[libc++][NFC] Create a new folder for config-related headers.

[var-const]

Summary

This is in preparation for adding more configuration macros for hardening purposes. __config is a large monolithic header that can be hard to follow because it contains many unrelated groups of macros. The idea is to split it into several headers each focused on a different aspect (e.g. ABI, support for older language versions, hardening modes in the future, etc.). The split headers are placed in a directory to reduce clutter at the top level.

[Mordante]

Could you add some information in the commit message why this is a good idea?

[var-const]

Feedback

[var-const]

Missing files

[ldionne]

libcxx/include/__config_dir/debug.h

10

I think I would avoid touching this one since you can't include if from` __config`. Also per the RFC this is mostly going to go away.

libcxx/include/module.modulemap.in

1811–1813

I think removing this should get rid of your circular dependency issue with modules.

[ldionne]

libcxx/utils/generate_iwyu_mapping.py

39–40

I wouldn't special case for __config_dir here.

The libcxx.imp file we generate right now is already incorrect in a few instances (for example we generate a line with { include: [ "@<__debug_utils/.*>", "private", "<debug_utils>", "public" ] },) -- let's figure out how to handle it correctly for all our internal directories at once, not here.

We probably want to do something like this:

internal_directories = ['__config_dir', '__debug_utils', etc...]
for i in detail_directories:
  if i in internal_direcotries:
    continue
  ...

Or if you want, I guess you could actually do this in this patch and handle the following directories: __debug_utils, __fwd, __pstl, __support.

[var-const]

In D151900#4387750, @Mordante wrote:

Could you add some information in the commit message why this is a good idea?

Added some comments to the patch description, please let me know what you think. This came out of my first attempts to add macros for configuring hardening modes. I find __config hard to navigate due to its size, and it seems to have a few "themes" that seem like a good fit to be split into separate, more focused headers. I thought to refactor __config first before adding even more stuff to it. I also hope that having more focused headers (e.g. __config_dir/language_support.h, __config_dir/abi.h) would make finding macros easier.

[var-const]

libcxx/utils/generate_iwyu_mapping.py

39–40

Done (added internal_directories).

[var-const]

Address feedback.

[Mordante]

In D151900#4402597, @var-const wrote:

In D151900#4387750, @Mordante wrote:

Could you add some information in the commit message why this is a good idea?

Added some comments to the patch description, please let me know what you think. This came out of my first attempts to add macros for configuring hardening modes. I find __config hard to navigate due to its size, and it seems to have a few "themes" that seem like a good fit to be split into separate, more focused headers. I thought to refactor __config first before adding even more stuff to it. I also hope that having more focused headers (e.g. __config_dir/language_support.h, __config_dir/abi.h) would make finding macros easier.

Thanks! I agree the file is somewhat large and hard to navigate.

I think granularizing this header has some pitfalls as mention in my comment, but I think we can find ways to guard against them.

libcxx/include/__config_dir/base.h

12

I actually would rather like to see how you envision the final split, this is the normal way how we granularize headers.

I also think we should never include one of the granularized headers from headers outside of __config/, except from config. Here I feel that including the granularized headers could easily result in bugs. A define not set might be on purpose or a bug due to forgetting an include.
So I think we need generated tests verify tests that give an error when I write code like

#include <__config/constexpr.h>

From a header like <format>.

[ldionne]

libcxx/include/__config_dir/base.h

12

+1, this makes sense to me. Here's a few categories we spotted easily during live review:

environment.h or versions.h // detects compiler and language version
abi.h // all the ABI flags
visibility.h // all the macros related to visibility annotations, DLL_VIS, etc.
compiler_shims.h // maybe for things like `#define __has_attribute(x) 0` depending on what's the use of those
random.h // we have stuff related to random device
endian.h // endianness detection
????.h // detection of stuff like _LIBCPP_HAS_OBJC_ARC
deprecation.h // we have a bunch of deprecation macros

I still suggest we keep the uncategorized rest into base.h or we might end up with really small headers, but I'd be fine with that too.

[var-const]

Granularize most of <__config>.

[var-const]

@Mordante I gave granularizing a shot. There's still feedback to address, but I uploaded the split headers in case you'd like to take a look. Some notes:

• for splitting, some headers had to be split because they are essentially dependencies for other headers (e.g. that's why I split object_format.h even though it's very small). For others, I went mostly by size of the category, but sometimes created really small headers if the macros seemed focused on something very specific (e.g. objc.h). There definitely is some overlap between different categories, so I'm very open to suggestions on how to rearrange / combine / etc.;
• base.h probably can be renamed now (it feels more like "misc").

One important thing was to make sure that new small headers don't rely on macros from other headers that they don't include. Unfortunately since we rely on #if defined, forgetting to include a necessary header will often result in a silent error (I presume, I didn't test that yet). To make it easier, I created the base_umbrella.h header that contains the most commonly used "core" headers and decided to include it everywhere (except the core headers themselves). There are still a few places that include stuff like abi.h and c_std_library.h.

This problem existed before (it was quite possible to add new macros somewhere in the middle of the file and have them rely on something that wasn't defined yet). I wonder if moving to #if checks instead of #if defined would be a good idea.

[var-const]

libcxx/include/__config_dir/base_umbrella.h

17 ↗

(On Diff #529505)

Perhaps features.h, object_format.h and versions.h should be merged into e.g. environment.h?

[Mordante]

I like the direction this is going, still somewhat hesitant since we don't have good guards against directly including subheaders. I want to think a bit about that.

libcxx/include/__config_dir/attributes.h

21–33 ↗

(On Diff #529505)

Maybe in a followup remove the blank lines.

libcxx/include/__config_dir/base_umbrella.h

13 ↗

(On Diff #529505)

Why do we need this header?
If we need it we need to think of a better name, umbrella is not descriptive.

libcxx/include/__config_dir/c_std_library.h

11 ↗

(On Diff #529505)

How about libc_support.h, when I saw c std library I thought about the c headers in the standard.

libcxx/include/__config_dir/compiler_shims.h

11 ↗

(On Diff #529505)

Likewise would I call this compiler_support.h

libcxx/include/__config_dir/platform_msvc.h

11 ↗

(On Diff #529505)

Is this MSVC or Windows in general?

libcxx/include/__config_dir/versions.h

30 ↗

(On Diff #529505)

Why not at the top?

62–67 ↗

(On Diff #529505)

Maybe in a followup move C++03 in the NOLINT block.

73–82 ↗

(On Diff #529505)

In general I sometimes feel some pats can be placed in other places, the borders are not very strong.
(I've no real suggestions for improvements, parts are just in the eye of the beholder.)

This I feel stronger about, I would like this in platform_msvc.h

libcxx/include/module.modulemap.in

4

We should document that __config_dir is excluded since it only contains macros and no named declarations.
(I assume that Clang modules also only care about named declarations.)

[ldionne]

libcxx/include/__config_dir/base.h

21–49

This could move to aligned_allocation.h or features.h.

51–58

Let's move this to abi.h.

100–110

__config_dir/locale.h?

112–116

We can move this to objc.h, I think.

libcxx/include/__config_dir/base_umbrella.h

13 ↗

(On Diff #529505)

I think the intent is to avoid the issue where you're using a macro but forget to include the header that defines it. I think we should instead find a way to catch that systematically and not introduce this header, just IWYU from all the config headers.

17 ↗

(On Diff #529505)

IMO this is fine as-is, at least to begin with.

libcxx/include/__config_dir/c_std_library.h

40–43 ↗

(On Diff #529505)

I think this would belong to __config_dir/locale.h.

libcxx/include/__config_dir/versions.h

30 ↗

(On Diff #529505)

I think we need the compiler detection to be enabled even when we get included in C mode. That was for <stdatomic.h> IIRC.

Honestly my preference would be for all of __config_dir to be include-able in C mode, but I'd do that in a follow-up.

[var-const]

At this point, this patch is stale and hard to rebase. I might want to revisit this in the future, but abandoning for now.

libcxx/CMakeLists.txt

option(LIBCXX_ENABLE_WIDE_CHARACTERS
    support the C functionality for wide characters. When wide characters are
    not supported, several parts of the library will be disabled, notably the
    wide character specializations of std::basic_string." ON)
 option(LIBCXX_ENABLE_VENDOR_AVAILABILITY_ANNOTATIONS
   "Whether to turn on vendor availability annotations on declarations that depend
    on definitions in a shared library. By default, we assume that we're not building
    libc++ for any specific vendor, and we disable those annotations. Vendors wishing
    to provide compile-time errors when using features unavailable on some version of
-   the shared library they shipped should turn this on and see `include/__availability`
-   for more details." OFF)
+   the shared library they shipped should turn this on and see
+   `include/__config_dir/availability.h` for more details." OFF)
 option(LIBCXX_ENABLE_CLANG_TIDY "Whether to compile and run clang-tidy checks" OFF)
 
 if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
   set(LIBCXX_DEFAULT_TEST_CONFIG "llvm-libc++-shared-gcc.cfg.in")
 elseif(MINGW)
   set(LIBCXX_DEFAULT_TEST_CONFIG "llvm-libc++-mingw.cfg.in")
 elseif(WIN32) # clang-cl
   if (LIBCXX_ENABLE_SHARED)

libcxx/include/CMakeLists.txt

set(files
   __atomic/atomic_sync.h
   __atomic/check_memory_order.h
   __atomic/contention_t.h
   __atomic/cxx_atomic_impl.h
   __atomic/fence.h
   __atomic/is_always_lock_free.h
   __atomic/kill_dependency.h
   __atomic/memory_order.h
-  __availability
   __bit/bit_cast.h
   __bit/bit_ceil.h
   __bit/bit_floor.h
   __bit/bit_log2.h
   __bit/bit_width.h
   __bit/blsr.h
   __bit/byteswap.h
   __bit/countl.h
set(files
   __concepts/regular.h
   __concepts/relation.h
   __concepts/same_as.h
   __concepts/semiregular.h
   __concepts/swappable.h
   __concepts/totally_ordered.h
   __condition_variable/condition_variable.h
   __config
+  __config_dir/availability.h
+  __config_dir/base.h
+  __config_dir/debug.h
   __coroutine/coroutine_handle.h
   __coroutine/coroutine_traits.h
   __coroutine/noop_coroutine_handle.h
   __coroutine/trivial_awaitables.h
-  __debug
   __debug_utils/randomize_range.h
   __debug_utils/strict_weak_ordering_check.h
   __exception/exception.h
   __exception/exception_ptr.h
   __exception/nested_exception.h
   __exception/operations.h
   __exception/terminate.h
   __expected/bad_expected_access.h

libcxx/include/__algorithm/comp_ref_type.h

 //===----------------------------------------------------------------------===//
 //
 // 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___ALGORITHM_COMP_REF_TYPE_H
 #define _LIBCPP___ALGORITHM_COMP_REF_TYPE_H
 
 #include <__config>
-#include <__debug>
+#include <__config_dir/debug.h>
 #include <__utility/declval.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 

libcxx/include/__algorithm/nth_element.h

 //===----------------------------------------------------------------------===//
 //
 // 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___ALGORITHM_NTH_ELEMENT_H
 #define _LIBCPP___ALGORITHM_NTH_ELEMENT_H
 
 #include <__algorithm/comp.h>
 #include <__algorithm/comp_ref_type.h>
 #include <__algorithm/iterator_operations.h>
 #include <__algorithm/sort.h>
 #include <__config>
-#include <__debug>
+#include <__config_dir/debug.h>
 #include <__debug_utils/randomize_range.h>
 #include <__iterator/iterator_traits.h>
 #include <__utility/move.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 

libcxx/include/__algorithm/partial_sort.h

 
 #include <__algorithm/comp.h>
 #include <__algorithm/comp_ref_type.h>
 #include <__algorithm/iterator_operations.h>
 #include <__algorithm/make_heap.h>
 #include <__algorithm/sift_down.h>
 #include <__algorithm/sort_heap.h>
 #include <__config>
-#include <__debug>
+#include <__config_dir/debug.h>
 #include <__debug_utils/randomize_range.h>
 #include <__iterator/iterator_traits.h>
 #include <__type_traits/is_copy_assignable.h>
 #include <__type_traits/is_copy_constructible.h>
 #include <__utility/move.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header

libcxx/include/__algorithm/shuffle.h

 //===----------------------------------------------------------------------===//
 //
 // 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___ALGORITHM_SHUFFLE_H
 #define _LIBCPP___ALGORITHM_SHUFFLE_H
 
 #include <__algorithm/iterator_operations.h>
 #include <__config>
-#include <__debug>
+#include <__config_dir/debug.h>
 #include <__iterator/iterator_traits.h>
 #include <__random/uniform_int_distribution.h>
 #include <__utility/forward.h>
 #include <__utility/move.h>
 #include <__utility/swap.h>
 #include <cstddef>
 #include <cstdint>
 

libcxx/include/__algorithm/sort.h

 #include <__algorithm/min_element.h>
 #include <__algorithm/partial_sort.h>
 #include <__algorithm/unwrap_iter.h>
 #include <__assert>
 #include <__bit/blsr.h>
 #include <__bit/countl.h>
 #include <__bit/countr.h>
 #include <__config>
-#include <__debug>
+#include <__config_dir/debug.h>
 #include <__debug_utils/randomize_range.h>
 #include <__debug_utils/strict_weak_ordering_check.h>
 #include <__functional/operations.h>
 #include <__functional/ranges_operations.h>
 #include <__iterator/iterator_traits.h>
 #include <__type_traits/conditional.h>
 #include <__type_traits/disjunction.h>
 #include <__type_traits/is_arithmetic.h>

libcxx/include/__algorithm/three_way_comp_ref_type.h

 //===----------------------------------------------------------------------===//
 //
 // 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___ALGORITHM_THREE_WAY_COMP_REF_TYPE_H
 #define _LIBCPP___ALGORITHM_THREE_WAY_COMP_REF_TYPE_H
 
 #include <__compare/ordering.h>
 #include <__config>
-#include <__debug>
+#include <__config_dir/debug.h>
 #include <__utility/declval.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 

libcxx/include/__assert

 // -*- 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___ASSERT
 #define _LIBCPP___ASSERT
 
-#include <__config>
+#include <__config_dir/base.h>
 #include <__verbose_abort>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 // Automatically enable assertions when the debug mode is enabled.
 #if defined(_LIBCPP_ENABLE_DEBUG_MODE)

libcxx/include/__atomic/atomic_base.h

 //===----------------------------------------------------------------------===//
 //
 // 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___ATOMIC_ATOMIC_BASE_H
 #define _LIBCPP___ATOMIC_ATOMIC_BASE_H
 
 #include <__atomic/atomic_sync.h>
 #include <__atomic/check_memory_order.h>
 #include <__atomic/cxx_atomic_impl.h>
 #include <__atomic/is_always_lock_free.h>
 #include <__atomic/memory_order.h>
-#include <__availability>
 #include <__config>
 #include <__memory/addressof.h>
 #include <__type_traits/is_integral.h>
 #include <__type_traits/is_nothrow_default_constructible.h>
 #include <__type_traits/is_same.h>
 #include <version>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)

libcxx/include/__atomic/atomic_sync.h

 //===----------------------------------------------------------------------===//
 //
 // 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___ATOMIC_ATOMIC_SYNC_H
 #define _LIBCPP___ATOMIC_ATOMIC_SYNC_H
 
 #include <__atomic/contention_t.h>
 #include <__atomic/cxx_atomic_impl.h>
 #include <__atomic/memory_order.h>
-#include <__availability>
 #include <__chrono/duration.h>
 #include <__config>
 #include <__memory/addressof.h>
 #include <__thread/poll_with_backoff.h>
 #include <__threading_support>
 #include <__type_traits/decay.h>
 #include <cstring>
 

libcxx/include/__charconv/to_chars_floating_point.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___CHARCONV_TO_CHARS_FLOATING_POINT_H
 #define _LIBCPP___CHARCONV_TO_CHARS_FLOATING_POINT_H
 
-#include <__availability>
 #include <__charconv/chars_format.h>
 #include <__charconv/to_chars_result.h>
 #include <__config>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 

libcxx/include/__chrono/file_clock.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_FILE_CLOCK_H
 #define _LIBCPP___CHRONO_FILE_CLOCK_H
 
-#include <__availability>
 #include <__chrono/duration.h>
 #include <__chrono/system_clock.h>
 #include <__chrono/time_point.h>
 #include <__config>
 #include <ratio>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header

libcxx/include/__config

 // -*- 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___CONFIG
 #define _LIBCPP___CONFIG
 
