[ObjC] Allow declaring __strong pointer fields in structs in Objective-C

ARC mode.

Declaring __strong pointer fields in structs was not allowed in
Objective-C ARC until now because that would make the struct non-trivial
to default-initialize, copy/move, and destroy, which is not something C
was designed to do. This patch lifts that restriction.

Special functions for non-trivial C structs are synthesized that are
needed to default-initialize, copy/move, and destroy the structs and
manage the ownership of the objects the __strong pointer fields point
to. Non-trivial structs passed to functions are destructed in the callee
function.

rdar://problem/33599681

Differential Revision: https://reviews.llvm.org/D41228

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@326307 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 3 insertions, 1 deletions

diff --git a/lib/AST/Decl.cpp b/lib/AST/Decl.cpp
index c4da87c013..eb2c770b5f 100644
--- a/lib/AST/Decl.cpp
+++ b/lib/AST/Decl.cpp
@@ -3929,7 +3929,9 @@ RecordDecl::RecordDecl(Kind DK, TagKind TK, const ASTContext &C,
     : TagDecl(DK, TK, C, DC, IdLoc, Id, PrevDecl, StartLoc),
       HasFlexibleArrayMember(false), AnonymousStructOrUnion(false),
       HasObjectMember(false), HasVolatileMember(false),
-      LoadedFieldsFromExternalStorage(false) {
+      LoadedFieldsFromExternalStorage(false),
+      NonTrivialToPrimitiveDefaultInitialize(false),
+      NonTrivialToPrimitiveCopy(false), NonTrivialToPrimitiveDestroy(false) {
   assert(classof(static_cast<Decl*>(this)) && "Invalid Kind!");
 }