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Yao
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// 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.
//
// This header file defines macros for declaring attributes for functions,
// types, and variables.
//
// These macros are used within Abseil and allow the compiler to optimize, where
// applicable, certain function calls.
//
// Most macros here are exposing GCC or Clang features, and are stubbed out for
// other compilers.
//
// GCC attributes documentation:
// https://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc/Function-Attributes.html
// https://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc/Variable-Attributes.html
// https://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc/Type-Attributes.html
//
// Most attributes in this file are already supported by GCC 4.7. However, some
// of them are not supported in older version of Clang. Thus, we check
// `__has_attribute()` first. If the check fails, we check if we are on GCC and
// assume the attribute exists on GCC (which is verified on GCC 4.7).
#ifndef ABSL_BASE_ATTRIBUTES_H_
#define ABSL_BASE_ATTRIBUTES_H_
#include "absl/base/config.h"
// ABSL_HAVE_ATTRIBUTE
//
// A function-like feature checking macro that is a wrapper around
// `__has_attribute`, which is defined by GCC 5+ and Clang and evaluates to a
// nonzero constant integer if the attribute is supported or 0 if not.
//
// It evaluates to zero if `__has_attribute` is not defined by the compiler.
//
// GCC: https://gcc.gnu.org/gcc-5/changes.html
// Clang: https://clang.llvm.org/docs/LanguageExtensions.html
#ifdef __has_attribute
#define ABSL_HAVE_ATTRIBUTE(x) __has_attribute(x)
#else
#define ABSL_HAVE_ATTRIBUTE(x) 0
#endif
// ABSL_HAVE_CPP_ATTRIBUTE
//
// A function-like feature checking macro that accepts C++11 style attributes.
// It's a wrapper around `__has_cpp_attribute`, defined by ISO C++ SD-6
// (https://en.cppreference.com/w/cpp/experimental/feature_test). If we don't
// find `__has_cpp_attribute`, will evaluate to 0.
#if defined(__cplusplus) && defined(__has_cpp_attribute)
// NOTE: requiring __cplusplus above should not be necessary, but
// works around https://bugs.llvm.org/show_bug.cgi?id=23435.
#define ABSL_HAVE_CPP_ATTRIBUTE(x) __has_cpp_attribute(x)
#else
#define ABSL_HAVE_CPP_ATTRIBUTE(x) 0
#endif
// -----------------------------------------------------------------------------
// Function Attributes
// -----------------------------------------------------------------------------
//
// GCC: https://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html
// Clang: https://clang.llvm.org/docs/AttributeReference.html
// ABSL_PRINTF_ATTRIBUTE
// ABSL_SCANF_ATTRIBUTE
//
// Tells the compiler to perform `printf` format string checking if the
// compiler supports it; see the 'format' attribute in
// <https://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc/Function-Attributes.html>.
//
// Note: As the GCC manual states, "[s]ince non-static C++ methods
// have an implicit 'this' argument, the arguments of such methods
// should be counted from two, not one."
#if ABSL_HAVE_ATTRIBUTE(format) || (defined(__GNUC__) && !defined(__clang__))
#define ABSL_PRINTF_ATTRIBUTE(string_index, first_to_check) \
__attribute__((__format__(__printf__, string_index, first_to_check)))
#define ABSL_SCANF_ATTRIBUTE(string_index, first_to_check) \
__attribute__((__format__(__scanf__, string_index, first_to_check)))
#else
#define ABSL_PRINTF_ATTRIBUTE(string_index, first_to_check)
#define ABSL_SCANF_ATTRIBUTE(string_index, first_to_check)
#endif
// ABSL_ATTRIBUTE_ALWAYS_INLINE
// ABSL_ATTRIBUTE_NOINLINE
//
// Forces functions to either inline or not inline. Introduced in gcc 3.1.
#if ABSL_HAVE_ATTRIBUTE(always_inline) || \
(defined(__GNUC__) && !defined(__clang__))
#define ABSL_ATTRIBUTE_ALWAYS_INLINE __attribute__((always_inline))
#define ABSL_HAVE_ATTRIBUTE_ALWAYS_INLINE 1
#else
#define ABSL_ATTRIBUTE_ALWAYS_INLINE
#endif
#if ABSL_HAVE_ATTRIBUTE(noinline) || (defined(__GNUC__) && !defined(__clang__))
#define ABSL_ATTRIBUTE_NOINLINE __attribute__((noinline))
#define ABSL_HAVE_ATTRIBUTE_NOINLINE 1
#else
#define ABSL_ATTRIBUTE_NOINLINE
#endif
// ABSL_ATTRIBUTE_NO_TAIL_CALL
//
// Prevents the compiler from optimizing away stack frames for functions which
// end in a call to another function.
