<rdar://problem/7263113> Make clang produce gcc's objc_assign_StrongCast as a result of type-cast of an ivar in assignment.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@83150 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/CGExpr.cpp

@@ -719,8 +719,18 @@ void setObjCGCLValueClass(const ASTContext &Ctx, const Expr *E, LValue &LV) {
   }
   else if (const UnaryOperator *Exp = dyn_cast<UnaryOperator>(E))
     setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
-  else if (const ParenExpr *Exp = dyn_cast<ParenExpr>(E))
+  else if (const ParenExpr *Exp = dyn_cast<ParenExpr>(E)) {
     setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
+    if (LV.isObjCIvar()) {
+      // If cast is to a structure pointer, follow gcc's behavior and make it
+      // a non-ivar write-barrier.
+      QualType ExpTy = E->getType();
+      if (ExpTy->isPointerType())
+        ExpTy = ExpTy->getAs<PointerType>()->getPointeeType();
+      if (ExpTy->isRecordType())
+        LV.SetObjCIvar(LV, false); 
+    }        
+  }
   else if (const ImplicitCastExpr *Exp = dyn_cast<ImplicitCastExpr>(E))
     setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
   else if (const CStyleCastExpr *Exp = dyn_cast<CStyleCastExpr>(E))

test/CodeGenObjC/objc2-write-barrier-5.m

@@ -0,0 +1,27 @@
+// RUN: clang-cc -triple x86_64-apple-darwin10 -fobjc-gc -emit-llvm -o %t %s &&
+// RUN: grep objc_assign_ivar %t | count 0 &&
+// RUN: grep objc_assign_strongCast %t | count 5 &&
+// RUN: true
+
+@interface TestUnarchiver 
+{
+	void  *allUnarchivedObjects;
+}
+@end
+
+@implementation TestUnarchiver
+
+struct unarchive_list {
+    int ifield;
+    id *list;
+};
+
+- (id)init {
+    (*((struct unarchive_list *)allUnarchivedObjects)).list = 0;
+    ((struct unarchive_list *)allUnarchivedObjects)->list = 0;
+    (**((struct unarchive_list **)allUnarchivedObjects)).list = 0;
+    (*((struct unarchive_list **)allUnarchivedObjects))->list = 0;
+    return 0;
+}
+
+@end