[libc++] Remove availability markup for std::format

[ldionne]

Summary

std::format is currently experimental, so there is technically no
deployment target requirement for it (since the only symbols required
for it are in libc++experimental.a).

However, some parts of std::format depend indirectly on the floating
point std::to_chars implementation, which does have deployment target
requirements.

This patch removes all the availability format for std::format and
updates the XFAILs in the tests to properly explain why they fail
on old deployment targets, when they do. It also changes a couple
of tests to avoid depending on floating-point std::to_chars when
it isn't fundamental to the test.

Finally, some tests are marked as XFAIL but I added a comment saying

TODO FMT This test should not require std::to_chars(floating-point)

These tests do not fundamentally depend on floating-point std::to_chars,
however they end up failing because calling std::format even without a
floating-point argument to format will end up requiring floating-point
std::to_chars. I believe this is an implementation artifact that could
be avoided in all cases where we know the format string at compile-time.
In the tests, I added the TODO comment only to the places where we could
do better and actually avoid relying on floating-point std::to_chars
because we know the format string at compile-time.

[Mordante]

Attempts to fix CI.

[Mordante]

Attempts to fix CI.

[Mordante]

Attempts to fix CI.

[Mordante]

Attempt to fix CI.

[Mordante]

Test CI.

[Mordante]

CI testing.

[Mordante]

CI test

[Mordante]

More tests

[Mordante]

CI test

[Mordante]

Attempt to fix the CI.

[Mordante]

CI fixes

[Mordante]

CI fixes

[Mordante]

Attempts to fix CI.

[Mordante]

CI fixes.

[Mordante]

Rebased, formatted, and reenable the entire CI.

[Mordante]

CI fixes.

[Mordante]

Fixes CI.

[ldionne]

libcxx/include/__chrono/formatter.h

52

This really looks like a compiler bug to me. Would you be able to get a smaller reproducer for the issue? We could get it fixed in Clang.

libcxx/test/std/utilities/format/format.functions/vformat_to.locale.pass.cpp

15

I think that should work too, and IMO it's easier to read.

[Mordante]

libcxx/include/__chrono/formatter.h

52

I have hard time to get a reproducer, I probably want to investigate it at a later time.

[Mordante]

Rebased and addresses review comments.

[Mordante]

CI fixes.

[Mordante]

CI fixes.

[Mordante]

CI fixes.

[ldionne]

Commandeering per offline discussion.

[ldionne]

Update

[ldionne]

Update with commit message.

[ldionne]

libcxx/include/__chrono/formatter.h

44

Most of these changes are removals. The interesting change to see is actually where the annotations were kept, but this diff doesn't show it. As a summary, only the following entities still have the attribute after this change:

operator<<(chrono types) // those use std::format
std::format, std::vformat and everything else in format_functions.h // those use floating-point to_chars indirectly sometimes
formatter<floating-point> in formatter_floating_point.h // those are the only ones that use to_chars directly

All the other _LIBCPP_AVAILABILITY_FORMAT are gone cause they don't use to_chars.

libcxx/include/__format/format_functions.h

442

I want to call this out -- this is terrible but omitting this creates huge problems with the attribute. I am not convinced this is acceptable.

[ldionne]

Add test to check that availability markup triggers appropriately and fix clang-format.

[Mordante]

Thanks for picking this up! I have a few questions regarding formatters that could be used with floating-point types. I really wonder whether removing their availability macros is correct.

libcxx/include/__availability

266 ↗

(On Diff #506080)

I assume this answers the question of the removal if the macro in classes, right?

libcxx/include/__chrono/ostream.h

95

Depending on the answer regarding the usage of floating-point in general I need to check whether this one can call to_chars(floating-point). The _Rep can be a floating-point type, the same may apply to a few other chrono formatters.

libcxx/include/__format/container_adaptor.h

40 ↗

(On Diff #506080)

These containers can contain floating-point values too.

libcxx/include/__format/format_functions.h

442

Interesting. I guess that explains why I had to use the availability macro at a lot of places.

Can we add a TODO FMT Make non-templated when removing _LIBCPP_AVAILABILITY_FORMAT.

libcxx/include/__format/format_parse_context.h

62–63

Is the removal of _LIBCPP_AVAILABILITY_FORMAT really correct since the format_error's destructor in experimental library. I haven't looked whether basic_format_arg can throw. I know for certain formatter::parse can throw.

libcxx/include/__format/formatter_tuple.h

42 ↗

(On Diff #506080)

A tuple may contain a floating-point value.

libcxx/include/__format/range_default_formatter.h

87 ↗

(On Diff #506080)

The sequence, map, and set version may be used with floating-point types.

171 ↗

(On Diff #506080)

If it doesn't hurt I prefer to keep this one and remove it in D145853 instead.

libcxx/include/__format/range_formatter.h

43 ↗

(On Diff #506080)

_Tp may be a floating-point type.

libcxx/test/libcxx/utilities/format/format.availability.verify.cpp

15 ↗

(On Diff #506080)

Just curious, do we have these tests for other availability macros too?

libcxx/test/std/time/time.syn/formatter.month.pass.cpp

14

Is this on your list to investigate?

[ldionne]

libcxx/include/__availability

266 ↗

(On Diff #506080)

I am not certain I understand the question. I went through your comments but I don't remember seeing something related to removal of the macro in classes. Can you clarify?

libcxx/include/__chrono/ostream.h

95

If it does, then that would be guarded by the availability macros on std::to_chars(floating-point) itself. IOW, if this ends up calling something that could be missing from the dylib on your deployment target, it'll be caught because std::to_chars(floating-point) is annotated properly.

libcxx/include/__format/container_adaptor.h

40 ↗

(On Diff #506080)

As we discussed: yes, but in that case, the code will fail to compile due to the availability markup on the floating point formatter instantiated within. But using a container adaptor without any floating point in it should work, and it shouldn't fail to compile.

libcxx/include/__format/format_functions.h

442

We can add a TODO, however it would likely be super long lived since we probably won't remove _LIBCPP_AVAILABILITY_FORMAT before a long long time, aka when we drop support for the OS in which those will first be introduced. That'll be years.

However, I think what we should do is fix this problem in Clang, since that's clearly (?) a Clang bug.

libcxx/include/__format/format_parse_context.h

62–63

Since that's a static library, the destructor is effectively compiled into the user's binary, removing the deployment target requirement. Putting it in a static library is as-if it has been defined in the headers from a where-the-code-ends-up-compiled perspective.

libcxx/include/__format/formatter_tuple.h

42 ↗

(On Diff #506080)

Same answer as for container adaptors!

libcxx/include/__format/range_default_formatter.h

87 ↗

(On Diff #506080)

Same answer as for container adaptors!

171 ↗

(On Diff #506080)

I guess I am fine with either, but I don't understand why you'd remove that in D145853. If your concern is about merge conflicts, I am fine with rebasing this change on top of yours. Leaving comment open to determine what to do.

libcxx/include/__format/range_formatter.h

43 ↗

(On Diff #506080)

Same answer as for container adaptors!

libcxx/test/libcxx/utilities/format/format.availability.verify.cpp

15 ↗

(On Diff #506080)

We have a few, for example libcxx/test/libcxx/thread/barrier.availability.verify.cpp.

libcxx/test/std/time/time.syn/formatter.month.pass.cpp

14

Yes, I would like to get to it eventually, but I won't lie to you, it'll take me some time.

[ldionne]

Fix CI issue and rebase.

[ldionne]

Fix a few filesystem tests failing on old deployment targets

[ldionne]

Rebase onto main.

[Mordante]

This really starts to look nice, there are a few minor issues. After that I want to have look at the final patch before approving.

libcxx/include/__availability

266 ↗

(On Diff #506080)

Mainly why we can now remove all AVAILABILITY macros in the classes. I think it's mainly a conclusion for me since you answered the other questions.

libcxx/include/__format/container_adaptor.h

40 ↗

(On Diff #506080)

I think the only thing that puzzles my then is why not remove the _LIBCPP_AVAILABILITY_FORMAT from libcxx/include/__format/formatter_floating_point.h and and let that use transitive depend on to_char(floating-point).

libcxx/include/__format/format_functions.h

442

That makes me want a TODO FMT even more and then a link to the Clang bug-report or the rdar number.

libcxx/test/libcxx/utilities/format/format.availability.verify.cpp

15 ↗

(On Diff #506080)

Thanks, I hadn't noticed these before.

libcxx/test/std/time/time.syn/formatter.month.pass.cpp

14

It would be interesting to know what you found thusfar, maybe discuss it on our next 1:1. I don't see this part as a blocker.

I would like to see TODO FMT instead of just TODO. This is consistent with the other format related TODOs.

[ldionne]

libcxx/include/__availability

266 ↗

(On Diff #506080)

I don't think any of the classes were using std::to_chars(floating-point) directly, so that's why I removed the annotations from them.

libcxx/include/__format/container_adaptor.h

40 ↗

(On Diff #506080)

That's actually a great point. I think I can go one step further and remove _LIBCPP_AVAILABILITY_FORMAT altogether. If you use something from <format> and it ends up using std::to_chars(floating-point), then so be it, you'll get a compiler error. If not then no compiler error. I think that actually makes the most sense.

If we have a deployment requirement for std::format itself, then we can re-add markup.

libcxx/include/__format/format_functions.h

442

Ok, I reduced and created http://llvm.org/PR61563. I'll link to it.

[ldionne]

Remove format-specific availability markup, which isn't actually needed.

[Mordante]

libcxx/include/__format/container_adaptor.h

40 ↗

(On Diff #506080)

I agree, removing it altogether was on my mind too, but I wasn't sure whether it was possible, hence the question regarding the floating_point formatter. I assume you intend to remove them everywhere so I will not review this version further. Please let me know if you want me to review this version first.

I think I will move the format_error destructor to the header, then we won't need an availability macro. I'm not sure whether that will impact Apple users. But let's discuss that at another time.

libcxx/include/__format/format_functions.h

442

Thanks!

[ldionne]

libcxx/include/__format/container_adaptor.h

40 ↗

(On Diff #506080)

In the current state of this patch, all _LIBCPP_AVAILABILITY_FORMAT should be gone. I think I would like to get this one reviewed and landed and then I will rebase the other patches in the stack on top of it. Does that make sense?

[ldionne]

Rebase and fix formatting.

[Mordante]

LGTM!

libcxx/include/__format/container_adaptor.h

40 ↗

(On Diff #506080)

Yes that sounds good. I just wanted to avoid spending time reviewing, with the chance the patch would be reworked again. The current patch is indeed what I expected the patch would look like :-)

libcxx/include/__format/range_default_formatter.h

171 ↗

(On Diff #506080)

It would prevent a merge conflict, but since you remove the macro from __availability I will have to deal with the conflict.

[ldionne]

Try to re-trigger CI. I don't understand why the job is skipped and the CI reports as green.

[ldionne]

Looks like this passed, shipping.

libcxx/include/__chrono/formatter.h

 // -*- C++ -*-
 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP___CHRONO_FORMATTER_H
 #define _LIBCPP___CHRONO_FORMATTER_H
 
+#include <__availability>
 #include <__chrono/convert_to_tm.h>
 #include <__chrono/day.h>
 #include <__chrono/duration.h>
 #include <__chrono/hh_mm_ss.h>
 #include <__chrono/month.h>
 #include <__chrono/ostream.h>
 #include <__chrono/parser_std_format_spec.h>
 #include <__chrono/statically_widen.h>

 #include <cmath>
 #include <ctime>
 #include <sstream>
 #include <string>
 #include <string_view>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)
+// On Apple back-deployment targets the format functions are not available with
+// and #ifndef. This will cause compilation failures when using these
+// functions. Therefore make these functions unavailable when used on these
+// platforms.
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT) && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 namespace __formatter {
 
 /// Formats a time based on a tm struct.
 ///
 /// This formatter passes the formatting to time_put which uses strftime. When
 /// the value is outside the valid range it's unspecified what strftime will
 /// output. For example weekday 8 can print 1 when the day is processed modulo
_LIBCPP_HIDE_FROM_ABI auto format(const _Tp& __value, auto& __ctx) const -> decltype(__ctx.out()) const {
     return __formatter::__format_chrono(
         __value, __ctx, __parser_.__parser_.__get_parsed_chrono_specifications(__ctx), __parser_.__chrono_specs_);
   }
 
   __format_spec::__parser_chrono<_CharT> __parser_;
 };
 
 template <class _Rep, class _Period, __fmt_char_type _CharT>
-struct formatter<chrono::duration<_Rep, _Period>, _CharT> : public __formatter_chrono<_CharT> {
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT  formatter<chrono::duration<_Rep, _Period>, _CharT> : public __formatter_chrono<_CharT> {
 public:
   using _Base = __formatter_chrono<_CharT>;
 