-#include <__config_site>
-
-#if defined(_MSC_VER) && !defined(__clang__)
-#  if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#    define _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
-#  endif
-#endif
-
-#ifndef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
-#  pragma GCC system_header
-#endif
-
-#if defined(__apple_build_version__)
-// Given AppleClang XX.Y.Z, _LIBCPP_APPLE_CLANG_VER is XXYZ (e.g. AppleClang 14.0.3 => 1403)
-#  define _LIBCPP_COMPILER_CLANG_BASED
-#  define _LIBCPP_APPLE_CLANG_VER (__apple_build_version__ / 10000)
-#elif defined(__clang__)
-#  define _LIBCPP_COMPILER_CLANG_BASED
-#  define _LIBCPP_CLANG_VER (__clang_major__ * 100 + __clang_minor__)
-#elif defined(__GNUC__)
-#  define _LIBCPP_COMPILER_GCC
-#endif
-
-#ifdef __cplusplus
-
-// _LIBCPP_VERSION represents the version of libc++, which matches the version of LLVM.
-// Given a LLVM release LLVM XX.YY.ZZ (e.g. LLVM 17.0.1 == 17.00.01), _LIBCPP_VERSION is
-// defined to XXYYZZ.
-#  define _LIBCPP_VERSION 170000
-
-#  define _LIBCPP_CONCAT_IMPL(_X, _Y) _X##_Y
-#  define _LIBCPP_CONCAT(_X, _Y) _LIBCPP_CONCAT_IMPL(_X, _Y)
-
-// Valid C++ identifier that revs with every libc++ version. This can be used to
-// generate identifiers that must be unique for every released libc++ version.
-#  define _LIBCPP_VERSIONED_IDENTIFIER _LIBCPP_CONCAT(v, _LIBCPP_VERSION)
-
-#  if __STDC_HOSTED__ == 0
-#    define _LIBCPP_FREESTANDING
-#  endif
-
-// NOLINTBEGIN(libcpp-cpp-version-check)
-#  ifndef _LIBCPP_STD_VER
-#    if __cplusplus <= 201103L
-#      define _LIBCPP_STD_VER 11
-#    elif __cplusplus <= 201402L
-#      define _LIBCPP_STD_VER 14
-#    elif __cplusplus <= 201703L
-#      define _LIBCPP_STD_VER 17
-#    elif __cplusplus <= 202002L
-#      define _LIBCPP_STD_VER 20
-#    elif __cplusplus <= 202302L
-#      define _LIBCPP_STD_VER 23
-#    else
-// Expected release year of the next C++ standard
-#      define _LIBCPP_STD_VER 26
-#    endif
-#  endif // _LIBCPP_STD_VER
-// NOLINTEND(libcpp-cpp-version-check)
-
-#  if defined(__ELF__)
-#    define _LIBCPP_OBJECT_FORMAT_ELF 1
-#  elif defined(__MACH__)
-#    define _LIBCPP_OBJECT_FORMAT_MACHO 1
-#  elif defined(_WIN32)
-#    define _LIBCPP_OBJECT_FORMAT_COFF 1
-#  elif defined(__wasm__)
-#    define _LIBCPP_OBJECT_FORMAT_WASM 1
-#  elif defined(_AIX)
-#    define _LIBCPP_OBJECT_FORMAT_XCOFF 1
-#  else
-// ... add new file formats here ...
-#  endif
-
-#  if _LIBCPP_ABI_VERSION >= 2
-// Change short string representation so that string data starts at offset 0,
-// improving its alignment in some cases.
-#    define _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
-// Fix deque iterator type in order to support incomplete types.
-#    define _LIBCPP_ABI_INCOMPLETE_TYPES_IN_DEQUE
-// Fix undefined behavior in how std::list stores its linked nodes.
-#    define _LIBCPP_ABI_LIST_REMOVE_NODE_POINTER_UB
-// Fix undefined behavior in  how __tree stores its end and parent nodes.
-#    define _LIBCPP_ABI_TREE_REMOVE_NODE_POINTER_UB
-// Fix undefined behavior in how __hash_table stores its pointer types.
-#    define _LIBCPP_ABI_FIX_UNORDERED_NODE_POINTER_UB
-#    define _LIBCPP_ABI_FORWARD_LIST_REMOVE_NODE_POINTER_UB
-#    define _LIBCPP_ABI_FIX_UNORDERED_CONTAINER_SIZE_TYPE
-// Define a key function for `bad_function_call` in the library, to centralize
-// its vtable and typeinfo to libc++ rather than having all other libraries
-// using that class define their own copies.
-#    define _LIBCPP_ABI_BAD_FUNCTION_CALL_KEY_FUNCTION
-// Override the default return value of exception::what() for
-// bad_function_call::what() with a string that is specific to
-// bad_function_call (see http://wg21.link/LWG2233). This is an ABI break
-// because it changes the vtable layout of bad_function_call.
-#    define _LIBCPP_ABI_BAD_FUNCTION_CALL_GOOD_WHAT_MESSAGE
-// Enable optimized version of __do_get_(un)signed which avoids redundant copies.
-#    define _LIBCPP_ABI_OPTIMIZED_LOCALE_NUM_GET
-// Give reverse_iterator<T> one data member of type T, not two.
-// Also, in C++17 and later, don't derive iterator types from std::iterator.
-#    define _LIBCPP_ABI_NO_ITERATOR_BASES
-// Use the smallest possible integer type to represent the index of the variant.
-// Previously libc++ used "unsigned int" exclusively.
-#    define _LIBCPP_ABI_VARIANT_INDEX_TYPE_OPTIMIZATION
-// Unstable attempt to provide a more optimized std::function
-#    define _LIBCPP_ABI_OPTIMIZED_FUNCTION
-// All the regex constants must be distinct and nonzero.
-#    define _LIBCPP_ABI_REGEX_CONSTANTS_NONZERO
-// Re-worked external template instantiations for std::string with a focus on
-// performance and fast-path inlining.
-#    define _LIBCPP_ABI_STRING_OPTIMIZED_EXTERNAL_INSTANTIATION
-// Enable clang::trivial_abi on std::unique_ptr.
-#    define _LIBCPP_ABI_ENABLE_UNIQUE_PTR_TRIVIAL_ABI
-// Enable clang::trivial_abi on std::shared_ptr and std::weak_ptr
-#    define _LIBCPP_ABI_ENABLE_SHARED_PTR_TRIVIAL_ABI
-// std::random_device holds some state when it uses an implementation that gets
-// entropy from a file (see _LIBCPP_USING_DEV_RANDOM). When switching from this
-// implementation to another one on a platform that has already shipped
-// std::random_device, one needs to retain the same object layout to remain ABI
-// compatible. This switch removes these workarounds for platforms that don't care
-// about ABI compatibility.
-#    define _LIBCPP_ABI_NO_RANDOM_DEVICE_COMPATIBILITY_LAYOUT
-// Don't export the legacy __basic_string_common class and its methods from the built library.
-#    define _LIBCPP_ABI_DO_NOT_EXPORT_BASIC_STRING_COMMON
-// Don't export the legacy __vector_base_common class and its methods from the built library.
-#    define _LIBCPP_ABI_DO_NOT_EXPORT_VECTOR_BASE_COMMON
-// According to the Standard, `bitset::operator[] const` returns bool
-#    define _LIBCPP_ABI_BITSET_VECTOR_BOOL_CONST_SUBSCRIPT_RETURN_BOOL
-// Fix the implementation of CityHash used for std::hash<fundamental-type>.
-// This is an ABI break because `std::hash` will return a different result,
-// which means that hashing the same object in translation units built against
-// different versions of libc++ can return inconsistent results. This is especially
-// tricky since std::hash is used in the implementation of unordered containers.
-//
-// The incorrect implementation of CityHash has the problem that it drops some
-// bits on the floor.
-#    define _LIBCPP_ABI_FIX_CITYHASH_IMPLEMENTATION
-// Remove the base 10 implementation of std::to_chars from the dylib.
-// The implementation moved to the header, but we still export the symbols from
-// the dylib for backwards compatibility.
-#    define _LIBCPP_ABI_DO_NOT_EXPORT_TO_CHARS_BASE_10
-#  elif _LIBCPP_ABI_VERSION == 1
-#    if !(defined(_LIBCPP_OBJECT_FORMAT_COFF) || defined(_LIBCPP_OBJECT_FORMAT_XCOFF))
-// Enable compiling copies of now inline methods into the dylib to support
-// applications compiled against older libraries. This is unnecessary with
-// COFF dllexport semantics, since dllexport forces a non-inline definition
-// of inline functions to be emitted anyway. Our own non-inline copy would
-// conflict with the dllexport-emitted copy, so we disable it. For XCOFF,
-// the linker will take issue with the symbols in the shared object if the
-// weak inline methods get visibility (such as from -fvisibility-inlines-hidden),
-// so disable it.
-#      define _LIBCPP_DEPRECATED_ABI_LEGACY_LIBRARY_DEFINITIONS_FOR_INLINE_FUNCTIONS
-#    endif
-// Feature macros for disabling pre ABI v1 features. All of these options
-// are deprecated.
-#    if defined(__FreeBSD__)
-#      define _LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR
-#    endif
-// For XCOFF linkers, we have problems if we see a weak hidden version of a symbol
-// in user code (like you get with -fvisibility-inlines-hidden) and then a strong def
-// in the library, so we need to always rely on the library version.
-#    if defined(_AIX)
-#      define _LIBCPP_ABI_BAD_FUNCTION_CALL_KEY_FUNCTION
-#    endif
-#  endif
-
-#  if defined(_LIBCPP_BUILDING_LIBRARY) || _LIBCPP_ABI_VERSION >= 2
-// Enable additional explicit instantiations of iostreams components. This
-// reduces the number of weak definitions generated in programs that use
-// iostreams by providing a single strong definition in the shared library.
-#    define _LIBCPP_ABI_ENABLE_ADDITIONAL_IOSTREAM_EXPLICIT_INSTANTIATIONS_1
-
-// Define a key function for `bad_function_call` in the library, to centralize
-// its vtable and typeinfo to libc++ rather than having all other libraries
-// using that class define their own copies.
-#    define _LIBCPP_ABI_BAD_FUNCTION_CALL_KEY_FUNCTION
-#  endif
-
-#  define _LIBCPP_TOSTRING2(x) #x
-#  define _LIBCPP_TOSTRING(x) _LIBCPP_TOSTRING2(x)
-
-// NOLINTNEXTLINE(libcpp-cpp-version-check)
-#  if __cplusplus < 201103L
-#    define _LIBCPP_CXX03_LANG
-#  endif
-
-#  ifndef __has_attribute
-#    define __has_attribute(__x) 0
-#  endif
-
-#  ifndef __has_builtin
-#    define __has_builtin(__x) 0
-#  endif
-
-#  ifndef __has_extension
-#    define __has_extension(__x) 0
-#  endif
-
-#  ifndef __has_feature
-#    define __has_feature(__x) 0
-#  endif
-
-#  ifndef __has_cpp_attribute
-#    define __has_cpp_attribute(__x) 0
-#  endif
-
-#  ifndef __has_constexpr_builtin
-#    define __has_constexpr_builtin(x) 0
-#  endif
-
-// '__is_identifier' returns '0' if '__x' is a reserved identifier provided by
-// the compiler and '1' otherwise.
-#  ifndef __is_identifier
-#    define __is_identifier(__x) 1
-#  endif
-
-#  ifndef __has_declspec_attribute
-#    define __has_declspec_attribute(__x) 0
-#  endif
-
-#  define __has_keyword(__x) !(__is_identifier(__x))
-
-#  ifndef __has_include
-#    define __has_include(...) 0
-#  endif
-
-#  if !defined(_LIBCPP_COMPILER_CLANG_BASED) && __cplusplus < 201103L
-#    error "libc++ only supports C++03 with Clang-based compilers. Please enable C++11"
-#  endif
-
-// FIXME: ABI detection should be done via compiler builtin macros. This
-// is just a placeholder until Clang implements such macros. For now assume
-// that Windows compilers pretending to be MSVC++ target the Microsoft ABI,
-// and allow the user to explicitly specify the ABI to handle cases where this
-// heuristic falls short.
-#  if defined(_LIBCPP_ABI_FORCE_ITANIUM) && defined(_LIBCPP_ABI_FORCE_MICROSOFT)
-#    error "Only one of _LIBCPP_ABI_FORCE_ITANIUM and _LIBCPP_ABI_FORCE_MICROSOFT can be defined"
-#  elif defined(_LIBCPP_ABI_FORCE_ITANIUM)
-#    define _LIBCPP_ABI_ITANIUM
-#  elif defined(_LIBCPP_ABI_FORCE_MICROSOFT)
-#    define _LIBCPP_ABI_MICROSOFT
-#  else
-#    if defined(_WIN32) && defined(_MSC_VER)
-#      define _LIBCPP_ABI_MICROSOFT
-#    else
-#      define _LIBCPP_ABI_ITANIUM
-#    endif
-#  endif
-
-#  if defined(_LIBCPP_ABI_MICROSOFT) && !defined(_LIBCPP_NO_VCRUNTIME)
-#    define _LIBCPP_ABI_VCRUNTIME
-#  endif
-
-#  if __has_feature(experimental_library)
-#    ifndef _LIBCPP_ENABLE_EXPERIMENTAL
-#      define _LIBCPP_ENABLE_EXPERIMENTAL
-#    endif
-#  endif
-
-// Incomplete features get their own specific disabling flags. This makes it
-// easier to grep for target specific flags once the feature is complete.
-#  if !defined(_LIBCPP_ENABLE_EXPERIMENTAL) && !defined(_LIBCPP_BUILDING_LIBRARY)
-#    define _LIBCPP_HAS_NO_INCOMPLETE_PSTL
-#  endif
-
-// Need to detect which libc we're using if we're on Linux.
-#  if defined(__linux__)
-#    include <features.h>
-#    if defined(__GLIBC_PREREQ)
-#      define _LIBCPP_GLIBC_PREREQ(a, b) __GLIBC_PREREQ(a, b)
-#    else
-#      define _LIBCPP_GLIBC_PREREQ(a, b) 0
-#    endif // defined(__GLIBC_PREREQ)
-#  endif   // defined(__linux__)
-
-#  if defined(__MVS__)
-#    include <features.h> // for __NATIVE_ASCII_F
-#  endif
-
-#  ifdef __LITTLE_ENDIAN__
-#    if __LITTLE_ENDIAN__
-#      define _LIBCPP_LITTLE_ENDIAN
-#    endif // __LITTLE_ENDIAN__
-#  endif   // __LITTLE_ENDIAN__
-
-#  ifdef __BIG_ENDIAN__
-#    if __BIG_ENDIAN__
-#      define _LIBCPP_BIG_ENDIAN
-#    endif // __BIG_ENDIAN__
-#  endif   // __BIG_ENDIAN__
-
-#  ifdef __BYTE_ORDER__
-#    if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
-#      define _LIBCPP_LITTLE_ENDIAN
-#    elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
-#      define _LIBCPP_BIG_ENDIAN
-#    endif // __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
-#  endif   // __BYTE_ORDER__
-
-#  ifdef __FreeBSD__
-#    include <sys/endian.h>
-#    include <osreldate.h>
-#    if _BYTE_ORDER == _LITTLE_ENDIAN
-#      define _LIBCPP_LITTLE_ENDIAN
-#    else // _BYTE_ORDER == _LITTLE_ENDIAN
-#      define _LIBCPP_BIG_ENDIAN
-#    endif // _BYTE_ORDER == _LITTLE_ENDIAN
-#  endif   // __FreeBSD__
-
-#  if defined(__NetBSD__) || defined(__OpenBSD__)
-#    include <sys/endian.h>
-#    if _BYTE_ORDER == _LITTLE_ENDIAN
-#      define _LIBCPP_LITTLE_ENDIAN
-#    else // _BYTE_ORDER == _LITTLE_ENDIAN
-#      define _LIBCPP_BIG_ENDIAN
-#    endif // _BYTE_ORDER == _LITTLE_ENDIAN
-#  endif   // defined(__NetBSD__) || defined(__OpenBSD__)
-
-#  if defined(_WIN32)
-#    define _LIBCPP_WIN32API
-#    define _LIBCPP_LITTLE_ENDIAN
-#    define _LIBCPP_SHORT_WCHAR 1
-// Both MinGW and native MSVC provide a "MSVC"-like environment
-#    define _LIBCPP_MSVCRT_LIKE
-// If mingw not explicitly detected, assume using MS C runtime only if
-// a MS compatibility version is specified.
-#    if defined(_MSC_VER) && !defined(__MINGW32__)
-#      define _LIBCPP_MSVCRT // Using Microsoft's C Runtime library
-#    endif
-#    if (defined(_M_AMD64) || defined(__x86_64__)) || (defined(_M_ARM) || defined(__arm__))
-#      define _LIBCPP_HAS_BITSCAN64
-#    endif
-#    define _LIBCPP_HAS_OPEN_WITH_WCHAR
-#  endif // defined(_WIN32)
-
-#  if defined(_AIX) && !defined(__64BIT__)
-// The size of wchar is 2 byte on 32-bit mode on AIX.
-#    define _LIBCPP_SHORT_WCHAR 1
-#  endif
-
-// Libc++ supports various implementations of std::random_device.
-//
-// _LIBCPP_USING_DEV_RANDOM
-//      Read entropy from the given file, by default `/dev/urandom`.
-//      If a token is provided, it is assumed to be the path to a file
-//      to read entropy from. This is the default behavior if nothing
-//      else is specified. This implementation requires storing state
-//      inside `std::random_device`.
-//
-// _LIBCPP_USING_ARC4_RANDOM
-//      Use arc4random(). This allows obtaining random data even when
-//      using sandboxing mechanisms. On some platforms like Apple, this
-//      is the recommended source of entropy for user-space programs.
-//      When this option is used, the token passed to `std::random_device`'s
-//      constructor *must* be "/dev/urandom" -- anything else is an error.
-//
-// _LIBCPP_USING_GETENTROPY
-//      Use getentropy().
-//      When this option is used, the token passed to `std::random_device`'s
-//      constructor *must* be "/dev/urandom" -- anything else is an error.
-//
-// _LIBCPP_USING_FUCHSIA_CPRNG
-//      Use Fuchsia's zx_cprng_draw() system call, which is specified to
-//      deliver high-quality entropy and cannot fail.
-//      When this option is used, the token passed to `std::random_device`'s
-//      constructor *must* be "/dev/urandom" -- anything else is an error.
-//
-// _LIBCPP_USING_NACL_RANDOM
-//      NaCl's sandbox (which PNaCl also runs in) doesn't allow filesystem access,
-//      including accesses to the special files under `/dev`. This implementation
-//      uses the NaCL syscall `nacl_secure_random_init()` to get entropy.
-//      When this option is used, the token passed to `std::random_device`'s
-//      constructor *must* be "/dev/urandom" -- anything else is an error.
-//
-// _LIBCPP_USING_WIN32_RANDOM
-//      Use rand_s(), for use on Windows.
-//      When this option is used, the token passed to `std::random_device`'s
-//      constructor *must* be "/dev/urandom" -- anything else is an error.
-#  if defined(__APPLE__) || defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__) ||                     \
-      defined(__DragonFly__)
-#    define _LIBCPP_USING_ARC4_RANDOM
-#  elif defined(__wasi__) || defined(__EMSCRIPTEN__)
-#    define _LIBCPP_USING_GETENTROPY
-#  elif defined(__Fuchsia__)
-#    define _LIBCPP_USING_FUCHSIA_CPRNG
-#  elif defined(__native_client__)
-#    define _LIBCPP_USING_NACL_RANDOM
-#  elif defined(_LIBCPP_WIN32API)
-#    define _LIBCPP_USING_WIN32_RANDOM
-#  else
-#    define _LIBCPP_USING_DEV_RANDOM
-#  endif
-
-#  if !defined(_LIBCPP_LITTLE_ENDIAN) && !defined(_LIBCPP_BIG_ENDIAN)
-#    include <endian.h>
-#    if __BYTE_ORDER == __LITTLE_ENDIAN
-#      define _LIBCPP_LITTLE_ENDIAN
-#    elif __BYTE_ORDER == __BIG_ENDIAN
-#      define _LIBCPP_BIG_ENDIAN
-#    else // __BYTE_ORDER == __BIG_ENDIAN
-#      error unable to determine endian
-#    endif
-#  endif // !defined(_LIBCPP_LITTLE_ENDIAN) && !defined(_LIBCPP_BIG_ENDIAN)
-
-#  if __has_attribute(__no_sanitize__) && !defined(_LIBCPP_COMPILER_GCC)
-#    define _LIBCPP_NO_CFI __attribute__((__no_sanitize__("cfi")))
-#  else
-#    define _LIBCPP_NO_CFI
-#  endif
-
-#  ifndef _LIBCPP_CXX03_LANG
-
-#    define _LIBCPP_ALIGNOF(_Tp) alignof(_Tp)
-#    define _ALIGNAS_TYPE(x) alignas(x)
-#    define _ALIGNAS(x) alignas(x)
-#    define _LIBCPP_NORETURN [[noreturn]]
-#    define _NOEXCEPT noexcept
-#    define _NOEXCEPT_(x) noexcept(x)
-#    define _LIBCPP_CONSTEXPR constexpr
-
-#  else
-
-#    define _LIBCPP_ALIGNOF(_Tp) _Alignof(_Tp)
-#    define _ALIGNAS_TYPE(x) __attribute__((__aligned__(_LIBCPP_ALIGNOF(x))))
-#    define _ALIGNAS(x) __attribute__((__aligned__(x)))
-#    define _LIBCPP_NORETURN __attribute__((__noreturn__))
-#    define _LIBCPP_HAS_NO_NOEXCEPT
-#    define nullptr __nullptr
-#    define _NOEXCEPT throw()
-#    define _NOEXCEPT_(x)
-#    define static_assert(...) _Static_assert(__VA_ARGS__)
-#    define decltype(...) __decltype(__VA_ARGS__)
-#    define _LIBCPP_CONSTEXPR
-
-typedef __char16_t char16_t;
-typedef __char32_t char32_t;
-
-#  endif
-
-#  if !defined(__cpp_exceptions) || __cpp_exceptions < 199711L
-#    define _LIBCPP_HAS_NO_EXCEPTIONS
-#  endif
-
-#  define _LIBCPP_PREFERRED_ALIGNOF(_Tp) __alignof(_Tp)
-
-#  if defined(_LIBCPP_COMPILER_CLANG_BASED)
-
-#    if defined(__APPLE__) && !defined(__i386__) && !defined(__x86_64__) && (!defined(__arm__) || __ARM_ARCH_7K__ >= 2)
-#      define _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
-#    endif
-
-// Objective-C++ features (opt-in)
-#    if __has_feature(objc_arc)
-#      define _LIBCPP_HAS_OBJC_ARC
-#    endif
-
-#    if __has_feature(objc_arc_weak)
-#      define _LIBCPP_HAS_OBJC_ARC_WEAK
-#    endif
-
-#    if __has_extension(blocks)
-#      define _LIBCPP_HAS_EXTENSION_BLOCKS
-#    endif
-
-#    if defined(_LIBCPP_HAS_EXTENSION_BLOCKS) && defined(__APPLE__)
-#      define _LIBCPP_HAS_BLOCKS_RUNTIME
-#    endif
-
-#    if !__has_feature(address_sanitizer)
-#      define _LIBCPP_HAS_NO_ASAN
-#    endif
-
-// Allow for build-time disabling of unsigned integer sanitization
-#    if __has_attribute(no_sanitize)
-#      define _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK __attribute__((__no_sanitize__("unsigned-integer-overflow")))
-#    endif
-
-#    define _LIBCPP_ALWAYS_INLINE __attribute__((__always_inline__))
-
-#    define _LIBCPP_DISABLE_EXTENSION_WARNING __extension__
-
-#  elif defined(_LIBCPP_COMPILER_GCC)
-
-#    if !defined(__SANITIZE_ADDRESS__)
-#      define _LIBCPP_HAS_NO_ASAN
-#    endif
-
-#    define _LIBCPP_ALWAYS_INLINE __attribute__((__always_inline__))
-
-#    define _LIBCPP_DISABLE_EXTENSION_WARNING __extension__
-
-#  endif // _LIBCPP_COMPILER_[CLANG|GCC]
-
-#  if defined(_LIBCPP_OBJECT_FORMAT_COFF)
-
-#    ifdef _DLL
-#      define _LIBCPP_CRT_FUNC __declspec(dllimport)
-#    else
-#      define _LIBCPP_CRT_FUNC
-#    endif
-
-#    if defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS) || (defined(__MINGW32__) && !defined(_LIBCPP_BUILDING_LIBRARY))
-#      define _LIBCPP_DLL_VIS
-#      define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS
-#      define _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS
-#      define _LIBCPP_OVERRIDABLE_FUNC_VIS
-#      define _LIBCPP_EXPORTED_FROM_ABI
-#    elif defined(_LIBCPP_BUILDING_LIBRARY)
-#      define _LIBCPP_DLL_VIS __declspec(dllexport)
-#      if defined(__MINGW32__)
-#        define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS _LIBCPP_DLL_VIS
-#        define _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS
-#      else
-#        define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS
-#        define _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS _LIBCPP_DLL_VIS
-#      endif
-#      define _LIBCPP_OVERRIDABLE_FUNC_VIS _LIBCPP_DLL_VIS
-#      define _LIBCPP_EXPORTED_FROM_ABI __declspec(dllexport)
-#    else
-#      define _LIBCPP_DLL_VIS __declspec(dllimport)
-#      define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS _LIBCPP_DLL_VIS
-#      define _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS
-#      define _LIBCPP_OVERRIDABLE_FUNC_VIS
-#      define _LIBCPP_EXPORTED_FROM_ABI __declspec(dllimport)
-#    endif
-
-#    define _LIBCPP_TYPE_VIS _LIBCPP_DLL_VIS
-#    define _LIBCPP_FUNC_VIS _LIBCPP_DLL_VIS
-#    define _LIBCPP_EXCEPTION_ABI _LIBCPP_DLL_VIS
-#    define _LIBCPP_HIDDEN
-#    define _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
-#    define _LIBCPP_TEMPLATE_VIS
-#    define _LIBCPP_TEMPLATE_DATA_VIS
-#    define _LIBCPP_ENUM_VIS
-
-#  else
-
-#    if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
-#      define _LIBCPP_VISIBILITY(vis) __attribute__((__visibility__(vis)))
-#    else
-#      define _LIBCPP_VISIBILITY(vis)
-#    endif
-
-#    define _LIBCPP_HIDDEN _LIBCPP_VISIBILITY("hidden")
-#    define _LIBCPP_FUNC_VIS _LIBCPP_VISIBILITY("default")
-#    define _LIBCPP_TYPE_VIS _LIBCPP_VISIBILITY("default")
-#    define _LIBCPP_TEMPLATE_DATA_VIS _LIBCPP_VISIBILITY("default")
-#    define _LIBCPP_EXPORTED_FROM_ABI _LIBCPP_VISIBILITY("default")
-#    define _LIBCPP_EXCEPTION_ABI _LIBCPP_VISIBILITY("default")
-#    define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS _LIBCPP_VISIBILITY("default")
-#    define _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS
-
-// TODO: Make this a proper customization point or remove the option to override it.
-#    ifndef _LIBCPP_OVERRIDABLE_FUNC_VIS
-#      define _LIBCPP_OVERRIDABLE_FUNC_VIS _LIBCPP_VISIBILITY("default")
-#    endif
-
-#    if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
-// The inline should be removed once PR32114 is resolved
-#      define _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS inline _LIBCPP_HIDDEN
-#    else
-#      define _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
-#    endif
-
-#    if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
-#      if __has_attribute(__type_visibility__)
-#        define _LIBCPP_TEMPLATE_VIS __attribute__((__type_visibility__("default")))
-#      else
-#        define _LIBCPP_TEMPLATE_VIS __attribute__((__visibility__("default")))
-#      endif
-#    else
-#      define _LIBCPP_TEMPLATE_VIS
-#    endif
-
-#    if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS) && __has_attribute(__type_visibility__)
-#      define _LIBCPP_ENUM_VIS __attribute__((__type_visibility__("default")))
-#    else
-#      define _LIBCPP_ENUM_VIS
-#    endif
-
-#  endif // defined(_LIBCPP_OBJECT_FORMAT_COFF)
-
-#  if __has_attribute(exclude_from_explicit_instantiation)
-#    define _LIBCPP_EXCLUDE_FROM_EXPLICIT_INSTANTIATION __attribute__((__exclude_from_explicit_instantiation__))
-#  else
-// Try to approximate the effect of exclude_from_explicit_instantiation
-// (which is that entities are not assumed to be provided by explicit
-// template instantiations in the dylib) by always inlining those entities.
-#    define _LIBCPP_EXCLUDE_FROM_EXPLICIT_INSTANTIATION _LIBCPP_ALWAYS_INLINE
-#  endif
-
-// This macro marks a symbol as being hidden from libc++'s ABI. This is achieved
-// on two levels:
-// 1. The symbol is given hidden visibility, which ensures that users won't start exporting
-//    symbols from their dynamic library by means of using the libc++ headers. This ensures
-//    that those symbols stay private to the dynamic library in which it is defined.
-//
-// 2. The symbol is given an ABI tag that changes with each version of libc++. This ensures
-//    that no ODR violation can arise from mixing two TUs compiled with different versions
-//    of libc++ where we would have changed the definition of a symbol. If the symbols shared
-//    the same name, the ODR would require that their definitions be token-by-token equivalent,
-//    which basically prevents us from being able to make any change to any function in our
-//    headers. Using this ABI tag ensures that the symbol name is "bumped" artificially at
-//    each release, which lets us change the definition of these symbols at our leisure.
-//    Note that historically, this has been achieved in various ways, including force-inlining
-//    all functions or giving internal linkage to all functions. Both these (previous) solutions
-//    suffer from drawbacks that lead notably to code bloat.
-//
-// Note that we use _LIBCPP_EXCLUDE_FROM_EXPLICIT_INSTANTIATION to ensure that we don't depend
-// on _LIBCPP_HIDE_FROM_ABI methods of classes explicitly instantiated in the dynamic library.
-//
-// Also note that the _LIBCPP_HIDE_FROM_ABI_VIRTUAL macro should be used on virtual functions
-// instead of _LIBCPP_HIDE_FROM_ABI. That macro does not use an ABI tag. Indeed, the mangled
-// name of a virtual function is part of its ABI, since some architectures like arm64e can sign
-// the virtual function pointer in the vtable based on the mangled name of the function. Since
-// we use an ABI tag that changes with each released version, the mangled name of the virtual
-// function would change, which is incorrect. Note that it doesn't make much sense to change
-// the implementation of a virtual function in an ABI-incompatible way in the first place,
-// since that would be an ABI break anyway. Hence, the lack of ABI tag should not be noticeable.
-//
-// TODO: We provide a escape hatch with _LIBCPP_NO_ABI_TAG for folks who want to avoid increasing
-//       the length of symbols with an ABI tag. In practice, we should remove the escape hatch and
-//       use compression mangling instead, see https://github.com/itanium-cxx-abi/cxx-abi/issues/70.
-#  ifndef _LIBCPP_NO_ABI_TAG
-#    define _LIBCPP_HIDE_FROM_ABI                                                                                      \
-      _LIBCPP_HIDDEN _LIBCPP_EXCLUDE_FROM_EXPLICIT_INSTANTIATION                                                       \
-          __attribute__((__abi_tag__(_LIBCPP_TOSTRING(_LIBCPP_VERSIONED_IDENTIFIER))))
-#  else
-#    define _LIBCPP_HIDE_FROM_ABI _LIBCPP_HIDDEN _LIBCPP_EXCLUDE_FROM_EXPLICIT_INSTANTIATION
-#  endif
-#  define _LIBCPP_HIDE_FROM_ABI_VIRTUAL _LIBCPP_HIDDEN _LIBCPP_EXCLUDE_FROM_EXPLICIT_INSTANTIATION
-
-// This macro provides a HIDE_FROM_ABI equivalent that can be applied to extern
-// "C" function, as those lack mangling.
-#  define _LIBCPP_HIDE_FROM_ABI_C _LIBCPP_HIDDEN _LIBCPP_EXCLUDE_FROM_EXPLICIT_INSTANTIATION
-
-#  ifdef _LIBCPP_BUILDING_LIBRARY
-#    if _LIBCPP_ABI_VERSION > 1
-#      define _LIBCPP_HIDE_FROM_ABI_AFTER_V1 _LIBCPP_HIDE_FROM_ABI
-#    else
-#      define _LIBCPP_HIDE_FROM_ABI_AFTER_V1
-#    endif
-#  else
-#    define _LIBCPP_HIDE_FROM_ABI_AFTER_V1 _LIBCPP_HIDE_FROM_ABI
