2 * Copyright 2017-present Facebook, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
20 #include <type_traits>
22 #include <folly/portability/Config.h>
24 #include <folly/CPortability.h>
26 // Unaligned loads and stores
28 #if FOLLY_HAVE_UNALIGNED_ACCESS
29 constexpr bool kHasUnalignedAccess = true;
31 constexpr bool kHasUnalignedAccess = false;
34 namespace portability_detail {
36 template <typename I, I A, I B>
37 using integral_max = std::integral_constant<I, (A < B) ? B : A>;
39 template <typename I, I A, I... Bs>
40 struct integral_sequence_max
41 : integral_max<I, A, integral_sequence_max<I, Bs...>::value> {};
43 template <typename I, I A>
44 struct integral_sequence_max<I, A> : std::integral_constant<I, A> {};
46 template <typename... Ts>
47 using max_alignment = integral_sequence_max<size_t, alignof(Ts)...>;
49 using max_basic_alignment = max_alignment<
64 } // namespace portability_detail
66 constexpr size_t max_align_v = portability_detail::max_basic_alignment::value;
68 // max_align_t is a type which is aligned at least as strictly as the
69 // most-aligned basic type (see the specification of std::max_align_t). This
70 // implementation exists because 32-bit iOS platforms have a broken
71 // std::max_align_t (see below).
73 // You should refer to this as `::folly::max_align_t` in portable code, even if
74 // you have `using namespace folly;` because C11 defines a global namespace
75 // `max_align_t` type.
77 // To be certain, we consider every non-void fundamental type specified by the
78 // standard. On most platforms `long double` would be enough, but iOS 32-bit
79 // has an 8-byte aligned `double` and `long long int` and a 4-byte aligned
82 // So far we've covered locals and other non-allocated storage, but we also need
83 // confidence that allocated storage from `malloc`, `new`, etc will also be
84 // suitable for objects with this alignment reuirement.
86 // Apple document that their implementation of malloc will issue 16-byte
87 // granularity chunks for small allocations (large allocations are page-size
88 // granularity and page-aligned). We think that allocated storage will be
89 // suitable for these objects based on the following assumptions:
91 // 1. 16-byte granularity also means 16-byte aligned.
92 // 2. `new` and other allocators follow the `malloc` rules.
94 // We also have some anecdotal evidence: we don't see lots of misaligned-storage
95 // crashes on 32-bit iOS apps that use `double`.
97 // Apple's allocation reference: http://bit.ly/malloc-small
98 struct alignas(max_align_v) max_align_t {};
102 // compiler specific attribute translation
103 // msvc should come first, so if clang is in msvc mode it gets the right defines
105 #if defined(__clang__) || defined(__GNUC__)
106 # define FOLLY_ALIGNED(size) __attribute__((__aligned__(size)))
107 #elif defined(_MSC_VER)
108 # define FOLLY_ALIGNED(size) __declspec(align(size))
110 # error Cannot define FOLLY_ALIGNED on this platform
112 #define FOLLY_ALIGNED_MAX FOLLY_ALIGNED(::folly::max_align_v)
114 // NOTE: this will only do checking in msvc with versions that support /analyze
116 # ifdef _USE_ATTRIBUTES_FOR_SAL
117 # undef _USE_ATTRIBUTES_FOR_SAL
120 # define _USE_ATTRIBUTES_FOR_SAL 1
121 # include <sal.h> // @manual
122 # define FOLLY_PRINTF_FORMAT _Printf_format_string_
123 # define FOLLY_PRINTF_FORMAT_ATTR(format_param, dots_param) /**/
125 # define FOLLY_PRINTF_FORMAT /**/
126 # define FOLLY_PRINTF_FORMAT_ATTR(format_param, dots_param) \
127 __attribute__((__format__(__printf__, format_param, dots_param)))
131 #if defined(__clang__) || defined(__GNUC__)
132 # define FOLLY_DEPRECATED(msg) __attribute__((__deprecated__(msg)))
133 #elif defined(_MSC_VER)
134 # define FOLLY_DEPRECATED(msg) __declspec(deprecated(msg))
136 # define FOLLY_DEPRECATED(msg)
139 // warn unused result
140 #if defined(__has_cpp_attribute)
141 #if __has_cpp_attribute(nodiscard)
