libcxx/include/__cxx03/__configuration/availability.h

   1 // -*- C++ -*-
   2 //===----------------------------------------------------------------------===//
   3 //
   4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   5 // See https://llvm.org/LICENSE.txt for license information.
   6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 #ifndef _LIBCPP___CONFIGURATION_AVAILABILITY_H
  11 #define _LIBCPP___CONFIGURATION_AVAILABILITY_H
  12
  13 #include <__cxx03/__configuration/compiler.h>
  14 #include <__cxx03/__configuration/language.h>
  15
  16 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  17 #  pragma GCC system_header
  18 #endif
  19
  20 // Libc++ is shipped by various vendors. In particular, it is used as a system
  21 // library on macOS, iOS and other Apple platforms. In order for users to be
  22 // able to compile a binary that is intended to be deployed to an older version
  23 // of a platform, Clang provides availability attributes [1]. These attributes
  24 // can be placed on declarations and are used to describe the life cycle of a
  25 // symbol in the library.
  26 //
  27 // The main goal is to ensure a compile-time error if a symbol that hasn't been
  28 // introduced in a previously released library is used in a program that targets
  29 // that previously released library. Normally, this would be a load-time error
  30 // when one tries to launch the program against the older library.
  31 //
  32 // For example, the filesystem library was introduced in the dylib in LLVM 9.
  33 // On Apple platforms, this corresponds to macOS 10.15. If a user compiles on
  34 // a macOS 10.15 host but targets macOS 10.13 with their program, the compiler
  35 // would normally not complain (because the required declarations are in the
  36 // headers), but the dynamic loader would fail to find the symbols when actually
  37 // trying to launch the program on macOS 10.13. To turn this into a compile-time
  38 // issue instead, declarations are annotated with when they were introduced, and
  39 // the compiler can produce a diagnostic if the program references something that
  40 // isn't available on the deployment target.
  41 //
  42 // This mechanism is general in nature, and any vendor can add their markup to
  43 // the library (see below). Whenever a new feature is added that requires support
  44 // in the shared library, two macros are added below to allow marking the feature
  45 // as unavailable:
  46 // 1. A macro named `_LIBCPP_AVAILABILITY_HAS_<feature>` which must be defined
  47 //    to `_LIBCPP_INTRODUCED_IN_<version>` for the appropriate LLVM version.
  48 // 2. A macro named `_LIBCPP_AVAILABILITY_<feature>`, which must be defined to
  49 //    `_LIBCPP_INTRODUCED_IN_<version>_MARKUP` for the appropriate LLVM version.
  50 //
  51 // When vendors decide to ship the feature as part of their shared library, they
  52 // can update the `_LIBCPP_INTRODUCED_IN_<version>` macro (and the markup counterpart)
  53 // based on the platform version they shipped that version of LLVM in. The library
  54 // will then use this markup to provide an optimal user experience on these platforms.
  55 //
  56 // Furthermore, many features in the standard library have corresponding
  57 // feature-test macros. The `_LIBCPP_AVAILABILITY_HAS_<feature>` macros
  58 // are checked by the corresponding feature-test macros generated by
  59 // generate_feature_test_macro_components.py to ensure that the library
  60 // doesn't announce a feature as being implemented if it is unavailable on
  61 // the deployment target.
  62 //
  63 // Note that this mechanism is disabled by default in the "upstream" libc++.
  64 // Availability annotations are only meaningful when shipping libc++ inside
  65 // a platform (i.e. as a system library), and so vendors that want them should
  66 // turn those annotations on at CMake configuration time.
  67 //
  68 // [1]: https://clang.llvm.org/docs/AttributeReference.html#availability
  69
  70 // For backwards compatibility, allow users to define _LIBCPP_DISABLE_AVAILABILITY
  71 // for a while.
  72 #if defined(_LIBCPP_DISABLE_AVAILABILITY)
  73 #  if !defined(_LIBCPP_HAS_NO_VENDOR_AVAILABILITY_ANNOTATIONS)
  74 #    define _LIBCPP_HAS_NO_VENDOR_AVAILABILITY_ANNOTATIONS
  75 #  endif
  76 #endif
  77
  78 // Availability markup is disabled when building the library, or when a non-Clang
  79 // compiler is used because only Clang supports the necessary attributes.
