tvl-depot/absl/base/config.h
Abseil Team 37dd2562ec Export of internal Abseil changes
--
8bdb2020150ed0fd4a4e520e454dc5f54e33f776 by Eric Fiselier <ericwf@google.com>:

Workaround bug in GCC 9.2 and after.

PiperOrigin-RevId: 291982551

--
47ff4820e595f96c082a90d733725f6882d83e3b by Abseil Team <absl-team@google.com>:

Improve ABSL_ATTRIBUTE_PACKED documentation

Recommend to apply ABSL_ATTRIBUTE_PACKED to structure members instead of to an entire structure because applying this attribute to an entire structure may cause the compiler to generate suboptimal code. It reduces the alignment of the data structure from a value larger than one to one. When applied to a structure, ABSL_ATTRIBUTE_PACKED reduces the alignment of a structure (alignof()) to 1. As a result, the compiler can no longer assume that e.g. uint32 members are aligned on a four byte boundary and hence is forced to use single-byte load and store instructions on CPU architectures that do not support non-aligned loads or stores.

PiperOrigin-RevId: 291977920

--
902b7a86f860da699d3a2e5c738be5ef73ede3b4 by Mark Barolak <mbar@google.com>:

Internal change

PiperOrigin-RevId: 291963048

--
bb3bd3247e376d53a3080b105f13ec7566d3ae50 by Abseil Team <absl-team@google.com>:

Support the C++17 insert_or_assign() API in btree_map.

PiperOrigin-RevId: 291945474

--
ff3b3cfcbbc64f086f95501f48d49426bcde356f by Gennadiy Rozental <rogeeff@google.com>:

Import of CCTZ from GitHub.

PiperOrigin-RevId: 291861110

--
fd465cd9cbbacd3962f67a7346d6462edaddd809 by Derek Mauro <dmauro@google.com>:

Add flaky=1 to beta_distribution_test.

PiperOrigin-RevId: 291757364

--
3603adfb59c4128c542b670952cce250d59e1f67 by Derek Mauro <dmauro@google.com>:

Separate the initialization of NumCPUs() and NominalCPUFrequency()

The OSS version of Abseil never needs to call NominalCPUFrequency().
In some configurations, initializing NominalCPUFrequency() requires
spending at least 3ms measuring the CPU frequency. By separating the
initialization from NumCPUs(), which is called in most configurations,
we can save at least 3ms of program startup time.

PiperOrigin-RevId: 291737273

--
bea9e4a6bff5a0351d340deab966641867e08c4d by Abseil Team <absl-team@google.com>:

Change the cmake library names not to have a redundant `absl_` prefix.

PiperOrigin-RevId: 291640501

--
501b602ef260cd7c8c527342581ceffb3c5b6d4c by Gennadiy Rozental <rogeeff@google.com>:

Introducing benchmark for absl::GetFlag.

PiperOrigin-RevId: 291433394

--
4eeaddc788da4b91c272a8adca77ca6dbbbc1d44 by Xiaoyi Zhang <zhangxy@google.com>:

fix: Add support for more ARM processors detection

Import of https://github.com/abseil/abseil-cpp/pull/608

PiperOrigin-RevId: 291420397

--
a3087a8e883c5d71de7d9bd4ec8f4db5142dfcf5 by Derek Mauro <dmauro@google.com>:

Removes the flaky raw_hash_set prefetch test

PiperOrigin-RevId: 291197079

--
aad6c2121c102ac36216e771c83227cf3e3bfd66 by Andy Soffer <asoffer@google.com>:

Enable building Abseil as a DLL.
This is currently experimental and unsupported.

This CL does a few things:
1. Adds the ABSL_DLL macro to any class holding a static data member, or to global constants in headers.
2. Adds a whitelist of all files in the DLL and all the build targets that are conglomerated into the DLL.
3. When BUILD_SHARED_LIBS is specified, any build target that would be in the DLL still exists, but we swap out all of it's dependencies so it just depends on abseil_dll

PiperOrigin-RevId: 291192055

--
5e888cd6f2a7722805d41f872108a03a84e421c7 by Mark Barolak <mbar@google.com>:

Move absl/strings/internal/escaping.{cc,h} into internal build targets.

This puts absl/strings/internal/escaping.h behind a whitelist and it also resolves https://github.com/abseil/abseil-cpp/issues/604.

PiperOrigin-RevId: 291173320

--
166836d24970da87587c1728036f53f05a28f0af by Eric Fiselier <ericwf@google.com>:

Internal Change.

PiperOrigin-RevId: 291012718

--
996ddb3dffda02440fa93f30ca5d71b14b688875 by Abseil Team <absl-team@google.com>:

Fix shared libraries log spam for built-in types in absl::GetFlag

PiperOrigin-RevId: 290772743
GitOrigin-RevId: 8bdb2020150ed0fd4a4e520e454dc5f54e33f776
Change-Id: I8bf2265dd14ebbace220a1b6b982bb5040ad2a26
2020-01-28 16:07:41 -05:00

665 lines
25 KiB
C++

//
// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// -----------------------------------------------------------------------------
// File: config.h
// -----------------------------------------------------------------------------
//
// This header file defines a set of macros for checking the presence of
// important compiler and platform features. Such macros can be used to
// produce portable code by parameterizing compilation based on the presence or
// lack of a given feature.
//
// We define a "feature" as some interface we wish to program to: for example,
// a library function or system call. A value of `1` indicates support for
// that feature; any other value indicates the feature support is undefined.
//
// Example:
//
// Suppose a programmer wants to write a program that uses the 'mmap()' system
// call. The Abseil macro for that feature (`ABSL_HAVE_MMAP`) allows you to
// selectively include the `mmap.h` header and bracket code using that feature
// in the macro:
//
// #include "absl/base/config.h"
//
// #ifdef ABSL_HAVE_MMAP
// #include "sys/mman.h"
// #endif //ABSL_HAVE_MMAP
//
// ...
// #ifdef ABSL_HAVE_MMAP
// void *ptr = mmap(...);
// ...
// #endif // ABSL_HAVE_MMAP
#ifndef ABSL_BASE_CONFIG_H_
#define ABSL_BASE_CONFIG_H_
// Included for the __GLIBC__ macro (or similar macros on other systems).
#include <limits.h>
#ifdef __cplusplus
// Included for __GLIBCXX__, _LIBCPP_VERSION
#include <cstddef>
#endif // __cplusplus
#if defined(__APPLE__)
// Included for TARGET_OS_IPHONE, __IPHONE_OS_VERSION_MIN_REQUIRED,
// __IPHONE_8_0.
#include <Availability.h>
#include <TargetConditionals.h>
#endif
#include "absl/base/options.h"
#include "absl/base/policy_checks.h"
// Helper macro to convert a CPP variable to a string literal.
#define ABSL_INTERNAL_DO_TOKEN_STR(x) #x
#define ABSL_INTERNAL_TOKEN_STR(x) ABSL_INTERNAL_DO_TOKEN_STR(x)
// -----------------------------------------------------------------------------
// Abseil namespace annotations
// -----------------------------------------------------------------------------
// ABSL_NAMESPACE_BEGIN/ABSL_NAMESPACE_END
//
// An annotation placed at the beginning/end of each `namespace absl` scope.
// This is used to inject an inline namespace.
//
// The proper way to write Abseil code in the `absl` namespace is:
//
// namespace absl {
// ABSL_NAMESPACE_BEGIN
//
// void Foo(); // absl::Foo().
//
// ABSL_NAMESPACE_END
// } // namespace absl
//
// Users of Abseil should not use these macros, because users of Abseil should
// not write `namespace absl {` in their own code for any reason. (Abseil does
// not support forward declarations of its own types, nor does it support
// user-provided specialization of Abseil templates. Code that violates these
// rules may be broken without warning.)
#if !defined(ABSL_OPTION_USE_INLINE_NAMESPACE) || \
!defined(ABSL_OPTION_INLINE_NAMESPACE_NAME)
#error options.h is misconfigured.
#endif
// Check that ABSL_OPTION_INLINE_NAMESPACE_NAME is neither "head" nor ""
#if defined(__cplusplus) && ABSL_OPTION_USE_INLINE_NAMESPACE == 1
#define ABSL_INTERNAL_INLINE_NAMESPACE_STR \
ABSL_INTERNAL_TOKEN_STR(ABSL_OPTION_INLINE_NAMESPACE_NAME)
static_assert(ABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != '\0',
"options.h misconfigured: ABSL_OPTION_INLINE_NAMESPACE_NAME must "
"not be empty.");
static_assert(ABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||
ABSL_INTERNAL_INLINE_NAMESPACE_STR[1] != 'e' ||
ABSL_INTERNAL_INLINE_NAMESPACE_STR[2] != 'a' ||
ABSL_INTERNAL_INLINE_NAMESPACE_STR[3] != 'd' ||
ABSL_INTERNAL_INLINE_NAMESPACE_STR[4] != '\0',
"options.h misconfigured: ABSL_OPTION_INLINE_NAMESPACE_NAME must "
"be changed to a new, unique identifier name.");
#endif
#if ABSL_OPTION_USE_INLINE_NAMESPACE == 0
#define ABSL_NAMESPACE_BEGIN
#define ABSL_NAMESPACE_END
#elif ABSL_OPTION_USE_INLINE_NAMESPACE == 1
#define ABSL_NAMESPACE_BEGIN \
inline namespace ABSL_OPTION_INLINE_NAMESPACE_NAME {
#define ABSL_NAMESPACE_END }
#else
#error options.h is misconfigured.
#endif
// -----------------------------------------------------------------------------
// Compiler Feature Checks
// -----------------------------------------------------------------------------
// ABSL_HAVE_BUILTIN()
//
// Checks whether the compiler supports a Clang Feature Checking Macro, and if
// so, checks whether it supports the provided builtin function "x" where x
// is one of the functions noted in
// https://clang.llvm.org/docs/LanguageExtensions.html
//
// Note: Use this macro to avoid an extra level of #ifdef __has_builtin check.
// http://releases.llvm.org/3.3/tools/clang/docs/LanguageExtensions.html
#ifdef __has_builtin
#define ABSL_HAVE_BUILTIN(x) __has_builtin(x)
#else
#define ABSL_HAVE_BUILTIN(x) 0
#endif
#if defined(__is_identifier)
#define ABSL_INTERNAL_HAS_KEYWORD(x) !(__is_identifier(x))
#else
#define ABSL_INTERNAL_HAS_KEYWORD(x) 0
#endif
// ABSL_HAVE_TLS is defined to 1 when __thread should be supported.
// We assume __thread is supported on Linux when compiled with Clang or compiled
// against libstdc++ with _GLIBCXX_HAVE_TLS defined.
#ifdef ABSL_HAVE_TLS
#error ABSL_HAVE_TLS cannot be directly set
#elif defined(__linux__) && (defined(__clang__) || defined(_GLIBCXX_HAVE_TLS))
#define ABSL_HAVE_TLS 1
#endif
// ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE
//
// Checks whether `std::is_trivially_destructible<T>` is supported.
//
// Notes: All supported compilers using libc++ support this feature, as does
// gcc >= 4.8.1 using libstdc++, and Visual Studio.
#ifdef ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE
#error ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE cannot be directly set
#elif defined(_LIBCPP_VERSION) || \
(!defined(__clang__) && defined(__GNUC__) && defined(__GLIBCXX__) && \
(__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8))) || \
defined(_MSC_VER)
#define ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE 1
#endif
// ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE
//
// Checks whether `std::is_trivially_default_constructible<T>` and
// `std::is_trivially_copy_constructible<T>` are supported.
// ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE
//
// Checks whether `std::is_trivially_copy_assignable<T>` is supported.
// Notes: Clang with libc++ supports these features, as does gcc >= 5.1 with
// either libc++ or libstdc++, and Visual Studio (but not NVCC).
#if defined(ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE)
#error ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE cannot be directly set