-#  endif
-
-// Just so we can migrate to the new macros gradually.
-#  define _LIBCPP_INLINE_VISIBILITY _LIBCPP_HIDE_FROM_ABI
-
-// Inline namespaces are available in Clang/GCC/MSVC regardless of C++ dialect.
-// clang-format off
-#  define _LIBCPP_BEGIN_NAMESPACE_STD namespace std { inline namespace _LIBCPP_ABI_NAMESPACE {
-#  define _LIBCPP_END_NAMESPACE_STD }}
-#  define _VSTD std
-
-_LIBCPP_BEGIN_NAMESPACE_STD _LIBCPP_END_NAMESPACE_STD
-
-#  if _LIBCPP_STD_VER >= 17
-#    define _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM                                                                         \
-       _LIBCPP_BEGIN_NAMESPACE_STD inline namespace __fs { namespace filesystem {
-#  else
-#    define _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM                                                                         \
-      _LIBCPP_BEGIN_NAMESPACE_STD namespace __fs { namespace filesystem {
-#  endif
-
-#  define _LIBCPP_END_NAMESPACE_FILESYSTEM _LIBCPP_END_NAMESPACE_STD }}
-// clang-format on
-
-#  define _VSTD_FS std::__fs::filesystem
-
-#  if __has_attribute(__enable_if__)
-#    define _LIBCPP_PREFERRED_OVERLOAD __attribute__((__enable_if__(true, "")))
-#  endif
-
-#  ifndef __SIZEOF_INT128__
-#    define _LIBCPP_HAS_NO_INT128
-#  endif
-
-#  if __has_attribute(__malloc__)
-#    define _LIBCPP_NOALIAS __attribute__((__malloc__))
-#  else
-#    define _LIBCPP_NOALIAS
-#  endif
-
-#  if __has_attribute(__using_if_exists__)
-#    define _LIBCPP_USING_IF_EXISTS __attribute__((__using_if_exists__))
-#  else
-#    define _LIBCPP_USING_IF_EXISTS
-#  endif
-
-#  ifdef _LIBCPP_CXX03_LANG
-#    define _LIBCPP_DECLARE_STRONG_ENUM(x)                                                                             \
-      struct _LIBCPP_TYPE_VIS x {                                                                                      \
-        enum __lx
-// clang-format off
-#    define _LIBCPP_DECLARE_STRONG_ENUM_EPILOG(x)                                                                      \
-      __lx __v_;                                                                                                       \
-      _LIBCPP_INLINE_VISIBILITY x(__lx __v) : __v_(__v) {}                                                             \
-      _LIBCPP_INLINE_VISIBILITY explicit x(int __v) : __v_(static_cast<__lx>(__v)) {}                                  \
-      _LIBCPP_INLINE_VISIBILITY operator int() const { return __v_; }                                                  \
-      };
-// clang-format on
-
-#  else // _LIBCPP_CXX03_LANG
-#    define _LIBCPP_DECLARE_STRONG_ENUM(x) enum class _LIBCPP_ENUM_VIS x
-#    define _LIBCPP_DECLARE_STRONG_ENUM_EPILOG(x)
-#  endif // _LIBCPP_CXX03_LANG
-
-#  if defined(__APPLE__) || defined(__FreeBSD__) || defined(_LIBCPP_MSVCRT_LIKE) || defined(__NetBSD__)
-#    define _LIBCPP_LOCALE__L_EXTENSIONS 1
-#  endif
-
-#  ifdef __FreeBSD__
-#    define _DECLARE_C99_LDBL_MATH 1
-#  endif
-
-// If we are getting operator new from the MSVC CRT, then allocation overloads
-// for align_val_t were added in 19.12, aka VS 2017 version 15.3.
-#  if defined(_LIBCPP_MSVCRT) && defined(_MSC_VER) && _MSC_VER < 1912
-#    define _LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION
-#  elif defined(_LIBCPP_ABI_VCRUNTIME) && !defined(__cpp_aligned_new)
-// We're deferring to Microsoft's STL to provide aligned new et al. We don't
-// have it unless the language feature test macro is defined.
-#    define _LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION
-#  elif defined(__MVS__)
-#    define _LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION
-#  endif
-
-#  if defined(_LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION) || (!defined(__cpp_aligned_new) || __cpp_aligned_new < 201606)
-#    define _LIBCPP_HAS_NO_ALIGNED_ALLOCATION
-#  endif
-
-// It is not yet possible to use aligned_alloc() on all Apple platforms since
-// 10.15 was the first version to ship an implementation of aligned_alloc().
-#  if defined(__APPLE__)
-#    if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) &&                                                     \
-         __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 101500)
-#      define _LIBCPP_HAS_NO_C11_ALIGNED_ALLOC
-#    endif
-#  elif defined(__ANDROID__) && __ANDROID_API__ < 28
-// Android only provides aligned_alloc when targeting API 28 or higher.
-#    define _LIBCPP_HAS_NO_C11_ALIGNED_ALLOC
-#  endif
-
-#  if defined(__APPLE__) || defined(__FreeBSD__)
-#    define _LIBCPP_HAS_DEFAULTRUNELOCALE
-#  endif
-
-#  if defined(__APPLE__) || defined(__FreeBSD__)
-#    define _LIBCPP_WCTYPE_IS_MASK
-#  endif
-
-#  if _LIBCPP_STD_VER <= 17 || !defined(__cpp_char8_t)
-#    define _LIBCPP_HAS_NO_CHAR8_T
-#  endif
-
-// Deprecation macros.
-//
-// Deprecations warnings are always enabled, except when users explicitly opt-out
-// by defining _LIBCPP_DISABLE_DEPRECATION_WARNINGS.
-#  if !defined(_LIBCPP_DISABLE_DEPRECATION_WARNINGS)
-#    if __has_attribute(__deprecated__)
-#      define _LIBCPP_DEPRECATED __attribute__((__deprecated__))
-#      define _LIBCPP_DEPRECATED_(m) __attribute__((__deprecated__(m)))
-#    elif _LIBCPP_STD_VER >= 14
-#      define _LIBCPP_DEPRECATED [[deprecated]]
-#      define _LIBCPP_DEPRECATED_(m) [[deprecated(m)]]
-#    else
-#      define _LIBCPP_DEPRECATED
-#      define _LIBCPP_DEPRECATED_(m)
-#    endif
-#  else
-#    define _LIBCPP_DEPRECATED
-#    define _LIBCPP_DEPRECATED_(m)
-#  endif
-
-#  if !defined(_LIBCPP_CXX03_LANG)
-#    define _LIBCPP_DEPRECATED_IN_CXX11 _LIBCPP_DEPRECATED
-#  else
-#    define _LIBCPP_DEPRECATED_IN_CXX11
-#  endif
-
-#  if _LIBCPP_STD_VER >= 14
-#    define _LIBCPP_DEPRECATED_IN_CXX14 _LIBCPP_DEPRECATED
-#  else
-#    define _LIBCPP_DEPRECATED_IN_CXX14
-#  endif
-
-#  if _LIBCPP_STD_VER >= 17
-#    define _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_DEPRECATED
-#  else
-#    define _LIBCPP_DEPRECATED_IN_CXX17
-#  endif
-
-#  if _LIBCPP_STD_VER >= 20
-#    define _LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_DEPRECATED
-#  else
-#    define _LIBCPP_DEPRECATED_IN_CXX20
-#  endif
-
-#if _LIBCPP_STD_VER >= 23
-#  define _LIBCPP_DEPRECATED_IN_CXX23 _LIBCPP_DEPRECATED
-#else
-#  define _LIBCPP_DEPRECATED_IN_CXX23
-#endif
-
-#  if !defined(_LIBCPP_HAS_NO_CHAR8_T)
-#    define _LIBCPP_DEPRECATED_WITH_CHAR8_T _LIBCPP_DEPRECATED
-#  else
-#    define _LIBCPP_DEPRECATED_WITH_CHAR8_T
-#  endif
-
-// Macros to enter and leave a state where deprecation warnings are suppressed.
-#  if defined(_LIBCPP_COMPILER_CLANG_BASED) || defined(_LIBCPP_COMPILER_GCC)
-#    define _LIBCPP_SUPPRESS_DEPRECATED_PUSH                                                                           \
-      _Pragma("GCC diagnostic push") _Pragma("GCC diagnostic ignored \"-Wdeprecated\"")                                \
-          _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
-#    define _LIBCPP_SUPPRESS_DEPRECATED_POP _Pragma("GCC diagnostic pop")
-#  else
-#    define _LIBCPP_SUPPRESS_DEPRECATED_PUSH
-#    define _LIBCPP_SUPPRESS_DEPRECATED_POP
-#  endif
-
-#  if _LIBCPP_STD_VER <= 11
-#    define _LIBCPP_EXPLICIT_SINCE_CXX14
-#  else
-#    define _LIBCPP_EXPLICIT_SINCE_CXX14 explicit
-#  endif
-
-#  if _LIBCPP_STD_VER >= 23
-#    define _LIBCPP_EXPLICIT_SINCE_CXX23 explicit
-#  else
-#    define _LIBCPP_EXPLICIT_SINCE_CXX23
-#  endif
-
-#  if _LIBCPP_STD_VER >= 14
-#    define _LIBCPP_CONSTEXPR_SINCE_CXX14 constexpr
-#  else
-#    define _LIBCPP_CONSTEXPR_SINCE_CXX14
-#  endif
-
-#  if _LIBCPP_STD_VER >= 17
-#    define _LIBCPP_CONSTEXPR_SINCE_CXX17 constexpr
-#  else
-#    define _LIBCPP_CONSTEXPR_SINCE_CXX17
-#  endif
-
-#  if _LIBCPP_STD_VER >= 20
-#    define _LIBCPP_CONSTEXPR_SINCE_CXX20 constexpr
-#  else
-#    define _LIBCPP_CONSTEXPR_SINCE_CXX20
-#  endif
-
-#  if _LIBCPP_STD_VER >= 23
-#    define _LIBCPP_CONSTEXPR_SINCE_CXX23 constexpr
-#  else
-#    define _LIBCPP_CONSTEXPR_SINCE_CXX23
-#  endif
-
-#  if __has_cpp_attribute(nodiscard)
-#    define _LIBCPP_NODISCARD [[__nodiscard__]]
-#  else
-// We can't use GCC's [[gnu::warn_unused_result]] and
-// __attribute__((warn_unused_result)), because GCC does not silence them via
-// (void) cast.
-#    define _LIBCPP_NODISCARD
-#  endif
-
-// _LIBCPP_NODISCARD_EXT may be used to apply [[nodiscard]] to entities not
-// specified as such as an extension.
-#  if !defined(_LIBCPP_DISABLE_NODISCARD_EXT)
-#    define _LIBCPP_NODISCARD_EXT _LIBCPP_NODISCARD
-#  else
-#    define _LIBCPP_NODISCARD_EXT
-#  endif
-
-#  if _LIBCPP_STD_VER >= 20 || !defined(_LIBCPP_DISABLE_NODISCARD_EXT)
-#    define _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_NODISCARD
-#  else
-#    define _LIBCPP_NODISCARD_AFTER_CXX17
-#  endif
-
-#  if __has_attribute(__no_destroy__)
-#    define _LIBCPP_NO_DESTROY __attribute__((__no_destroy__))
-#  else
-#    define _LIBCPP_NO_DESTROY
-#  endif
-
-#  ifndef _LIBCPP_HAS_NO_ASAN
-    extern "C" _LIBCPP_FUNC_VIS void
-    __sanitizer_annotate_contiguous_container(const void*, const void*, const void*, const void*);
-#  endif
-
-// Try to find out if RTTI is disabled.
-#  if !defined(__cpp_rtti) || __cpp_rtti < 199711L
-#    define _LIBCPP_HAS_NO_RTTI
-#  endif
-
-#  ifndef _LIBCPP_WEAK
-#    define _LIBCPP_WEAK __attribute__((__weak__))
-#  endif
-
-// Thread API
-// clang-format off
-#  if !defined(_LIBCPP_HAS_NO_THREADS) &&                                                                              \
-      !defined(_LIBCPP_HAS_THREAD_API_PTHREAD) &&                                                                      \
-      !defined(_LIBCPP_HAS_THREAD_API_WIN32) &&                                                                        \
-      !defined(_LIBCPP_HAS_THREAD_API_EXTERNAL)
-
-#    if defined(__FreeBSD__) ||                                                                                        \
-        defined(__wasi__) ||                                                                                           \
-        defined(__NetBSD__) ||                                                                                         \
-        defined(__OpenBSD__) ||                                                                                        \
-        defined(__NuttX__) ||                                                                                          \
-        defined(__linux__) ||                                                                                          \
-        defined(__GNU__) ||                                                                                            \
-        defined(__APPLE__) ||                                                                                          \
-        defined(__MVS__) ||                                                                                            \
-        defined(_AIX) ||                                                                                               \
-        defined(__EMSCRIPTEN__)
-// clang-format on
-#      define _LIBCPP_HAS_THREAD_API_PTHREAD
-#    elif defined(__Fuchsia__)
-// TODO(44575): Switch to C11 thread API when possible.
-#      define _LIBCPP_HAS_THREAD_API_PTHREAD
-#    elif defined(_LIBCPP_WIN32API)
-#      define _LIBCPP_HAS_THREAD_API_WIN32
-#    else
-#      error "No thread API"
-#    endif // _LIBCPP_HAS_THREAD_API
-#  endif   // _LIBCPP_HAS_NO_THREADS
-
-#  if defined(_LIBCPP_HAS_THREAD_API_PTHREAD)
-#    if defined(__ANDROID__) && __ANDROID_API__ >= 30
-#      define _LIBCPP_HAS_COND_CLOCKWAIT
-#    elif defined(_LIBCPP_GLIBC_PREREQ)
-#      if _LIBCPP_GLIBC_PREREQ(2, 30)
-#        define _LIBCPP_HAS_COND_CLOCKWAIT
-#      endif
-#    endif
-#  endif
-
-#  if defined(_LIBCPP_HAS_NO_THREADS) && defined(_LIBCPP_HAS_THREAD_API_PTHREAD)
-#    error _LIBCPP_HAS_THREAD_API_PTHREAD may only be defined when \
-       _LIBCPP_HAS_NO_THREADS is not defined.
-#  endif
-
-#  if defined(_LIBCPP_HAS_NO_THREADS) && defined(_LIBCPP_HAS_THREAD_API_EXTERNAL)
-#    error _LIBCPP_HAS_THREAD_API_EXTERNAL may not be defined when \
-       _LIBCPP_HAS_NO_THREADS is defined.
-#  endif
-
-#  if defined(_LIBCPP_HAS_NO_MONOTONIC_CLOCK) && !defined(_LIBCPP_HAS_NO_THREADS)
-#    error _LIBCPP_HAS_NO_MONOTONIC_CLOCK may only be defined when \
-       _LIBCPP_HAS_NO_THREADS is defined.
-#  endif
-
-#  if !defined(_LIBCPP_HAS_NO_THREADS) && !defined(__STDCPP_THREADS__)
-#    define __STDCPP_THREADS__ 1
-#  endif
-
-// The glibc and Bionic implementation of pthreads implements
-// pthread_mutex_destroy as nop for regular mutexes. Additionally, Win32
-// mutexes have no destroy mechanism.
-//
-// This optimization can't be performed on Apple platforms, where
-// pthread_mutex_destroy can allow the kernel to release resources.
-// See https://llvm.org/D64298 for details.
-//
-// TODO(EricWF): Enable this optimization on Bionic after speaking to their
-//               respective stakeholders.
-// clang-format off
-#  if (defined(_LIBCPP_HAS_THREAD_API_PTHREAD) && defined(__GLIBC__)) ||                                               \
-      (defined(_LIBCPP_HAS_THREAD_API_C11) && defined(__Fuchsia__)) ||                                                 \
-       defined(_LIBCPP_HAS_THREAD_API_WIN32)
-// clang-format on
-#    define _LIBCPP_HAS_TRIVIAL_MUTEX_DESTRUCTION
-#  endif
-
-// Destroying a condvar is a nop on Windows.
-//
-// This optimization can't be performed on Apple platforms, where
-// pthread_cond_destroy can allow the kernel to release resources.
-// See https://llvm.org/D64298 for details.
-//
-// TODO(EricWF): This is potentially true for some pthread implementations
-// as well.
-#  if (defined(_LIBCPP_HAS_THREAD_API_C11) && defined(__Fuchsia__)) || defined(_LIBCPP_HAS_THREAD_API_WIN32)