#if ABSL_HAVE_ATTRIBUTE(disable_tail_calls)
#define ABSL_HAVE_ATTRIBUTE_NO_TAIL_CALL 1
#define ABSL_ATTRIBUTE_NO_TAIL_CALL __attribute__((disable_tail_calls))
#elif defined(__GNUC__) && !defined(__clang__) && !defined(__e2k__)
#define ABSL_HAVE_ATTRIBUTE_NO_TAIL_CALL 1
#define ABSL_ATTRIBUTE_NO_TAIL_CALL \
__attribute__((optimize("no-optimize-sibling-calls")))
#else
#define ABSL_ATTRIBUTE_NO_TAIL_CALL
#define ABSL_HAVE_ATTRIBUTE_NO_TAIL_CALL 0
#endif
// ABSL_ATTRIBUTE_WEAK
//
// Tags a function as weak for the purposes of compilation and linking.
// Weak attributes did not work properly in LLVM's Windows backend before
// 9.0.0, so disable them there. See https://bugs.llvm.org/show_bug.cgi?id=37598
// for further information.
// The MinGW compiler doesn't complain about the weak attribute until the link
// step, presumably because Windows doesn't use ELF binaries.
#if (ABSL_HAVE_ATTRIBUTE(weak) || \
(defined(__GNUC__) && !defined(__clang__))) && \
(!defined(_WIN32) || (defined(__clang__) && __clang_major__ >= 9)) && \
!defined(__MINGW32__)
#undef ABSL_ATTRIBUTE_WEAK
#define ABSL_ATTRIBUTE_WEAK __attribute__((weak))
#define ABSL_HAVE_ATTRIBUTE_WEAK 1
#else
#define ABSL_ATTRIBUTE_WEAK
#define ABSL_HAVE_ATTRIBUTE_WEAK 0
#endif
// ABSL_ATTRIBUTE_NONNULL
//
// Tells the compiler either (a) that a particular function parameter
// should be a non-null pointer, or (b) that all pointer arguments should
// be non-null.
//
// Note: As the GCC manual states, "[s]ince non-static C++ methods
// have an implicit 'this' argument, the arguments of such methods
// should be counted from two, not one."
//
// Args are indexed starting at 1.
//
// For non-static class member functions, the implicit `this` argument
// is arg 1, and the first explicit argument is arg 2. For static class member
// functions, there is no implicit `this`, and the first explicit argument is
// arg 1.
//
// Example:
//
// /* arg_a cannot be null, but arg_b can */
// void Function(void* arg_a, void* arg_b) ABSL_ATTRIBUTE_NONNULL(1);
//
// class C {
// /* arg_a cannot be null, but arg_b can */
// void Method(void* arg_a, void* arg_b) ABSL_ATTRIBUTE_NONNULL(2);
//
// /* arg_a cannot be null, but arg_b can */
// static void StaticMethod(void* arg_a, void* arg_b)
// ABSL_ATTRIBUTE_NONNULL(1);
// };
//
// If no arguments are provided, then all pointer arguments should be non-null.
//
// /* No pointer arguments may be null. */
// void Function(void* arg_a, void* arg_b, int arg_c) ABSL_ATTRIBUTE_NONNULL();
//
// NOTE: The GCC nonnull attribute actually accepts a list of arguments, but
// ABSL_ATTRIBUTE_NONNULL does not.
#if ABSL_HAVE_ATTRIBUTE(nonnull) || (defined(__GNUC__) && !defined(__clang__))
#define ABSL_ATTRIBUTE_NONNULL(arg_index) __attribute__((nonnull(arg_index)))
#else
#define ABSL_ATTRIBUTE_NONNULL(...)
#endif
// ABSL_ATTRIBUTE_NORETURN
//
// Tells the compiler that a given function never returns.
#if ABSL_HAVE_ATTRIBUTE(noreturn) || (defined(__GNUC__) && !defined(__clang__))
#define ABSL_ATTRIBUTE_NORETURN __attribute__((noreturn))
#elif defined(_MSC_VER)
#define ABSL_ATTRIBUTE_NORETURN __declspec(noreturn)
#else
#define ABSL_ATTRIBUTE_NORETURN
#endif
// ABSL_ATTRIBUTE_NO_SANITIZE_ADDRESS
//
// Tells the AddressSanitizer (or other memory testing tools) to ignore a given
// function. Useful for cases when a function reads random locations on stack,
// calls _exit from a cloned subprocess, deliberately accesses buffer
// out of bounds or does other scary things with memory.
// NOTE: GCC supports AddressSanitizer(asan) since 4.8.
