[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
llvm-svn: 326307
diff --git a/clang/docs/LanguageExtensions.rst b/clang/docs/LanguageExtensions.rst
index 6d9bbcb..bb9b4c1 100644
--- a/clang/docs/LanguageExtensions.rst
+++ b/clang/docs/LanguageExtensions.rst
@@ -1191,12 +1191,14 @@
Clang provides support for :doc:`automated reference counting
<AutomaticReferenceCounting>` in Objective-C, which eliminates the need
-for manual ``retain``/``release``/``autorelease`` message sends. There are two
+for manual ``retain``/``release``/``autorelease`` message sends. There are three
feature macros associated with automatic reference counting:
``__has_feature(objc_arc)`` indicates the availability of automated reference
counting in general, while ``__has_feature(objc_arc_weak)`` indicates that
automated reference counting also includes support for ``__weak`` pointers to
-Objective-C objects.
+Objective-C objects. ``__has_feature(objc_arc_fields)`` indicates that C structs
+are allowed to have fields that are pointers to Objective-C objects managed by
+automatic reference counting.
.. _objc-fixed-enum: