| // -*- 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 the compiler |
| // doesn't support the proper attributes. |
| #if defined(_LIBCPP_BUILDING_LIBRARY) || \ |
| defined(_LIBCXXABI_BUILDING_LIBRARY) || \ |
| !__has_feature(attribute_availability_with_strict) || \ |
| !__has_feature(attribute_availability_in_templates) || \ |
| !__has_extension(pragma_clang_attribute_external_declaration) |
| # 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 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 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 |
| |
| // 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 |
| |
| // 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 |
| |
| // 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 |
| |
| #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 |
| |
| // <filesystem> |
| # 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) |
| # 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))) |
| # 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") |
| |
| // std::to_chars(floating-point) |
| # 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) |
| # 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 |
| # 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) |
| # 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 |
| # 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) |
| # 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)) |
| |
| # 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) |
| # 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 |
| |
| #endif // _LIBCPP___AVAILABILITY |