142 #define FOLLY_NODISCARD [[nodiscard]]
145 #if !defined FOLLY_NODISCARD
146 #if defined(_MSC_VER) && (_MSC_VER >= 1700)
147 #define FOLLY_NODISCARD _Check_return_
148 #elif defined(__clang__) || defined(__GNUC__)
149 #define FOLLY_NODISCARD __attribute__((__warn_unused_result__))
151 #define FOLLY_NODISCARD
157 # define FOLLY_TARGET_ATTRIBUTE(target)
159 # define FOLLY_TARGET_ATTRIBUTE(target) __attribute__((__target__(target)))
162 // detection for 64 bit
163 #if defined(__x86_64__) || defined(_M_X64)
169 #if defined(__aarch64__)
170 # define FOLLY_AARCH64 1
172 # define FOLLY_AARCH64 0
175 #if defined (__powerpc64__)
176 # define FOLLY_PPC64 1
178 # define FOLLY_PPC64 0
182 constexpr bool kIsArchAmd64 = FOLLY_X64 == 1;
183 constexpr bool kIsArchAArch64 = FOLLY_AARCH64 == 1;
184 constexpr bool kIsArchPPC64 = FOLLY_PPC64 == 1;
189 #if FOLLY_SANITIZE_ADDRESS
190 constexpr bool kIsSanitizeAddress = true;
192 constexpr bool kIsSanitizeAddress = false;
195 #if FOLLY_SANITIZE_THREAD
196 constexpr bool kIsSanitizeThread = true;
198 constexpr bool kIsSanitizeThread = false;
202 constexpr bool kIsSanitize = true;
204 constexpr bool kIsSanitize = false;
208 // packing is very ugly in msvc
210 # define FOLLY_PACK_ATTR /**/
211 # define FOLLY_PACK_PUSH __pragma(pack(push, 1))
212 # define FOLLY_PACK_POP __pragma(pack(pop))
213 #elif defined(__clang__) || defined(__GNUC__)
214 # define FOLLY_PACK_ATTR __attribute__((__packed__))
215 # define FOLLY_PACK_PUSH /**/
216 # define FOLLY_PACK_POP /**/
218 # define FOLLY_PACK_ATTR /**/
219 # define FOLLY_PACK_PUSH /**/
220 # define FOLLY_PACK_POP /**/
223 // Generalize warning push/pop.
224 #if defined(_MSC_VER)
225 # define FOLLY_PUSH_WARNING __pragma(warning(push))
226 # define FOLLY_POP_WARNING __pragma(warning(pop))
227 // Disable the GCC warnings.
228 # define FOLLY_GCC_DISABLE_WARNING(warningName)
229 # define FOLLY_MSVC_DISABLE_WARNING(warningNumber) __pragma(warning(disable: warningNumber))
230 #elif defined(__clang__) || defined(__GNUC__)
231 # define FOLLY_PUSH_WARNING _Pragma("GCC diagnostic push")
232 # define FOLLY_POP_WARNING _Pragma("GCC diagnostic pop")
233 # define FOLLY_GCC_DISABLE_WARNING_INTERNAL2(warningName) #warningName
234 # define FOLLY_GCC_DISABLE_WARNING(warningName) \
236 FOLLY_GCC_DISABLE_WARNING_INTERNAL2(GCC diagnostic ignored warningName))
237 // Disable the MSVC warnings.
238 # define FOLLY_MSVC_DISABLE_WARNING(warningNumber)
240 # define FOLLY_PUSH_WARNING
241 # define FOLLY_POP_WARNING
242 # define FOLLY_GCC_DISABLE_WARNING(warningName)
243 # define FOLLY_MSVC_DISABLE_WARNING(warningNumber)
246 #ifdef FOLLY_HAVE_SHADOW_LOCAL_WARNINGS
247 #define FOLLY_GCC_DISABLE_NEW_SHADOW_WARNINGS \
248 FOLLY_GCC_DISABLE_WARNING("-Wshadow-compatible-local") \
249 FOLLY_GCC_DISABLE_WARNING("-Wshadow-local")
251 #define FOLLY_GCC_DISABLE_NEW_SHADOW_WARNINGS /* empty */
254 /* Platform specific TLS support
255 * gcc implements __thread
256 * msvc implements __declspec(thread)
257 * the semantics are the same
258 * (but remember __thread has different semantics when using emutls (ex. apple))
260 #if defined(_MSC_VER)
261 # define FOLLY_TLS __declspec(thread)
262 #elif defined(__GNUC__) || defined(__clang__)
263 # define FOLLY_TLS __thread
265 # error cannot define platform specific thread local storage
272 // It turns out that GNU libstdc++ and LLVM libc++ differ on how they implement
273 // the 'std' namespace; the latter uses inline namespaces. Wrap this decision
274 // up in a macro to make forward-declarations easier.
276 #include <__config> // @manual
277 #define FOLLY_NAMESPACE_STD_BEGIN _LIBCPP_BEGIN_NAMESPACE_STD
278 #define FOLLY_NAMESPACE_STD_END _LIBCPP_END_NAMESPACE_STD
280 #define FOLLY_NAMESPACE_STD_BEGIN namespace std {
281 #define FOLLY_NAMESPACE_STD_END }
284 // If the new c++ ABI is used, __cxx11 inline namespace needs to be added to
285 // some types, e.g. std::list.