   _LIBCPP_HIDE_FROM_ABI constexpr auto parse(basic_format_parse_context<_CharT>& __parse_ctx)
       -> decltype(__parse_ctx.begin()) {
     // [time.format]/1
     // Giving a precision specification in the chrono-format-spec is valid only
     // for std::chrono::duration types where the representation type Rep is a
public:
   using _Base = __formatter_chrono<_CharT>;
 
   _LIBCPP_HIDE_FROM_ABI constexpr auto parse(basic_format_parse_context<_CharT>& __parse_ctx)
       -> decltype(__parse_ctx.begin()) {
     return _Base::__parse(__parse_ctx, __format_spec::__fields_chrono, __format_spec::__flags::__weekday);
   }
 };
 
-#endif // if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT) && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif //  _LIBCPP___CHRONO_FORMATTER_H

libcxx/include/__chrono/ostream.h

 // -*- C++ -*-
 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP___CHRONO_OSTREAM_H
 #define _LIBCPP___CHRONO_OSTREAM_H
 
+#include <__availability>
 #include <__chrono/day.h>
 #include <__chrono/duration.h>
 #include <__chrono/month.h>
 #include <__chrono/statically_widen.h>
 #include <__chrono/weekday.h>
 #include <__chrono/year.h>
 #include <__concepts/same_as.h>
 #include <__config>
 #include <__format/format_functions.h>
 #include <ostream>
 #include <ratio>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)
+// On Apple back-deployment targets the format functions are not available with
+// and #ifndef. This will cause compilation failures when using these
+// functions. Therefore make these functions unavailable when used on these
+// platforms.
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT) && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 namespace chrono {
 
 // Depending on the type the return is a const _CharT* or a basic_string<_CharT>
 template <class _CharT, class _Period>
 _LIBCPP_HIDE_FROM_ABI auto __units_suffix() {
   // TODO FMT LWG issue the suffixes are always char and not STATICALLY-WIDEN'ed.
   if constexpr (same_as<typename _Period::type, atto>)
else if constexpr (same_as<typename _Period::type, ratio<86400>>)
     return _LIBCPP_STATICALLY_WIDEN(_CharT, "d");
   else if constexpr (_Period::den == 1)
     return std::format(_LIBCPP_STATICALLY_WIDEN(_CharT, "[{}]s"), _Period::num);
   else
     return std::format(_LIBCPP_STATICALLY_WIDEN(_CharT, "[{}/{}]s"), _Period::num, _Period::den);
 }
 
 template <class _CharT, class _Traits, class _Rep, class _Period>
 _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT basic_ostream<_CharT, _Traits>&
 operator<<(basic_ostream<_CharT, _Traits>& __os, const duration<_Rep, _Period>& __d) {
   basic_ostringstream<_CharT, _Traits> __s;
   __s.flags(__os.flags());
   __s.imbue(__os.getloc());
   __s.precision(__os.precision());
   __s << __d.count() << chrono::__units_suffix<_CharT, _Period>();
   return __os << __s.str();
 }
operator<<(basic_ostream<_CharT, _Traits>& __os, const weekday& __wd) {
   return __os << (__wd.ok() ? std::format(__os.getloc(), _LIBCPP_STATICALLY_WIDEN(_CharT, "{:L%a}"), __wd)
                             : std::format(__os.getloc(), // TODO FMT Standard mandated locale isn't used.
                                           _LIBCPP_STATICALLY_WIDEN(_CharT, "{} is not a valid weekday"),
                                           static_cast<unsigned>(__wd.c_encoding())));
 }
 
 } // namespace chrono
 
-#endif //if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)
+#endif //if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT) && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___CHRONO_OSTREAM_H

libcxx/include/__chrono/parser_std_format_spec.h

 // -*- C++ -*-
 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP___CHRONO_PARSER_STD_FORMAT_SPEC_H
 #define _LIBCPP___CHRONO_PARSER_STD_FORMAT_SPEC_H
 
+#include <__availability>
 #include <__config>
 #include <__format/concepts.h>
 #include <__format/format_error.h>
 #include <__format/format_parse_context.h>
 #include <__format/formatter_string.h>
 #include <__format/parser_std_format_spec.h>
 #include <string_view>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)
+// When format is not available on Apple back-deployment targets the
+// compilation will fail. This is caused by instantiating templates where CTAD
+// is used. (This might be a compiler bug.) To avoid instantiations make this
+// header a NOP when used on back-deployment targets.
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT) && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 namespace __format_spec {
 
 // By not placing this constant in the formatter class it's not duplicated for char and wchar_t
 inline constexpr __fields __fields_chrono_fractional{
     .__precision_ = true, .__locale_specific_form_ = true, .__type_ = false};
 inline constexpr __fields __fields_chrono{.__locale_specific_form_ = true, .__type_ = false};
 
__parse_modifier_O(const _CharT*& __begin, const _CharT* __end, __flags __flags) {
     default:
       std::__throw_format_error("The date time type specifier for modifier O is invalid");
     }
   }
 };
 
 } // namespace __format_spec
 
-#endif //_LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT) && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___CHRONO_PARSER_STD_FORMAT_SPEC_H

libcxx/include/__format/concepts.h

 // -*- C++ -*-
 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP___FORMAT_CONCEPTS_H
 #define _LIBCPP___FORMAT_CONCEPTS_H
 
+#include <__availability>
 #include <__concepts/same_as.h>
 #include <__concepts/semiregular.h>
 #include <__config>
 #include <__format/format_fwd.h>
 #include <__format/format_parse_context.h>
 #include <type_traits>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 #if _LIBCPP_STD_VER > 17
 
 /// The character type specializations of \ref formatter.
 template <class _CharT>
 concept __fmt_char_type =
     same_as<_CharT, char>
 #  ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
     || same_as<_CharT, wchar_t>
 #  endif
     ;
 
+// When format is not available on Apple back-deployment targets the
+// compilation will fail. This is caused by instantiating templates where CTAD
+// is used. (This might be a compiler bug.) To avoid instantiations make this
+// header a NOP when used on back-deployment targets.
+//
+// Note the concept above is used in other places and doesn't suffer from the
+// CTAD issue.
+#if !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
+
 // The output iterator isn't specified. A formatter should accept any
 // output_iterator. This iterator is a minimal iterator to test the concept.
 // (Note testing for (w)format_context would be a valid choice, but requires
 // selecting the proper one depending on the type of _CharT.)
 template <class _CharT>
 using __fmt_iter_for = _CharT*;
 
 template <class _Tp, class _CharT>
 concept __formattable =
     (semiregular<formatter<remove_cvref_t<_Tp>, _CharT>>) &&
     requires(formatter<remove_cvref_t<_Tp>, _CharT> __f,
              const formatter<remove_cvref_t<_Tp>, _CharT> __cf,
              _Tp __t,
              basic_format_context<__fmt_iter_for<_CharT>, _CharT> __fc,
              basic_format_parse_context<_CharT> __pc) {
       { __f.parse(__pc) } -> same_as<typename basic_format_parse_context<_CharT>::iterator>;
       { __cf.format(__t, __fc) } -> same_as<__fmt_iter_for<_CharT>>;
     };
 
 #  if _LIBCPP_STD_VER > 20
 template <class _Tp, class _CharT>
 concept formattable = __formattable<_Tp, _CharT>;
 #  endif //_LIBCPP_STD_VER > 20
-#endif //_LIBCPP_STD_VER > 17
+#endif // !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
+
+#endif // _LIBCPP_STD_VER > 17
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___FORMAT_CONCEPTS_H

libcxx/include/__format/format_arg.h

 // -*- C++ -*-
 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP___FORMAT_FORMAT_ARG_H
 #define _LIBCPP___FORMAT_FORMAT_ARG_H
 
 #include <__assert>
+#include <__availability>
 #include <__concepts/arithmetic.h>
 #include <__config>
 #include <__format/format_error.h>
 #include <__format/format_fwd.h>
 #include <__format/format_parse_context.h>
 #include <__functional/invoke.h>
 #include <__memory/addressof.h>
 #include <__utility/forward.h>
 #include <__utility/unreachable.h>
 #include <__variant/monostate.h>
 #include <string>
 #include <string_view>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if _LIBCPP_STD_VER > 17
+// When format is not available on Apple back-deployment targets the
+// compilation will fail. This is caused by instantiating templates where CTAD
+// is used. (This might be a compiler bug.) To avoid instantiations make this
+// header a NOP when used on back-deployment targets.
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 namespace __format {
 /// The type stored in @ref basic_format_arg.
 ///
 /// @note The 128-bit types are unconditionally in the list to avoid the values
 /// of the enums to depend on the availability of 128-bit integers.
 ///
 /// @note The value is stored as a 5-bit value in the __packed_arg_t_bits. This
constexpr __arg_t __get_packed_type(uint64_t __types, size_t __id) {
   return static_cast<__format::__arg_t>(__types & __packed_arg_t_mask);
 }
 
 } // namespace __format
 
 // This function is not user obervable, so it can directly use the non-standard
 // types of the "variant". See __arg_t for more details.
 template <class _Visitor, class _Context>
-_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT decltype(auto)
+_LIBCPP_HIDE_FROM_ABI decltype(auto)
 __visit_format_arg(_Visitor&& __vis, basic_format_arg<_Context> __arg) {
   switch (__arg.__type_) {
   case __format::__arg_t::__none:
     return _VSTD::invoke(_VSTD::forward<_Visitor>(__vis), __arg.__value_.__monostate_);
   case __format::__arg_t::__boolean:
     return _VSTD::invoke(_VSTD::forward<_Visitor>(__vis), __arg.__value_.__boolean_);
   case __format::__arg_t::__char_type:
     return _VSTD::invoke(_VSTD::forward<_Visitor>(__vis), __arg.__value_.__char_type_);
public:
   __format::__arg_t __type_;
 
   _LIBCPP_HIDE_FROM_ABI explicit basic_format_arg(__format::__arg_t __type,
                                                   __basic_format_arg_value<_Context> __value) noexcept
       : __value_(__value), __type_(__type) {}
 };
 
 template <class _Context>
-class _LIBCPP_TEMPLATE_VIS basic_format_arg<_Context>::handle {
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT basic_format_arg<_Context>::handle {
 public:
   _LIBCPP_HIDE_FROM_ABI
   void format(basic_format_parse_context<char_type>& __parse_ctx, _Context& __ctx) const {
     __handle_.__format_(__parse_ctx, __ctx, __handle_.__ptr_);
   }
 
   _LIBCPP_HIDE_FROM_ABI explicit handle(typename __basic_format_arg_value<_Context>::__handle& __handle) noexcept
       : __handle_(__handle) {}
case __format::__arg_t::__u128: {
     return _VSTD::invoke(_VSTD::forward<_Visitor>(__vis), typename basic_format_arg<_Context>::handle{__h});
   }
 #  endif
   default:
     return _VSTD::__visit_format_arg(_VSTD::forward<_Visitor>(__vis), __arg);
   }
 }
 
-#endif //_LIBCPP_STD_VER > 17
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___FORMAT_FORMAT_ARG_H

libcxx/include/__format/format_arg_store.h

 // -*- C++ -*-
 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP___FORMAT_FORMAT_ARG_STORE_H
 #define _LIBCPP___FORMAT_FORMAT_ARG_STORE_H
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
+#include <__availability>
 #include <__concepts/arithmetic.h>
 #include <__concepts/same_as.h>
 #include <__config>
 #include <__format/concepts.h>
 #include <__format/format_arg.h>
 #include <__utility/forward.h>
 #include <cstring>
 #include <string>
 #include <string_view>
 #include <type_traits>
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if _LIBCPP_STD_VER > 17
+// When format is not available on Apple back-deployment targets the
+// compilation will fail. This header is disabled due to CTAD failures
+// in included headers.
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 namespace __format {
 
 /// \returns The @c __arg_t based on the type of the formatting argument.
 ///
 /// \pre \c __formattable<_Tp, typename _Context::char_type>
 template <class _Context, class _Tp>
 consteval __arg_t __determine_arg_t();
struct _LIBCPP_TEMPLATE_VIS __format_arg_store {
 
   using _Storage = conditional_t<__format::__use_packed_format_arg_store(sizeof...(_Args)),
                                  __format::__packed_format_arg_store<_Context, sizeof...(_Args)>,
                                  __format::__unpacked_format_arg_store<_Context, sizeof...(_Args)>>;
 
   _Storage __storage;
 };
 
-#endif //_LIBCPP_STD_VER > 17
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___FORMAT_FORMAT_ARG_STORE_H

libcxx/include/__format/format_args.h

 #include <cstdint>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if _LIBCPP_STD_VER > 17
+// When format is not available on Apple back-deployment targets the
+// compilation will fail. This header is disabled due to CTAD failures
+// in included headers.
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 template <class _Context>
 class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT basic_format_args {
 public:
   _LIBCPP_HIDE_FROM_ABI basic_format_args() noexcept = default;
 
   template <class... _Args>
   _LIBCPP_HIDE_FROM_ABI basic_format_args(const __format_arg_store<_Context, _Args...>& __store) noexcept
struct {
       const __basic_format_arg_value<_Context>* __values_;
       uint64_t __types_;
     };
     const basic_format_arg<_Context>* __args_;
   };
 };
 _LIBCPP_CTAD_SUPPORTED_FOR_TYPE(basic_format_args);
 
-#endif //_LIBCPP_STD_VER > 17
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___FORMAT_FORMAT_ARGS_H

libcxx/include/__format/format_context.h

 #endif
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if _LIBCPP_STD_VER > 17
+// When format is not available on Apple back-deployment targets the
+// compilation will fail. This header is disabled due to CTAD failures
+// in included headers.
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 template <class _OutIt, class _CharT>
 requires output_iterator<_OutIt, const _CharT&>
 class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT basic_format_context;
 
 #ifndef _LIBCPP_HAS_NO_LOCALIZATION
 /**
  * Helper to create a basic_format_context.