-#    define _LIBCPP_HAS_TRIVIAL_CONDVAR_DESTRUCTION
-#  endif
-
-// Some systems do not provide gets() in their C library, for security reasons.
-#  if defined(_LIBCPP_MSVCRT) || (defined(__FreeBSD_version) && __FreeBSD_version >= 1300043) || defined(__OpenBSD__)
-#    define _LIBCPP_C_HAS_NO_GETS
-#  endif
-
-#  if defined(__BIONIC__) || defined(__NuttX__) || defined(__Fuchsia__) || defined(__wasi__) ||                        \
-      defined(_LIBCPP_HAS_MUSL_LIBC) || defined(__OpenBSD__)
-#    define _LIBCPP_PROVIDES_DEFAULT_RUNE_TABLE
-#  endif
-
-#  if __has_feature(cxx_atomic) || __has_extension(c_atomic) || __has_keyword(_Atomic)
-#    define _LIBCPP_HAS_C_ATOMIC_IMP
-#  elif defined(_LIBCPP_COMPILER_GCC)
-#    define _LIBCPP_HAS_GCC_ATOMIC_IMP
-#  endif
-
-#  if !defined(_LIBCPP_HAS_C_ATOMIC_IMP) && !defined(_LIBCPP_HAS_GCC_ATOMIC_IMP) &&                                    \
-      !defined(_LIBCPP_HAS_EXTERNAL_ATOMIC_IMP)
-#    define _LIBCPP_HAS_NO_ATOMIC_HEADER
-#  else
-#    ifndef _LIBCPP_ATOMIC_FLAG_TYPE
-#      define _LIBCPP_ATOMIC_FLAG_TYPE bool
-#    endif
-#    ifdef _LIBCPP_FREESTANDING
-#      define _LIBCPP_ATOMIC_ONLY_USE_BUILTINS
-#    endif
-#  endif
-
-#  ifndef _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
-#    define _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
-#  endif
-
-#  if defined(_LIBCPP_ENABLE_THREAD_SAFETY_ANNOTATIONS)
-#    if defined(__clang__) && __has_attribute(acquire_capability)
-// Work around the attribute handling in clang.  When both __declspec and
-// __attribute__ are present, the processing goes awry preventing the definition
-// of the types. In MinGW mode, __declspec evaluates to __attribute__, and thus
-// combining the two does work.
-#      if !defined(_MSC_VER)
-#        define _LIBCPP_HAS_THREAD_SAFETY_ANNOTATIONS
-#      endif
-#    endif
-#  endif
-
-#  ifdef _LIBCPP_HAS_THREAD_SAFETY_ANNOTATIONS
-#    define _LIBCPP_THREAD_SAFETY_ANNOTATION(x) __attribute__((x))
-#  else
-#    define _LIBCPP_THREAD_SAFETY_ANNOTATION(x)
-#  endif
-
-#  if _LIBCPP_STD_VER >= 20
-#    define _LIBCPP_CONSTINIT constinit
-#  elif __has_attribute(__require_constant_initialization__)
-#    define _LIBCPP_CONSTINIT __attribute__((__require_constant_initialization__))
-#  else
-#    define _LIBCPP_CONSTINIT
-#  endif
-
-#  if __has_attribute(__diagnose_if__) && !defined(_LIBCPP_DISABLE_ADDITIONAL_DIAGNOSTICS)
-#    define _LIBCPP_DIAGNOSE_WARNING(...) __attribute__((__diagnose_if__(__VA_ARGS__, "warning")))
-#  else
-#    define _LIBCPP_DIAGNOSE_WARNING(...)
-#  endif
-
-// Use a function like macro to imply that it must be followed by a semicolon
-#  if __has_cpp_attribute(fallthrough)
-#    define _LIBCPP_FALLTHROUGH() [[fallthrough]]
-#  elif __has_attribute(__fallthrough__)
-#    define _LIBCPP_FALLTHROUGH() __attribute__((__fallthrough__))
-#  else
-#    define _LIBCPP_FALLTHROUGH() ((void)0)
-#  endif
-
-#  if __has_cpp_attribute(_Clang::__lifetimebound__)
-#    define _LIBCPP_LIFETIMEBOUND [[_Clang::__lifetimebound__]]
-#  else
-#    define _LIBCPP_LIFETIMEBOUND
-#  endif
-
-#  if __has_attribute(__nodebug__)
-#    define _LIBCPP_NODEBUG __attribute__((__nodebug__))
-#  else
-#    define _LIBCPP_NODEBUG
-#  endif
-
-#  if __has_attribute(__standalone_debug__)
-#    define _LIBCPP_STANDALONE_DEBUG __attribute__((__standalone_debug__))
-#  else
-#    define _LIBCPP_STANDALONE_DEBUG
-#  endif
-
-#  if __has_attribute(__preferred_name__)
-#    define _LIBCPP_PREFERRED_NAME(x) __attribute__((__preferred_name__(x)))
-#  else
-#    define _LIBCPP_PREFERRED_NAME(x)
-#  endif
-
-// We often repeat things just for handling wide characters in the library.
-// When wide characters are disabled, it can be useful to have a quick way of
-// disabling it without having to resort to #if-#endif, which has a larger
-// impact on readability.
-#  if defined(_LIBCPP_HAS_NO_WIDE_CHARACTERS)
-#    define _LIBCPP_IF_WIDE_CHARACTERS(...)
-#  else
-#    define _LIBCPP_IF_WIDE_CHARACTERS(...) __VA_ARGS__
-#  endif
-
-#  if defined(_LIBCPP_ABI_MICROSOFT) && __has_declspec_attribute(empty_bases)
-#    define _LIBCPP_DECLSPEC_EMPTY_BASES __declspec(empty_bases)
-#  else
-#    define _LIBCPP_DECLSPEC_EMPTY_BASES
-#  endif
-
-#  if defined(_LIBCPP_ENABLE_CXX17_REMOVED_FEATURES)
-#    define _LIBCPP_ENABLE_CXX17_REMOVED_AUTO_PTR
-#    define _LIBCPP_ENABLE_CXX17_REMOVED_BINDERS
-#    define _LIBCPP_ENABLE_CXX17_REMOVED_RANDOM_SHUFFLE
-#    define _LIBCPP_ENABLE_CXX17_REMOVED_UNEXPECTED_FUNCTIONS
-#    define _LIBCPP_ENABLE_CXX17_REMOVED_UNARY_BINARY_FUNCTION
-#  endif // _LIBCPP_ENABLE_CXX17_REMOVED_FEATURES
-
-#  if defined(_LIBCPP_ENABLE_CXX20_REMOVED_FEATURES)
-#    define _LIBCPP_ENABLE_CXX20_REMOVED_ALLOCATOR_MEMBERS
-#    define _LIBCPP_ENABLE_CXX20_REMOVED_ALLOCATOR_VOID_SPECIALIZATION
-#    define _LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS
-#    define _LIBCPP_ENABLE_CXX20_REMOVED_NEGATORS
-#    define _LIBCPP_ENABLE_CXX20_REMOVED_RAW_STORAGE_ITERATOR
-#    define _LIBCPP_ENABLE_CXX20_REMOVED_TYPE_TRAITS
-#  endif // _LIBCPP_ENABLE_CXX20_REMOVED_FEATURES
-
-#  define _LIBCPP_PUSH_MACROS _Pragma("push_macro(\"min\")") _Pragma("push_macro(\"max\")")
-#  define _LIBCPP_POP_MACROS _Pragma("pop_macro(\"min\")") _Pragma("pop_macro(\"max\")")
-
-#  ifndef _LIBCPP_NO_AUTO_LINK
-#    if defined(_LIBCPP_ABI_MICROSOFT) && !defined(_LIBCPP_BUILDING_LIBRARY)
-#      if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
-#        pragma comment(lib, "c++.lib")
-#      else
-#        pragma comment(lib, "libc++.lib")
-#      endif
-#    endif // defined(_LIBCPP_ABI_MICROSOFT) && !defined(_LIBCPP_BUILDING_LIBRARY)
-#  endif   // _LIBCPP_NO_AUTO_LINK
-
-// Configures the fopen close-on-exec mode character, if any. This string will
-// be appended to any mode string used by fstream for fopen/fdopen.
-//
-// Not all platforms support this, but it helps avoid fd-leaks on platforms that
-// do.
-#  if defined(__BIONIC__)
-#    define _LIBCPP_FOPEN_CLOEXEC_MODE "e"
-#  else
-#    define _LIBCPP_FOPEN_CLOEXEC_MODE
-#  endif
-
-// Support for _FILE_OFFSET_BITS=64 landed gradually in Android, so the full set
-// of functions used in cstdio may not be available for low API levels when
-// using 64-bit file offsets on LP32.
-#  if defined(__BIONIC__) && defined(__USE_FILE_OFFSET64) && __ANDROID_API__ < 24
-#    define _LIBCPP_HAS_NO_FGETPOS_FSETPOS
-#  endif
-
-#  if __has_attribute(__init_priority__)
-#    define _LIBCPP_INIT_PRIORITY_MAX __attribute__((__init_priority__(100)))
-#  else
-#    define _LIBCPP_INIT_PRIORITY_MAX
-#  endif
-
-#  if __has_attribute(__format__)
-// The attribute uses 1-based indices for ordinary and static member functions.
-// The attribute uses 2-based indices for non-static member functions.
-#    define _LIBCPP_ATTRIBUTE_FORMAT(archetype, format_string_index, first_format_arg_index)                           \
-      __attribute__((__format__(archetype, format_string_index, first_format_arg_index)))
-#  else
-#    define _LIBCPP_ATTRIBUTE_FORMAT(archetype, format_string_index, first_format_arg_index) /* nothing */
-#  endif
-
-#  if __has_cpp_attribute(msvc::no_unique_address)
-// MSVC implements [[no_unique_address]] as a silent no-op currently.
-// (If/when MSVC breaks its C++ ABI, it will be changed to work as intended.)
-// However, MSVC implements [[msvc::no_unique_address]] which does what
-// [[no_unique_address]] is supposed to do, in general.
-
-// Clang-cl does not yet (14.0) implement either [[no_unique_address]] or
-// [[msvc::no_unique_address]] though. If/when it does implement
-// [[msvc::no_unique_address]], this should be preferred though.
-#    define _LIBCPP_NO_UNIQUE_ADDRESS [[msvc::no_unique_address]]
-#  elif __has_cpp_attribute(no_unique_address)
-#    define _LIBCPP_NO_UNIQUE_ADDRESS [[__no_unique_address__]]
-#  else
-#    define _LIBCPP_NO_UNIQUE_ADDRESS /* nothing */
-// Note that this can be replaced by #error as soon as clang-cl
-// implements msvc::no_unique_address, since there should be no C++20
-// compiler that doesn't support one of the two attributes at that point.
-// We generally don't want to use this macro outside of C++20-only code,
-// because using it conditionally in one language version only would make
-// the ABI inconsistent.
-#  endif
-
-#  ifdef _LIBCPP_COMPILER_CLANG_BASED
-#    define _LIBCPP_DIAGNOSTIC_PUSH _Pragma("clang diagnostic push")
-#    define _LIBCPP_DIAGNOSTIC_POP _Pragma("clang diagnostic pop")
-#    define _LIBCPP_CLANG_DIAGNOSTIC_IGNORED(str) _Pragma(_LIBCPP_TOSTRING(clang diagnostic ignored str))
-#    define _LIBCPP_GCC_DIAGNOSTIC_IGNORED(str)
-#  elif defined(_LIBCPP_COMPILER_GCC)
-#    define _LIBCPP_DIAGNOSTIC_PUSH _Pragma("GCC diagnostic push")
-#    define _LIBCPP_DIAGNOSTIC_POP _Pragma("GCC diagnostic pop")
-#    define _LIBCPP_CLANG_DIAGNOSTIC_IGNORED(str)
-#    define _LIBCPP_GCC_DIAGNOSTIC_IGNORED(str) _Pragma(_LIBCPP_TOSTRING(GCC diagnostic ignored str))
-#  else
-#    define _LIBCPP_DIAGNOSTIC_PUSH
-#    define _LIBCPP_DIAGNOSTIC_POP
-#    define _LIBCPP_CLANG_DIAGNOSTIC_IGNORED(str)
-#    define _LIBCPP_GCC_DIAGNOSTIC_IGNORED(str)
-#  endif
-
-#  if defined(_AIX) && !defined(_LIBCPP_COMPILER_GCC)
-#    define _LIBCPP_PACKED_BYTE_FOR_AIX _Pragma("pack(1)")
-#    define _LIBCPP_PACKED_BYTE_FOR_AIX_END _Pragma("pack(pop)")
-#  else
-#    define _LIBCPP_PACKED_BYTE_FOR_AIX     /* empty */
-#    define _LIBCPP_PACKED_BYTE_FOR_AIX_END /* empty */
-#  endif
-
-#  if __has_attribute(__packed__)
-#    define _LIBCPP_PACKED __attribute__((__packed__))
-#  else
-#    define _LIBCPP_PACKED
-#  endif
-
-// c8rtomb() and mbrtoc8() were added in C++20 and C23. Support for these
-// functions is gradually being added to existing C libraries. The conditions
-// below check for known C library versions and conditions under which these
-// functions are declared by the C library.
-#  define _LIBCPP_HAS_NO_C8RTOMB_MBRTOC8
-// GNU libc 2.36 and newer declare c8rtomb() and mbrtoc8() in C++ modes if
-// __cpp_char8_t is defined or if C2X extensions are enabled. Determining
-// the latter depends on internal GNU libc details that are not appropriate
-// to depend on here, so any declarations present when __cpp_char8_t is not
-// defined are ignored.
-#  if defined(_LIBCPP_GLIBC_PREREQ)
-#    if _LIBCPP_GLIBC_PREREQ(2, 36) && defined(__cpp_char8_t)
-#      undef _LIBCPP_HAS_NO_C8RTOMB_MBRTOC8
-#    endif
-#  endif
-
-// There are a handful of public standard library types that are intended to
-// support CTAD but don't need any explicit deduction guides to do so. This
-// macro is used to mark them as such, which suppresses the
-// '-Wctad-maybe-unsupported' compiler warning when CTAD is used in user code
-// with these classes.
-#  if _LIBCPP_STD_VER >= 17
-#    ifdef _LIBCPP_COMPILER_CLANG_BASED
-#      define _LIBCPP_CTAD_SUPPORTED_FOR_TYPE(_ClassName)                                                              \
-        template <class... _Tag>                                                                                       \
-        [[maybe_unused]] _ClassName(typename _Tag::__allow_ctad...)->_ClassName<_Tag...>
-#    else
-#      define _LIBCPP_CTAD_SUPPORTED_FOR_TYPE(ClassName)                                                               \
-        template <class... _Tag>                                                                                       \
-        ClassName(typename _Tag::__allow_ctad...)->ClassName<_Tag...>
-#    endif
-#  else
-#    define _LIBCPP_CTAD_SUPPORTED_FOR_TYPE(_ClassName) static_assert(true, "")
-#  endif
-
-// TODO(varconst): currently, there are bugs in Clang's intrinsics when handling Objective-C++ `id`, so don't use
-// compiler intrinsics in the Objective-C++ mode.
-#  ifdef __OBJC__
-#    define _LIBCPP_WORKAROUND_OBJCXX_COMPILER_INTRINSICS
-#  endif
-
-// TODO: Make this a proper configuration option
-#define _PSTL_PAR_BACKEND_SERIAL
-
-#define _PSTL_PRAGMA(x) _Pragma(#    x)
-
-// Enable SIMD for compilers that support OpenMP 4.0
-#if (defined(_OPENMP) && _OPENMP >= 201307)
-
-#  define _PSTL_UDR_PRESENT
-#  define _PSTL_PRAGMA_SIMD _PSTL_PRAGMA(omp simd)
-#  define _PSTL_PRAGMA_DECLARE_SIMD _PSTL_PRAGMA(omp declare simd)
-#  define _PSTL_PRAGMA_SIMD_REDUCTION(PRM) _PSTL_PRAGMA(omp simd reduction(PRM))
-#  define _PSTL_PRAGMA_SIMD_SCAN(PRM) _PSTL_PRAGMA(omp simd reduction(inscan, PRM))
-#  define _PSTL_PRAGMA_SIMD_INCLUSIVE_SCAN(PRM) _PSTL_PRAGMA(omp scan inclusive(PRM))
-#  define _PSTL_PRAGMA_SIMD_EXCLUSIVE_SCAN(PRM) _PSTL_PRAGMA(omp scan exclusive(PRM))
-
-// Declaration of reduction functor, where
-// NAME - the name of the functor
-// OP - type of the callable object with the reduction operation
-// omp_in - refers to the local partial result
-// omp_out - refers to the final value of the combiner operator
-// omp_priv - refers to the private copy of the initial value
-// omp_orig - refers to the original variable to be reduced
-#  define _PSTL_PRAGMA_DECLARE_REDUCTION(NAME, OP)                                                                     \
-    _PSTL_PRAGMA(omp declare reduction(NAME:OP : omp_out(omp_in)) initializer(omp_priv = omp_orig))
-
-#else // (defined(_OPENMP) && _OPENMP >= 201307)
-
-#  define _PSTL_PRAGMA_SIMD
-#  define _PSTL_PRAGMA_DECLARE_SIMD
-#  define _PSTL_PRAGMA_SIMD_REDUCTION(PRM)
-#  define _PSTL_PRAGMA_SIMD_SCAN(PRM)
-#  define _PSTL_PRAGMA_SIMD_INCLUSIVE_SCAN(PRM)
-#  define _PSTL_PRAGMA_SIMD_EXCLUSIVE_SCAN(PRM)
-#  define _PSTL_PRAGMA_DECLARE_REDUCTION(NAME, OP)
-
-#endif // (defined(_OPENMP) && _OPENMP >= 201307)
-
-#define _PSTL_USE_NONTEMPORAL_STORES_IF_ALLOWED
-
-#endif // __cplusplus
+#include <__config_dir/availability.h>
+#include <__config_dir/base.h>
 
