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- // -*- 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
- #include <__config>
- #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
- // of a platform, Clang provides availability attributes [1]. These attributes
- // can be placed on declarations and are used to describe the life cycle of a
- // symbol in the library.
- //
- // The main goal is to ensure a compile-time error if a symbol that hasn't been
- // introduced in a previously released library is used in a program that targets
- // that previously released library. Normally, this would be a load-time error
- // when one tries to launch the program against the older library.
- //
- // For example, the filesystem library was introduced in the dylib in macOS 10.15.
- // If a user compiles on a macOS 10.15 host but targets macOS 10.13 with their
- // program, the compiler would normally not complain (because the required
- // declarations are in the headers), but the dynamic loader would fail to find
- // the symbols when actually trying to launch the program on macOS 10.13. To
- // turn this into a compile-time issue instead, declarations are annotated with
- // when they were introduced, and the compiler can produce a diagnostic if the
- // program references something that isn't available on the deployment target.
- //
- // This mechanism is general in nature, and any vendor can add their markup to
- // the library (see below). Whenever a new feature is added that requires support
- // in the shared library, two macros are added below to allow marking the feature
- // as unavailable:
- // 1. A macro named `_LIBCPP_AVAILABILITY_HAS_NO_<feature>` which must be defined
- // exactly when compiling for a target that doesn't support the feature.
- // 2. A macro named `_LIBCPP_AVAILABILITY_<feature>`, which must always be defined
- // and must expand to the proper availability attribute for the platform.
- //
- // When vendors decide to ship the feature as part of their shared library, they
- // can update these macros appropriately for their platform, and the library will
- // use those to provide an optimal user experience.
- //
- // Furthermore, many features in the standard library have corresponding
- // feature-test macros. The `_LIBCPP_AVAILABILITY_HAS_NO_<feature>` macros
- // are checked by the corresponding feature-test macros generated by
- // generate_feature_test_macro_components.py to ensure that the library
- // doesn't announce a feature as being implemented if it is unavailable on
- // the deployment target.
- //
- // Note that this mechanism is disabled by default in the "upstream" libc++.
- // Availability annotations are only meaningful when shipping libc++ inside
- // a platform (i.e. as a system library), and so vendors that want them should
- // turn those annotations on at CMake configuration time.
- //
- // [1]: https://clang.llvm.org/docs/AttributeReference.html#availability
- // For backwards compatibility, allow users to define _LIBCPP_DISABLE_AVAILABILITY
- // for a while.
- #if defined(_LIBCPP_DISABLE_AVAILABILITY)
- # if !defined(_LIBCPP_HAS_NO_VENDOR_AVAILABILITY_ANNOTATIONS)
- # define _LIBCPP_HAS_NO_VENDOR_AVAILABILITY_ANNOTATIONS
- # endif
- #endif
- // Availability markup is disabled when building the library, or when a non-Clang
- // compiler is used because only Clang supports the necessary attributes.
- // doesn't support the proper attributes.
- #if defined(_LIBCPP_BUILDING_LIBRARY) || defined(_LIBCXXABI_BUILDING_LIBRARY) || !defined(_LIBCPP_COMPILER_CLANG_BASED)
- # if !defined(_LIBCPP_HAS_NO_VENDOR_AVAILABILITY_ANNOTATIONS)
- # define _LIBCPP_HAS_NO_VENDOR_AVAILABILITY_ANNOTATIONS
- # endif
- #endif
- #if defined(_LIBCPP_HAS_NO_VENDOR_AVAILABILITY_ANNOTATIONS)
- // These macros control the availability of std::bad_optional_access and
- // other exception types. These were put in the shared library to prevent
- // code bloat from every user program defining the vtable for these exception
- // types.
- //
- // Note that when exceptions are disabled, the methods that normally throw
- // these exceptions can be used even on older deployment targets, but those
- // methods will abort instead of throwing.
- # define _LIBCPP_AVAILABILITY_HAS_BAD_OPTIONAL_ACCESS 1
- # define _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS
- # define _LIBCPP_AVAILABILITY_HAS_BAD_VARIANT_ACCESS 1
- # define _LIBCPP_AVAILABILITY_BAD_VARIANT_ACCESS
- # define _LIBCPP_AVAILABILITY_HAS_BAD_ANY_CAST 1
- # define _LIBCPP_AVAILABILITY_BAD_ANY_CAST
- // These macros control the availability of all parts of <filesystem> that
- // depend on something in the dylib.
- # define _LIBCPP_AVAILABILITY_HAS_FILESYSTEM_LIBRARY 1
- # define _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY
- # define _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY_PUSH
- # define _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY_POP
- // This controls the availability of the C++20 synchronization library,
- // which requires shared library support for various operations
- // (see libcxx/src/atomic.cpp). This includes <barier>, <latch>,
- // <semaphore>, and notification functions on std::atomic.
- # define _LIBCPP_AVAILABILITY_HAS_SYNC 1
- # define _LIBCPP_AVAILABILITY_SYNC
- // 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.
