[libcxx-commits] [libcxx] 23e1ed6 - [libc++] Split up ABI and platform configuration to their own headers (#90863)
via libcxx-commits
libcxx-commits at lists.llvm.org
Tue May 28 04:22:11 PDT 2024
Author: Louis Dionne
Date: 2024-05-28T07:22:06-04:00
New Revision: 23e1ed65c2c3eb1f80f7eeb4897ec843492c5451
URL: https://github.com/llvm/llvm-project/commit/23e1ed65c2c3eb1f80f7eeb4897ec843492c5451
DIFF: https://github.com/llvm/llvm-project/commit/23e1ed65c2c3eb1f80f7eeb4897ec843492c5451.diff
LOG: [libc++] Split up ABI and platform configuration to their own headers (#90863)
This is a first step towards splitting up the <__config> header. The
<__config> header is large and rather disorganized at this point,
leading to confusion and subtle mistakes. For example, we never noticed
that the string layout used on arm64 was only enabled for the Clang
compiler, as the setting being in the compiler == clang block was
probably never intentional.
The danger of splitting up the <__config> header is to implicitly use
undefined macros that should have been defined prior to their usage,
however this can be remediated with -Wundef and we've started moving
towards -Wundef enforceable macros.
Added:
libcxx/include/__configuration/abi.h
libcxx/include/__configuration/compiler.h
libcxx/include/__configuration/platform.h
Modified:
libcxx/include/CMakeLists.txt
libcxx/include/__config
libcxx/include/module.modulemap
libcxx/utils/generate_iwyu_mapping.py
Removed:
################################################################################
diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
index 33ee5b26bd621..161d7a7d215bd 100644
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -314,6 +314,9 @@ set(files
__concepts/totally_ordered.h
__condition_variable/condition_variable.h
__config
+ __configuration/abi.h
+ __configuration/compiler.h
+ __configuration/platform.h
__coroutine/coroutine_handle.h
__coroutine/coroutine_traits.h
__coroutine/noop_coroutine_handle.h
diff --git a/libcxx/include/__config b/libcxx/include/__config
index 104a244cc82cc..e048dad52c466 100644
--- a/libcxx/include/__config
+++ b/libcxx/include/__config
@@ -11,41 +11,16 @@
#define _LIBCPP___CONFIG
#include <__config_site>
+#include <__configuration/abi.h>
+#include <__configuration/compiler.h>
+#include <__configuration/platform.h>
#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
-# define _LIBCPP_GCC_VER (__GNUC__ * 100 + __GNUC_MINOR__)
-#endif
-
#ifdef __cplusplus
-// Warn if a compiler version is used that is not supported anymore
-// LLVM RELEASE Update the minimum compiler versions
-# if defined(_LIBCPP_CLANG_VER)
-# if _LIBCPP_CLANG_VER < 1700
-# warning "Libc++ only supports Clang 17 and later"
-# endif
-# elif defined(_LIBCPP_APPLE_CLANG_VER)
-# if _LIBCPP_APPLE_CLANG_VER < 1500
-# warning "Libc++ only supports AppleClang 15 and later"
-# endif
-# elif defined(_LIBCPP_GCC_VER)
-# if _LIBCPP_GCC_VER < 1300
-# warning "Libc++ only supports GCC 13 and later"
-# endif
-# endif
-
// The attributes supported by clang are documented at https://clang.llvm.org/docs/AttributeReference.html
// _LIBCPP_VERSION represents the version of libc++, which matches the version of LLVM.
@@ -79,135 +54,6 @@
# 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
-
-// ABI {
-
-# 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
-// 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 on platforms that sign and authenticate vtable function pointers
-// because it changes the mangling of the virtual function located in the vtable, which
-// changes how it gets signed.
-# 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
diff erent result,
-// which means that hashing the same object in translation units built against
-//
diff erent 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
-// Define std::array/std::string_view iterators to be __wrap_iters instead of raw
-// pointers, which prevents people from relying on a non-portable implementation
-// detail. This is especially useful because enabling bounded iterators hardening
-// requires code not to make these assumptions.
-# define _LIBCPP_ABI_USE_WRAP_ITER_IN_STD_ARRAY
-# define _LIBCPP_ABI_USE_WRAP_ITER_IN_STD_STRING_VIEW
-# 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__) && __FreeBSD__ < 14
-# define _LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR
-# endif
-# endif
-
-// We had some bugs where we use [[no_unique_address]] together with construct_at,
-// which causes UB as the call on construct_at could write to overlapping subobjects
-//
-// https://github.com/llvm/llvm-project/issues/70506
-// https://github.com/llvm/llvm-project/issues/70494
-//
-// To fix the bug we had to change the ABI of some classes to remove [[no_unique_address]] under certain conditions.