 #endif // _LIBCPP___CONFIG

libcxx/include/__config_dir/availability.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___AVAILABILITY
-#define _LIBCPP___AVAILABILITY
+#ifndef _LIBCPP___CONFIG_DIR_AVAILABILITY_H
+#define _LIBCPP___CONFIG_DIR_AVAILABILITY_H
 
-#include <__config>
+#include <__config_dir/base.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 // Libc++ is shipped by various vendors. In particular, it is used as a system
 // library on macOS, iOS and other Apple platforms. In order for users to be
 // able to compile a binary that is intended to be deployed to an older version

 #   define _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
 #else
 #   define _LIBCPP_AVAILABILITY_FUTURE                    _LIBCPP_AVAILABILITY_FUTURE_ERROR
 #   define _LIBCPP_AVAILABILITY_THROW_BAD_ANY_CAST        _LIBCPP_AVAILABILITY_BAD_ANY_CAST
 #   define _LIBCPP_AVAILABILITY_THROW_BAD_OPTIONAL_ACCESS _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS
 #   define _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS  _LIBCPP_AVAILABILITY_BAD_VARIANT_ACCESS
 #endif
 
-#endif // _LIBCPP___AVAILABILITY
+#endif // _LIBCPP___CONFIG_DIR_AVAILABILITY_H

libcxx/include/__config_dir/base.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___CONFIG
-#define _LIBCPP___CONFIG
+#ifndef _LIBCPP___CONFIG_DIR_BASE_H
+#define _LIBCPP___CONFIG_DIR_BASE_H
 
 #include <__config_site>
 
 #if defined(_MSC_VER) && !defined(__clang__)
 #  if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #    define _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
 #  endif
 #endif
 
 #ifndef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
 #  pragma GCC system_header
 #endif
 
 #if defined(__apple_build_version__)
 // Given AppleClang XX.Y.Z, _LIBCPP_APPLE_CLANG_VER is XXYZ (e.g. AppleClang 14.0.3 => 1403)
 #  define _LIBCPP_COMPILER_CLANG_BASED
 #  define _LIBCPP_APPLE_CLANG_VER (__apple_build_version__ / 10000)
 #elif defined(__clang__)
 #  define _LIBCPP_COMPILER_CLANG_BASED
 #  define _LIBCPP_CLANG_VER (__clang_major__ * 100 + __clang_minor__)
 #elif defined(__GNUC__)
 #  define _LIBCPP_COMPILER_GCC
 #endif
 
 #ifdef __cplusplus
 
 // _LIBCPP_VERSION represents the version of libc++, which matches the version of LLVM.
 // Given a LLVM release LLVM XX.YY.ZZ (e.g. LLVM 17.0.1 == 17.00.01), _LIBCPP_VERSION is
 // defined to XXYYZZ.
 #  define _LIBCPP_VERSION 170000
 
 #  define _LIBCPP_CONCAT_IMPL(_X, _Y) _X##_Y
 #  define _LIBCPP_CONCAT(_X, _Y) _LIBCPP_CONCAT_IMPL(_X, _Y)
 
 // Valid C++ identifier that revs with every libc++ version. This can be used to
 // generate identifiers that must be unique for every released libc++ version.
 #  define _LIBCPP_VERSIONED_IDENTIFIER _LIBCPP_CONCAT(v, _LIBCPP_VERSION)
 
 #  if __STDC_HOSTED__ == 0
 #    define _LIBCPP_FREESTANDING
 #  endif
 
 // NOLINTBEGIN(libcpp-cpp-version-check)
 #  ifndef _LIBCPP_STD_VER
 #    if __cplusplus <= 201103L
 #      define _LIBCPP_STD_VER 11
 #    elif __cplusplus <= 201402L
 #      define _LIBCPP_STD_VER 14
 #    elif __cplusplus <= 201703L
 #      define _LIBCPP_STD_VER 17
 #    elif __cplusplus <= 202002L
 #      define _LIBCPP_STD_VER 20
 #    elif __cplusplus <= 202302L
 #      define _LIBCPP_STD_VER 23
 #    else

 #    define _LIBCPP_ABI_INCOMPLETE_TYPES_IN_DEQUE
 // Fix undefined behavior in how std::list stores its linked nodes.
 #    define _LIBCPP_ABI_LIST_REMOVE_NODE_POINTER_UB
 // Fix undefined behavior in  how __tree stores its end and parent nodes.
 #    define _LIBCPP_ABI_TREE_REMOVE_NODE_POINTER_UB
 // Fix undefined behavior in how __hash_table stores its pointer types.
 #    define _LIBCPP_ABI_FIX_UNORDERED_NODE_POINTER_UB
 #    define _LIBCPP_ABI_FORWARD_LIST_REMOVE_NODE_POINTER_UB
 #    define _LIBCPP_ABI_FIX_UNORDERED_CONTAINER_SIZE_TYPE
 // Define a key function for `bad_function_call` in the library, to centralize
 // its vtable and typeinfo to libc++ rather than having all other libraries
 // using that class define their own copies.
 #    define _LIBCPP_ABI_BAD_FUNCTION_CALL_KEY_FUNCTION
 // Override the default return value of exception::what() for
 // bad_function_call::what() with a string that is specific to
 // bad_function_call (see http://wg21.link/LWG2233). This is an ABI break
 // because it changes the vtable layout of bad_function_call.
 #    define _LIBCPP_ABI_BAD_FUNCTION_CALL_GOOD_WHAT_MESSAGE
 // Enable optimized version of __do_get_(un)signed which avoids redundant copies.
 #    define _LIBCPP_ABI_OPTIMIZED_LOCALE_NUM_GET
 // Give reverse_iterator<T> one data member of type T, not two.
 // Also, in C++17 and later, don't derive iterator types from std::iterator.
 #    define _LIBCPP_ABI_NO_ITERATOR_BASES
 // Use the smallest possible integer type to represent the index of the variant.
 // Previously libc++ used "unsigned int" exclusively.
 #    define _LIBCPP_ABI_VARIANT_INDEX_TYPE_OPTIMIZATION
 // Unstable attempt to provide a more optimized std::function
 #    define _LIBCPP_ABI_OPTIMIZED_FUNCTION
 // All the regex constants must be distinct and nonzero.
 #    define _LIBCPP_ABI_REGEX_CONSTANTS_NONZERO
 // Re-worked external template instantiations for std::string with a focus on
 // performance and fast-path inlining.
 #    define _LIBCPP_ABI_STRING_OPTIMIZED_EXTERNAL_INSTANTIATION

 #  define _PSTL_PRAGMA_DECLARE_REDUCTION(NAME, OP)
 
 #endif // (defined(_OPENMP) && _OPENMP >= 201307)
 
 #define _PSTL_USE_NONTEMPORAL_STORES_IF_ALLOWED
 
 #endif // __cplusplus
 
-#endif // _LIBCPP___CONFIG
+#endif // _LIBCPP___CONFIG_DIR_BASE_H

libcxx/include/__config_dir/debug.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___DEBUG
-#define _LIBCPP___DEBUG
+#ifndef _LIBCPP___CONFIG_DIR_DEBUG_H
+#define _LIBCPP___CONFIG_DIR_DEBUG_H
 
 #include <__assert>
-#include <__config>
+#include <__config_dir/base.h>
 #include <__type_traits/is_constant_evaluated.h>
 #include <cstddef>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 #if defined(_LIBCPP_ENABLE_DEBUG_MODE) && !defined(_LIBCPP_CXX03_LANG) && !defined(_LIBCPP_DEBUG_RANDOMIZE_UNSPECIFIED_STABILITY)
if (!__libcpp_is_constant_evaluated())
         __get_db()->__invalidate_all(__c);
 #else
     (void)(__c);
 #endif
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
-#endif // _LIBCPP___DEBUG
+#endif // _LIBCPP___CONFIG_DIR_DEBUG_H

libcxx/include/__exception/operations.h

 //===----------------------------------------------------------------------===//
 //
 // 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___EXCEPTION_OPERATIONS_H
 #define _LIBCPP___EXCEPTION_OPERATIONS_H
 
-#include <__availability>
 #include <__config>
 #include <cstddef>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 namespace std { // purposefully not using versioning namespace

libcxx/include/__filesystem/copy_options.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___FILESYSTEM_COPY_OPTIONS_H
 #define _LIBCPP___FILESYSTEM_COPY_OPTIONS_H
 
-#include <__availability>
 #include <__config>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 #ifndef _LIBCPP_CXX03_LANG
 

libcxx/include/__filesystem/directory_entry.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___FILESYSTEM_DIRECTORY_ENTRY_H
 #define _LIBCPP___FILESYSTEM_DIRECTORY_ENTRY_H
 
-#include <__availability>
 #include <__chrono/time_point.h>
 #include <__compare/ordering.h>
 #include <__config>
 #include <__filesystem/file_status.h>
 #include <__filesystem/file_time_type.h>
 #include <__filesystem/file_type.h>
 #include <__filesystem/filesystem_error.h>
 #include <__filesystem/operations.h>

libcxx/include/__filesystem/directory_iterator.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___FILESYSTEM_DIRECTORY_ITERATOR_H
 #define _LIBCPP___FILESYSTEM_DIRECTORY_ITERATOR_H
 
 #include <__assert>
-#include <__availability>
 #include <__config>
 #include <__filesystem/directory_entry.h>
 #include <__filesystem/directory_options.h>
 #include <__filesystem/path.h>
 #include <__iterator/iterator_traits.h>
 #include <__memory/shared_ptr.h>
 #include <__ranges/enable_borrowed_range.h>
 #include <__ranges/enable_view.h>

libcxx/include/__filesystem/directory_options.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___FILESYSTEM_DIRECTORY_OPTIONS_H
 #define _LIBCPP___FILESYSTEM_DIRECTORY_OPTIONS_H
 
-#include <__availability>
 #include <__config>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 #ifndef _LIBCPP_CXX03_LANG
 

libcxx/include/__filesystem/file_status.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___FILESYSTEM_FILE_STATUS_H
 #define _LIBCPP___FILESYSTEM_FILE_STATUS_H
 
-#include <__availability>
 #include <__config>
 #include <__filesystem/file_type.h>
 #include <__filesystem/perms.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 

libcxx/include/__filesystem/file_time_type.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___FILESYSTEM_FILE_TIME_TYPE_H
 #define _LIBCPP___FILESYSTEM_FILE_TIME_TYPE_H
 
-#include <__availability>
 #include <__chrono/file_clock.h>
 #include <__chrono/time_point.h>
 #include <__config>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 

libcxx/include/__filesystem/file_type.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___FILESYSTEM_FILE_TYPE_H
 #define _LIBCPP___FILESYSTEM_FILE_TYPE_H
 
-#include <__availability>
 #include <__config>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 #ifndef _LIBCPP_CXX03_LANG
 

libcxx/include/__filesystem/filesystem_error.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___FILESYSTEM_FILESYSTEM_ERROR_H
 #define _LIBCPP___FILESYSTEM_FILESYSTEM_ERROR_H
 
-#include <__availability>
 #include <__config>
 #include <__filesystem/path.h>
 #include <__memory/shared_ptr.h>
 #include <__system_error/error_code.h>
 #include <__system_error/system_error.h>
 #include <__utility/forward.h>
 #include <__verbose_abort>
 #include <iosfwd>

libcxx/include/__filesystem/operations.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___FILESYSTEM_OPERATIONS_H
 #define _LIBCPP___FILESYSTEM_OPERATIONS_H
 
-#include <__availability>
 #include <__chrono/time_point.h>
 #include <__config>
 #include <__filesystem/copy_options.h>
 #include <__filesystem/file_status.h>
 #include <__filesystem/file_time_type.h>
 #include <__filesystem/file_type.h>
 #include <__filesystem/path.h>
 #include <__filesystem/perm_options.h>

libcxx/include/__filesystem/path.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___FILESYSTEM_PATH_H
 #define _LIBCPP___FILESYSTEM_PATH_H
 
 #include <__algorithm/replace.h>
 #include <__algorithm/replace_copy.h>
-#include <__availability>
 #include <__config>
 #include <__functional/unary_function.h>
 #include <__fwd/hash.h>
 #include <__iterator/back_insert_iterator.h>
 #include <__iterator/iterator_traits.h>
 #include <__type_traits/decay.h>
 #include <__type_traits/is_pointer.h>
 #include <__type_traits/remove_const.h>

libcxx/include/__filesystem/path_iterator.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___FILESYSTEM_PATH_ITERATOR_H
 #define _LIBCPP___FILESYSTEM_PATH_ITERATOR_H
 
 #include <__assert>
-#include <__availability>
 #include <__config>
 #include <__filesystem/path.h>
 #include <__iterator/iterator_traits.h>
 #include <cstddef>
 #include <string>
 #include <string_view>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)

libcxx/include/__filesystem/perm_options.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___FILESYSTEM_PERM_OPTIONS_H
 #define _LIBCPP___FILESYSTEM_PERM_OPTIONS_H
 
-#include <__availability>
 #include <__config>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 #ifndef _LIBCPP_CXX03_LANG
 

libcxx/include/__filesystem/perms.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___FILESYSTEM_PERMS_H
 #define _LIBCPP___FILESYSTEM_PERMS_H
 
-#include <__availability>
 #include <__config>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 #ifndef _LIBCPP_CXX03_LANG
 

libcxx/include/__filesystem/recursive_directory_iterator.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___FILESYSTEM_RECURSIVE_DIRECTORY_ITERATOR_H
 #define _LIBCPP___FILESYSTEM_RECURSIVE_DIRECTORY_ITERATOR_H
 
-#include <__availability>
 #include <__config>
 #include <__filesystem/directory_entry.h>
 #include <__filesystem/directory_options.h>
 #include <__filesystem/path.h>
 #include <__iterator/iterator_traits.h>
 #include <__memory/shared_ptr.h>
 #include <__ranges/enable_borrowed_range.h>
 #include <__ranges/enable_view.h>

libcxx/include/__filesystem/space_info.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___FILESYSTEM_SPACE_INFO_H
 #define _LIBCPP___FILESYSTEM_SPACE_INFO_H
 
-#include <__availability>
 #include <__config>
 #include <cstdint>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 #ifndef _LIBCPP_CXX03_LANG

libcxx/include/__filesystem/u8path.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___FILESYSTEM_U8PATH_H
 #define _LIBCPP___FILESYSTEM_U8PATH_H
 
 #include <__algorithm/unwrap_iter.h>
-#include <__availability>
 #include <__config>
 #include <__filesystem/path.h>
 #include <string>
 
 // Only required on Windows for __widen_from_utf8, and included conservatively
 // because it requires support for localization.
 #if defined(_LIBCPP_WIN32API)
 # include <locale>

libcxx/include/__format/container_adaptor.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_CONTAINER_ADAPTOR_H
 #define _LIBCPP___FORMAT_CONTAINER_ADAPTOR_H
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
-#include <__availability>
 #include <__config>
 #include <__format/concepts.h>
 #include <__format/formatter.h>
 #include <__format/range_default_formatter.h>
 #include <__ranges/all.h>
 #include <__ranges/ref_view.h>
 #include <__type_traits/is_const.h>
 #include <__type_traits/maybe_const.h>

libcxx/include/__format/format_args.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_ARGS_H
 #define _LIBCPP___FORMAT_FORMAT_ARGS_H
 
-#include <__availability>
 #include <__config>
 #include <__format/format_arg.h>
 #include <__format/format_arg_store.h>
 #include <__format/format_fwd.h>
 #include <cstddef>
 #include <cstdint>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)

libcxx/include/__format/format_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_CONTEXT_H
 #define _LIBCPP___FORMAT_FORMAT_CONTEXT_H
 
-#include <__availability>
 #include <__concepts/same_as.h>
 #include <__config>
 #include <__format/buffer.h>
 #include <__format/format_arg.h>
 #include <__format/format_arg_store.h>
 #include <__format/format_args.h>
 #include <__format/format_error.h>
 #include <__format/format_fwd.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
 