  80 #if defined(_LIBCPP_BUILDING_LIBRARY) || defined(_LIBCXXABI_BUILDING_LIBRARY) || !defined(_LIBCPP_COMPILER_CLANG_BASED)
  81 #  if !defined(_LIBCPP_HAS_NO_VENDOR_AVAILABILITY_ANNOTATIONS)
  82 #    define _LIBCPP_HAS_NO_VENDOR_AVAILABILITY_ANNOTATIONS
  83 #  endif
  84 #endif
  85
  86 // When availability annotations are disabled, we take for granted that features introduced
  87 // in all versions of the library are available.
  88 #if defined(_LIBCPP_HAS_NO_VENDOR_AVAILABILITY_ANNOTATIONS)
  89
  90 #  define _LIBCPP_INTRODUCED_IN_LLVM_19 1
  91 #  define _LIBCPP_INTRODUCED_IN_LLVM_19_ATTRIBUTE /* nothing */
  92
  93 #  define _LIBCPP_INTRODUCED_IN_LLVM_18 1
  94 #  define _LIBCPP_INTRODUCED_IN_LLVM_18_ATTRIBUTE /* nothing */
  95
  96 #  define _LIBCPP_INTRODUCED_IN_LLVM_17 1
  97 #  define _LIBCPP_INTRODUCED_IN_LLVM_17_ATTRIBUTE /* nothing */
  98
  99 #  define _LIBCPP_INTRODUCED_IN_LLVM_16 1
 100 #  define _LIBCPP_INTRODUCED_IN_LLVM_16_ATTRIBUTE /* nothing */
 101
 102 #  define _LIBCPP_INTRODUCED_IN_LLVM_15 1
 103 #  define _LIBCPP_INTRODUCED_IN_LLVM_15_ATTRIBUTE /* nothing */
 104
 105 #  define _LIBCPP_INTRODUCED_IN_LLVM_14 1
 106 #  define _LIBCPP_INTRODUCED_IN_LLVM_14_ATTRIBUTE /* nothing */
 107
 108 #  define _LIBCPP_INTRODUCED_IN_LLVM_13 1
 109 #  define _LIBCPP_INTRODUCED_IN_LLVM_13_ATTRIBUTE /* nothing */
 110
 111 #  define _LIBCPP_INTRODUCED_IN_LLVM_12 1
 112 #  define _LIBCPP_INTRODUCED_IN_LLVM_12_ATTRIBUTE /* nothing */
 113
 114 #  define _LIBCPP_INTRODUCED_IN_LLVM_11 1
 115 #  define _LIBCPP_INTRODUCED_IN_LLVM_11_ATTRIBUTE /* nothing */
 116
 117 #  define _LIBCPP_INTRODUCED_IN_LLVM_10 1
 118 #  define _LIBCPP_INTRODUCED_IN_LLVM_10_ATTRIBUTE /* nothing */
 119
 120 #  define _LIBCPP_INTRODUCED_IN_LLVM_9 1
 121 #  define _LIBCPP_INTRODUCED_IN_LLVM_9_ATTRIBUTE      /* nothing */
 122 #  define _LIBCPP_INTRODUCED_IN_LLVM_9_ATTRIBUTE_PUSH /* nothing */
 123 #  define _LIBCPP_INTRODUCED_IN_LLVM_9_ATTRIBUTE_POP  /* nothing */
 124
 125 #  define _LIBCPP_INTRODUCED_IN_LLVM_8 1
 126 #  define _LIBCPP_INTRODUCED_IN_LLVM_8_ATTRIBUTE /* nothing */
 127
 128 #  define _LIBCPP_INTRODUCED_IN_LLVM_4 1
 129 #  define _LIBCPP_INTRODUCED_IN_LLVM_4_ATTRIBUTE /* nothing */
 130
 131 #elif defined(__APPLE__)
 132
 133 // clang-format off
 134
 135 // LLVM 19
 136 // TODO: Fill this in
 137 #  define _LIBCPP_INTRODUCED_IN_LLVM_19 0
 138 #  define _LIBCPP_INTRODUCED_IN_LLVM_19_ATTRIBUTE __attribute__((unavailable))
 139
 140 // LLVM 18
 141 // TODO: Fill this in
 142 #  define _LIBCPP_INTRODUCED_IN_LLVM_18 0
 143 #  define _LIBCPP_INTRODUCED_IN_LLVM_18_ATTRIBUTE __attribute__((unavailable))
 144
 145 // LLVM 17
 146 #  if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 140400) ||       \
 147       (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 170400) ||     \
 148       (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 170400) ||             \
 149       (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 100400)
 150 #    define _LIBCPP_INTRODUCED_IN_LLVM_17 0
 151 #  else
 152 #    define _LIBCPP_INTRODUCED_IN_LLVM_17 1
 153 #  endif
 154 #  define _LIBCPP_INTRODUCED_IN_LLVM_17_ATTRIBUTE                                                                 \
 155     __attribute__((availability(macos, strict, introduced = 14.4)))                                               \
 156     __attribute__((availability(ios, strict, introduced = 17.4)))                                                 \
 157     __attribute__((availability(tvos, strict, introduced = 17.4)))                                                \
 158     __attribute__((availability(watchos, strict, introduced = 10.4)))
 159
 160 // LLVM 16
 161 #  if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 140000) ||       \
 162       (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 170000) ||     \
 163       (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 170000) ||             \
 164       (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 100000)
 165 #    define _LIBCPP_INTRODUCED_IN_LLVM_16 0
 166 #  else
 167 #    define _LIBCPP_INTRODUCED_IN_LLVM_16 1