-// The macro below is used for all classes whose ABI have changed as part of fixing these bugs.
-# define _LIBCPP_ABI_LLVM18_NO_UNIQUE_ADDRESS __attribute__((__abi_tag__("llvm18_nua")))
-
-// Changes the iterator type of select containers (see below) to a bounded iterator that keeps track of whether it's
-// within the bounds of the original container and asserts it on every dereference.
-//
-// ABI impact: changes the iterator type of the relevant containers.
-//
-// Supported containers:
-// - `span`;
-// - `string_view`;
-// - `array`.
-// #define _LIBCPP_ABI_BOUNDED_ITERATORS
-
-// } ABI
-
// HARDENING {
// TODO(hardening): deprecate this in LLVM 19.
@@ -411,31 +257,10 @@ _LIBCPP_HARDENING_MODE_DEBUG
# define _LIBCPP_HAS_NO_EXPERIMENTAL_SYNCSTREAM
# 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
-# ifndef __BYTE_ORDER__
-# error \
- "Your compiler doesn't seem to define __BYTE_ORDER__, which is required by libc++ to know the endianness of your target platform"
-# endif
-
-# 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__
-
# if defined(_WIN32)
# define _LIBCPP_WIN32API
# define _LIBCPP_SHORT_WCHAR 1
@@ -547,19 +372,6 @@ typedef __char32_t char32_t;
# if defined(_LIBCPP_COMPILER_CLANG_BASED)
-# if defined(__APPLE__)
-# if defined(__i386__) || defined(__x86_64__)
-// use old string layout on x86_64 and i386
-# elif defined(__arm__)
-// use old string layout on arm (which does not include aarch64/arm64), except on watch ABIs
-# if defined(__ARM_ARCH_7K__) && __ARM_ARCH_7K__ >= 2
-# define _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
-# endif
-# else
-# define _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
-# endif
-# endif
-
// Objective-C++ features (opt-in)
# if __has_feature(objc_arc)
# define _LIBCPP_HAS_OBJC_ARC
diff --git a/libcxx/include/__configuration/abi.h b/libcxx/include/__configuration/abi.h
new file mode 100644
index 0000000000000..c570b9aaba48d
--- /dev/null
+++ b/libcxx/include/__configuration/abi.h
@@ -0,0 +1,147 @@
+// -*- 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___CONFIGURATION_ABI_H
+#define _LIBCPP___CONFIGURATION_ABI_H
+
+#include <__config_site>
+#include <__configuration/compiler.h>
+#include <__configuration/platform.h>
+
+#ifndef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
+# pragma GCC system_header
+#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
+// 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 on platforms that sign and authenticate vtable function pointers
+// because it changes the mangling of the virtual function located in the vtable, which
+// changes how it gets signed.
+# 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
diff erent result,
+// which means that hashing the same object in translation units built against
+//
diff erent 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
+// Define std::array/std::string_view iterators to be __wrap_iters instead of raw
+// pointers, which prevents people from relying on a non-portable implementation
+// detail. This is especially useful because enabling bounded iterators hardening
+// requires code not to make these assumptions.
+# define _LIBCPP_ABI_USE_WRAP_ITER_IN_STD_ARRAY
+# define _LIBCPP_ABI_USE_WRAP_ITER_IN_STD_STRING_VIEW
+#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__) && __FreeBSD__ < 14
+# define _LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR
+# endif
+#endif
+
+// We had some bugs where we use [[no_unique_address]] together with construct_at,
+// which causes UB as the call on construct_at could write to overlapping subobjects
+//
+// https://github.com/llvm/llvm-project/issues/70506
+// https://github.com/llvm/llvm-project/issues/70494
+//
+// To fix the bug we had to change the ABI of some classes to remove [[no_unique_address]] under certain conditions.
+// The macro below is used for all classes whose ABI have changed as part of fixing these bugs.
+#define _LIBCPP_ABI_LLVM18_NO_UNIQUE_ADDRESS __attribute__((__abi_tag__("llvm18_nua")))
+
+// Changes the iterator type of select containers (see below) to a bounded iterator that keeps track of whether it's
+// within the bounds of the original container and asserts it on every dereference.
