Fix a pair of bugs relating to properties in ARC.

First, when synthesizing an explicitly strong/retain/copy property
of Class type, don't pretend during compatibility checking that the
property is actually assign.  Instead, resolve incompatibilities
by secretly changing the type of *implicitly* __unsafe_unretained
Class ivars to be strong.  This is moderately evil but better than
what we were doing.

Second, when synthesizing the setter for a strong property of
non-retainable type, be sure to use objc_setProperty.  This is
possible when the property is decorated with the NSObject
attribute.  This is an ugly, ugly corner of the language, and
we probably ought to deprecate it.

The first is rdar://problem/12039404;  the second was noticed by
inspection while fixing the first.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@162244 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 10 insertions, 1 deletions

diff --git a/lib/CodeGen/CGObjC.cpp b/lib/CodeGen/CGObjC.cpp
index 4ac172d1cb..e0762846dc 100644
--- a/lib/CodeGen/CGObjC.cpp
+++ b/lib/CodeGen/CGObjC.cpp
@@ -613,7 +613,16 @@ PropertyImplStrategy::PropertyImplStrategy(CodeGenModule &CGM,
     // which translates to objc_storeStrong.  This isn't required, but
     // it's slightly nicer.
     } else if (CGM.getLangOpts().ObjCAutoRefCount && !IsAtomic) {
-      Kind = Expression;
+      // Using standard expression emission for the setter is only
+      // acceptable if the ivar is __strong, which won't be true if
+      // the property is annotated with __attribute__((NSObject)).
+      // TODO: falling all the way back to objc_setProperty here is
+      // just laziness, though;  we could still use objc_storeStrong
+      // if we hacked it right.
+      if (ivarType.getObjCLifetime() == Qualifiers::OCL_Strong)
+        Kind = Expression;
+      else
+        Kind = SetPropertyAndExpressionGet;
       return;
 
     // Otherwise, we need to at least use setProperty.  However, if