 _LIBCPP_HIDE_FROM_ABI basic_format_context<_OutIt, _CharT>
 __format_context_create(
     _OutIt __out_it,
     basic_format_args<basic_format_context<_OutIt, _CharT>> __args) {
   return _VSTD::basic_format_context(_VSTD::move(__out_it), __args);
 }
 #endif
 
-using format_context =
+using format_context = _LIBCPP_AVAILABILITY_FORMAT
     basic_format_context<back_insert_iterator<__format::__output_buffer<char>>,
                          char>;
 #ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
-using wformat_context = basic_format_context<
+using wformat_context = _LIBCPP_AVAILABILITY_FORMAT basic_format_context<
     back_insert_iterator<__format::__output_buffer<wchar_t>>, wchar_t>;
 #endif
 
 template <class _OutIt, class _CharT>
 requires output_iterator<_OutIt, const _CharT&>
 class
     // clang-format off
     _LIBCPP_TEMPLATE_VIS
#else
   _LIBCPP_HIDE_FROM_ABI
   explicit basic_format_context(_OutIt __out_it,
                                 basic_format_args<basic_format_context> __args)
       : __out_it_(_VSTD::move(__out_it)), __args_(__args) {}
 #endif
 };
 _LIBCPP_CTAD_SUPPORTED_FOR_TYPE(basic_format_context);
 
-#endif //_LIBCPP_STD_VER > 17
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___FORMAT_FORMAT_CONTEXT_H

libcxx/include/__format/format_functions.h

 // -*- C++ -*-
 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP___FORMAT_FORMAT_FUNCTIONS
 #define _LIBCPP___FORMAT_FORMAT_FUNCTIONS
 
-// TODO FMT This is added to fix Apple back-deployment.
-#include <version>
-#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)
+// When format is not available on Apple back-deployment targets the
+// compilation will fail. This is caused by instantiating templates where CTAD
+// is used. (This might be a compiler bug.) To avoid instantiations make this
+// header a NOP when used on back-deployment targets.
+#include <__config>
+#include <__availability>
+#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT) && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 #include <__algorithm/clamp.h>
 #include <__availability>
 #include <__concepts/convertible_to.h>
 #include <__concepts/same_as.h>
 #include <__config>
 #include <__debug>
 #include <__format/buffer.h>

 
 #if _LIBCPP_STD_VER > 17
 
 // TODO FMT Evaluate which templates should be external templates. This
 // improves the efficiency of the header. However since the header is still
 // under heavy development and not all classes are stable it makes no sense
 // to do this optimization now.
 
-using format_args = basic_format_args<format_context>;
+using format_args = _LIBCPP_AVAILABILITY_FORMAT basic_format_args<format_context>;
 #ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
-using wformat_args = basic_format_args<wformat_context>;
+using wformat_args = _LIBCPP_AVAILABILITY_FORMAT basic_format_args<wformat_context>;
 #endif
 
 template <class _Context = format_context, class... _Args>
 _LIBCPP_HIDE_FROM_ABI __format_arg_store<_Context, _Args...> make_format_args(_Args&&... __args) {
   return _VSTD::__format_arg_store<_Context, _Args...>(__args...);
 }
 
 #ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
while (__begin != __end) {
     *__out_it++ = *__begin++;
   }
   return __out_it;
 }
 
 } // namespace __format
 
 template <class _CharT, class... _Args>
-struct _LIBCPP_TEMPLATE_VIS basic_format_string {
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT basic_format_string {
   template <class _Tp>
     requires convertible_to<const _Tp&, basic_string_view<_CharT>>
-  consteval basic_format_string(const _Tp& __str) : __str_{__str} {
     __format::__vformat_to(basic_format_parse_context<_CharT>{__str_, sizeof...(_Args)},
                            _Context{__types_.data(), __handles_.data(), sizeof...(_Args)});
   }
 
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT constexpr basic_string_view<_CharT> get() const noexcept {
+  _LIBCPP_HIDE_FROM_ABI constexpr basic_string_view<_CharT> get() const noexcept {
     return __str_;
   }
 
 private:
   basic_string_view<_CharT> __str_;
 
   using _Context = __format::__compile_time_basic_format_context<_CharT>;
 
if (__format::__determine_arg_t<_Context, _Tp>() == __format::__arg_t::__handle)
       __handle.template __enable<_Tp>();
 
     return __handle;
   }()...};
 #    endif
 };
 
 template <class... _Args>
-using format_string = basic_format_string<char, type_identity_t<_Args>...>;
+using format_string = _LIBCPP_AVAILABILITY_FORMAT basic_format_string<char, type_identity_t<_Args>...>;
 
 #ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
 template <class... _Args>
-using wformat_string = basic_format_string<wchar_t, type_identity_t<_Args>...>;
+using wformat_string = _LIBCPP_AVAILABILITY_FORMAT basic_format_string<wchar_t, type_identity_t<_Args>...>;
 #endif
 
 template <class _OutIt, class _CharT, class _FormatOutIt>
-requires(output_iterator<_OutIt, const _CharT&>) _LIBCPP_HIDE_FROM_ABI _OutIt
+requires(output_iterator<_OutIt, const _CharT&>) _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT _OutIt
     __vformat_to(
         _OutIt __out_it, basic_string_view<_CharT> __fmt,
         basic_format_args<basic_format_context<_FormatOutIt, _CharT>> __args) {
   if constexpr (same_as<_OutIt, _FormatOutIt>)
     return _VSTD::__format::__vformat_to(basic_format_parse_context{__fmt, __args.__size()},
                                          _VSTD::__format_context_create(_VSTD::move(__out_it), __args));
   else {
     __format::__format_buffer<_OutIt, _CharT> __buffer{_VSTD::move(__out_it)};

 template <output_iterator<const wchar_t&> _OutIt, class... _Args>
 _LIBCPP_ALWAYS_INLINE _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT _OutIt
 format_to(_OutIt __out_it, wformat_string<_Args...> __fmt, _Args&&... __args) {
   return _VSTD::vformat_to(_VSTD::move(__out_it), __fmt.get(),
                            _VSTD::make_wformat_args(__args...));
 }
 #endif
 
 _LIBCPP_ALWAYS_INLINE inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT string
 vformat(string_view __fmt, format_args __args) {
   string __res;
   _VSTD::vformat_to(_VSTD::back_inserter(__res), __fmt, __args);
   return __res;
 }
 
 #ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
 _LIBCPP_ALWAYS_INLINE inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT wstring

 
 #endif // _LIBCPP_HAS_NO_LOCALIZATION
 
 
 #endif //_LIBCPP_STD_VER > 17
 
 _LIBCPP_END_NAMESPACE_STD
 
-#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)
+#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT) && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 #endif // _LIBCPP___FORMAT_FORMAT_FUNCTIONS

libcxx/include/__format/format_parse_context.h

 // -*- C++ -*-
 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP___FORMAT_FORMAT_PARSE_CONTEXT_H
 #define _LIBCPP___FORMAT_FORMAT_PARSE_CONTEXT_H
 
+#include <__availability>
 #include <__config>
 #include <__format/format_error.h>
 #include <string_view>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if _LIBCPP_STD_VER > 17
+// When format is not available on Apple back-deployment targets the
+// compilation will fail. This is caused by instantiating templates where CTAD
+// is used. (This might be a compiler bug.) To avoid instantiations make this
+// header a NOP when used on back-deployment targets.
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 template <class _CharT>
 class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT basic_format_parse_context {
 public:
   using char_type = _CharT;
   using const_iterator = typename basic_string_view<_CharT>::const_iterator;
   using iterator = const_iterator;
 
_LIBCPP_HIDE_FROM_ABI constexpr const_iterator end() const noexcept {
     return __end_;
   }
   _LIBCPP_HIDE_FROM_ABI constexpr void advance_to(const_iterator __it) {
     __begin_ = __it;
   }
 
   _LIBCPP_HIDE_FROM_ABI constexpr size_t next_arg_id() {
     if (__indexing_ == __manual)
       __throw_format_error("Using automatic argument numbering in manual "
                            "argument numbering mode");
 
     if (__indexing_ == __unknown)
       __indexing_ = __automatic;
     return __next_arg_id_++;
   }
   _LIBCPP_HIDE_FROM_ABI constexpr void check_arg_id(size_t __id) {
     if (__indexing_ == __automatic)
       __throw_format_error("Using manual argument numbering in automatic "
private:
   iterator __end_;
   enum _Indexing { __unknown, __manual, __automatic };
   _Indexing __indexing_;
   size_t __next_arg_id_;
   size_t __num_args_;
 };
 _LIBCPP_CTAD_SUPPORTED_FOR_TYPE(basic_format_parse_context);
 
-using format_parse_context = basic_format_parse_context<char>;
+using format_parse_context = _LIBCPP_AVAILABILITY_FORMAT basic_format_parse_context<char>;
 #ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
-using wformat_parse_context = basic_format_parse_context<wchar_t>;
+using wformat_parse_context = _LIBCPP_AVAILABILITY_FORMAT basic_format_parse_context<wchar_t>;
 #endif
 
-#endif //_LIBCPP_STD_VER > 17
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___FORMAT_FORMAT_PARSE_CONTEXT_H

libcxx/include/__format/formatter_bool.h

 #endif
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if _LIBCPP_STD_VER > 17
+// When format is not available on Apple back-deployment targets the
+// compilation will fail. This is caused by instantiating templates where CTAD
+// is used. (This might be a compiler bug.) To avoid instantiations make this
+// header a NOP when used on back-deployment targets.
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 template <__fmt_char_type _CharT>
 struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<bool, _CharT> {
 public:
   _LIBCPP_HIDE_FROM_ABI constexpr auto
   parse(basic_format_parse_context<_CharT>& __parse_ctx) -> decltype(__parse_ctx.begin()) {
     auto __result = __parser_.__parse(__parse_ctx, __format_spec::__fields_integral);
     __format_spec::__process_parsed_bool(__parser_);
default:
       _LIBCPP_ASSERT(false, "The parse function should have validated the type");
       __libcpp_unreachable();
     }
   }
 
   __format_spec::__parser<_CharT> __parser_;
 };
 
-#endif //_LIBCPP_STD_VER > 17
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___FORMAT_FORMATTER_BOOL_H

libcxx/include/__format/formatter_char.h

 #include <__type_traits/is_signed.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if _LIBCPP_STD_VER > 17
+// When format is not available on Apple back-deployment targets the
+// compilation will fail. This is caused by instantiating templates where CTAD
+// is used. (This might be a compiler bug.) To avoid instantiations make this
+// header a NOP when used on back-deployment targets.
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 template <__fmt_char_type _CharT>
-struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT __formatter_char {
+struct _LIBCPP_TEMPLATE_VIS __formatter_char {
 public:
   _LIBCPP_HIDE_FROM_ABI constexpr auto
   parse(basic_format_parse_context<_CharT>& __parse_ctx) -> decltype(__parse_ctx.begin()) {
     auto __result = __parser_.__parse(__parse_ctx, __format_spec::__fields_integral);
     __format_spec::__process_parsed_char(__parser_);
     return __result;
   }
 

 struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<char, wchar_t> : public __formatter_char<wchar_t> {};
 
 template <>
 struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<wchar_t, wchar_t> : public __formatter_char<wchar_t> {
 };
 