 #include <__algorithm/clamp.h>
-#include <__availability>
 #include <__concepts/convertible_to.h>
 #include <__concepts/same_as.h>
 #include <__config>
-#include <__debug>
+#include <__config_dir/debug.h>
 #include <__format/buffer.h>
 #include <__format/format_arg.h>
 #include <__format/format_arg_store.h>
 #include <__format/format_args.h>
 #include <__format/format_context.h>
 #include <__format/format_error.h>
 #include <__format/format_parse_context.h>
 #include <__format/format_string.h>

libcxx/include/__format/format_fwd.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_FWD_H
 #define _LIBCPP___FORMAT_FORMAT_FWD_H
 
-#include <__availability>
 #include <__config>
 #include <__iterator/concepts.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD

libcxx/include/__format/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___FORMAT_FORMATTER_H
 #define _LIBCPP___FORMAT_FORMATTER_H
 
-#include <__availability>
 #include <__config>
 #include <__format/format_fwd.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD

libcxx/include/__format/formatter_bool.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_BOOL_H
 #define _LIBCPP___FORMAT_FORMATTER_BOOL_H
 
 #include <__algorithm/copy.h>
-#include <__availability>
 #include <__config>
-#include <__debug>
+#include <__config_dir/debug.h>
 #include <__format/concepts.h>
 #include <__format/format_error.h>
 #include <__format/format_parse_context.h>
 #include <__format/formatter.h>
 #include <__format/formatter_integral.h>
 #include <__format/parser_std_format_spec.h>
 #include <__utility/unreachable.h>
 #include <string_view>

libcxx/include/__format/formatter_char.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_CHAR_H
 #define _LIBCPP___FORMAT_FORMATTER_CHAR_H
 
-#include <__availability>
 #include <__concepts/same_as.h>
 #include <__config>
 #include <__format/concepts.h>
 #include <__format/format_parse_context.h>
 #include <__format/formatter.h>
 #include <__format/formatter_integral.h>
 #include <__format/formatter_output.h>
 #include <__format/parser_std_format_spec.h>

libcxx/include/__format/formatter_integer.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_INTEGER_H
 #define _LIBCPP___FORMAT_FORMATTER_INTEGER_H
 
-#include <__availability>
 #include <__concepts/arithmetic.h>
 #include <__config>
 #include <__format/concepts.h>
 #include <__format/format_parse_context.h>
 #include <__format/formatter.h>
 #include <__format/formatter_integral.h>
 #include <__format/formatter_output.h>
 #include <__format/parser_std_format_spec.h>

libcxx/include/__format/formatter_pointer.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_POINTER_H
 #define _LIBCPP___FORMAT_FORMATTER_POINTER_H
 
-#include <__availability>
 #include <__config>
 #include <__format/concepts.h>
 #include <__format/format_parse_context.h>
 #include <__format/formatter.h>
 #include <__format/formatter_integral.h>
 #include <__format/formatter_output.h>
 #include <__format/parser_std_format_spec.h>
 #include <cstddef>

libcxx/include/__format/formatter_string.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_STRING_H
 #define _LIBCPP___FORMAT_FORMATTER_STRING_H
 
-#include <__availability>
 #include <__config>
 #include <__format/concepts.h>
 #include <__format/format_parse_context.h>
 #include <__format/formatter.h>
 #include <__format/formatter_output.h>
 #include <__format/parser_std_format_spec.h>
 #include <__utility/move.h>
 #include <string>

libcxx/include/__format/formatter_tuple.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_TUPLE_H
 #define _LIBCPP___FORMAT_FORMATTER_TUPLE_H
 
 #include <__algorithm/ranges_copy.h>
-#include <__availability>
 #include <__chrono/statically_widen.h>
 #include <__config>
 #include <__format/buffer.h>
 #include <__format/concepts.h>
 #include <__format/format_args.h>
 #include <__format/format_context.h>
 #include <__format/format_error.h>
 #include <__format/format_parse_context.h>

libcxx/include/__format/parser_std_format_spec.h

 
 #include <__algorithm/copy_n.h>
 #include <__algorithm/find_if.h>
 #include <__algorithm/min.h>
 #include <__assert>
 #include <__concepts/arithmetic.h>
 #include <__concepts/same_as.h>
 #include <__config>
-#include <__debug>
 #include <__format/format_arg.h>
 #include <__format/format_error.h>
 #include <__format/format_parse_context.h>
 #include <__format/format_string.h>
 #include <__format/unicode.h>
 #include <__format/width_estimation_table.h>
 #include <__iterator/concepts.h>
 #include <__iterator/readable_traits.h> // iter_value_t

libcxx/include/__format/range_default_formatter.h

 #ifndef _LIBCPP___FORMAT_RANGE_DEFAULT_FORMATTER_H
 #define _LIBCPP___FORMAT_RANGE_DEFAULT_FORMATTER_H
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 #include <__algorithm/ranges_copy.h>
-#include <__availability>
 #include <__chrono/statically_widen.h>
 #include <__concepts/same_as.h>
 #include <__config>
 #include <__format/concepts.h>
 #include <__format/formatter.h>
 #include <__format/range_formatter.h>
 #include <__iterator/back_insert_iterator.h>
 #include <__ranges/concepts.h>

libcxx/include/__format/range_formatter.h

 #ifndef _LIBCPP___FORMAT_RANGE_FORMATTER_H
 #define _LIBCPP___FORMAT_RANGE_FORMATTER_H
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 #include <__algorithm/ranges_copy.h>
-#include <__availability>
 #include <__chrono/statically_widen.h>
 #include <__concepts/same_as.h>
 #include <__config>
 #include <__format/buffer.h>
 #include <__format/concepts.h>
 #include <__format/format_args.h>
 #include <__format/format_context.h>
 #include <__format/format_error.h>

libcxx/include/__hash_table

 #ifndef _LIBCPP___HASH_TABLE
 #define _LIBCPP___HASH_TABLE
 
 #include <__algorithm/max.h>
 #include <__algorithm/min.h>
 #include <__assert>
 #include <__bit/countl.h>
 #include <__config>
-#include <__debug>
+#include <__config_dir/debug.h>
 #include <__functional/hash.h>
 #include <__functional/invoke.h>
 #include <__iterator/iterator_traits.h>
 #include <__memory/addressof.h>
 #include <__memory/allocator_traits.h>
 #include <__memory/compressed_pair.h>
 #include <__memory/pointer_traits.h>
 #include <__memory/swap_allocator.h>

libcxx/include/__iterator/wrap_iter.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___ITERATOR_WRAP_ITER_H
 #define _LIBCPP___ITERATOR_WRAP_ITER_H
 
 #include <__config>
-#include <__debug>
+#include <__config_dir/debug.h>
 #include <__iterator/iterator_traits.h>
 #include <__memory/addressof.h>
 #include <__memory/pointer_traits.h>
 #include <__type_traits/enable_if.h>
 #include <__type_traits/is_convertible.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header

libcxx/include/__locale

 // -*- 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___LOCALE
 #define _LIBCPP___LOCALE
 
-#include <__availability>
 #include <__config>
 #include <__type_traits/make_unsigned.h>
 #include <cctype>
 #include <clocale>
 #include <cstdint>
 #include <cstdlib>
 #include <mutex>
 #include <string>

libcxx/include/__memory/shared_ptr.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___MEMORY_SHARED_PTR_H
 #define _LIBCPP___MEMORY_SHARED_PTR_H
 
-#include <__availability>
 #include <__compare/compare_three_way.h>
 #include <__compare/ordering.h>
 #include <__config>
 #include <__functional/binary_function.h>
 #include <__functional/operations.h>
 #include <__functional/reference_wrapper.h>
 #include <__iterator/access.h>
 #include <__memory/addressof.h>

libcxx/include/__ranges/filter_view.h

 #define _LIBCPP___RANGES_FILTER_VIEW_H
 
 #include <__algorithm/ranges_find_if.h>
 #include <__concepts/constructible.h>
 #include <__concepts/copyable.h>
 #include <__concepts/derived_from.h>
 #include <__concepts/equality_comparable.h>
 #include <__config>
-#include <__debug>
+#include <__config_dir/debug.h>
 #include <__functional/bind_back.h>
 #include <__functional/invoke.h>
 #include <__functional/reference_wrapper.h>
 #include <__iterator/concepts.h>
 #include <__iterator/iter_move.h>
 #include <__iterator/iter_swap.h>
 #include <__iterator/iterator_traits.h>
 #include <__memory/addressof.h>

libcxx/include/__stop_token/stop_callback.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___STOP_TOKEN_STOP_CALLBACK_H
 #define _LIBCPP___STOP_TOKEN_STOP_CALLBACK_H
 
-#include <__availability>
 #include <__concepts/constructible.h>
 #include <__concepts/destructible.h>
 #include <__concepts/invocable.h>
 #include <__config>
 #include <__stop_token/intrusive_shared_ptr.h>
 #include <__stop_token/stop_state.h>
 #include <__stop_token/stop_token.h>
 #include <__type_traits/is_nothrow_constructible.h>

libcxx/include/__stop_token/stop_source.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___STOP_TOKEN_STOP_SOURCE_H
 #define _LIBCPP___STOP_TOKEN_STOP_SOURCE_H
 
-#include <__availability>
 #include <__config>
 #include <__stop_token/intrusive_shared_ptr.h>
 #include <__stop_token/stop_state.h>
 #include <__stop_token/stop_token.h>
 #include <__utility/move.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header

libcxx/include/__stop_token/stop_state.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___STOP_TOKEN_STOP_STATE_H
 #define _LIBCPP___STOP_TOKEN_STOP_STATE_H
 
-#include <__availability>
 #include <__config>
 #include <__stop_token/atomic_unique_lock.h>
 #include <__stop_token/intrusive_list_view.h>
 #include <atomic>
 #include <thread>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header

libcxx/include/__stop_token/stop_token.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___STOP_TOKEN_STOP_TOKEN_H
 #define _LIBCPP___STOP_TOKEN_STOP_TOKEN_H
 
-#include <__availability>
 #include <__config>
 #include <__stop_token/intrusive_shared_ptr.h>
 #include <__stop_token/stop_state.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 

libcxx/include/__thread/poll_with_backoff.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___THREAD_POLL_WITH_BACKOFF_H
 #define _LIBCPP___THREAD_POLL_WITH_BACKOFF_H
 
-#include <__availability>
 #include <__chrono/duration.h>
 #include <__chrono/high_resolution_clock.h>
 #include <__config>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 

libcxx/include/__threading_support

 // -*- 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___THREADING_SUPPORT
 #define _LIBCPP___THREADING_SUPPORT
 
-#include <__availability>
 #include <__chrono/convert_to_timespec.h>
 #include <__chrono/duration.h>
 #include <__compare/ordering.h>
 #include <__config>
 #include <__fwd/hash.h>
 #include <__thread/poll_with_backoff.h>
 #include <errno.h>
 #include <iosfwd>

libcxx/include/__tree

 // -*- 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___TREE
 #define _LIBCPP___TREE
 
 #include <__algorithm/min.h>
 #include <__assert>
 #include <__config>
-#include <__debug>
+#include <__config_dir/debug.h>
 #include <__functional/invoke.h>
 #include <__iterator/distance.h>
 #include <__iterator/iterator_traits.h>
 #include <__iterator/next.h>
 #include <__memory/addressof.h>
 #include <__memory/allocator_traits.h>
 #include <__memory/compressed_pair.h>
 #include <__memory/pointer_traits.h>

libcxx/include/__verbose_abort

 // -*- 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___VERBOSE_ABORT
 #define _LIBCPP___VERBOSE_ABORT
 
-#include <__availability>
 #include <__config>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 

libcxx/include/algorithm

template <class BidirectionalIterator, class Compare>
     constexpr bool     // constexpr in C++20
     prev_permutation(BidirectionalIterator first, BidirectionalIterator last, Compare comp);
 }  // std
 
 */
 
 #include <__assert> // all public C++ headers provide the assertion handler
 #include <__config>
-#include <__debug>
+#include <__config_dir/debug.h>
 #include <cstddef>
 #include <version>
 
 #include <__algorithm/adjacent_find.h>
 #include <__algorithm/all_of.h>
 #include <__algorithm/any_of.h>
 #include <__algorithm/binary_search.h>
 #include <__algorithm/clamp.h>

libcxx/include/any

namespace std {
   template<class ValueType>
     ValueType* any_cast(any* operand) noexcept;
 
 } // namespace std
 
 */
 
 #include <__assert> // all public C++ headers provide the assertion handler
-#include <__availability>
 #include <__config>
 #include <__memory/allocator.h>
 #include <__memory/allocator_destructor.h>
 #include <__memory/allocator_traits.h>
 #include <__memory/unique_ptr.h>
 #include <__type_traits/add_const.h>
 #include <__type_traits/add_pointer.h>
 #include <__type_traits/aligned_storage.h>

libcxx/include/barrier

 
 }
 
 */
 
 #include <__assert> // all public C++ headers provide the assertion handler
 #include <__atomic/atomic_base.h>
 #include <__atomic/memory_order.h>
-#include <__availability>
 #include <__config>
 #include <__memory/unique_ptr.h>
 #include <__thread/poll_with_backoff.h>
 #include <__thread/timed_backoff_policy.h>
 #include <__utility/move.h>
 #include <cstddef>
 #include <cstdint>
 #include <limits>

libcxx/include/charconv

 #include <__charconv/tables.h>
 #include <__charconv/to_chars.h>
 #include <__charconv/to_chars_base_10.h>
 #include <__charconv/to_chars_floating_point.h>
 #include <__charconv/to_chars_integral.h>
 #include <__charconv/to_chars_result.h>
 #include <__charconv/traits.h>
 #include <__config>
-#include <__debug>
+#include <__config_dir/debug.h>
 #include <__system_error/errc.h>
 #include <cmath> // for log2f
 #include <cstdint>
 #include <limits>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif

libcxx/include/fstream

 typedef basic_fstream<wchar_t> wfstream;
 
 }  // std
 
 */
 
 #include <__algorithm/max.h>
 #include <__assert> // all public C++ headers provide the assertion handler
-#include <__availability>
 #include <__config>
 #include <__fwd/fstream.h>
 #include <__locale>
 #include <__utility/move.h>
 #include <__utility/swap.h>
 #include <__utility/unreachable.h>
 #include <cstdio>
 #include <istream>

libcxx/include/functional

POLICY:  For non-variadic implementations, the number of arguments is limited
          will be minimal.
 