#elif defined(ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE)
#error ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE cannot directly set
#elif (defined(__clang__) && defined(_LIBCPP_VERSION)) || \
(!defined(__clang__) && defined(__GNUC__) && \
(__GNUC__ > 7 || (__GNUC__ == 7 && __GNUC_MINOR__ >= 4)) && \
(defined(_LIBCPP_VERSION) || defined(__GLIBCXX__))) || \
(defined(_MSC_VER) && !defined(__NVCC__))
#define ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE 1
#define ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE 1
#endif
// ABSL_HAVE_SOURCE_LOCATION_CURRENT
//
// Indicates whether `absl::SourceLocation::current()` will return useful
// information in some contexts.
#ifndef ABSL_HAVE_SOURCE_LOCATION_CURRENT
#if ABSL_INTERNAL_HAS_KEYWORD(__builtin_LINE) && \
ABSL_INTERNAL_HAS_KEYWORD(__builtin_FILE)
#define ABSL_HAVE_SOURCE_LOCATION_CURRENT 1
#endif
#endif
// ABSL_HAVE_THREAD_LOCAL
//
// Checks whether C++11's `thread_local` storage duration specifier is
// supported.
#ifdef ABSL_HAVE_THREAD_LOCAL
#error ABSL_HAVE_THREAD_LOCAL cannot be directly set
#elif defined(__APPLE__)
// Notes:
// * Xcode's clang did not support `thread_local` until version 8, and
// even then not for all iOS < 9.0.
// * Xcode 9.3 started disallowing `thread_local` for 32-bit iOS simulator
// targeting iOS 9.x.
// * Xcode 10 moves the deployment target check for iOS < 9.0 to link time
// making __has_feature unreliable there.
//
// Otherwise, `__has_feature` is only supported by Clang so it has be inside
// `defined(__APPLE__)` check.
#if __has_feature(cxx_thread_local) && \
!(TARGET_OS_IPHONE && __IPHONE_OS_VERSION_MIN_REQUIRED < __IPHONE_9_0)
#define ABSL_HAVE_THREAD_LOCAL 1
#endif
#else // !defined(__APPLE__)
#define ABSL_HAVE_THREAD_LOCAL 1
#endif
// There are platforms for which TLS should not be used even though the compiler
// makes it seem like it's supported (Android NDK < r12b for example).
// This is primarily because of linker problems and toolchain misconfiguration:
// Abseil does not intend to support this indefinitely. Currently, the newest
// toolchain that we intend to support that requires this behavior is the
// r11 NDK - allowing for a 5 year support window on that means this option
// is likely to be removed around June of 2021.
// TLS isn't supported until NDK r12b per
// https://developer.android.com/ndk/downloads/revision_history.html
// Since NDK r16, `__NDK_MAJOR__` and `__NDK_MINOR__` are defined in
// <android/ndk-version.h>. For NDK < r16, users should define these macros,
// e.g. `-D__NDK_MAJOR__=11 -D__NKD_MINOR__=0` for NDK r11.
#if defined(__ANDROID__) && defined(__clang__)
#if __has_include(<android/ndk-version.h>)
#include <android/ndk-version.h>
#endif // __has_include(<android/ndk-version.h>)
#if defined(__ANDROID__) && defined(__clang__) && defined(__NDK_MAJOR__) && \
defined(__NDK_MINOR__) && \
((__NDK_MAJOR__ < 12) || ((__NDK_MAJOR__ == 12) && (__NDK_MINOR__ < 1)))
#undef ABSL_HAVE_TLS
#undef ABSL_HAVE_THREAD_LOCAL
#endif
#endif // defined(__ANDROID__) && defined(__clang__)
// Emscripten doesn't yet support `thread_local` or `__thread`.
// https://github.com/emscripten-core/emscripten/issues/3502
#if defined(__EMSCRIPTEN__)
#undef ABSL_HAVE_TLS
#undef ABSL_HAVE_THREAD_LOCAL
#endif // defined(__EMSCRIPTEN__)
// ABSL_HAVE_INTRINSIC_INT128
//
// Checks whether the __int128 compiler extension for a 128-bit integral type is
// supported.
//
// Note: __SIZEOF_INT128__ is defined by Clang and GCC when __int128 is