 #  endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
 
-#endif //_LIBCPP_STD_VER > 17
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___FORMAT_FORMATTER_CHAR_H

libcxx/include/__format/formatter_floating_point.h

 #  pragma GCC system_header
 #endif
 
 _LIBCPP_PUSH_MACROS
 #include <__undef_macros>
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if _LIBCPP_STD_VER > 17
+// When format is not available on Apple back-deployment targets the
+// compilation will fail. This is caused by instantiating templates where CTAD
+// is used. (This might be a compiler bug.) To avoid instantiations make this
+// header a NOP when used on back-deployment targets.
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 namespace __formatter {
 
 template <floating_point _Tp>
 _LIBCPP_HIDE_FROM_ABI char* __to_buffer(char* __first, char* __last, _Tp __value) {
   to_chars_result __r = _VSTD::to_chars(__first, __last, __value);
   _LIBCPP_ASSERT(__r.ec == errc(0), "Internal buffer too small");
   return __r.ptr;
struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<float, _CharT>
     : public __formatter_floating_point<_CharT> {};
 template <__fmt_char_type _CharT>
 struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<double, _CharT>
     : public __formatter_floating_point<_CharT> {};
 template <__fmt_char_type _CharT>
 struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<long double, _CharT>
     : public __formatter_floating_point<_CharT> {};
 
-#endif //_LIBCPP_STD_VER > 17
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 _LIBCPP_END_NAMESPACE_STD
 
 _LIBCPP_POP_MACROS
 
 #endif // _LIBCPP___FORMAT_FORMATTER_FLOATING_POINT_H

libcxx/include/__format/formatter_integer.h

 #include <type_traits>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
     _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if _LIBCPP_STD_VER > 17
+// When format is not available on Apple back-deployment targets the
+// compilation will fail. This is caused by instantiating templates where CTAD
+// is used. (This might be a compiler bug.) To avoid instantiations make this
+// header a NOP when used on back-deployment targets.
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
     template <__fmt_char_type _CharT>
-    struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT __formatter_integer {
+    struct _LIBCPP_TEMPLATE_VIS __formatter_integer {
 
 public:
   _LIBCPP_HIDE_FROM_ABI constexpr auto
   parse(basic_format_parse_context<_CharT>& __parse_ctx) -> decltype(__parse_ctx.begin()) {
     auto __result = __parser_.__parse(__parse_ctx, __format_spec::__fields_integral);
     __format_spec::__process_parsed_integer(__parser_);
     return __result;
   }

 struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<unsigned long long, _CharT>
     : public __formatter_integer<_CharT> {};
 #  ifndef _LIBCPP_HAS_NO_INT128
 template <__fmt_char_type _CharT>
 struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<__uint128_t, _CharT>
     : public __formatter_integer<_CharT> {};
 #  endif
 
-#endif //_LIBCPP_STD_VER > 17
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___FORMAT_FORMATTER_INTEGER_H

libcxx/include/__format/formatter_integral.h

 // -*- C++ -*-
 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP___FORMAT_FORMATTER_INTEGRAL_H
 #define _LIBCPP___FORMAT_FORMATTER_INTEGRAL_H
 
+#include <__availability>
 #include <__concepts/arithmetic.h>
 #include <__concepts/same_as.h>
 #include <__config>
 #include <__format/concepts.h>
 #include <__format/format_error.h>
 #include <__format/formatter_output.h>
 #include <__format/parser_std_format_spec.h>
 #include <__utility/unreachable.h>

 #  pragma GCC system_header
 #endif
 
 _LIBCPP_PUSH_MACROS
 #include <__undef_macros>
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if _LIBCPP_STD_VER > 17
+// When format is not available on Apple back-deployment targets the
+// compilation will fail. This header is disabled due to CTAD failures
+// in included headers.
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 namespace __formatter {
 
 //
 // Generic
 //
 
 _LIBCPP_HIDE_FROM_ABI inline char* __insert_sign(char* __buf, bool __negative, __format_spec::__sign __sign) {

 #  endif
   basic_string_view<_CharT> __str =
       __value ? __formatter::__bool_strings<_CharT>::__true : __formatter::__bool_strings<_CharT>::__false;
   return __formatter::__write(__str.begin(), __str.end(), __ctx.out(), __specs);
 }
 
 } // namespace __formatter
 
-#endif //_LIBCPP_STD_VER > 17
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 _LIBCPP_END_NAMESPACE_STD
 
 _LIBCPP_POP_MACROS
 
 #endif // _LIBCPP___FORMAT_FORMATTER_INTEGRAL_H

libcxx/include/__format/formatter_output.h

 // -*- C++ -*-
 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP___FORMAT_FORMATTER_OUTPUT_H
 #define _LIBCPP___FORMAT_FORMATTER_OUTPUT_H
 
+#include <__availability>
 #include <__algorithm/ranges_copy.h>
 #include <__algorithm/ranges_fill_n.h>
 #include <__algorithm/ranges_transform.h>
 #include <__chrono/statically_widen.h>
 #include <__concepts/same_as.h>
 #include <__config>
 #include <__format/buffer.h>
 #include <__format/concepts.h>

 #include <string_view>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if _LIBCPP_STD_VER > 17
+// When format is not available on Apple back-deployment targets the
+// compilation will fail. This header is disabled due to CTAD failures
+// in included headers.
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 namespace __formatter {
 
 _LIBCPP_HIDE_FROM_ABI constexpr char __hex_to_upper(char __c) {
   switch (__c) {
   case 'a':
     return 'A';
   case 'b':
__format_escaped_string(basic_string_view<_CharT> __values,
   __str += _CharT('"');
   return __formatter::__write_string(basic_string_view{__str}, _VSTD::move(__out_it), __specs);
 }
 
 #  endif // _LIBCPP_STD_VER > 20
 
 } // namespace __formatter
 
-#endif //_LIBCPP_STD_VER > 17
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___FORMAT_FORMATTER_OUTPUT_H

libcxx/include/__format/formatter_pointer.h

 #include <cstdint>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if _LIBCPP_STD_VER > 17
+// When format is not available on Apple back-deployment targets the
+// compilation will fail. This is caused by instantiating templates where CTAD
+// is used. (This might be a compiler bug.) To avoid instantiations make this
+// header a NOP when used on back-deployment targets.
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 template <__fmt_char_type _CharT>
 struct _LIBCPP_TEMPLATE_VIS __formatter_pointer {
 public:
   constexpr __formatter_pointer() { __parser_.__alignment_ = __format_spec::__alignment::__right; }
 
   _LIBCPP_HIDE_FROM_ABI constexpr auto
   parse(basic_format_parse_context<_CharT>& __parse_ctx) -> decltype(__parse_ctx.begin()) {
struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<nullptr_t, _CharT>
     : public __formatter_pointer<_CharT> {};
 template <__fmt_char_type _CharT>
 struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<void*, _CharT> : public __formatter_pointer<_CharT> {
 };
 template <__fmt_char_type _CharT>
 struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<const void*, _CharT>
     : public __formatter_pointer<_CharT> {};
 
-#endif //_LIBCPP_STD_VER > 17
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___FORMAT_FORMATTER_POINTER_H

libcxx/include/__format/formatter_string.h

 #include <string_view>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if _LIBCPP_STD_VER > 17
+// When format is not available on Apple back-deployment targets the
+// compilation will fail. This is caused by instantiating templates where CTAD
+// is used. (This might be a compiler bug.) To avoid instantiations make this
+// header a NOP when used on back-deployment targets.
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 template <__fmt_char_type _CharT>
 struct _LIBCPP_TEMPLATE_VIS __formatter_string {
 public:
   _LIBCPP_HIDE_FROM_ABI constexpr auto parse(basic_format_parse_context<_CharT>& __parse_ctx)
       -> decltype(__parse_ctx.begin()) {
     auto __result = __parser_.__parse(__parse_ctx, __format_spec::__fields_string);
     __format_spec::__process_display_type_string(__parser_.__type_);
struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<basic_string_view<_CharT, _Traits>, _CharT>
 
   _LIBCPP_HIDE_FROM_ABI auto format(basic_string_view<_CharT, _Traits> __str, auto& __ctx) const
       -> decltype(__ctx.out()) {
     // Drop _Traits to have one std::basic_string_view formatter.
     return _Base::format(basic_string_view<_CharT>(__str.data(), __str.size()), __ctx);
   }
 };
 
-#endif //_LIBCPP_STD_VER > 17
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___FORMAT_FORMATTER_STRING_H

libcxx/include/__format/parser_std_format_spec.h

 #  pragma GCC system_header
 #endif
 
 _LIBCPP_PUSH_MACROS
 #include <__undef_macros>
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if _LIBCPP_STD_VER > 17
+// When format is not available on Apple back-deployment targets the
+// compilation will fail. This is caused by instantiating templates where CTAD
+// is used. (This might be a compiler bug.) To avoid instantiations make this
+// header a NOP when used on back-deployment targets.
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 namespace __format_spec {
 
 template <class _CharT>
 _LIBCPP_HIDE_FROM_ABI constexpr __format::__parse_number_result< _CharT>
 __parse_arg_id(const _CharT* __begin, const _CharT* __end, auto& __parse_ctx) {
   // This function is a wrapper to call the real parser. But it does the
   // validation for the pre-conditions and post-conditions.
__estimate_column_width(basic_string_view<_CharT> __str, size_t __maximum, __column_width_rounding) noexcept {
   size_t __width_ = _VSTD::min(__str.size(), __maximum);
   return {__width_, __str.begin() + __width_};
 }
 
 #  endif // !defined(_LIBCPP_HAS_NO_UNICODE)
 
 } // namespace __format_spec
 
-#endif //_LIBCPP_STD_VER > 17
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
 
 _LIBCPP_END_NAMESPACE_STD
 
 _LIBCPP_POP_MACROS
 
 #endif // _LIBCPP___FORMAT_PARSER_STD_FORMAT_SPEC_H

libcxx/include/chrono

 // [time.syn]
 #include <compare>
 
 #if !defined(_LIBCPP_HAS_NO_LOCALIZATION) && !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT) && _LIBCPP_STD_VER > 17
 #  include <__chrono/formatter.h>
 #  include <__chrono/ostream.h>
 #  include <__chrono/parser_std_format_spec.h>
 #  include <__chrono/statically_widen.h>
-#endif
+#endif // !defined(_LIBCPP_HAS_NO_LOCALIZATION) && !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT) && _LIBCPP_STD_VER > 17
 
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 #if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
 #  include <concepts>
 #endif
 
 #endif // _LIBCPP_CHRONO

libcxx/test/libcxx/utilities/format/enable_insertable.compile.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 #include <format>
 #include <array>
 #include <deque>
 #include <forward_list>
 #include <list>
 #include <map>

libcxx/test/libcxx/utilities/format/format.arguments/format.arg/arg_t.compile.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // namespace __format { enum class __arg_t : uint8_t{...}; }
 
 #include <format>
 
 #include <type_traits>
 

libcxx/test/libcxx/utilities/format/format.formatter/format.context/types.compile.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // Class typedefs:
 // template<class Out, class charT>
 // class basic_format_context {
 // public:
 //   using iterator = Out
 //   using char_type = charT;

libcxx/test/libcxx/utilities/format/format.string/format.string.std/extended_grapheme_cluster.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 // TODO FMT Fix this test using GCC, it currently times out.
 // UNSUPPORTED: gcc-12
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // Tests the implementation of the extended grapheme cluster boundaries per
 // https://www.unicode.org/reports/tr29/#Grapheme_Cluster_Boundary_Rules
 //
 // The tests are based on the test data provided by Unicode
 // https://www.unicode.org/Public/UCD/latest/ucd/auxiliary/GraphemeBreakTest.txt
 

libcxx/test/std/time/time.cal/time.cal.day/time.cal.day.nonmembers/ostream.pass.cpp

 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
 // TODO FMT Investigate Windows issues.
 // UNSUPPORTED msvc, target={{.+}}-windows-gnu
 
 // REQUIRES: locale.fr_FR.UTF-8
 // REQUIRES: locale.ja_JP.UTF-8
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <chrono>
 // class day;
 
 // template<class charT, class traits>
 //   basic_ostream<charT, traits>&
 //     operator<<(basic_ostream<charT, traits>& os, const day& d);
 
 #include <chrono>

libcxx/test/std/time/time.cal/time.cal.month/time.cal.month.nonmembers/ostream.pass.cpp

 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
 // TODO FMT Investigate Windows issues.
 // UNSUPPORTED: msvc, target={{.+}}-windows-gnu
 
 // REQUIRES: locale.fr_FR.UTF-8
 // REQUIRES: locale.ja_JP.UTF-8
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <chrono>
 
 // class month;
 
 // template<class charT, class traits>
 //   basic_ostream<charT, traits>&
 //     operator<<(basic_ostream<charT, traits>& os, const month& month);
 

libcxx/test/std/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/ostream.pass.cpp

 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-localization
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
 // REQUIRES: locale.fr_FR.UTF-8
 // REQUIRES: locale.ja_JP.UTF-8
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <chrono>
 // class weekday;
 