- //
- // TODO: Enable additional explicit instantiations on GCC once it supports exclude_from_explicit_instantiation,
- // or once libc++ doesn't use the attribute anymore.
- // TODO: Enable them on Windows once https://llvm.org/PR41018 has been fixed.
- # if !defined(_LIBCPP_COMPILER_GCC) && !defined(_WIN32)
- # define _LIBCPP_AVAILABILITY_HAS_ADDITIONAL_IOSTREAM_EXPLICIT_INSTANTIATIONS_1 1
- # else
- # define _LIBCPP_AVAILABILITY_HAS_ADDITIONAL_IOSTREAM_EXPLICIT_INSTANTIATIONS_1 0
- # endif
- // This controls the availability of floating-point std::to_chars functions.
- // These overloads were added later than the integer overloads.
- # define _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT 1
- # define _LIBCPP_AVAILABILITY_TO_CHARS_FLOATING_POINT
- // This controls whether the library claims to provide a default verbose
- // termination function, and consequently whether the headers will try
- // to use it when the mechanism isn't overriden at compile-time.
- # define _LIBCPP_AVAILABILITY_HAS_VERBOSE_ABORT 1
- # define _LIBCPP_AVAILABILITY_VERBOSE_ABORT
- // This controls the availability of the C++17 std::pmr library,
- // which is implemented in large part in the built library.
- # define _LIBCPP_AVAILABILITY_HAS_PMR 1
- # define _LIBCPP_AVAILABILITY_PMR
- // These macros controls the availability of __cxa_init_primary_exception
- // in the built library, which std::make_exception_ptr might use
- // (see libcxx/include/__exception/exception_ptr.h).
- # define _LIBCPP_AVAILABILITY_HAS_INIT_PRIMARY_EXCEPTION 1
- # define _LIBCPP_AVAILABILITY_INIT_PRIMARY_EXCEPTION
- // This controls the availability of C++23 <print>, which
- // has a dependency on the built library (it needs access to
- // the underlying buffer types of std::cout, std::cerr, and std::clog.
- # define _LIBCPP_AVAILABILITY_HAS_PRINT 1
- # define _LIBCPP_AVAILABILITY_PRINT
- // This controls the availability of the C++20 time zone database.
- // The parser code is built in the library.
- # define _LIBCPP_AVAILABILITY_HAS_TZDB 1
- # define _LIBCPP_AVAILABILITY_TZDB
- #elif defined(__APPLE__)
- # define _LIBCPP_AVAILABILITY_HAS_BAD_OPTIONAL_ACCESS \
- (!defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) || __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ >= 50000)
- # define _LIBCPP_AVAILABILITY_HAS_BAD_VARIANT_ACCESS _LIBCPP_AVAILABILITY_HAS_BAD_OPTIONAL_ACCESS
- # define _LIBCPP_AVAILABILITY_HAS_BAD_ANY_CAST _LIBCPP_AVAILABILITY_HAS_BAD_OPTIONAL_ACCESS
- # define _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS __attribute__((availability(watchos, strict, introduced = 5.0)))
- # define _LIBCPP_AVAILABILITY_BAD_VARIANT_ACCESS _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS
- # define _LIBCPP_AVAILABILITY_BAD_ANY_CAST _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS
- // TODO: Update once this is released
- # define _LIBCPP_AVAILABILITY_HAS_INIT_PRIMARY_EXCEPTION 0
- # define _LIBCPP_AVAILABILITY_INIT_PRIMARY_EXCEPTION __attribute__((unavailable))
- // <filesystem>
- // clang-format off
- # if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 101500) || \
- (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 130000) || \
- (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 130000) || \
- (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 60000)
- // clang-format on
- # define _LIBCPP_AVAILABILITY_HAS_FILESYSTEM_LIBRARY 0
- # else
- # define _LIBCPP_AVAILABILITY_HAS_FILESYSTEM_LIBRARY 1
- # endif
- # define _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY \
- __attribute__((availability(macos, strict, introduced = 10.15))) \
- __attribute__((availability(ios, strict, introduced = 13.0))) \
- __attribute__((availability(tvos, strict, introduced = 13.0))) \
- __attribute__((availability(watchos, strict, introduced = 6.0)))
- // clang-format off
- # define _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY_PUSH \
- _Pragma("clang attribute push(__attribute__((availability(macos,strict,introduced=10.15))), apply_to=any(function,record))") \
- _Pragma("clang attribute push(__attribute__((availability(ios,strict,introduced=13.0))), apply_to=any(function,record))") \
- _Pragma("clang attribute push(__attribute__((availability(tvos,strict,introduced=13.0))), apply_to=any(function,record))") \
- _Pragma("clang attribute push(__attribute__((availability(watchos,strict,introduced=6.0))), apply_to=any(function,record))")
- # define _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY_POP \
- _Pragma("clang attribute pop") \
- _Pragma("clang attribute pop") \
- _Pragma("clang attribute pop") \
- _Pragma("clang attribute pop")
- // clang-format on
- // std::to_chars(floating-point)
- // clang-format off
- # if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 130300) || \
- (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 160300) || \
- (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 160300) || \