// supported, but we avoid using it in certain cases:
// * On Clang:
// * Building using Clang for Windows, where the Clang runtime library has
// 128-bit support only on LP64 architectures, but Windows is LLP64.
// * On Nvidia's nvcc:
// * nvcc also defines __GNUC__ and __SIZEOF_INT128__, but not all versions
// actually support __int128.
#ifdef ABSL_HAVE_INTRINSIC_INT128
#error ABSL_HAVE_INTRINSIC_INT128 cannot be directly set
#elif defined(__SIZEOF_INT128__)
#if (defined(__clang__) && !defined(_WIN32)) || \
(defined(__CUDACC__) && __CUDACC_VER_MAJOR__ >= 9) || \
(defined(__GNUC__) && !defined(__clang__) && !defined(__CUDACC__))
#define ABSL_HAVE_INTRINSIC_INT128 1
#elif defined(__CUDACC__)
// __CUDACC_VER__ is a full version number before CUDA 9, and is defined to a
// string explaining that it has been removed starting with CUDA 9. We use
// nested #ifs because there is no short-circuiting in the preprocessor.
// NOTE: `__CUDACC__` could be undefined while `__CUDACC_VER__` is defined.
#if __CUDACC_VER__ >= 70000
#define ABSL_HAVE_INTRINSIC_INT128 1
#endif // __CUDACC_VER__ >= 70000
#endif // defined(__CUDACC__)
#endif // ABSL_HAVE_INTRINSIC_INT128
// ABSL_HAVE_EXCEPTIONS
//
// Checks whether the compiler both supports and enables exceptions. Many
// compilers support a "no exceptions" mode that disables exceptions.
//
// Generally, when ABSL_HAVE_EXCEPTIONS is not defined:
//
// * Code using `throw` and `try` may not compile.
// * The `noexcept` specifier will still compile and behave as normal.
// * The `noexcept` operator may still return `false`.
//
// For further details, consult the compiler's documentation.
#ifdef ABSL_HAVE_EXCEPTIONS
#error ABSL_HAVE_EXCEPTIONS cannot be directly set.
#elif defined(__clang__)
// TODO(calabrese)
// Switch to using __cpp_exceptions when we no longer support versions < 3.6.
// For details on this check, see:
// http://releases.llvm.org/3.6.0/tools/clang/docs/ReleaseNotes.html#the-exceptions-macro
#if defined(__EXCEPTIONS) && __has_feature(cxx_exceptions)
#define ABSL_HAVE_EXCEPTIONS 1
#endif // defined(__EXCEPTIONS) && __has_feature(cxx_exceptions)
// Handle remaining special cases and default to exceptions being supported.
#elif !(defined(__GNUC__) && (__GNUC__ < 5) && !defined(__EXCEPTIONS)) && \
!(defined(__GNUC__) && (__GNUC__ >= 5) && !defined(__cpp_exceptions)) && \
!(defined(_MSC_VER) && !defined(_CPPUNWIND))
#define ABSL_HAVE_EXCEPTIONS 1
#endif
// -----------------------------------------------------------------------------
// Platform Feature Checks
// -----------------------------------------------------------------------------
// Currently supported operating systems and associated preprocessor
// symbols:
//
// Linux and Linux-derived __linux__
// Android __ANDROID__ (implies __linux__)
// Linux (non-Android) __linux__ && !__ANDROID__
// Darwin (macOS and iOS) __APPLE__
// Akaros (http://akaros.org) __ros__
// Windows _WIN32
// NaCL __native_client__
// AsmJS __asmjs__
// WebAssembly __wasm__
// Fuchsia __Fuchsia__
//
// Note that since Android defines both __ANDROID__ and __linux__, one
// may probe for either Linux or Android by simply testing for __linux__.
// ABSL_HAVE_MMAP
//
// Checks whether the platform has an mmap(2) implementation as defined in
// POSIX.1-2001.
#ifdef ABSL_HAVE_MMAP
#error ABSL_HAVE_MMAP cannot be directly set
#elif defined(__linux__) || defined(__APPLE__) || defined(__FreeBSD__) || \
defined(__ros__) || defined(__native_client__) || defined(__asmjs__) || \