 // template<class charT, class traits>
 //   basic_ostream<charT, traits>&
 //     operator<<(basic_ostream<charT, traits>& os, const weekday& wd);
 
 #include <chrono>

libcxx/test/std/time/time.cal/time.cal.year/time.cal.year.nonmembers/ostream.pass.cpp

 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
 // TODO FMT Investigate Windows issues.
 // UNSUPPORTED: msvc, target={{.+}}-windows-gnu
 
 // REQUIRES: locale.fr_FR.UTF-8
 // REQUIRES: locale.ja_JP.UTF-8
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <chrono>
 // class year;
 
 // template<class charT, class traits>
 //   basic_ostream<charT, traits>&
 //     operator<<(basic_ostream<charT, traits>& os, const year& year);
 
 #include <chrono>

libcxx/test/std/time/time.duration/time.duration.nonmember/ostream.pass.cpp

 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
 // TODO FMT Investigate Windows issues.
 // UNSUPPORTED: msvc, target={{.+}}-windows-gnu
 
 // REQUIRES: locale.fr_FR.UTF-8
 // REQUIRES: locale.ja_JP.UTF-8
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <chrono>
 
 // template<class Rep, class Period = ratio<1>> class duration;
 
 // template<class charT, class traits, class Rep, class Period>
 //   basic_ostream<charT, traits>&
 //     operator<<(basic_ostream<charT, traits>& os,
 //                const duration<Rep, Period>& d);

libcxx/test/std/time/time.syn/formatter.day.pass.cpp

 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
 // TODO FMT Investigate Windows issues.
 // UNSUPPORTED: msvc, target={{.+}}-windows-gnu
 
 // REQUIRES: locale.fr_FR.UTF-8
 // REQUIRES: locale.ja_JP.UTF-8
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <chrono>
 
 // template<class charT> struct formatter<chrono::day, charT>;
 
 #include <chrono>
 #include <format>
 
 #include <cassert>

libcxx/test/std/time/time.syn/formatter.duration.pass.cpp

 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
 // TODO FMT Investigate Windows issues.
 // UNSUPPORTED: msvc, target={{.+}}-windows-gnu
 
 // REQUIRES: locale.fr_FR.UTF-8
 // REQUIRES: locale.ja_JP.UTF-8
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <chrono>
 
 //  template<class Rep, class Period, class charT>
 //    struct formatter<chrono::duration<Rep, Period>, charT>;
 
 #include <chrono>
 #include <format>
 

libcxx/test/std/time/time.syn/formatter.month.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-localization
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
 // REQUIRES: locale.fr_FR.UTF-8
 // REQUIRES: locale.ja_JP.UTF-8
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <chrono>
 
 // template<class charT> struct formatter<chrono::month, charT>;
 
 #include <chrono>
 #include <format>
 
 #include <cassert>

libcxx/test/std/time/time.syn/formatter.weekday.pass.cpp

 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
 // TODO FMT Investigate Windows issues.
 // UNSUPPORTED: msvc, target={{.+}}-windows-gnu
 
 // REQUIRES: locale.fr_FR.UTF-8
 // REQUIRES: locale.ja_JP.UTF-8
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <chrono>
 
 // template<class charT> struct formatter<chrono::weekday, charT>;
 
 #include <chrono>
 #include <format>
 
 #include <cassert>

libcxx/test/std/time/time.syn/formatter.year.pass.cpp

 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
 // TODO FMT Investigate Windows issues.
 // UNSUPPORTED: msvc, target={{.+}}-windows-gnu
 
 // REQUIRES: locale.fr_FR.UTF-8
 // REQUIRES: locale.ja_JP.UTF-8
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <chrono>
 
 // template<class charT> struct formatter<chrono::year, charT>;
 
 #include <chrono>
 #include <format>
 
 #include <cassert>

libcxx/test/std/utilities/format/format.arguments/format.arg.store/make_format_args.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // template<class Context = format_context, class... Args>
 // format-arg-store<Context, Args...> make_format_args(const Args&... args);
 
 #include <cassert>
 #include <format>
 #include <iterator>

libcxx/test/std/utilities/format/format.arguments/format.arg.store/make_format_args.sh.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 // UNSUPPORTED: no-wide-characters
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // Validate it works regardless of the signedness of `char`.
 // RUN: %{cxx} %{flags} %{compile_flags} -fsigned-char -fsyntax-only %s
 // RUN: %{cxx} %{flags} %{compile_flags} -funsigned-char -fsyntax-only %s
 
 // <format>
 
 // [format.arg]/5.2
 // - otherwise, if T is char and char_type is wchar_t, initializes value with static_cast<wchar_t>(v);
 
 #include <format>
 #include <string>
 
 void test() {
   std::make_format_args<std::basic_format_context<
       std::back_insert_iterator<std::basic_string<wchar_t>>, wchar_t>>('c');
 }

libcxx/test/std/utilities/format/format.arguments/format.arg.store/make_wformat_args.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 // XFAIL: no-wide-characters
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // template<class... Args>
 //   format-arg-store<wformat_context, Args...>
 //   make_wformat_args(const Args&... args);
 
 #include <cassert>
 #include <format>

libcxx/test/std/utilities/format/format.arguments/format.arg/ctor.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // basic_format_arg() noexcept;
 
 // The class has several exposition only private constructors. These are tested
 // in visit_format_arg.pass.cpp
 
 #include <format>

libcxx/test/std/utilities/format/format.arguments/format.arg/operator_bool.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // explicit operator bool() const noexcept
 //
 // Note more testing is done in the unit test for:
 // template<class Visitor, class Context>
 //   see below visit_format_arg(Visitor&& vis, basic_format_arg<Context> arg);
 

libcxx/test/std/utilities/format/format.arguments/format.args/ctor.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // basic_format_args() noexcept;
 // template<class... Args>
 //   basic_format_args(const format-arg-store<Context, Args...>& store) noexcept;
 
 #include <format>
 #include <cassert>

libcxx/test/std/utilities/format/format.arguments/format.args/types.compile.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // Namespace std typedefs:
 // using format_args = basic_format_args<format_context>;
 // using wformat_args = basic_format_args<wformat_context>;
 
 #include <format>
 #include <vector>

libcxx/test/std/utilities/format/format.fmt.string/ctor.verify.cpp

 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
 // libc++ supports basic_format_string in C++20 as an extension
 // UNSUPPORTED: !stdlib=libc++ && c++20
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // template<class charT, class... Args>
 // class basic_format_string<charT, type_identity_t<Args>...>
 //
 // template<class T> consteval basic_format_string(const T& s);
 //
 // This constructor does the compile-time format string validation for the

libcxx/test/std/utilities/format/format.fmt.string/get.pass.cpp

 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
 // libc++ supports basic_format_string in C++20 as an extension
 // UNSUPPORTED: !stdlib=libc++ && c++20
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // template<class charT, class... Args>
 // class basic_format_string<charT, type_identity_t<Args>...>
 //
 // constexpr basic_string_view<charT> get() const noexcept { return str; }
 
 #include <format>

libcxx/test/std/utilities/format/format.fmt.string/types.compile.pass.cpp

 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
 // libc++ supports basic_format_string in C++20 as an extension
 // UNSUPPORTED: !stdlib=libc++ && c++20
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 //  template<class... Args>
 //    using format_string =
 //      basic_format_string<char, type_identity_t<Args>...>;
 //  template<class... Args>
 //    using wformat_string =
 //      basic_format_string<wchar_t, type_identity_t<Args>...>;

libcxx/test/std/utilities/format/format.formattable/concept.formattable.compile.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // template<class T, class charT>
 // concept formattable = ...
 
 #include <array>
 #include <bitset>
 #include <bitset>

libcxx/test/std/utilities/format/format.formatter/format.context/format.context/advance_to.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // void advance_to(iterator it);
 
 #include <format>
 #include <cassert>
 #include <string>
 

libcxx/test/std/utilities/format/format.formatter/format.context/format.context/arg.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // basic_format_arg<basic_format_context> arg(size_t id) const;
 
 #include <format>
 #include <cassert>
 
 #include "test_basic_format_arg.h"

libcxx/test/std/utilities/format/format.formatter/format.context/format.context/ctor.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-localization
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
 // REQUIRES: locale.en_US.UTF-8
 // REQUIRES: locale.fr_FR.UTF-8
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // The Standard does not specifiy a constructor
 // basic_format_context(Out out,
 //                      basic_format_args<basic_format_context> args,
 //                      std::optional<std::::locale>&& loc = std::nullopt);
 // If compiled with -D_LIBCPP_HAS_NO_LOCALIZATION
 // basic_format_context(Out out,

libcxx/test/std/utilities/format/format.formatter/format.context/format.context/locale.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-localization
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
 // REQUIRES: locale.en_US.UTF-8
 // REQUIRES: locale.fr_FR.UTF-8
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // std::locale locale();
 
 #include <format>
 #include <cassert>
 
 #include "make_string.h"

libcxx/test/std/utilities/format/format.formatter/format.context/format.context/out.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // iterator out();
 
 #include <format>
 #include <cassert>
 #include <string>
 

libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.handle.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // A user defined formatter using
 // template<class Context>
 // class basic_format_arg<Context>::handle
 
 #include <format>
 

libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.bool.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // [format.formatter.spec]:
 // Each header that declares the template `formatter` provides the following
 // enabled specializations:
 // For each `charT`, for each cv-unqualified arithmetic type `ArithmeticT`
 // other than char, wchar_t, char8_t, char16_t, or char32_t, a specialization
 //    template<> struct formatter<ArithmeticT, charT>

libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.c_string.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // C++23 the formatter is a debug-enabled specialization.
 // [format.formatter.spec]:
 // Each header that declares the template `formatter` provides the following
 // enabled specializations:
 // For each `charT`, the string type specializations
 //   template<> struct formatter<charT*, charT>;

libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.char.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // C++23 the formatter is a debug-enabled specialization.
 // [format.formatter.spec]:
 // Each header that declares the template `formatter` provides the following
 // enabled specializations:
 // The specializations
 //   template<> struct formatter<char, char>;

libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.char_array.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 // TODO FMT __builtin_memcpy isn't constexpr in GCC
 // UNSUPPORTED: gcc-12
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // C++23 the formatter is a debug-enabled specialization.
 // [format.functions]/25
 //   Preconditions: formatter<remove_cvref_t<Ti>, charT> meets the
 //   BasicFormatter requirements ([formatter.requirements]) for each Ti in
 //   Args.
 

libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.const_char_array.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 // TODO FMT Evaluate gcc-12 status
 // UNSUPPORTED: gcc-12
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // C++23 the formatter is a debug-enabled specialization.
 // [format.formatter.spec]:
 // Each header that declares the template `formatter` provides the following
 // enabled specializations:
 // For each `charT`, the string type specializations
 //   template<size_t N> struct formatter<const charT[N], charT>;

libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.floating_point.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // [format.formatter.spec]:
 // Each header that declares the template `formatter` provides the following
 // enabled specializations:
 // For each `charT`, for each cv-unqualified arithmetic type `ArithmeticT`
 // other than char, wchar_t, char8_t, char16_t, or char32_t, a specialization
 //    template<> struct formatter<ArithmeticT, charT>

libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.pointer.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // [format.formatter.spec]:
 // Each header that declares the template `formatter` provides the following
 // enabled specializations:
 // ...
 // For each charT, the pointer type specializations
 // - template<> struct formatter<nullptr_t, charT>;

libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.signed_integral.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // [format.formatter.spec]:
 // Each header that declares the template `formatter` provides the following
 // enabled specializations:
 // For each `charT`, for each cv-unqualified arithmetic type `ArithmeticT`
 // other than char, wchar_t, char8_t, char16_t, or char32_t, a specialization
 //    template<> struct formatter<ArithmeticT, charT>

libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.string.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // C++23 the formatter is a debug-enabled specialization.
 // [format.formatter.spec]:
 // Each header that declares the template `formatter` provides the following
 // enabled specializations:
 // For each `charT`, the string type specializations
 //   template<class traits, class Allocator>

libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.unsigned_integral.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // [format.formatter.spec]:
 // Each header that declares the template `formatter` provides the following
 // enabled specializations:
 // For each `charT`, for each cv-unqualified arithmetic type `ArithmeticT`
 // other than char, wchar_t, char8_t, char16_t, or char32_t, a specialization
 //    template<> struct formatter<ArithmeticT, charT>

libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/advance_to.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // constexpr void advance_to(const_iterator it);
 
 #include <format>
 
 #include <cassert>
 #include <string_view>

libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/begin.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // constexpr begin() const noexcept;
 
 #include <format>
 
 #include <cassert>
 #include <string_view>

libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/check_arg_id.verify.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // constexpr void check_arg_id(size_t id);
 
 #include <format>
 
 #include "test_macros.h"
 
 constexpr bool test() {
   // [format.parse.ctx]/11

libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/ctor.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // constexpr explicit
 // basic_format_parse_context(basic_string_view<charT> fmt,
 //                            size_t num_args = 0) noexcept
 
 #include <format>
 

libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/end.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // constexpr end() const noexcept;
 
 #include <format>
 
 #include <cassert>
 #include <string_view>

libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/types.compile.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // Class typedefs:
 // template<class charT>
 // class basic_format_parse_context {
 // public:
 //   using char_type = charT;
 //   using const_iterator = typename basic_string_view<charT>::const_iterator;

libcxx/test/std/utilities/format/format.functions/P2418.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
 // Tests whether a move only type can be formatted. This is required by
 // P2418R2 "Add support for std::generator-like types to std::format"
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 #include <format>
 #include <cassert>
 
 #include "MoveOnly.h"
 #include "make_string.h"
 #include "test_macros.h"

libcxx/test/std/utilities/format/format.functions/ascii.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // Force unicode to be disabled.
 // ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_HAS_NO_UNICODE
 
 // <format>
 
 // Tests Unicode is ignored and handled as ASCII.
 
