[libc++] Rename the macro for the LLVM 18 ABI tag used in ranges (#208464)

We typically use macros like _LIBCPP_ABI_XYZ for ABI settings that can
be configured by the user. Since _LIBCPP_ABI_LLVM18_NO_UNIQUE_ADDRESS is
not one of those, rename it to make it clearer it's an ABI tag
attribute.

As a drive-by remove the definition in the frozen C++03 config header
since it should never be needed (Ranges are not provided in C++03).

libcxx/include/__configuration/abi.h

@@ -96,7 +96,7 @@
 //
 // To fix the bug we had to change the ABI of some classes to remove [[no_unique_address]] under certain conditions.
 // The macro below is used for all classes whose ABI have changed as part of fixing these bugs.
-#define _LIBCPP_ABI_LLVM18_NO_UNIQUE_ADDRESS __attribute__((__abi_tag__("llvm18_nua")))
+#define _LIBCPP_LLVM18_NO_UNIQUE_ADDRESS_ABI_TAG __attribute__((__abi_tag__("llvm18_nua")))
 
 // [[msvc::no_unique_address]] seems to mostly affect empty classes, so the padding scheme for Itanium doesn't work.
 #if defined(_LIBCPP_ABI_MICROSOFT) && !defined(_LIBCPP_ABI_NO_COMPRESSED_PAIR_PADDING)

libcxx/include/__cxx03/__configuration/abi.h

@@ -121,16 +121,6 @@
 #  endif
 #endif
 
-// We had some bugs where we use [[no_unique_address]] together with construct_at,
-// which causes UB as the call on construct_at could write to overlapping subobjects
-//
-// https://github.com/llvm/llvm-project/issues/70506
-// https://github.com/llvm/llvm-project/issues/70494
-//
-// To fix the bug we had to change the ABI of some classes to remove [[no_unique_address]] under certain conditions.
-// The macro below is used for all classes whose ABI have changed as part of fixing these bugs.
-#define _LIBCPP_ABI_LLVM18_NO_UNIQUE_ADDRESS __attribute__((__abi_tag__("llvm18_nua")))
-
 // Changes the iterator type of select containers (see below) to a bounded iterator that keeps track of whether it's
 // within the bounds of the original container and asserts it on every dereference.
 //

libcxx/include/__ranges/chunk_by_view.h

@@ -54,7 +54,7 @@ namespace ranges {
 
 template <forward_range _View, indirect_binary_predicate<iterator_t<_View>, iterator_t<_View>> _Pred>
   requires view<_View> && is_object_v<_Pred>
-class _LIBCPP_ABI_LLVM18_NO_UNIQUE_ADDRESS chunk_by_view : public view_interface<chunk_by_view<_View, _Pred>> {
+class _LIBCPP_LLVM18_NO_UNIQUE_ADDRESS_ABI_TAG chunk_by_view : public view_interface<chunk_by_view<_View, _Pred>> {
   _LIBCPP_NO_UNIQUE_ADDRESS _View __base_ = _View();
   _LIBCPP_NO_UNIQUE_ADDRESS __movable_box<_Pred> __pred_;
 

libcxx/include/__ranges/drop_while_view.h

@@ -48,7 +48,7 @@ namespace ranges {
 
 template <view _View, class _Pred>
   requires input_range<_View> && is_object_v<_Pred> && indirect_unary_predicate<const _Pred, iterator_t<_View>>
-class _LIBCPP_ABI_LLVM18_NO_UNIQUE_ADDRESS drop_while_view : public view_interface<drop_while_view<_View, _Pred>> {
+class _LIBCPP_LLVM18_NO_UNIQUE_ADDRESS_ABI_TAG drop_while_view : public view_interface<drop_while_view<_View, _Pred>> {
 public:
   _LIBCPP_HIDE_FROM_ABI drop_while_view()
     requires default_initializable<_View> && default_initializable<_Pred>

libcxx/include/__ranges/filter_view.h

@@ -54,7 +54,7 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 namespace ranges {
 template <input_range _View, indirect_unary_predicate<iterator_t<_View>> _Pred>
   requires view<_View> && is_object_v<_Pred>
-class _LIBCPP_ABI_LLVM18_NO_UNIQUE_ADDRESS filter_view : public view_interface<filter_view<_View, _Pred>> {
+class _LIBCPP_LLVM18_NO_UNIQUE_ADDRESS_ABI_TAG filter_view : public view_interface<filter_view<_View, _Pred>> {
   _LIBCPP_NO_UNIQUE_ADDRESS _View __base_ = _View();
   _LIBCPP_NO_UNIQUE_ADDRESS __movable_box<_Pred> __pred_;
 

libcxx/include/__ranges/repeat_view.h

@@ -74,7 +74,7 @@ struct __fn;
 template <move_constructible _Tp, semiregular _Bound = unreachable_sentinel_t>
   requires(is_object_v<_Tp> && same_as<_Tp, remove_cv_t<_Tp>> &&
            (__integer_like_with_usable_difference_type<_Bound> || same_as<_Bound, unreachable_sentinel_t>))
-class _LIBCPP_ABI_LLVM18_NO_UNIQUE_ADDRESS repeat_view : public view_interface<repeat_view<_Tp, _Bound>> {
+class _LIBCPP_LLVM18_NO_UNIQUE_ADDRESS_ABI_TAG repeat_view : public view_interface<repeat_view<_Tp, _Bound>> {
   friend struct views::__take::__fn;
   friend struct views::__drop::__fn;
   class __iterator;

libcxx/include/__ranges/single_view.h

@@ -41,7 +41,7 @@ template <move_constructible _Tp>
 template <copy_constructible _Tp>
 #  endif
   requires is_object_v<_Tp>
-class _LIBCPP_ABI_LLVM18_NO_UNIQUE_ADDRESS single_view : public view_interface<single_view<_Tp>> {
+class _LIBCPP_LLVM18_NO_UNIQUE_ADDRESS_ABI_TAG single_view : public view_interface<single_view<_Tp>> {
   _LIBCPP_NO_UNIQUE_ADDRESS __movable_box<_Tp> __value_;
 
 public:

libcxx/include/__ranges/take_while_view.h

@@ -46,7 +46,7 @@ namespace ranges {
 
 template <view _View, class _Pred>
   requires input_range<_View> && is_object_v<_Pred> && indirect_unary_predicate<const _Pred, iterator_t<_View>>
-class _LIBCPP_ABI_LLVM18_NO_UNIQUE_ADDRESS take_while_view : public view_interface<take_while_view<_View, _Pred>> {
+class _LIBCPP_LLVM18_NO_UNIQUE_ADDRESS_ABI_TAG take_while_view : public view_interface<take_while_view<_View, _Pred>> {
   template <bool>
   class __sentinel;
 

libcxx/include/__ranges/transform_view.h

@@ -71,7 +71,7 @@ template <input_range _View, move_constructible _Fn>
 template <input_range _View, copy_constructible _Fn>
 #  endif
   requires __transform_view_constraints<_View, _Fn>
-class _LIBCPP_ABI_LLVM18_NO_UNIQUE_ADDRESS transform_view : public view_interface<transform_view<_View, _Fn>> {
+class _LIBCPP_LLVM18_NO_UNIQUE_ADDRESS_ABI_TAG transform_view : public view_interface<transform_view<_View, _Fn>> {
   template <bool>
   class __iterator;
   template <bool>