 'CFAnnotatedObjectRef'}}
+  obj = (id)r2;
+  obj = (id)r3; // expected-error{{cast of C pointer type 'CFAnnotatedObjectRef' (aka 'const __CFAnnotatedObject *') to Objective-C pointer type 'id' requires a bridged cast}} expected-note{{use __bridge to convert directly}} expected-note{{use __bridge_transfer to transfer ownership of a +1 'CFAnnotatedObjectRef'}}
+}