[libc++] Rename _LIBCPP_INLINE_VISIBILITY to _LIBCPP_HIDE_FROM_ABI (#74095)

In preparation for running clang-format on the whole code base, we are
also removing mentions of the legacy _LIBCPP_INLINE_VISIBILITY macro in
favor of the newer _LIBCPP_HIDE_FROM_ABI.

We're still leaving the definition of _LIBCPP_INLINE_VISIBILITY to avoid
creating needless breakage in case some older patches are checked-in
with mentions of the old macro. After we branch for LLVM 18, we can do
another pass to clean up remaining uses of the macro that might have
gotten introduced by mistake (if any) and remove the macro itself at the
same time. This is just a minor convenience to smooth out the transition
as much as possible.

See
https://discourse.llvm.org/t/rfc-clang-formatting-all-of-libc-once-and-for-all
for the clang-format proposal.

1 files changed, 2 insertions, 2 deletions

diff --git a/libcxx/include/iosfwd b/libcxx/include/iosfwd
index 80c0c27..48fe28e 100644
--- a/libcxx/include/iosfwd
+++ b/libcxx/include/iosfwd
@@ -179,13 +179,13 @@ class __save_flags
     __save_flags(const __save_flags&);
     __save_flags& operator=(const __save_flags&);
 public:
-    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_HIDE_FROM_ABI
     explicit __save_flags(__stream_type& __stream)
         : __stream_(__stream),
           __fmtflags_(__stream.flags()),
           __fill_(__stream.fill())
         {}
-    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_HIDE_FROM_ABI
     ~__save_flags()
     {
         __stream_.flags(__fmtflags_);