 #include <format>

libcxx/test/std/utilities/format/format.functions/escaped_output.ascii.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // Force unicode to be disabled.
 // ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_HAS_NO_UNICODE
 
 // <format>
 
 // This test the debug string type for the formatter specializations for char
 // and string types. This tests ASCII strings, the tests assume every char32_t value is valid ASCII.
 

libcxx/test/std/utilities/format/format.functions/escaped_output.unicode.pass.cpp

 
 // This version runs the test when the platform has Unicode support.
 // UNSUPPORTED: libcpp-has-no-unicode
 
 // TODO FMT Investigate Windows and AIX issues.
 // UNSUPPORTED: msvc, target={{.+}}-windows-gnu
 // UNSUPPORTED: LIBCXX-AIX-FIXME
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // This test the debug string type for the formatter specializations for char
 // and string types. This tests Unicode strings.
 
 #include <format>
 
 #include <cassert>

libcxx/test/std/utilities/format/format.functions/format.locale.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-localization
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 // TODO FMT Evaluate gcc-12 status
 // UNSUPPORTED:gcc-12
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // template<class... Args>
 //   string format(const locale& loc, format-string<Args...> fmt, const Args&... args);
 // template<class... Args>
 //   wstring format(const locale& loc, wformat-string<Args...> fmt, const Args&... args);
 
 #include <format>

libcxx/test/std/utilities/format/format.functions/format.locale.verify.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-localization
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // Basic test to validate ill-formed code is properly detected.
 
 // <format>
 
 // template<class... Args>
 //   string format(const locale& loc, format-string<Args...> fmt, const Args&... args);
 // template<class... Args>
 //   wstring format(const locale& loc, wformat-string<Args...> fmt, const Args&... args);

libcxx/test/std/utilities/format/format.functions/format.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 // TODO FMT Evaluate gcc-12 status
 // UNSUPPORTED: gcc-12
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // Note this formatter shows additional information when tests are failing.
 // This aids the development. Since other formatters fail in the same fashion
 // they don't have this additional output.
 
 // <format>
 
 // template<class... Args>
 //   string format(format-string<Args...> fmt, const Args&... args);

libcxx/test/std/utilities/format/format.functions/format.verify.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // Basic test to validate ill-formed code is properly detected.
 
 // <format>
 
 // template<class... Args>
 //   string format(format-string<Args...> fmt, const Args&... args);
 // template<class... Args>
 //   wstring format(wformat-string<Args...> fmt, const Args&... args);

libcxx/test/std/utilities/format/format.functions/format_to.locale.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-localization
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 // TODO FMT Evaluate gcc-12 status
 // UNSUPPORTED: gcc-12
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // template<class Out, class... Args>
 //   Out format_to(Out out, const locale& loc,
 //                 format-string<Args...> fmt, const Args&... args);
 // template<class Out, class... Args>
 //   Out format_to(Out out, const locale& loc,
 //                 wformat-string<Args...> fmt, const Args&... args);

libcxx/test/std/utilities/format/format.functions/format_to.locale.verify.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-localization
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // Basic test to validate ill-formed code is properly detected.
 
 // <format>
 
 // template<class Out, class... Args>
 //   Out format_to(Out out, const locale& loc,
 //                 format-string<Args...> fmt, const Args&... args);
 // template<class Out, class... Args>

libcxx/test/std/utilities/format/format.functions/format_to.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 // TODO FMT Evaluate gcc-12 status
 // UNSUPPORTED: gcc-12
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // template<class Out, class... Args>
 //   Out format_to(Out out, format-string<Args...> fmt, const Args&... args);
 // template<class Out, class... Args>
 //   Out format_to(Out out, wformat-string<Args...> fmt, const Args&... args);
 
 #include <format>

libcxx/test/std/utilities/format/format.functions/format_to.verify.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // Basic test to validate ill-formed code is properly detected.
 
 // template<class Out, class... Args>
 //   Out format_to(Out out, format-string<Args...> fmt, const Args&... args);
 // template<class Out, class... Args>
 //   Out format_to(Out out, wformat-string<Args...> fmt, const Args&... args);

libcxx/test/std/utilities/format/format.functions/format_to_n.locale.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-localization
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 // TODO FMT Evaluate gcc-12 status
 // UNSUPPORTED: gcc-12
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // template<class Out, class... Args>
 //   format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
 //                                       const locale& loc, format-string<Args...> fmt,
 //                                       const Args&... args);
 // template<class Out, class... Args>
 //   format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,

libcxx/test/std/utilities/format/format.functions/format_to_n.locale.verify.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-localization
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // Basic test to validate ill-formed code is properly detected.
 
 // <format>
 
 // template<class Out, class... Args>
 //   format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
 //                                       const locale& loc, format-string<Args...> fmt,
 //                                       const Args&... args);

libcxx/test/std/utilities/format/format.functions/format_to_n.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 // TODO FMT Evaluate gcc-12 status
 // UNSUPPORTED: gcc-12
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // template<class Out, class... Args>
 //   format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
 //                                       format-string<Args...> fmt, const Args&... args);
 // template<class Out, class... Args>
 //   format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
 //                                       wformat-string<Args...> fmt, const Args&... args);

libcxx/test/std/utilities/format/format.functions/format_to_n.verify.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // Basic test to validate ill-formed code is properly detected.
 
 // <format>
 
 // template<class Out, class... Args>
 //   format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
 //                                       format-string<Args...> fmt, const Args&... args);
 // template<class Out, class... Args>

libcxx/test/std/utilities/format/format.functions/formatted_size.locale.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-localization
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 // TODO FMT Evaluate gcc-12 status
 // UNSUPPORTED: gcc-12
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // template<class... Args>
 //   size_t formatted_size(const locale& loc,
 //                         format-string<Args...> fmt, const Args&... args);
 // template<class... Args>
 //   size_t formatted_size(const locale& loc,
 //                         wformat-string<Args...> fmt, const Args&... args);

libcxx/test/std/utilities/format/format.functions/formatted_size.locale.verify.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-localization
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // Basic test to validate ill-formed code is properly detected.
 
 // <format>
 
 // template<class... Args>
 //   size_t formatted_size(const locale& loc,
 //                         format-string<Args...> fmt, const Args&... args);
 // template<class... Args>

libcxx/test/std/utilities/format/format.functions/formatted_size.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 // TODO FMT Evaluate gcc-12 status
 // UNSUPPORTED: gcc-12
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // template<class... Args>
 //   size_t formatted_size(format-string<Args...> fmt, const Args&... args);
 // template<class... Args>
 //   size_t formatted_size(wformat-string<Args...> fmt, const Args&... args);
 
 #include <format>

libcxx/test/std/utilities/format/format.functions/formatted_size.verify.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // Basic test to validate ill-formed code is properly detected.
 
 // <format>
 
 // template<class... Args>
 //   size_t formatted_size(format-string<Args...> fmt, const Args&... args);
 // template<class... Args>
 //   size_t formatted_size(wformat-string<Args...> fmt, const Args&... args);

libcxx/test/std/utilities/format/format.functions/locale-specific_form.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-localization
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
 // TODO FMT Evaluate gcc-12 status
 // UNSUPPORTED: gcc-12
 
 // REQUIRES: locale.en_US.UTF-8
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // This test the locale-specific form for these formatting functions:
 //
 //  // [format.functions], formatting functions
 //  template<class... Args>
 //    string format(string_view fmt, const Args&... args);
 //  template<class... Args>

libcxx/test/std/utilities/format/format.functions/unicode.pass.cpp

 
 // This version runs the test when the platform has Unicode support.
 // UNSUPPORTED: libcpp-has-no-unicode
 
 // TODO FMT Investigate Windows and AIX issues.
 // UNSUPPORTED msvc, target={{.+}}-windows-gnu
 // UNSUPPORTED: LIBCXX-AIX-FIXME
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // Tests the Unicode width support of the standard format specifiers.
 // It tests [format.string.std]/8 - 11:
 // - Properly determining the estimated with of a unicode string.
 // - Properly truncating to the wanted maximum width.
 
 // More specific extended grapheme cluster boundary rules are tested in

libcxx/test/std/utilities/format/format.functions/vformat.locale.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-localization
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 // TODO FMT Evaluate gcc-12 status
 // UNSUPPORTED: gcc-12
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // string vformat(const locale& loc, string_view fmt, format_args args);
 // wstring vformat(const locale& loc, wstring_view fmt, wformat_args args);
 
 #include <format>
 #include <cassert>
 #include <vector>

libcxx/test/std/utilities/format/format.functions/vformat.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 // TODO FMT Evaluate gcc-12 status
 // UNSUPPORTED: gcc-12
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // string vformat(string_view fmt, format_args args);
 // wstring vformat(wstring_view fmt, wformat_args args);
 
 #include <format>
 #include <cassert>
 #include <vector>

libcxx/test/std/utilities/format/format.functions/vformat_to.locale.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-localization
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 // TODO FMT Evaluate gcc-12 status
 // UNSUPPORTED: gcc-12
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // template<class Out>
 //   Out vformat_to(Out out, const locale& loc, string_view fmt,
 //                  format_args args);
 // template<class Out>
 //    Out vformat_to(Out out, const locale& loc, wstring_view fmt,
 //                   wformat_args args);

libcxx/test/std/utilities/format/format.functions/vformat_to.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 // TODO FMT Evaluate gcc-12 status
 // UNSUPPORTED: gcc-12
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // template<class Out>
 //   Out vformat_to(Out out, string_view fmt, format_args args);
 // template<class Out>
 //    Out vformat_to(Out out, wstring_view fmt, wformat_args_t args);
 
 #include <format>

libcxx/test/std/utilities/format/format.syn/format_to_n_result.pass.cpp

 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// This test requires the dylib support introduced in D92214.
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
+
 // <format>
 
 // struct format_to_n_result
 
 // [format.syn]/1
 // The class template format_to_n_result has the template parameters, data
 // members, and special members specified above. It has no base classes or
 // members other than those specified.