// https://gcc.gnu.org/gcc-4.8/changes.html
#if defined(ABSL_HAVE_ADDRESS_SANITIZER) && \
ABSL_HAVE_ATTRIBUTE(no_sanitize_address)
#define ABSL_ATTRIBUTE_NO_SANITIZE_ADDRESS __attribute__((no_sanitize_address))
#elif defined(ABSL_HAVE_ADDRESS_SANITIZER) && defined(_MSC_VER) && \
_MSC_VER >= 1928
// https://docs.microsoft.com/en-us/cpp/cpp/no-sanitize-address
#define ABSL_ATTRIBUTE_NO_SANITIZE_ADDRESS __declspec(no_sanitize_address)
#elif defined(ABSL_HAVE_HWADDRESS_SANITIZER) && ABSL_HAVE_ATTRIBUTE(no_sanitize)
// HWAddressSanitizer is a sanitizer similar to AddressSanitizer, which uses CPU
// features to detect similar bugs with less CPU and memory overhead.
// NOTE: GCC supports HWAddressSanitizer(hwasan) since 11.
// https://gcc.gnu.org/gcc-11/changes.html
#define ABSL_ATTRIBUTE_NO_SANITIZE_ADDRESS \
__attribute__((no_sanitize("hwaddress")))
#else
#define ABSL_ATTRIBUTE_NO_SANITIZE_ADDRESS
#endif
// ABSL_ATTRIBUTE_NO_SANITIZE_MEMORY
//
// Tells the MemorySanitizer to relax the handling of a given function. All "Use
// of uninitialized value" warnings from such functions will be suppressed, and
// all values loaded from memory will be considered fully initialized. This
// attribute is similar to the ABSL_ATTRIBUTE_NO_SANITIZE_ADDRESS attribute
// above, but deals with initialized-ness rather than addressability issues.
// NOTE: MemorySanitizer(msan) is supported by Clang but not GCC.
#if ABSL_HAVE_ATTRIBUTE(no_sanitize_memory)
#define ABSL_ATTRIBUTE_NO_SANITIZE_MEMORY __attribute__((no_sanitize_memory))
#else
#define ABSL_ATTRIBUTE_NO_SANITIZE_MEMORY
#endif
// ABSL_ATTRIBUTE_NO_SANITIZE_THREAD
//
// Tells the ThreadSanitizer to not instrument a given function.
// NOTE: GCC supports ThreadSanitizer(tsan) since 4.8.
// https://gcc.gnu.org/gcc-4.8/changes.html
#if ABSL_HAVE_ATTRIBUTE(no_sanitize_thread)
#define ABSL_ATTRIBUTE_NO_SANITIZE_THREAD __attribute__((no_sanitize_thread))
#else
#define ABSL_ATTRIBUTE_NO_SANITIZE_THREAD
#endif
// ABSL_ATTRIBUTE_NO_SANITIZE_UNDEFINED
//
// Tells the UndefinedSanitizer to ignore a given function. Useful for cases
// where certain behavior (eg. division by zero) is being used intentionally.
// NOTE: GCC supports UndefinedBehaviorSanitizer(ubsan) since 4.9.
// https://gcc.gnu.org/gcc-4.9/changes.html
#if ABSL_HAVE_ATTRIBUTE(no_sanitize_undefined)
#define ABSL_ATTRIBUTE_NO_SANITIZE_UNDEFINED \
__attribute__((no_sanitize_undefined))
#elif ABSL_HAVE_ATTRIBUTE(no_sanitize)
#define ABSL_ATTRIBUTE_NO_SANITIZE_UNDEFINED \
__attribute__((no_sanitize("undefined")))
#else
#define ABSL_ATTRIBUTE_NO_SANITIZE_UNDEFINED
#endif
// ABSL_ATTRIBUTE_NO_SANITIZE_CFI
//
// Tells the ControlFlowIntegrity sanitizer to not instrument a given function.
// See https://clang.llvm.org/docs/ControlFlowIntegrity.html for details.
#if ABSL_HAVE_ATTRIBUTE(no_sanitize) && defined(__llvm__)
#define ABSL_ATTRIBUTE_NO_SANITIZE_CFI __attribute__((no_sanitize("cfi")))
#else
#define ABSL_ATTRIBUTE_NO_SANITIZE_CFI
#endif
// ABSL_ATTRIBUTE_NO_SANITIZE_SAFESTACK
//
// Tells the SafeStack to not instrument a given function.
// See https://clang.llvm.org/docs/SafeStack.html for details.
#if ABSL_HAVE_ATTRIBUTE(no_sanitize)
#define ABSL_ATTRIBUTE_NO_SANITIZE_SAFESTACK \
__attribute__((no_sanitize("safe-stack")))
#else
#define ABSL_ATTRIBUTE_NO_SANITIZE_SAFESTACK
#endif
// ABSL_ATTRIBUTE_RETURNS_NONNULL
//
// Tells the compiler that a particular function never returns a null pointer.