 168 #  endif
 169 #  define _LIBCPP_INTRODUCED_IN_LLVM_16_ATTRIBUTE                                                                 \
 170     __attribute__((availability(macos, strict, introduced = 14.0)))                                               \
 171     __attribute__((availability(ios, strict, introduced = 17.0)))                                                 \
 172     __attribute__((availability(tvos, strict, introduced = 17.0)))                                                \
 173     __attribute__((availability(watchos, strict, introduced = 10.0)))
 174
 175 // LLVM 15
 176 #  if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 130400) ||   \
 177       (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 160500) || \
 178       (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 160500) ||         \
 179       (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 90500)
 180 #    define _LIBCPP_INTRODUCED_IN_LLVM_15 0
 181 #  else
 182 #    define _LIBCPP_INTRODUCED_IN_LLVM_15 1
 183 #  endif
 184 #  define _LIBCPP_INTRODUCED_IN_LLVM_15_ATTRIBUTE                                                                 \
 185     __attribute__((availability(macos, strict, introduced = 13.4)))                                               \
 186     __attribute__((availability(ios, strict, introduced = 16.5)))                                                 \
 187     __attribute__((availability(tvos, strict, introduced = 16.5)))                                                \
 188     __attribute__((availability(watchos, strict, introduced = 9.5)))
 189
 190 // LLVM 14
 191 #  define _LIBCPP_INTRODUCED_IN_LLVM_14 _LIBCPP_INTRODUCED_IN_LLVM_15
 192 #  define _LIBCPP_INTRODUCED_IN_LLVM_14_ATTRIBUTE _LIBCPP_INTRODUCED_IN_LLVM_15_ATTRIBUTE
 193
 194 // LLVM 13
 195 #  if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 130000) ||   \
 196       (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 160000) || \
 197       (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 160000) ||         \
 198       (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 90000)
 199 #    define _LIBCPP_INTRODUCED_IN_LLVM_13 0
 200 #  else
 201 #    define _LIBCPP_INTRODUCED_IN_LLVM_13 1
 202 #  endif
 203 #  define _LIBCPP_INTRODUCED_IN_LLVM_13_ATTRIBUTE                                                                 \
 204     __attribute__((availability(macos, strict, introduced = 13.0)))                                               \
 205     __attribute__((availability(ios, strict, introduced = 16.0)))                                                 \
 206     __attribute__((availability(tvos, strict, introduced = 16.0)))                                                \
 207     __attribute__((availability(watchos, strict, introduced = 9.0)))
 208
 209 // LLVM 12
 210 #  if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 120300)   ||     \
 211       (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 150300) ||     \
 212       (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 150300)         ||     \
 213       (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 80300)
 214 #    define _LIBCPP_INTRODUCED_IN_LLVM_12 0
 215 #  else
 216 #    define _LIBCPP_INTRODUCED_IN_LLVM_12 1
 217 #  endif
 218 #  define _LIBCPP_INTRODUCED_IN_LLVM_12_ATTRIBUTE                                                                 \
 219     __attribute__((availability(macos, strict, introduced = 12.3)))                                               \
 220     __attribute__((availability(ios, strict, introduced = 15.3)))                                                 \
 221     __attribute__((availability(tvos, strict, introduced = 15.3)))                                                \
 222     __attribute__((availability(watchos, strict, introduced = 8.3)))
 223
 224 // LLVM 11
 225 #  if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 110000) ||   \
 226       (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 140000) || \
 227       (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 140000) ||         \