libcxx/utils/ci/buildkite-pipeline.yml

 # (Note the image isn't updated daily.) The LLVM_HEAD_VERSION contains that
 # version number. The Linux CI runners for GCC use the latest stable version.
 # Theses numbers are available in all runners, making it easier to update the
 # version number.
 env:
     LLVM_HEAD_VERSION: "16"
     GCC_STABLE_VERSION: "12"
 steps:
-  #
-  # Light pre-commit tests for things like formatting or when people forget
-  # to update generated files.
-  #
-  - label: "Format"
-    command: "libcxx/utils/ci/run-buildbot check-format"
-    artifact_paths:
-      - "**/clang-format.patch"
-    agents:
-      queue: "libcxx-builders"
-      os: "linux"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-    soft_fail:
-        - exit_status: 1
-    timeout_in_minutes: 120
-
-  - label: "Generated output"
-    command: "libcxx/utils/ci/run-buildbot check-generated-output"
-    artifact_paths:
-      - "**/generated_output.patch"
-      - "**/generated_output.status"
-    agents:
-      queue: "libcxx-builders"
-      os: "linux"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-    timeout_in_minutes: 120
-
-  - label: "Documentation"
-    command: "libcxx/utils/ci/run-buildbot documentation"
-    artifact_paths:
-      - "**/test-results.xml"
-    agents:
-      queue: "libcxx-builders"
-      os: "linux"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-    timeout_in_minutes: 120
-
-  #
-  # General testing with the default configuration, under all the supported
-  # Standard modes, with Clang and GCC. This catches most issues upfront.
-  # The goal of this step is to catch most issues while being very fast.
-  #
-  - wait
-
-  - label: "GCC ${GCC_STABLE_VERSION} / C++latest"
-    command: "libcxx/utils/ci/run-buildbot generic-gcc"
-    artifact_paths:
-      - "**/test-results.xml"
-      - "**/*.abilist"
-    env:
-        CC: "gcc-${GCC_STABLE_VERSION}"
-        CXX: "g++-${GCC_STABLE_VERSION}"
-    agents:
-      queue: "libcxx-builders"
-      os: "linux"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-    timeout_in_minutes: 120
-
-  - label: "C++2b"
-    command: "libcxx/utils/ci/run-buildbot generic-cxx2b"
-    artifact_paths:
-      - "**/test-results.xml"
-      - "**/*.abilist"
-    env:
-        CC: "clang-${LLVM_HEAD_VERSION}"
-        CXX: "clang++-${LLVM_HEAD_VERSION}"
-    agents:
-      queue: "libcxx-builders"
-      os: "linux"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-    timeout_in_minutes: 120
-
-  - label: "Modular build"
-    command: "libcxx/utils/ci/run-buildbot generic-modules"
-    artifact_paths:
-      - "**/test-results.xml"
-      - "**/*.abilist"
-    env:
-        CC: "clang-${LLVM_HEAD_VERSION}"
-        CXX: "clang++-${LLVM_HEAD_VERSION}"
-    agents:
-      queue: "libcxx-builders"
-      os: "linux"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-    timeout_in_minutes: 120
-
-  - label: "C++11"
-    command: "libcxx/utils/ci/run-buildbot generic-cxx11"
-    artifact_paths:
-      - "**/test-results.xml"
-      - "**/*.abilist"
-    env:
-        CC: "clang-${LLVM_HEAD_VERSION}"
-        CXX: "clang++-${LLVM_HEAD_VERSION}"
-    agents:
-      queue: "libcxx-builders"
-      os: "linux"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-    timeout_in_minutes: 120
-
-  - label: "C++03"
-    command: "libcxx/utils/ci/run-buildbot generic-cxx03"
-    artifact_paths:
-      - "**/test-results.xml"
-      - "**/*.abilist"
-    env:
-        CC: "clang-${LLVM_HEAD_VERSION}"
-        CXX: "clang++-${LLVM_HEAD_VERSION}"
-    agents:
-      queue: "libcxx-builders"
-      os: "linux"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-    timeout_in_minutes: 120
-
-  #
-  # All other supported configurations of libc++.
-  #
-  - wait
-
-  - label: "C++20"
-    command: "libcxx/utils/ci/run-buildbot generic-cxx20"
-    artifact_paths:
-      - "**/test-results.xml"
-      - "**/*.abilist"
-    env:
-        CC: "clang-${LLVM_HEAD_VERSION}"
-        CXX: "clang++-${LLVM_HEAD_VERSION}"
-    agents:
-      queue: "libcxx-builders"
-      os: "linux"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-    timeout_in_minutes: 120
-
-  - label: "C++17"
-    command: "libcxx/utils/ci/run-buildbot generic-cxx17"
-    artifact_paths:
-      - "**/test-results.xml"
-      - "**/*.abilist"
-    env:
-        CC: "clang-${LLVM_HEAD_VERSION}"
-        CXX: "clang++-${LLVM_HEAD_VERSION}"
-    agents:
-      queue: "libcxx-builders"
-      os: "linux"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-    timeout_in_minutes: 120
-
-  - label: "C++14"
-    command: "libcxx/utils/ci/run-buildbot generic-cxx14"
-    artifact_paths:
-      - "**/test-results.xml"
-      - "**/*.abilist"
-    env:
-        CC: "clang-${LLVM_HEAD_VERSION}"
-        CXX: "clang++-${LLVM_HEAD_VERSION}"
-    agents:
-      queue: "libcxx-builders"
-      os: "linux"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-    timeout_in_minutes: 120
-
-  # Tests with the supported compilers.
-  - label: "GCC ${GCC_STABLE_VERSION} / C++11"
-    command: "libcxx/utils/ci/run-buildbot generic-gcc-cxx11"
-    artifact_paths:
-      - "**/test-results.xml"
-      - "**/*.abilist"
-    env:
-        CC: "gcc-${GCC_STABLE_VERSION}"
-        CXX: "g++-${GCC_STABLE_VERSION}"
-    agents:
-      queue: "libcxx-builders"
-      os: "linux"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-    timeout_in_minutes: 120
-
-  - label: "Clang 14"
-    command: "libcxx/utils/ci/run-buildbot generic-cxx2b"
-    artifact_paths:
-      - "**/test-results.xml"
-      - "**/*.abilist"
-    env:
-        CC: "clang-14"
-        CXX: "clang++-14"
-    agents:
-      queue: "libcxx-builders"
-      os: "linux"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-    timeout_in_minutes: 120
-
-  - label: "Clang 15"
-    command: "libcxx/utils/ci/run-buildbot generic-cxx2b"
-    artifact_paths:
-      - "**/test-results.xml"
-      - "**/*.abilist"
-    env:
-        CC: "clang-15"
-        CXX: "clang++-15"
-    agents:
-      queue: "libcxx-builders"
-      os: "linux"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-    timeout_in_minutes: 120
-
-  # Tests with the sanitizers.
-  - group: "Sanitizers"
-    steps:
-    - label: "ASAN"
-      command: "libcxx/utils/ci/run-buildbot generic-asan"
-      artifact_paths:
-        - "**/test-results.xml"
-        - "**/*.abilist"
-      env:
-          CC: "clang-${LLVM_HEAD_VERSION}"
-          CXX: "clang++-${LLVM_HEAD_VERSION}"
-      agents:
-        queue: "libcxx-builders"
-        os: "linux"
-      retry:
-        automatic:
-          - exit_status: -1  # Agent was lost
-            limit: 2
-      timeout_in_minutes: 120
-
-    - label: "TSAN"
-      command: "libcxx/utils/ci/run-buildbot generic-tsan"
-      artifact_paths:
-        - "**/test-results.xml"
-        - "**/*.abilist"
-      env:
-          CC: "clang-${LLVM_HEAD_VERSION}"
-          CXX: "clang++-${LLVM_HEAD_VERSION}"
-      agents:
-        queue: "libcxx-builders"
-        os: "linux"
-      retry:
-        automatic:
-          - exit_status: -1  # Agent was lost
-            limit: 2
-      timeout_in_minutes: 120
-
-    - label: "UBSAN"
-      command: "libcxx/utils/ci/run-buildbot generic-ubsan"
-      artifact_paths:
-        - "**/test-results.xml"
-        - "**/*.abilist"
-      env:
-          CC: "clang-${LLVM_HEAD_VERSION}"
-          CXX: "clang++-${LLVM_HEAD_VERSION}"
-      agents:
-        queue: "libcxx-builders"
-        os: "linux"
-      retry:
-        automatic:
-          - exit_status: -1  # Agent was lost
-            limit: 2
-      timeout_in_minutes: 120
-
-    - label: "MSAN"
-      command: "libcxx/utils/ci/run-buildbot generic-msan"
-      artifact_paths:
-        - "**/test-results.xml"
-        - "**/*.abilist"
-      env:
-          CC: "clang-${LLVM_HEAD_VERSION}"
-          CXX: "clang++-${LLVM_HEAD_VERSION}"
-      agents:
-        queue: "libcxx-builders"
-        os: "linux"
-      retry:
-        automatic:
-          - exit_status: -1  # Agent was lost
-            limit: 2
-      timeout_in_minutes: 120
-
-  # Tests with the various supported ways to build libc++.
-  - label: "Bootstrapping build"
-    command: "libcxx/utils/ci/run-buildbot bootstrapping-build"
-    artifact_paths:
-      - "**/test-results.xml"
-      - "**/*.abilist"
-      - "**/crash_diagnostics/*"
-    env:
-        CC: "clang-${LLVM_HEAD_VERSION}"
-        CXX: "clang++-${LLVM_HEAD_VERSION}"
-        LLVM_SYMBOLIZER_PATH: "/usr/bin/llvm-symbolizer-${LLVM_HEAD_VERSION}"
-        CLANG_CRASH_DIAGNOSTICS_DIR: "crash_diagnostics"
-    agents:
-      queue: "libcxx-builders"
-      os: "linux"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-    timeout_in_minutes: 120
-
-  # Tests with various build configurations.
-  - label: "Static libraries"
-    command: "libcxx/utils/ci/run-buildbot generic-static"
-    artifact_paths:
-      - "**/test-results.xml"
-      - "**/*.abilist"
-    env:
-        CC: "clang-${LLVM_HEAD_VERSION}"
-        CXX: "clang++-${LLVM_HEAD_VERSION}"
-    agents:
-      queue: "libcxx-builders"
-      os: "linux"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-    timeout_in_minutes: 120
-
-  - label: "Shared library with merged ABI and unwinder libraries"
-    command: "libcxx/utils/ci/run-buildbot generic-merged"
-    artifact_paths:
-      - "**/test-results.xml"
-      - "**/*.abilist"
-    env:
-        CC: "clang-${LLVM_HEAD_VERSION}"
-        CXX: "clang++-${LLVM_HEAD_VERSION}"
-    agents:
-      queue: "libcxx-builders"
-      os: "linux"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-    timeout_in_minutes: 120
-
-  - label: "Assertions enabled"
-    command: "libcxx/utils/ci/run-buildbot generic-assertions"
-    artifact_paths:
-      - "**/test-results.xml"
-      - "**/*.abilist"
-    env:
-        CC: "clang-${LLVM_HEAD_VERSION}"
-        CXX: "clang++-${LLVM_HEAD_VERSION}"
-    agents:
-      queue: "libcxx-builders"
-      os: "linux"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-    timeout_in_minutes: 120
-
-  - label: "Debug mode"
-    command: "libcxx/utils/ci/run-buildbot generic-debug-mode"
-    artifact_paths:
-      - "**/test-results.xml"
-      - "**/*.abilist"
-    env:
-        CC: "clang-${LLVM_HEAD_VERSION}"
-        CXX: "clang++-${LLVM_HEAD_VERSION}"
-    agents:
-      queue: "libcxx-builders"
-      os: "linux"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-    timeout_in_minutes: 120
-
-  - label: "No transitive includes"
-    command: "libcxx/utils/ci/run-buildbot generic-no-transitive-includes"
-    artifact_paths:
-      - "**/test-results.xml"
-      - "**/*.abilist"
-    env:
-        CC: "clang-${LLVM_HEAD_VERSION}"
-        CXX: "clang++-${LLVM_HEAD_VERSION}"
-    agents:
-      queue: "libcxx-builders"
-      os: "linux"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-    timeout_in_minutes: 120
-
-  - label: "With LLVM's libunwind"
-    command: "libcxx/utils/ci/run-buildbot generic-with_llvm_unwinder"
-    artifact_paths:
-      - "**/test-results.xml"
-      - "**/*.abilist"
-    env:
-        CC: "clang-${LLVM_HEAD_VERSION}"
-        CXX: "clang++-${LLVM_HEAD_VERSION}"
-    agents:
-      queue: "libcxx-builders"
-      os: "linux"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-    timeout_in_minutes: 120
-
-  - group: "Parts disabled"
-    steps:
-    - label: "No threads"
-      command: "libcxx/utils/ci/run-buildbot generic-no-threads"
-      artifact_paths:
-        - "**/test-results.xml"
-        - "**/*.abilist"
-      env:
-          CC: "clang-${LLVM_HEAD_VERSION}"
-          CXX: "clang++-${LLVM_HEAD_VERSION}"
-      agents:
-        queue: "libcxx-builders"
-        os: "linux"
-      retry:
-        automatic:
-          - exit_status: -1  # Agent was lost
-            limit: 2
-      timeout_in_minutes: 120
-
-    - label: "No filesystem"
-      command: "libcxx/utils/ci/run-buildbot generic-no-filesystem"
-      artifact_paths:
-        - "**/test-results.xml"
-        - "**/*.abilist"
-      env:
-          CC: "clang-${LLVM_HEAD_VERSION}"
-          CXX: "clang++-${LLVM_HEAD_VERSION}"
-      agents:
-        queue: "libcxx-builders"
-        os: "linux"
-      retry:
-        automatic:
-          - exit_status: -1  # Agent was lost
-            limit: 2
-      timeout_in_minutes: 120
-
-    - label: "No random device"
-      command: "libcxx/utils/ci/run-buildbot generic-no-random_device"
-      artifact_paths:
-        - "**/test-results.xml"
-        - "**/*.abilist"
-      env:
-          CC: "clang-${LLVM_HEAD_VERSION}"
-          CXX: "clang++-${LLVM_HEAD_VERSION}"
-      agents:
-        queue: "libcxx-builders"
-        os: "linux"
-      retry:
-        automatic:
-          - exit_status: -1  # Agent was lost
-            limit: 2
-      timeout_in_minutes: 120
-
-    - label: "No fstream"
-      command: "libcxx/utils/ci/run-buildbot generic-no-fstream"
-      artifact_paths:
-        - "**/test-results.xml"
-        - "**/*.abilist"
-      env:
-          CC: "clang-${LLVM_HEAD_VERSION}"
-          CXX: "clang++-${LLVM_HEAD_VERSION}"
-      agents:
-        queue: "libcxx-builders"
-        os: "linux"
-      retry:
-        automatic:
-          - exit_status: -1  # Agent was lost
-            limit: 2
-      timeout_in_minutes: 120
-
-    - label: "No locale"
-      command: "libcxx/utils/ci/run-buildbot generic-no-localization"
-      artifact_paths:
-        - "**/test-results.xml"
-        - "**/*.abilist"
-      env:
-          CC: "clang-${LLVM_HEAD_VERSION}"
-          CXX: "clang++-${LLVM_HEAD_VERSION}"
-      agents:
-        queue: "libcxx-builders"
-        os: "linux"
-      retry:
-        automatic:
-          - exit_status: -1  # Agent was lost
-            limit: 2
-      timeout_in_minutes: 120
-
-    - label: "No Unicode"
-      command: "libcxx/utils/ci/run-buildbot generic-no-unicode"
-      artifact_paths:
-        - "**/test-results.xml"
-        - "**/*.abilist"
-      env:
-          CC: "clang-${LLVM_HEAD_VERSION}"
-          CXX: "clang++-${LLVM_HEAD_VERSION}"
-      agents:
-        queue: "libcxx-builders"
-        os: "linux"
-      retry:
-        automatic:
-          - exit_status: -1  # Agent was lost
-            limit: 2
-      timeout_in_minutes: 120
-
-    - label: "No wide characters"
-      command: "libcxx/utils/ci/run-buildbot generic-no-wide-characters"
-      artifact_paths:
-        - "**/test-results.xml"
-        - "**/*.abilist"
-      env:
-          CC: "clang-${LLVM_HEAD_VERSION}"
-          CXX: "clang++-${LLVM_HEAD_VERSION}"
-      agents:
-        queue: "libcxx-builders"
-        os: "linux"
-      retry:
-        automatic:
-          - exit_status: -1  # Agent was lost
-            limit: 2
-      timeout_in_minutes: 120
-
-    - label: "No experimental features"
-      command: "libcxx/utils/ci/run-buildbot generic-no-experimental"
-      artifact_paths:
-        - "**/test-results.xml"
-        - "**/*.abilist"
-      env:
-          CC: "clang-${LLVM_HEAD_VERSION}"
-          CXX: "clang++-${LLVM_HEAD_VERSION}"
-      agents:
-        queue: "libcxx-builders"
-        os: "linux"
-      retry:
-        automatic:
-          - exit_status: -1  # Agent was lost
-            limit: 2
-      timeout_in_minutes: 120
-
-    - label: "No exceptions"
-      command: "libcxx/utils/ci/run-buildbot generic-noexceptions"
-      artifact_paths:
-        - "**/test-results.xml"
-        - "**/*.abilist"
-      env:
-          CC: "clang-${LLVM_HEAD_VERSION}"
-          CXX: "clang++-${LLVM_HEAD_VERSION}"
-      agents:
-        queue: "libcxx-builders"
-        os: "linux"
-      retry:
-        automatic:
-          - exit_status: -1  # Agent was lost
-            limit: 2
-      timeout_in_minutes: 120
-
-  - label: "Unstable ABI"
-    command: "libcxx/utils/ci/run-buildbot generic-abi-unstable"
-    artifact_paths:
-      - "**/test-results.xml"
-      - "**/*.abilist"
-    env:
-        CC: "clang-${LLVM_HEAD_VERSION}"
-        CXX: "clang++-${LLVM_HEAD_VERSION}"
-    agents:
-      queue: "libcxx-builders"
-      os: "linux"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-    timeout_in_minutes: 120
-
-  # Other non-testing CI jobs
-  - label: "Benchmarks"
-    command: "libcxx/utils/ci/run-buildbot benchmarks"
-    artifact_paths:
-      - "**/test-results.xml"
-      - "**/*.abilist"
-    env:
-        CC: "clang-${LLVM_HEAD_VERSION}"
-        CXX: "clang++-${LLVM_HEAD_VERSION}"
-    agents:
-      queue: "libcxx-builders"
-      os: "linux"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-    timeout_in_minutes: 120
-
-  # Tests on non-Unix platforms
-  - group: ":windows: Windows"
-    steps:
-    - label: "Clang-cl (DLL)"
-      command: "bash libcxx/utils/ci/run-buildbot clang-cl-dll"
-      artifact_paths:
-        - "**/test-results.xml"
-        - "**/*.abilist"
-      agents:
-        queue: "windows"
-      retry:
-        automatic:
-          - exit_status: -1  # Agent was lost
-            limit: 2
-      timeout_in_minutes: 120
-
-    - label: "Clang-cl (Static)"
-      command: "bash libcxx/utils/ci/run-buildbot clang-cl-static"
-      artifact_paths:
-        - "**/test-results.xml"
-        - "**/*.abilist"
-      agents:
-        queue: "windows"
-      retry:
-        automatic:
-          - exit_status: -1  # Agent was lost
-            limit: 2
-      timeout_in_minutes: 120
-
-    - label: "Clang-cl (no vcruntime exceptions)"
-      command: "bash libcxx/utils/ci/run-buildbot clang-cl-no-vcruntime"
-      artifact_paths:
-        - "**/test-results.xml"
-        - "**/*.abilist"
-      agents:
-        queue: "windows"
-      retry:
-        automatic:
-          - exit_status: -1  # Agent was lost
-            limit: 2
-
-    - label: "MinGW (DLL, x86_64)"
-      command: "bash libcxx/utils/ci/run-buildbot mingw-dll"
-      artifact_paths:
-        - "**/test-results.xml"
-        - "**/*.abilist"
-      agents:
-        queue: "windows"
-      retry:
-        automatic:
-          - exit_status: -1  # Agent was lost
-            limit: 2
-      timeout_in_minutes: 120
-
-    - label: "MinGW (Static, x86_64)"
-      command: "bash libcxx/utils/ci/run-buildbot mingw-static"
-      artifact_paths:
-        - "**/test-results.xml"
-        - "**/*.abilist"
-      agents:
-        queue: "windows"
-      retry:
-        automatic:
-          - exit_status: -1  # Agent was lost
-            limit: 2
-      timeout_in_minutes: 120
-
-    - label: "MinGW (DLL, i686)"
-      command: "bash libcxx/utils/ci/run-buildbot mingw-dll-i686"
-      artifact_paths:
-        - "**/test-results.xml"
-        - "**/*.abilist"
-      agents:
-        queue: "windows"
-      retry:
-        automatic:
-          - exit_status: -1  # Agent was lost
-            limit: 2
-      timeout_in_minutes: 120
-
   - group: ":apple: Apple"
     steps:
     - label: "MacOS x86_64"
       command: "libcxx/utils/ci/run-buildbot generic-cxx20"
       artifact_paths:
         - "**/test-results.xml"
         - "**/*.abilist"
       agents:
- label: "Apple back-deployment with assertions enabled"
       agents:
         queue: "libcxx-builders"
         os: "macos"
       retry:
         automatic:
           - exit_status: -1  # Agent was lost
             limit: 2
       timeout_in_minutes: 120
-
-  - group: "ARM"
-    steps:
-    - label: "AArch64"
-      command: "libcxx/utils/ci/run-buildbot aarch64"
-      artifact_paths:
-        - "**/test-results.xml"
-        - "**/*.abilist"
-      agents:
-        queue: "libcxx-builders-linaro-arm"
-        arch: "aarch64"
-      retry:
-        automatic:
-          - exit_status: -1  # Agent was lost
-            limit: 2
-      timeout_in_minutes: 120
-
-    - label: "AArch64 -fno-exceptions"
-      command: "libcxx/utils/ci/run-buildbot aarch64-noexceptions"
-      artifact_paths:
-        - "**/test-results.xml"
-        - "**/*.abilist"
-      agents:
-        queue: "libcxx-builders-linaro-arm"
-        arch: "aarch64"
-      retry:
-        automatic:
-          - exit_status: -1  # Agent was lost
-            limit: 2
-      timeout_in_minutes: 120
-
-    - label: "Armv8"
-      command: "libcxx/utils/ci/run-buildbot armv8"
-      artifact_paths:
-        - "**/test-results.xml"
-        - "**/*.abilist"
-      agents:
-        queue: "libcxx-builders-linaro-arm"
-        arch: "armv8l"
-      retry:
-        automatic:
-          - exit_status: -1  # Agent was lost
-            limit: 2
-      timeout_in_minutes: 120
-
-    - label: "Armv8 -fno-exceptions"
-      command: "libcxx/utils/ci/run-buildbot armv8-noexceptions"
-      artifact_paths:
-        - "**/test-results.xml"
-        - "**/*.abilist"
-      agents:
-        queue: "libcxx-builders-linaro-arm"
-        arch: "armv8l"
-      retry:
-        automatic:
-          - exit_status: -1  # Agent was lost
-            limit: 2
-      timeout_in_minutes: 120
-
-    - label: "Armv7"
-      command: "libcxx/utils/ci/run-buildbot armv7"
-      artifact_paths:
-        - "**/test-results.xml"
-        - "**/*.abilist"
-      agents:
-        queue: "libcxx-builders-linaro-arm"
-        arch: "armv8l" # Compiling for v7, running on v8 hardware
-      retry:
-        automatic:
-          - exit_status: -1  # Agent was lost
-            limit: 2
-      timeout_in_minutes: 120
-
-    - label: "Armv7 -fno-exceptions"
-      command: "libcxx/utils/ci/run-buildbot armv7-noexceptions"
-      artifact_paths:
-        - "**/test-results.xml"
-        - "**/*.abilist"
-      agents:
-        queue: "libcxx-builders-linaro-arm"
-        arch: "armv8l" # Compiling for v7, running on v8 hardware
-      retry:
-        automatic:
-          - exit_status: -1  # Agent was lost
-            limit: 2
-      timeout_in_minutes: 120
-
-  - group: "AIX"
-    steps:
-    - label: "AIX (32-bit)"
-      command: "libcxx/utils/ci/run-buildbot aix"
-      artifact_paths:
-        - "**/test-results.xml"
-        - "**/*.abilist"
-      env:
-          CC: "clang"
-          CXX: "clang++"
-          OBJECT_MODE: "32"
-      agents:
-          queue: libcxx-builders
-          os: aix
-      retry:
-        automatic:
-          - exit_status: -1  # Agent was lost
-            limit: 2
-      timeout_in_minutes: 120
-
-    - label: "AIX (64-bit)"
-      command: "libcxx/utils/ci/run-buildbot aix"
-      artifact_paths:
-        - "**/test-results.xml"
-        - "**/*.abilist"
-      env:
-          CC: "clang"
-          CXX: "clang++"
-          OBJECT_MODE: "64"
-      agents:
-          queue: libcxx-builders
-          os: aix
-      retry:
-        automatic:
-          - exit_status: -1  # Agent was lost
-            limit: 2
-      timeout_in_minutes: 120