 */
 
 #include <__algorithm/search.h>
 #include <__assert> // all public C++ headers provide the assertion handler
 #include <__compare/compare_three_way.h>
 #include <__config>
-#include <__debug>
+#include <__config_dir/debug.h>
 #include <__functional/binary_function.h>
 #include <__functional/binary_negate.h>
 #include <__functional/bind.h>
 #include <__functional/bind_back.h>
 #include <__functional/bind_front.h>
 #include <__functional/binder1st.h>
 #include <__functional/binder2nd.h>
 #include <__functional/boyer_moore_searcher.h>

libcxx/include/future

 
 template <class R, class Alloc> struct uses_allocator<packaged_task<R>, Alloc>;
 
 }  // std
 
 */
 
 #include <__assert> // all public C++ headers provide the assertion handler
-#include <__availability>
 #include <__chrono/duration.h>
 #include <__chrono/time_point.h>
 #include <__config>
 #include <__exception/exception_ptr.h>
 #include <__memory/allocator.h>
 #include <__memory/allocator_arg_t.h>
 #include <__memory/allocator_destructor.h>
 #include <__memory/allocator_traits.h>

libcxx/include/iterator

 template <class E> constexpr const E* data(initializer_list<E> il) noexcept;      // C++17
 
 }  // std
 
 */
 
 #include <__assert> // all public C++ headers provide the assertion handler
 #include <__config>
-#include <__debug>
+#include <__config_dir/debug.h>
 #include <__iterator/access.h>
 #include <__iterator/advance.h>
 #include <__iterator/back_insert_iterator.h>
 #include <__iterator/bounded_iter.h>
 #include <__iterator/common_iterator.h>
 #include <__iterator/concepts.h>
 #include <__iterator/counted_iterator.h>
 #include <__iterator/data.h>

libcxx/include/latch

 }
 
 */
 
 #include <__assert> // all public C++ headers provide the assertion handler
 #include <__atomic/atomic_base.h>
 #include <__atomic/atomic_sync.h>
 #include <__atomic/memory_order.h>
-#include <__availability>
 #include <__config>
 #include <cstddef>
 #include <limits>
 #include <version>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif

libcxx/include/list

 
 #include <__algorithm/comp.h>
 #include <__algorithm/equal.h>
 #include <__algorithm/lexicographical_compare.h>
 #include <__algorithm/lexicographical_compare_three_way.h>
 #include <__algorithm/min.h>
 #include <__assert> // all public C++ headers provide the assertion handler
 #include <__config>
-#include <__debug>
+#include <__config_dir/debug.h>
 #include <__format/enable_insertable.h>
 #include <__iterator/distance.h>
 #include <__iterator/iterator_traits.h>
 #include <__iterator/move_iterator.h>
 #include <__iterator/next.h>
 #include <__iterator/prev.h>
 #include <__iterator/reverse_iterator.h>
 #include <__memory/addressof.h>

libcxx/include/locale

 #include <__algorithm/copy.h>
 #include <__algorithm/equal.h>
 #include <__algorithm/find.h>
 #include <__algorithm/max.h>
 #include <__algorithm/reverse.h>
 #include <__algorithm/unwrap_iter.h>
 #include <__assert> // all public C++ headers provide the assertion handler
 #include <__config>
-#include <__debug>
+#include <__config_dir/debug.h>
 #include <__iterator/access.h>
 #include <__iterator/back_insert_iterator.h>
 #include <__iterator/istreambuf_iterator.h>
 #include <__iterator/ostreambuf_iterator.h>
 #include <__locale>
 #include <__memory/unique_ptr.h>
 #include <__type_traits/make_unsigned.h>
 #include <cerrno>

libcxx/include/module.modulemap.in

 // define the module for __config outside of the top level 'std' module
 // since __config may be included from C headers which may create an
 // include cycle.
 module std_config [system] [extern_c] {
   textual header "__config"
   export *
 }
 
 module std [system] {
   // FIXME: The standard does not require that each of these submodules
   // re-exports its imported modules. We should provide an alternative form of
   // export that issues a warning if a name from the submodule is used, and
module vector {
     export *
   }
   module version {
     header "version"
     export *
   }
 
   // FIXME: These should be private.
-  module __assert            {         header "__assert"            export * }
-  module __availability      { private header "__availability"      export * }
-  module __bit_reference     { private header "__bit_reference"     export * }
-  module __debug             {         header "__debug"             export * }
-  module __hash_table        {         header "__hash_table"        export * }
+  module __assert            {         header "__assert"             export * }
+  module __bit_reference     { private header "__bit_reference"      export * }
+  module __debug             {         header "__config_dir/debug.h" export * }
+  module __hash_table        {         header "__hash_table"         export * }
   module __locale            {
     @requires_LIBCXX_ENABLE_LOCALIZATION@
     private header "__locale" export *
   }
   module __mbstate_t         { private header "__mbstate_t.h"       export * }
   module __node_handle       { private header "__node_handle"       export * }
   module __split_buffer      { private header "__split_buffer"      export * }
   module __std_mbstate_t     { private header "__std_mbstate_t.h"   export * }
   module __threading_support {         header "__threading_support" export * }
   module __tree              {         header "__tree"              export * }
   module __undef_macros      {         header "__undef_macros"      export * }
   module __verbose_abort     {         header "__verbose_abort"     export * }
 
+  module __config_dir {
+    module availability { private header "__config_dir/availability.h"}
+  }
+
   // This one needs to appear after __tree to work around issues with modules in Objective-C++ mode.
   module coroutine {
     header "coroutine"
     export compare
     export *
 
     module __coroutine {
       module coroutine_handle           { private header "__coroutine/coroutine_handle.h" }

libcxx/include/new

 void* operator new  (std::size_t size, void* ptr) noexcept;             // nodiscard in C++20
 void* operator new[](std::size_t size, void* ptr) noexcept;             // nodiscard in C++20
 void  operator delete  (void* ptr, void*) noexcept;
 void  operator delete[](void* ptr, void*) noexcept;
 
 */
 
 #include <__assert> // all public C++ headers provide the assertion handler
-#include <__availability>
 #include <__config>
 #include <__exception/exception.h>
 #include <__type_traits/alignment_of.h>
 #include <__type_traits/is_function.h>
 #include <__type_traits/is_same.h>
 #include <__type_traits/remove_cv.h>
 #include <__verbose_abort>
 #include <cstddef>

libcxx/include/optional

namespace std {
   template<class T>
     optional(T) -> optional<T>;
 
 } // namespace std
 
 */
 
 #include <__assert> // all public C++ headers provide the assertion handler
-#include <__availability>
 #include <__compare/compare_three_way_result.h>
 #include <__compare/three_way_comparable.h>
 #include <__concepts/invocable.h>
 #include <__config>
 #include <__functional/hash.h>
 #include <__functional/invoke.h>
 #include <__functional/reference_wrapper.h>
 #include <__functional/unary_function.h>

libcxx/include/semaphore

 }
 
 */
 
 #include <__assert> // all public C++ headers provide the assertion handler
 #include <__atomic/atomic_base.h>
 #include <__atomic/atomic_sync.h>
 #include <__atomic/memory_order.h>
-#include <__availability>
 #include <__chrono/time_point.h>
 #include <__config>
 #include <__thread/timed_backoff_policy.h>
 #include <__threading_support>
 #include <cstddef>
 #include <limits>
 #include <version>
 

libcxx/include/shared_mutex

 template <class Mutex>
     void swap(shared_lock<Mutex>& x, shared_lock<Mutex>& y) noexcept;
 
 }  // std
 
 */
 
 #include <__assert> // all public C++ headers provide the assertion handler
-#include <__availability>
 #include <__chrono/duration.h>
 #include <__chrono/steady_clock.h>
 #include <__chrono/time_point.h>
 #include <__condition_variable/condition_variable.h>
 #include <__config>
 #include <__memory/addressof.h>
 #include <__mutex/mutex.h>
 #include <__mutex/tag_types.h>

libcxx/include/span

template<class R>
     span(R&&) -> span<remove_reference_t<ranges::range_reference_t<R>>>;
 
 } // namespace std
 
 */
 
 #include <__assert> // all public C++ headers provide the assertion handler
 #include <__config>
-#include <__debug>
+#include <__config_dir/debug.h>
 #include <__fwd/span.h>
 #include <__iterator/bounded_iter.h>
 #include <__iterator/concepts.h>
 #include <__iterator/iterator_traits.h>
 #include <__iterator/wrap_iter.h>
 #include <__memory/pointer_traits.h>
 #include <__ranges/concepts.h>
 #include <__ranges/data.h>

libcxx/include/string

 */
 
 #include <__algorithm/max.h>
 #include <__algorithm/min.h>
 #include <__algorithm/remove.h>
 #include <__algorithm/remove_if.h>
 #include <__assert> // all public C++ headers provide the assertion handler
 #include <__config>
-#include <__debug>
+#include <__config_dir/debug.h>
 #include <__format/enable_insertable.h>
 #include <__functional/hash.h>
 #include <__functional/unary_function.h>
 #include <__fwd/string.h>
 #include <__ios/fpos.h>
 #include <__iterator/distance.h>
 #include <__iterator/iterator_traits.h>
 #include <__iterator/reverse_iterator.h>

libcxx/include/thread

 
 }  // this_thread
 
 }  // std
 
 */
 
 #include <__assert> // all public C++ headers provide the assertion handler
-#include <__availability>
 #include <__chrono/steady_clock.h>
 #include <__chrono/time_point.h>
 #include <__concepts/arithmetic.h>
 #include <__condition_variable/condition_variable.h>
 #include <__config>
 #include <__exception/terminate.h>
 #include <__format/concepts.h>
 #include <__format/format_parse_context.h>

libcxx/include/typeinfo

public:
     virtual const char* what() const noexcept;
 };
 
 }  // std
 
 */
 
 #include <__assert> // all public C++ headers provide the assertion handler
-#include <__availability>
 #include <__config>
 #include <__exception/exception.h>
 #include <__type_traits/is_constant_evaluated.h>
 #include <__verbose_abort>
 #include <cstddef>
 #include <cstdint>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)

libcxx/include/unordered_map

 
 }  // std
 
 */
 
 #include <__algorithm/is_permutation.h>
 #include <__assert> // all public C++ headers provide the assertion handler
 #include <__config>
-#include <__debug>
+#include <__config_dir/debug.h>
 #include <__functional/is_transparent.h>
 #include <__functional/operations.h>
 #include <__hash_table>
 #include <__iterator/distance.h>
 #include <__iterator/erase_if_container.h>
 #include <__iterator/iterator_traits.h>
 #include <__memory/addressof.h>
 #include <__memory/allocator.h>

libcxx/include/unordered_set

operator!=(const unordered_multiset<Value, Hash, Pred, Alloc>& x,
                const unordered_multiset<Value, Hash, Pred, Alloc>& y);
 }  // std
 
 */
 
 #include <__algorithm/is_permutation.h>
 #include <__assert> // all public C++ headers provide the assertion handler
 #include <__config>
-#include <__debug>
+#include <__config_dir/debug.h>
 #include <__functional/is_transparent.h>
 #include <__functional/operations.h>
 #include <__hash_table>
 #include <__iterator/distance.h>
 #include <__iterator/erase_if_container.h>
 #include <__iterator/iterator_traits.h>
 #include <__memory/addressof.h>
 #include <__memory/allocator.h>

libcxx/include/variant

namespace std {
   template <class... Types> struct hash<variant<Types...>>;
   template <> struct hash<monostate>;
 
 } // namespace std
 
 */
 
 #include <__assert> // all public C++ headers provide the assertion handler
-#include <__availability>
 #include <__compare/common_comparison_category.h>
 #include <__compare/compare_three_way_result.h>
 #include <__compare/three_way_comparable.h>
 #include <__config>
 #include <__exception/exception.h>
 #include <__functional/hash.h>
 #include <__functional/invoke.h>
 #include <__functional/operations.h>

libcxx/include/vector

 #include <__algorithm/remove.h>
 #include <__algorithm/remove_if.h>
 #include <__algorithm/rotate.h>
 #include <__algorithm/unwrap_iter.h>
 #include <__assert> // all public C++ headers provide the assertion handler
 #include <__bit_reference>
 #include <__concepts/same_as.h>
 #include <__config>
-#include <__debug>
+#include <__config_dir/debug.h>
 #include <__format/enable_insertable.h>
 #include <__format/formatter.h>
 #include <__format/formatter_bool.h>
 #include <__functional/hash.h>
 #include <__functional/unary_function.h>
 #include <__iterator/advance.h>
 #include <__iterator/distance.h>
 #include <__iterator/iterator_traits.h>

libcxx/src/debug.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
 //
 //===----------------------------------------------------------------------===//
 
 #include <__assert>
 #include <__config>
-#include <__debug>
+#include <__config_dir/debug.h>
 #include <__hash_table>
 #include <algorithm>
 #include <cstdio>
 #include <functional>
 #include <string>
 
 #ifndef _LIBCPP_HAS_NO_THREADS
 #  include <mutex>

libcxx/src/include/ryu/ryu.h

 #define _LIBCPP_SRC_INCLUDE_RYU_RYU_H
 
 // Avoid formatting to keep the changes with the original code minimal.
 // clang-format off
 
 #include <__charconv/chars_format.h>
 #include <__charconv/to_chars_result.h>
 #include <__config>
-#include <__debug>
+#include <__config_dir/debug.h>
 #include <__system_error/errc.h>
 #include <cstdint>
 #include <cstring>
 #include <type_traits>
 
 #include "include/ryu/f2s.h"
 #include "include/ryu/d2s.h"
 #include "include/ryu/d2fixed.h"

libcxx/src/optional.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
 //
 //===----------------------------------------------------------------------===//
 
-#include <__availability>
+#include <__config>
 #include <optional>
 
 namespace std
 {
 
 bad_optional_access::~bad_optional_access() noexcept = default;
 
 const char* bad_optional_access::what() const noexcept {

libcxx/test/support/container_debug_tests.h

 #ifndef _LIBCPP_VERSION
 #error This header may only be used for libc++ tests
 #endif
 
 #ifndef _LIBCPP_ENABLE_DEBUG_MODE
 #error The library must be built with the debug mode enabled in order to use this header
 #endif
 
-#include <__debug>
+#include <__config_dir/debug.h>
 #include <utility>
 #include <cstddef>
 #include <cstdlib>
 #include <cassert>
 
 #include "check_assertion.h"
 #include "test_allocator.h"
 #include "test_macros.h"

libcxx/utils/data/ignore_format.txt

 libcxx/include/__atomic/atomic_lock_free.h
 libcxx/include/__atomic/atomic_sync.h
 libcxx/include/__atomic/check_memory_order.h
 libcxx/include/__atomic/contention_t.h
 libcxx/include/__atomic/cxx_atomic_impl.h
 libcxx/include/__atomic/fence.h
 libcxx/include/__atomic/kill_dependency.h
 libcxx/include/__atomic/memory_order.h
-libcxx/include/__availability
 libcxx/include/barrier
 libcxx/include/__bit/bit_cast.h
 libcxx/include/__bit/bit_ceil.h
 libcxx/include/__bit/byteswap.h
 libcxx/include/__bit/countl.h
 libcxx/include/__bit/countr.h
 libcxx/include/__bit/endian.h
 libcxx/include/__bit/popcount.h

 libcxx/include/__concepts/regular.h
 libcxx/include/__concepts/relation.h
 libcxx/include/__concepts/same_as.h
 libcxx/include/__concepts/semiregular.h
 libcxx/include/__concepts/swappable.h
 libcxx/include/__concepts/totally_ordered.h
 libcxx/include/condition_variable
 libcxx/include/__config
+libcxx/include/__config_dir/availability.h
+libcxx/include/__config_dir/base.h
+libcxx/include/__config_dir/debug.h
 libcxx/include/__coroutine/coroutine_handle.h
 libcxx/include/__coroutine/coroutine_traits.h
 libcxx/include/__coroutine/noop_coroutine_handle.h
 libcxx/include/__coroutine/trivial_awaitables.h
 libcxx/include/cstddef
 libcxx/include/ctype.h
 libcxx/include/cuchar
-libcxx/include/__debug
 libcxx/include/__debug_utils/randomize_range.h
 libcxx/include/deque
 libcxx/include/errno.h
 libcxx/include/expected
 libcxx/include/__expected/expected.h
 libcxx/include/experimental/__config
 libcxx/include/experimental/iterator
 libcxx/include/experimental/map

libcxx/utils/generate_feature_test_macro_components.py

 #                   `libcxx_guard` must also be provided. This field is used
 #                   only to generate the unit tests for the feature-test macros.
 #                   It can't depend on macros defined in <__config> because the
 #                   `test/std/` parts of the test suite are intended to be
 #                   portable to any C++ standard library implementation, not
 #                   just libc++. It may depend on
 #                    * macros defined by the compiler itself, or
 #                    * macros generated by CMake.
-#                   In some cases we add also depend on macros defined in <__availability>.
+#                   In some cases we add also depend on macros defined in
+#                   <__config_dir/availability.h>.
 # libcxx_guard      An optional string field. When this field is provided,
 #                   `test_suite_guard` must also be provided. This field is used
 #                   only to guard the feature-test macro in <version>. It may
 #                   be the same as `test_suite_guard`, or it may depend on
 #                   macros defined in <__config>.
 # unimplemented     An optional Boolean field with the value `True`. This field
 #                   is only used when a feature isn't fully implemented. Once
 #                   you've fully implemented the feature, you should remove

libcxx/utils/generate_iwyu_mapping.py

for i in include.iterdir():
             continue
 
         if i.name.endswith(".h"):
             c_headers.append(i.name)
 
     result = []
     temporary_mappings = {"__locale_dir": "locale"}
     for i in detail_directories:
+        if i == "__config_dir":
+            continue
         public_header = temporary_mappings.get(i, i.lstrip("_"))
         result.append(f'{generate(f"@<{i}/.*>", public_header)},')
 
     for i in detail_files:
         public = []
         if i == "__assert":
             continue
-        elif i == "__availability":
-            continue
         elif i == "__bit_reference":
             continue
         elif i == "__bits":
             public = ["bits"]
         elif i == "__config_site.in":
             continue
         elif i == "__config":
             continue
-        elif i == "__debug":
-            continue
         elif i == "__errc":
             continue
         elif i == "__hash_table":
             public = ["unordered_map", "unordered_set"]
         elif i == "__locale":
             public = ["locale"]
         elif i == "__mbstate_t.h":
             continue

libcxx/utils/libcxx/test/header_information.py

lit_header_restrictions = {
     "thread": "// UNSUPPORTED: no-threads, c++03",
     "wchar.h": "// UNSUPPORTED: no-wide-characters",
     "wctype.h": "// UNSUPPORTED: no-wide-characters",
 }
 
 private_headers_still_public_in_modules = [
     "__assert",
     "__config",
+    "__config_dir/debug.h",
     "__config_site.in",
-    "__debug",
     "__hash_table",
     "__threading_support",
     "__tree",
     "__undef_macros",
     "__verbose_abort",
 ]
 
 # This table was produced manually, by grepping the TeX source of the Standard's