defined(__wasm__) || defined(__Fuchsia__) || defined(__sun) || \
defined(__ASYLO__)
#define ABSL_HAVE_MMAP 1
#endif
// ABSL_HAVE_PTHREAD_GETSCHEDPARAM
//
// Checks whether the platform implements the pthread_(get|set)schedparam(3)
// functions as defined in POSIX.1-2001.
#ifdef ABSL_HAVE_PTHREAD_GETSCHEDPARAM
#error ABSL_HAVE_PTHREAD_GETSCHEDPARAM cannot be directly set
#elif defined(__linux__) || defined(__APPLE__) || defined(__FreeBSD__) || \
defined(__ros__)
#define ABSL_HAVE_PTHREAD_GETSCHEDPARAM 1
#endif
// ABSL_HAVE_SCHED_YIELD
//
// Checks whether the platform implements sched_yield(2) as defined in
// POSIX.1-2001.
#ifdef ABSL_HAVE_SCHED_YIELD
#error ABSL_HAVE_SCHED_YIELD cannot be directly set
#elif defined(__linux__) || defined(__ros__) || defined(__native_client__)
#define ABSL_HAVE_SCHED_YIELD 1
#endif
// ABSL_HAVE_SEMAPHORE_H
//
// Checks whether the platform supports the <semaphore.h> header and sem_init(3)
// family of functions as standardized in POSIX.1-2001.
//
// Note: While Apple provides <semaphore.h> for both iOS and macOS, it is
// explicitly deprecated and will cause build failures if enabled for those
// platforms. We side-step the issue by not defining it here for Apple
// platforms.
#ifdef ABSL_HAVE_SEMAPHORE_H
#error ABSL_HAVE_SEMAPHORE_H cannot be directly set
#elif defined(__linux__) || defined(__ros__)
#define ABSL_HAVE_SEMAPHORE_H 1
#endif
// ABSL_HAVE_ALARM
//
// Checks whether the platform supports the <signal.h> header and alarm(2)
// function as standardized in POSIX.1-2001.
#ifdef ABSL_HAVE_ALARM
#error ABSL_HAVE_ALARM cannot be directly set
#elif defined(__GOOGLE_GRTE_VERSION__)
// feature tests for Google's GRTE
#define ABSL_HAVE_ALARM 1
#elif defined(__GLIBC__)
// feature test for glibc
#define ABSL_HAVE_ALARM 1
#elif defined(_MSC_VER)
// feature tests for Microsoft's library
#elif defined(__MINGW32__)
// mingw32 doesn't provide alarm(2):
// https://osdn.net/projects/mingw/scm/git/mingw-org-wsl/blobs/5.2-trunk/mingwrt/include/unistd.h
// mingw-w64 provides a no-op implementation:
// https://sourceforge.net/p/mingw-w64/mingw-w64/ci/master/tree/mingw-w64-crt/misc/alarm.c
#elif defined(__EMSCRIPTEN__)
// emscripten doesn't support signals
#elif defined(__Fuchsia__)
// Signals don't exist on fuchsia.
#elif defined(__native_client__)
#else
// other standard libraries
#define ABSL_HAVE_ALARM 1
#endif
// ABSL_IS_LITTLE_ENDIAN
// ABSL_IS_BIG_ENDIAN
//
// Checks the endianness of the platform.
//
// Notes: uses the built in endian macros provided by GCC (since 4.6) and
// Clang (since 3.2); see
// https://gcc.gnu.org/onlinedocs/cpp/Common-Predefined-Macros.html.
// Otherwise, if _WIN32, assume little endian. Otherwise, bail with an error.
#if defined(ABSL_IS_BIG_ENDIAN)
#error "ABSL_IS_BIG_ENDIAN cannot be directly set."
#endif
#if defined(ABSL_IS_LITTLE_ENDIAN)
#error "ABSL_IS_LITTLE_ENDIAN cannot be directly set."
#endif
#if (defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__) && \
__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__)
#define ABSL_IS_LITTLE_ENDIAN 1
#elif defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && \
__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
#define ABSL_IS_BIG_ENDIAN 1
#elif defined(_WIN32)
#define ABSL_IS_LITTLE_ENDIAN 1
#else
#error "absl endian detection needs to be set up for your compiler"
#endif
// macOS 10.13 and iOS 10.11 don't let you use <any>, <optional>, or <variant>
// even though the headers exist and are publicly noted to work. See