libcxx/utils/ci/run-buildbot

apple-system-backdeployment-assertions-*)
 
     arch="$(uname -m)"
     PARAMS="target_triple=${arch}-apple-macosx${DEPLOYMENT_TARGET}"
     PARAMS+=";cxx_runtime_root=${OSX_ROOTS}/macOS/libc++/${DEPLOYMENT_TARGET}"
     PARAMS+=";abi_runtime_root=${OSX_ROOTS}/macOS/libc++abi/${DEPLOYMENT_TARGET}"
     PARAMS+=";unwind_runtime_root=${OSX_ROOTS}/macOS/libunwind/${DEPLOYMENT_TARGET}"
     PARAMS+=";use_system_cxx_lib=True"
     PARAMS+=";enable_assertions=True"
-    # TODO: Enable experimental features during back-deployment -- right now some of the availability
-    #       annotations are incorrect, leading to test failures that could be avoided.
-    PARAMS+=";enable_experimental=False"
 
     generate-cmake -C "${MONOREPO_ROOT}/libcxx/cmake/caches/Apple.cmake" \
                    -DLIBCXX_TEST_CONFIG="apple-libc++-backdeployment.cfg.in" \
                    -DLIBCXXABI_TEST_CONFIG="apple-libc++abi-backdeployment.cfg.in" \
                    -DLIBUNWIND_TEST_CONFIG="apple-libunwind-backdeployment.cfg.in" \
                    -DLIBCXX_TEST_PARAMS="${PARAMS}" \
                    -DLIBCXXABI_TEST_PARAMS="${PARAMS}" \
                    -DLIBUNWIND_TEST_PARAMS="${PARAMS}"