- (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 90300)
- // clang-format on
- # define _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT 0
- # else
- # define _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT 1
- # endif
- # define _LIBCPP_AVAILABILITY_TO_CHARS_FLOATING_POINT \
- __attribute__((availability(macos, strict, introduced = 13.3))) \
- __attribute__((availability(ios, strict, introduced = 16.3))) \
- __attribute__((availability(tvos, strict, introduced = 16.3))) \
- __attribute__((availability(watchos, strict, introduced = 9.3)))
- // c++20 synchronization library
- // clang-format off
- # if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 110000) || \
- (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 140000) || \
- (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 140000) || \
- (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 70000)
- // clang-format on
- # define _LIBCPP_AVAILABILITY_HAS_SYNC 0
- # else
- # define _LIBCPP_AVAILABILITY_HAS_SYNC 1
- # endif
- # define _LIBCPP_AVAILABILITY_SYNC \
- __attribute__((availability(macos, strict, introduced = 11.0))) \
- __attribute__((availability(ios, strict, introduced = 14.0))) \
- __attribute__((availability(tvos, strict, introduced = 14.0))) \
- __attribute__((availability(watchos, strict, introduced = 7.0)))
- // __libcpp_verbose_abort
- // TODO: Update once this is released
- # define _LIBCPP_AVAILABILITY_HAS_VERBOSE_ABORT 0
- # define _LIBCPP_AVAILABILITY_VERBOSE_ABORT __attribute__((unavailable))
- // std::pmr
- // clang-format off
- # if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 140000) || \
- (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 170000) || \
- (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 170000) || \
- (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 100000)
- // clang-format on
- # define _LIBCPP_AVAILABILITY_HAS_PMR 0
- # else
- # define _LIBCPP_AVAILABILITY_HAS_PMR 1
- # endif
- // TODO: Enable std::pmr markup once https://github.com/llvm/llvm-project/issues/40340 has been fixed
- // Until then, it is possible for folks to try to use `std::pmr` when back-deploying to targets that don't support
- // it and it'll be a load-time error, but we don't have a good alternative because the library won't compile if we
- // use availability annotations until that bug has been fixed.
- # if 0
- # define _LIBCPP_AVAILABILITY_PMR \
- __attribute__((availability(macos, strict, introduced = 14.0))) \
- __attribute__((availability(ios, strict, introduced = 17.0))) \
- __attribute__((availability(tvos, strict, introduced = 17.0))) \
- __attribute__((availability(watchos, strict, introduced = 10.0)))
- # else
- # define _LIBCPP_AVAILABILITY_PMR
- # endif
- # define _LIBCPP_AVAILABILITY_HAS_TZDB 0
- # define _LIBCPP_AVAILABILITY_TZDB __attribute__((unavailable))
- // Warning: This availability macro works differently than the other macros.
- // The dylib part of print is not needed on Apple platforms. Therefore when
- // the macro is not available the code calling the dylib is commented out.
- // The macro _LIBCPP_AVAILABILITY_PRINT is not used.
- # define _LIBCPP_AVAILABILITY_HAS_PRINT 0
- # define _LIBCPP_AVAILABILITY_PRINT __attribute__((unavailable))
- // clang-format off
- # if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 120000) || \
- (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 150000) || \
- (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 150000) || \
- (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 80000)
- // clang-format on
- # define _LIBCPP_AVAILABILITY_HAS_ADDITIONAL_IOSTREAM_EXPLICIT_INSTANTIATIONS_1 0
- # else
- # define _LIBCPP_AVAILABILITY_HAS_ADDITIONAL_IOSTREAM_EXPLICIT_INSTANTIATIONS_1 1
- # endif
- #else
- // ...New vendors can add availability markup here...
- # error \
- "It looks like you're trying to enable vendor availability markup, but you haven't defined the corresponding macros yet!"
- #endif
- // Define availability attributes that depend on _LIBCPP_HAS_NO_EXCEPTIONS.
- // Those are defined in terms of the availability attributes above, and
- // should not be vendor-specific.
- #if defined(_LIBCPP_HAS_NO_EXCEPTIONS)
- # define _LIBCPP_AVAILABILITY_THROW_BAD_ANY_CAST
- # define _LIBCPP_AVAILABILITY_THROW_BAD_OPTIONAL_ACCESS
- # define _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
- #else
- # 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
- // Define availability attributes that depend on both
- // _LIBCPP_HAS_NO_EXCEPTIONS and _LIBCPP_HAS_NO_RTTI.
- #if defined(_LIBCPP_HAS_NO_EXCEPTIONS) || defined(_LIBCPP_HAS_NO_RTTI)
- # undef _LIBCPP_AVAILABILITY_HAS_INIT_PRIMARY_EXCEPTION
- # undef _LIBCPP_AVAILABILITY_INIT_PRIMARY_EXCEPTION
- # define _LIBCPP_AVAILABILITY_HAS_INIT_PRIMARY_EXCEPTION 0
- # define _LIBCPP_AVAILABILITY_INIT_PRIMARY_EXCEPTION
- #endif
- #endif // _LIBCPP___AVAILABILITY
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