 228       (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 70000)
 229 #    define _LIBCPP_INTRODUCED_IN_LLVM_11 0
 230 #  else
 231 #    define _LIBCPP_INTRODUCED_IN_LLVM_11 1
 232 #  endif
 233 #  define _LIBCPP_INTRODUCED_IN_LLVM_11_ATTRIBUTE                                                                 \
 234     __attribute__((availability(macos, strict, introduced = 11.0)))                                               \
 235     __attribute__((availability(ios, strict, introduced = 14.0)))                                                 \
 236     __attribute__((availability(tvos, strict, introduced = 14.0)))                                                \
 237     __attribute__((availability(watchos, strict, introduced = 7.0)))
 238
 239 // LLVM 10
 240 #  define _LIBCPP_INTRODUCED_IN_LLVM_10 _LIBCPP_INTRODUCED_IN_LLVM_11
 241 #  define _LIBCPP_INTRODUCED_IN_LLVM_10_ATTRIBUTE _LIBCPP_INTRODUCED_IN_LLVM_11_ATTRIBUTE
 242
 243 // LLVM 9
 244 #  if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 101500) ||   \
 245       (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 130000) || \
 246       (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 130000) ||         \
 247       (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 60000)
 248 #    define _LIBCPP_INTRODUCED_IN_LLVM_9 0
 249 #  else
 250 #    define _LIBCPP_INTRODUCED_IN_LLVM_9 1
 251 #  endif
 252 #  define _LIBCPP_INTRODUCED_IN_LLVM_9_ATTRIBUTE                                                                  \
 253     __attribute__((availability(macos, strict, introduced = 10.15)))                                              \
 254     __attribute__((availability(ios, strict, introduced = 13.0)))                                                 \
 255     __attribute__((availability(tvos, strict, introduced = 13.0)))                                                \
 256     __attribute__((availability(watchos, strict, introduced = 6.0)))
 257 #  define _LIBCPP_INTRODUCED_IN_LLVM_9_ATTRIBUTE_PUSH                                                                            \
 258     _Pragma("clang attribute push(__attribute__((availability(macos,strict,introduced=10.15))), apply_to=any(function,record))") \
 259     _Pragma("clang attribute push(__attribute__((availability(ios,strict,introduced=13.0))), apply_to=any(function,record))")    \
 260     _Pragma("clang attribute push(__attribute__((availability(tvos,strict,introduced=13.0))), apply_to=any(function,record))")   \
 261     _Pragma("clang attribute push(__attribute__((availability(watchos,strict,introduced=6.0))), apply_to=any(function,record))")
 262 #  define _LIBCPP_INTRODUCED_IN_LLVM_9_ATTRIBUTE_POP                                                                    \
 263     _Pragma("clang attribute pop") \
 264     _Pragma("clang attribute pop") \
 265     _Pragma("clang attribute pop") \
 266     _Pragma("clang attribute pop")
 267
 268 // LLVM 4
 269 #  if defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 50000
 270 #    define _LIBCPP_INTRODUCED_IN_LLVM_4 0
 271 #  else
 272 #    define _LIBCPP_INTRODUCED_IN_LLVM_4 1
 273 #  endif
 274 #  define _LIBCPP_INTRODUCED_IN_LLVM_4_ATTRIBUTE __attribute__((availability(watchos, strict, introduced = 5.0)))
 275
 276 // clang-format on
 277
 278 #else
 279
 280 // ...New vendors can add availability markup here...
 281
 282 #  error                                                                                                               \
 283       "It looks like you're trying to enable vendor availability markup, but you haven't defined the corresponding macros yet!"
 284
 285 #endif
 286
 287 // These macros control the availability of std::bad_optional_access and
 288 // other exception types. These were put in the shared library to prevent
 289 // code bloat from every user program defining the vtable for these exception
 290 // types.
 291 //
 292 // Note that when exceptions are disabled, the methods that normally throw
 293 // these exceptions can be used even on older deployment targets, but those
 294 // methods will abort instead of throwing.