// https://github.com/abseil/abseil-cpp/issues/207 and
// https://developer.apple.com/documentation/xcode_release_notes/xcode_10_release_notes
// libc++ spells out the availability requirements in the file
// llvm-project/libcxx/include/__config via the #define
// _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS.
#if defined(__APPLE__) && defined(_LIBCPP_VERSION) && \
((defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && \
__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 101400) || \
(defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && \
__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 120000) || \
(defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && \
__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 120000) || \
(defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && \
__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 50000))
#define ABSL_INTERNAL_APPLE_CXX17_TYPES_UNAVAILABLE 1
#else
#define ABSL_INTERNAL_APPLE_CXX17_TYPES_UNAVAILABLE 0
#endif
// ABSL_HAVE_STD_ANY
//
// Checks whether C++17 std::any is available by checking whether <any> exists.
#ifdef ABSL_HAVE_STD_ANY
#error "ABSL_HAVE_STD_ANY cannot be directly set."
#endif
#ifdef __has_include
#if __has_include(<any>) && __cplusplus >= 201703L && \
!ABSL_INTERNAL_APPLE_CXX17_TYPES_UNAVAILABLE
#define ABSL_HAVE_STD_ANY 1
#endif
#endif
// ABSL_HAVE_STD_OPTIONAL
//
// Checks whether C++17 std::optional is available.
#ifdef ABSL_HAVE_STD_OPTIONAL
#error "ABSL_HAVE_STD_OPTIONAL cannot be directly set."
#endif
#ifdef __has_include
#if __has_include(<optional>) && __cplusplus >= 201703L && \
!ABSL_INTERNAL_APPLE_CXX17_TYPES_UNAVAILABLE
#define ABSL_HAVE_STD_OPTIONAL 1
#endif
#endif
// ABSL_HAVE_STD_VARIANT
//
// Checks whether C++17 std::variant is available.
#ifdef ABSL_HAVE_STD_VARIANT
#error "ABSL_HAVE_STD_VARIANT cannot be directly set."
#endif
#ifdef __has_include
#if __has_include(<variant>) && __cplusplus >= 201703L && \
!ABSL_INTERNAL_APPLE_CXX17_TYPES_UNAVAILABLE
#define ABSL_HAVE_STD_VARIANT 1
#endif
#endif
// ABSL_HAVE_STD_STRING_VIEW
//
// Checks whether C++17 std::string_view is available.
#ifdef ABSL_HAVE_STD_STRING_VIEW
#error "ABSL_HAVE_STD_STRING_VIEW cannot be directly set."
#endif
#ifdef __has_include
#if __has_include(<string_view>) && __cplusplus >= 201703L
#define ABSL_HAVE_STD_STRING_VIEW 1
#endif
#endif
// For MSVC, `__has_include` is supported in VS 2017 15.3, which is later than
// the support for <optional>, <any>, <string_view>, <variant>. So we use
// _MSC_VER to check whether we have VS 2017 RTM (when <optional>, <any>,
// <string_view>, <variant> is implemented) or higher. Also, `__cplusplus` is
// not correctly set by MSVC, so we use `_MSVC_LANG` to check the language
// version.
// TODO(zhangxy): fix tests before enabling aliasing for `std::any`.
#if defined(_MSC_VER) && _MSC_VER >= 1910 && \
((defined(_MSVC_LANG) && _MSVC_LANG > 201402) || __cplusplus > 201402)
// #define ABSL_HAVE_STD_ANY 1
#define ABSL_HAVE_STD_OPTIONAL 1
#define ABSL_HAVE_STD_VARIANT 1
#define ABSL_HAVE_STD_STRING_VIEW 1
#endif
// ABSL_USES_STD_ANY
//
// Indicates whether absl::any is an alias for std::any.
#if !defined(ABSL_OPTION_USE_STD_ANY)
#error options.h is misconfigured.
#elif ABSL_OPTION_USE_STD_ANY == 0 || \
(ABSL_OPTION_USE_STD_ANY == 2 && !defined(ABSL_HAVE_STD_ANY))
#undef ABSL_USES_STD_ANY
#elif ABSL_OPTION_USE_STD_ANY == 1 || \
(ABSL_OPTION_USE_STD_ANY == 2 && defined(ABSL_HAVE_STD_ANY))
#define ABSL_USES_STD_ANY 1
#else
#error options.h is misconfigured.