286 #if _GLIBCXX_USE_CXX11_ABI
287 #define FOLLY_GLIBCXX_NAMESPACE_CXX11_BEGIN \
288 inline _GLIBCXX_BEGIN_NAMESPACE_CXX11
289 # define FOLLY_GLIBCXX_NAMESPACE_CXX11_END _GLIBCXX_END_NAMESPACE_CXX11
291 # define FOLLY_GLIBCXX_NAMESPACE_CXX11_BEGIN
292 # define FOLLY_GLIBCXX_NAMESPACE_CXX11_END
295 // MSVC specific defines
296 // mainly for posix compat
298 #include <folly/portability/SysTypes.h>
300 // compiler specific to compiler specific
302 # define __PRETTY_FUNCTION__ __FUNCSIG__
304 // Hide a GCC specific thing that breaks MSVC if left alone.
305 # define __extension__
307 // We have compiler support for the newest of the new, but
308 // MSVC doesn't tell us that.
316 constexpr auto kIsDebug = false;
318 constexpr auto kIsDebug = true;
325 // It's MSVC, so we just have to guess ... and allow an override
326 #ifdef FOLLY_ENDIAN_BE
327 constexpr auto kIsLittleEndian = false;
329 constexpr auto kIsLittleEndian = true;
332 constexpr auto kIsLittleEndian = __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__;
334 constexpr auto kIsBigEndian = !kIsLittleEndian;
338 # if defined(__SSE4_2__)
340 # define FOLLY_SSE_MINOR 2
341 # elif defined(__SSE4_1__)
343 # define FOLLY_SSE_MINOR 1
344 # elif defined(__SSE4__)
346 # define FOLLY_SSE_MINOR 0
347 # elif defined(__SSE3__)
349 # define FOLLY_SSE_MINOR 0
350 # elif defined(__SSE2__)
352 # define FOLLY_SSE_MINOR 0
353 # elif defined(__SSE__)
355 # define FOLLY_SSE_MINOR 0
358 # define FOLLY_SSE_MINOR 0
362 #define FOLLY_SSE_PREREQ(major, minor) \
363 (FOLLY_SSE > major || FOLLY_SSE == major && FOLLY_SSE_MINOR >= minor)
365 #if FOLLY_UNUSUAL_GFLAGS_NAMESPACE
366 namespace FOLLY_GFLAGS_NAMESPACE { }
368 using namespace FOLLY_GFLAGS_NAMESPACE;
369 } // namespace gflags
372 // for TARGET_OS_IPHONE
374 #include <TargetConditionals.h> // @manual
377 // RTTI may not be enabled for this compilation unit.
378 #if defined(__GXX_RTTI) || defined(__cpp_rtti) || \
379 (defined(_MSC_VER) && defined(_CPPRTTI))
380 # define FOLLY_HAS_RTTI 1
383 #if defined(__APPLE__) || defined(_MSC_VER)
384 #define FOLLY_STATIC_CTOR_PRIORITY_MAX
386 // 101 is the highest priority allowed by the init_priority attribute.
387 // This priority is already used by JEMalloc and other memory allocators so
388 // we will take the next one.
389 #define FOLLY_STATIC_CTOR_PRIORITY_MAX __attribute__((__init_priority__(102)))
395 constexpr auto kIsObjC = true;
397 constexpr auto kIsObjC = false;
401 constexpr auto kIsMobile = true;
403 constexpr auto kIsMobile = false;
406 #if defined(__linux__) && !FOLLY_MOBILE
407 constexpr auto kIsLinux = true;
409 constexpr auto kIsLinux = false;
413 constexpr auto kIsWindows = true;
414 constexpr auto kMscVer = _MSC_VER;
416 constexpr auto kIsWindows = false;
417 constexpr auto kMscVer = 0;
421 // Define FOLLY_USE_CPP14_CONSTEXPR to be true if the compiler's C++14
422 // constexpr support is "good enough".
423 #ifndef FOLLY_USE_CPP14_CONSTEXPR
424 #if defined(__clang__)
425 #define FOLLY_USE_CPP14_CONSTEXPR __cplusplus >= 201300L
426 #elif defined(__GNUC__)
427 #define FOLLY_USE_CPP14_CONSTEXPR __cplusplus >= 201304L
429 #define FOLLY_USE_CPP14_CONSTEXPR 0 // MSVC?
433 #if FOLLY_USE_CPP14_CONSTEXPR
434 #define FOLLY_CPP14_CONSTEXPR constexpr
436 #define FOLLY_CPP14_CONSTEXPR inline
439 #if __cpp_coroutines >= 201703L || (_MSC_VER && _RESUMABLE_FUNCTIONS_SUPPORTED)
440 #define FOLLY_HAS_COROUTINES 1
444 #if __cpp_noexcept_function_type >= 201510 || _MSC_FULL_VER >= 191225816
445 #define FOLLY_HAVE_NOEXCEPT_FUNCTION_TYPE 1