 295 #define _LIBCPP_AVAILABILITY_HAS_BAD_OPTIONAL_ACCESS _LIBCPP_INTRODUCED_IN_LLVM_4
 296 #define _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS _LIBCPP_INTRODUCED_IN_LLVM_4_ATTRIBUTE
 297
 298 #define _LIBCPP_AVAILABILITY_HAS_BAD_VARIANT_ACCESS _LIBCPP_INTRODUCED_IN_LLVM_4
 299 #define _LIBCPP_AVAILABILITY_BAD_VARIANT_ACCESS _LIBCPP_INTRODUCED_IN_LLVM_4_ATTRIBUTE
 300
 301 #define _LIBCPP_AVAILABILITY_HAS_BAD_ANY_CAST _LIBCPP_INTRODUCED_IN_LLVM_4
 302 #define _LIBCPP_AVAILABILITY_BAD_ANY_CAST _LIBCPP_INTRODUCED_IN_LLVM_4_ATTRIBUTE
 303
 304 // These macros control the availability of all parts of <filesystem> that
 305 // depend on something in the dylib.
 306 #define _LIBCPP_AVAILABILITY_HAS_FILESYSTEM_LIBRARY _LIBCPP_INTRODUCED_IN_LLVM_9
 307 #define _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY _LIBCPP_INTRODUCED_IN_LLVM_9_ATTRIBUTE
 308 #define _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY_PUSH _LIBCPP_INTRODUCED_IN_LLVM_9_ATTRIBUTE_PUSH
 309 #define _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY_POP _LIBCPP_INTRODUCED_IN_LLVM_9_ATTRIBUTE_POP
 310
 311 // This controls the availability of the C++20 synchronization library,
 312 // which requires shared library support for various operations
 313 // (see libcxx/src/atomic.cpp). This includes <barier>, <latch>,
 314 // <semaphore>, and notification functions on std::atomic.
 315 #define _LIBCPP_AVAILABILITY_HAS_SYNC _LIBCPP_INTRODUCED_IN_LLVM_11
 316 #define _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INTRODUCED_IN_LLVM_11_ATTRIBUTE
 317
 318 // Enable additional explicit instantiations of iostreams components. This
 319 // reduces the number of weak definitions generated in programs that use
 320 // iostreams by providing a single strong definition in the shared library.
 321 //
 322 // TODO: Enable additional explicit instantiations on GCC once it supports exclude_from_explicit_instantiation,
 323 //       or once libc++ doesn't use the attribute anymore.
 324 // TODO: Enable them on Windows once https://llvm.org/PR41018 has been fixed.
 325 #if !defined(_LIBCPP_COMPILER_GCC) && !defined(_WIN32)
 326 #  define _LIBCPP_AVAILABILITY_HAS_ADDITIONAL_IOSTREAM_EXPLICIT_INSTANTIATIONS_1 _LIBCPP_INTRODUCED_IN_LLVM_12
 327 #else
 328 #  define _LIBCPP_AVAILABILITY_HAS_ADDITIONAL_IOSTREAM_EXPLICIT_INSTANTIATIONS_1 0
 329 #endif
 330
 331 // This controls the availability of floating-point std::to_chars functions.
 332 // These overloads were added later than the integer overloads.
 333 #define _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT _LIBCPP_INTRODUCED_IN_LLVM_14
 334 #define _LIBCPP_AVAILABILITY_TO_CHARS_FLOATING_POINT _LIBCPP_INTRODUCED_IN_LLVM_14_ATTRIBUTE
 335
 336 // This controls whether the library claims to provide a default verbose
 337 // termination function, and consequently whether the headers will try
 338 // to use it when the mechanism isn't overriden at compile-time.
 339 #define _LIBCPP_AVAILABILITY_HAS_VERBOSE_ABORT _LIBCPP_INTRODUCED_IN_LLVM_15
 340 #define _LIBCPP_AVAILABILITY_VERBOSE_ABORT _LIBCPP_INTRODUCED_IN_LLVM_15_ATTRIBUTE
 341
 342 // This controls the availability of the C++17 std::pmr library,
 343 // which is implemented in large part in the built library.
 344 //
 345 // TODO: Enable std::pmr markup once https://github.com/llvm/llvm-project/issues/40340 has been fixed
 346 //       Until then, it is possible for folks to try to use `std::pmr` when back-deploying to targets that don't support
 347 //       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
 348 //       use availability annotations until that bug has been fixed.