#endif
// ABSL_USES_STD_OPTIONAL
//
// Indicates whether absl::optional is an alias for std::optional.
#if !defined(ABSL_OPTION_USE_STD_OPTIONAL)
#error options.h is misconfigured.
#elif ABSL_OPTION_USE_STD_OPTIONAL == 0 || \
(ABSL_OPTION_USE_STD_OPTIONAL == 2 && !defined(ABSL_HAVE_STD_OPTIONAL))
#undef ABSL_USES_STD_OPTIONAL
#elif ABSL_OPTION_USE_STD_OPTIONAL == 1 || \
(ABSL_OPTION_USE_STD_OPTIONAL == 2 && defined(ABSL_HAVE_STD_OPTIONAL))
#define ABSL_USES_STD_OPTIONAL 1
#else
#error options.h is misconfigured.
#endif
// ABSL_USES_STD_VARIANT
//
// Indicates whether absl::variant is an alias for std::variant.
#if !defined(ABSL_OPTION_USE_STD_VARIANT)
#error options.h is misconfigured.
#elif ABSL_OPTION_USE_STD_VARIANT == 0 || \
(ABSL_OPTION_USE_STD_VARIANT == 2 && !defined(ABSL_HAVE_STD_VARIANT))
#undef ABSL_USES_STD_VARIANT
#elif ABSL_OPTION_USE_STD_VARIANT == 1 || \
(ABSL_OPTION_USE_STD_VARIANT == 2 && defined(ABSL_HAVE_STD_VARIANT))
#define ABSL_USES_STD_VARIANT 1
#else
#error options.h is misconfigured.
#endif
// ABSL_USES_STD_STRING_VIEW
//
// Indicates whether absl::string_view is an alias for std::string_view.
#if !defined(ABSL_OPTION_USE_STD_STRING_VIEW)
#error options.h is misconfigured.
#elif ABSL_OPTION_USE_STD_STRING_VIEW == 0 || \
(ABSL_OPTION_USE_STD_STRING_VIEW == 2 && \
!defined(ABSL_HAVE_STD_STRING_VIEW))
#undef ABSL_USES_STD_STRING_VIEW
#elif ABSL_OPTION_USE_STD_STRING_VIEW == 1 || \
(ABSL_OPTION_USE_STD_STRING_VIEW == 2 && \
defined(ABSL_HAVE_STD_STRING_VIEW))
#define ABSL_USES_STD_STRING_VIEW 1
#else
#error options.h is misconfigured.
#endif
// In debug mode, MSVC 2017's std::variant throws a EXCEPTION_ACCESS_VIOLATION
// SEH exception from emplace for variant<SomeStruct> when constructing the
// struct can throw. This defeats some of variant_test and
// variant_exception_safety_test.
#if defined(_MSC_VER) && _MSC_VER >= 1700 && defined(_DEBUG)
#define ABSL_INTERNAL_MSVC_2017_DBG_MODE
#endif
// ABSL_INTERNAL_MANGLED_NS
// ABSL_INTERNAL_MANGLED_BACKREFERENCE
//
// Internal macros for building up mangled names in our internal fork of CCTZ.
// This implementation detail is only needed and provided for the MSVC build.
//
// These macros both expand to string literals. ABSL_INTERNAL_MANGLED_NS is
// the mangled spelling of the `absl` namespace, and
// ABSL_INTERNAL_MANGLED_BACKREFERENCE is a back-reference integer representing
// the proper count to skip past the CCTZ fork namespace names. (This number
// is one larger when there is an inline namespace name to skip.)
#if defined(_MSC_VER)
#if ABSL_OPTION_USE_INLINE_NAMESPACE == 0
#define ABSL_INTERNAL_MANGLED_NS "absl"
#define ABSL_INTERNAL_MANGLED_BACKREFERENCE "5"
#else
#define ABSL_INTERNAL_MANGLED_NS \
ABSL_INTERNAL_TOKEN_STR(ABSL_OPTION_INLINE_NAMESPACE_NAME) "@absl"
#define ABSL_INTERNAL_MANGLED_BACKREFERENCE "6"
#endif
#endif
#undef ABSL_INTERNAL_HAS_KEYWORD
// ABSL_DLL
//
// When building Abseil as a DLL, this macro expands to `__declspec(dllexport)`
// so we can annotate symbols appropriately as being exported. When used in
// headers consuming a DLL, this macro expands to `__declspec(dllimport)` so
// that consumers know the symbol is defined inside the DLL. In all other cases,
// the macro expands to nothing.
#if defined(_MSC_VER)
#if defined(ABSL_BUILD_DLL)
#define ABSL_DLL __declspec(dllexport)
#elif defined(ABSL_CONSUME_DLL)
#define ABSL_DLL __declspec(dllimport)
#else
#define ABSL_DLL
#endif
#else
#define ABSL_DLL
#endif // defined(_MSC_VER)
#endif // ABSL_BASE_CONFIG_H_