+//
+// ABI impact: changes the iterator type of the relevant containers.
+//
+// Supported containers:
+// - `span`;
+// - `string_view`;
+// - `array`.
+// #define _LIBCPP_ABI_BOUNDED_ITERATORS
+
+#if defined(_LIBCPP_COMPILER_CLANG_BASED)
+# if defined(__APPLE__)
+# if defined(__i386__) || defined(__x86_64__)
+// use old string layout on x86_64 and i386
+# elif defined(__arm__)
+// use old string layout on arm (which does not include aarch64/arm64), except on watch ABIs
+# if defined(__ARM_ARCH_7K__) && __ARM_ARCH_7K__ >= 2
+# define _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
+# endif
+# else
+# define _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
+# endif
+# endif
+#endif
+
+#endif // _LIBCPP___CONFIGURATION_ABI_H
diff --git a/libcxx/include/__configuration/compiler.h b/libcxx/include/__configuration/compiler.h
new file mode 100644
index 0000000000000..a9fc3498220ab
--- /dev/null
+++ b/libcxx/include/__configuration/compiler.h
@@ -0,0 +1,51 @@
+// -*- 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___CONFIGURATION_COMPILER_H
+#define _LIBCPP___CONFIGURATION_COMPILER_H
+
+#include <__config_site>
+
+#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
+# define _LIBCPP_GCC_VER (__GNUC__ * 100 + __GNUC_MINOR__)
+#endif
+
+#ifdef __cplusplus
+
+// Warn if a compiler version is used that is not supported anymore
+// LLVM RELEASE Update the minimum compiler versions
+# if defined(_LIBCPP_CLANG_VER)
+# if _LIBCPP_CLANG_VER < 1700
+# warning "Libc++ only supports Clang 17 and later"
+# endif
+# elif defined(_LIBCPP_APPLE_CLANG_VER)
+# if _LIBCPP_APPLE_CLANG_VER < 1500
+# warning "Libc++ only supports AppleClang 15 and later"
+# endif
+# elif defined(_LIBCPP_GCC_VER)
+# if _LIBCPP_GCC_VER < 1300
+# warning "Libc++ only supports GCC 13 and later"
+# endif
+# endif
+
+#endif
+
+#endif // _LIBCPP___CONFIGURATION_COMPILER_H
diff --git a/libcxx/include/__configuration/platform.h b/libcxx/include/__configuration/platform.h
new file mode 100644
index 0000000000000..27f68d04e8a8d
--- /dev/null
+++ b/libcxx/include/__configuration/platform.h
@@ -0,0 +1,54 @@
+// -*- 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___CONFIGURATION_PLATFORM_H
+#define _LIBCPP___CONFIGURATION_PLATFORM_H
+
+#include <__config_site>
+
+#ifndef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
+# pragma GCC system_header
+#endif
+
+#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
+
+// 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__)
+
+#ifndef __BYTE_ORDER__
+# error \
+ "Your compiler doesn't seem to define __BYTE_ORDER__, which is required by libc++ to know the endianness of your target platform"
+#endif
+
+#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 // _LIBCPP___CONFIGURATION_PLATFORM_H
diff --git a/libcxx/include/module.modulemap b/libcxx/include/module.modulemap
index ca0fbe2cc7ae8..1f7c2a183f63d 100644
--- a/libcxx/include/module.modulemap
+++ b/libcxx/include/module.modulemap
@@ -583,6 +583,9 @@ module std_private_fwd_bit_reference [system] {
}
module std_private_config [system] {
textual header "__config"
+ textual header "__configuration/abi.h"
+ textual header "__configuration/compiler.h"
+ textual header "__configuration/platform.h"
export *
}
module std_private_hash_table [system] {
diff --git a/libcxx/utils/generate_iwyu_mapping.py b/libcxx/utils/generate_iwyu_mapping.py
index b780fd54c6a4b..b0ebe1b9e93d2 100644
--- a/libcxx/utils/generate_iwyu_mapping.py
+++ b/libcxx/utils/generate_iwyu_mapping.py
@@ -22,6 +22,8 @@ def IWYU_mapping(header: str) -> typing.Optional[typing.List[str]]:
return ["bits"]
elif header in ("__bit_reference", "__fwd/bit_reference.h"):
return ["bitset", "vector"]
+ elif re.match("__configuration/.+", header) or header == "__config":
+ return ["version"]
elif header == "__hash_table":
return ["unordered_map", "unordered_set"]
elif header == "__locale":
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