 349 #define _LIBCPP_AVAILABILITY_HAS_PMR _LIBCPP_INTRODUCED_IN_LLVM_16
 350 #define _LIBCPP_AVAILABILITY_PMR
 351
 352 // These macros controls the availability of __cxa_init_primary_exception
 353 // in the built library, which std::make_exception_ptr might use
 354 // (see libcxx/include/__exception/exception_ptr.h).
 355 #define _LIBCPP_AVAILABILITY_HAS_INIT_PRIMARY_EXCEPTION _LIBCPP_INTRODUCED_IN_LLVM_18
 356 #define _LIBCPP_AVAILABILITY_INIT_PRIMARY_EXCEPTION _LIBCPP_INTRODUCED_IN_LLVM_18_ATTRIBUTE
 357
 358 // This controls the availability of C++23 <print>, which
 359 // has a dependency on the built library (it needs access to
 360 // the underlying buffer types of std::cout, std::cerr, and std::clog.
 361 #define _LIBCPP_AVAILABILITY_HAS_PRINT _LIBCPP_INTRODUCED_IN_LLVM_18
 362 #define _LIBCPP_AVAILABILITY_PRINT _LIBCPP_INTRODUCED_IN_LLVM_18_ATTRIBUTE
 363
 364 // This controls the availability of the C++20 time zone database.
 365 // The parser code is built in the library.
 366 #define _LIBCPP_AVAILABILITY_HAS_TZDB _LIBCPP_INTRODUCED_IN_LLVM_19
 367 #define _LIBCPP_AVAILABILITY_TZDB _LIBCPP_INTRODUCED_IN_LLVM_19_ATTRIBUTE
 368
 369 // These macros determine whether we assume that std::bad_function_call and
 370 // std::bad_expected_access provide a key function in the dylib. This allows
 371 // centralizing their vtable and typeinfo instead of having all TUs provide
 372 // a weak definition that then gets deduplicated.
 373 #define _LIBCPP_AVAILABILITY_HAS_BAD_FUNCTION_CALL_KEY_FUNCTION _LIBCPP_INTRODUCED_IN_LLVM_19
 374 #define _LIBCPP_AVAILABILITY_BAD_FUNCTION_CALL_KEY_FUNCTION _LIBCPP_INTRODUCED_IN_LLVM_19_ATTRIBUTE
 375 #define _LIBCPP_AVAILABILITY_HAS_BAD_EXPECTED_ACCESS_KEY_FUNCTION _LIBCPP_INTRODUCED_IN_LLVM_19
 376 #define _LIBCPP_AVAILABILITY_BAD_EXPECTED_ACCESS_KEY_FUNCTION _LIBCPP_INTRODUCED_IN_LLVM_19_ATTRIBUTE
 377
 378 // Define availability attributes that depend on _LIBCPP_HAS_NO_EXCEPTIONS.
 379 // Those are defined in terms of the availability attributes above, and
 380 // should not be vendor-specific.
 381 #if defined(_LIBCPP_HAS_NO_EXCEPTIONS)
 382 #  define _LIBCPP_AVAILABILITY_THROW_BAD_ANY_CAST
 383 #  define _LIBCPP_AVAILABILITY_THROW_BAD_OPTIONAL_ACCESS
 384 #  define _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
 385 #else
 386 #  define _LIBCPP_AVAILABILITY_THROW_BAD_ANY_CAST _LIBCPP_AVAILABILITY_BAD_ANY_CAST
 387 #  define _LIBCPP_AVAILABILITY_THROW_BAD_OPTIONAL_ACCESS _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS
 388 #  define _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS _LIBCPP_AVAILABILITY_BAD_VARIANT_ACCESS
 389 #endif
 390
 391 // Define availability attributes that depend on both
 392 // _LIBCPP_HAS_NO_EXCEPTIONS and _LIBCPP_HAS_NO_RTTI.
 393 #if defined(_LIBCPP_HAS_NO_EXCEPTIONS) || defined(_LIBCPP_HAS_NO_RTTI)
 394 #  undef _LIBCPP_AVAILABILITY_HAS_INIT_PRIMARY_EXCEPTION
 395 #  undef _LIBCPP_AVAILABILITY_INIT_PRIMARY_EXCEPTION
 396 #  define _LIBCPP_AVAILABILITY_HAS_INIT_PRIMARY_EXCEPTION 0
 397 #  define _LIBCPP_AVAILABILITY_INIT_PRIMARY_EXCEPTION
 398 #endif
 399
 400 #endif // _LIBCPP___CONFIGURATION_AVAILABILITY_H