#if ABSL_HAVE_ATTRIBUTE(returns_nonnull)
#define ABSL_ATTRIBUTE_RETURNS_NONNULL __attribute__((returns_nonnull))
#else
#define ABSL_ATTRIBUTE_RETURNS_NONNULL
#endif
// ABSL_HAVE_ATTRIBUTE_SECTION
//
// Indicates whether labeled sections are supported. Weak symbol support is
// a prerequisite. Labeled sections are not supported on Darwin/iOS.
#ifdef ABSL_HAVE_ATTRIBUTE_SECTION
#error ABSL_HAVE_ATTRIBUTE_SECTION cannot be directly set
#elif (ABSL_HAVE_ATTRIBUTE(section) || \
(defined(__GNUC__) && !defined(__clang__))) && \
!defined(__APPLE__) && ABSL_HAVE_ATTRIBUTE_WEAK
#define ABSL_HAVE_ATTRIBUTE_SECTION 1
// ABSL_ATTRIBUTE_SECTION
//
// Tells the compiler/linker to put a given function into a section and define
// `__start_ ## name` and `__stop_ ## name` symbols to bracket the section.
// This functionality is supported by GNU linker. Any function annotated with
// `ABSL_ATTRIBUTE_SECTION` must not be inlined, or it will be placed into
// whatever section its caller is placed into.
//
#ifndef ABSL_ATTRIBUTE_SECTION
#define ABSL_ATTRIBUTE_SECTION(name) \
__attribute__((section(#name))) __attribute__((noinline))
#endif
// ABSL_ATTRIBUTE_SECTION_VARIABLE
//
// Tells the compiler/linker to put a given variable into a section and define
// `__start_ ## name` and `__stop_ ## name` symbols to bracket the section.
// This functionality is supported by GNU linker.
#ifndef ABSL_ATTRIBUTE_SECTION_VARIABLE
#ifdef _AIX
// __attribute__((section(#name))) on AIX is achieved by using the `.csect`
// psudo op which includes an additional integer as part of its syntax indcating
// alignment. If data fall under different alignments then you might get a
// compilation error indicating a `Section type conflict`.
#define ABSL_ATTRIBUTE_SECTION_VARIABLE(name)
#else
#define ABSL_ATTRIBUTE_SECTION_VARIABLE(name) __attribute__((section(#name)))
#endif
#endif
// ABSL_DECLARE_ATTRIBUTE_SECTION_VARS
//
// A weak section declaration to be used as a global declaration
// for ABSL_ATTRIBUTE_SECTION_START|STOP(name) to compile and link
// even without functions with ABSL_ATTRIBUTE_SECTION(name).
// ABSL_DEFINE_ATTRIBUTE_SECTION should be in the exactly one file; it's
// a no-op on ELF but not on Mach-O.
//
#ifndef ABSL_DECLARE_ATTRIBUTE_SECTION_VARS
#define ABSL_DECLARE_ATTRIBUTE_SECTION_VARS(name) \
extern char __start_##name[] ABSL_ATTRIBUTE_WEAK; \
extern char __stop_##name[] ABSL_ATTRIBUTE_WEAK
#endif
#ifndef ABSL_DEFINE_ATTRIBUTE_SECTION_VARS
#define ABSL_INIT_ATTRIBUTE_SECTION_VARS(name)
#define ABSL_DEFINE_ATTRIBUTE_SECTION_VARS(name)
#endif
// ABSL_ATTRIBUTE_SECTION_START
//
// Returns `void*` pointers to start/end of a section of code with
// functions having ABSL_ATTRIBUTE_SECTION(name).
// Returns 0 if no such functions exist.
// One must ABSL_DECLARE_ATTRIBUTE_SECTION_VARS(name) for this to compile and
// link.
//
#define ABSL_ATTRIBUTE_SECTION_START(name) \
(reinterpret_cast<void *>(__start_##name))
#define ABSL_ATTRIBUTE_SECTION_STOP(name) \
(reinterpret_cast<void *>(__stop_##name))
#else // !ABSL_HAVE_ATTRIBUTE_SECTION
#define ABSL_HAVE_ATTRIBUTE_SECTION 0
// provide dummy definitions
#define ABSL_ATTRIBUTE_SECTION(name)
#define ABSL_ATTRIBUTE_SECTION_VARIABLE(name)
#define ABSL_INIT_ATTRIBUTE_SECTION_VARS(name)
#define ABSL_DEFINE_ATTRIBUTE_SECTION_VARS(name)
#define ABSL_DECLARE_ATTRIBUTE_SECTION_VARS(name)
#define ABSL_ATTRIBUTE_SECTION_START(name) (reinterpret_cast<void *>(0))
#define ABSL_ATTRIBUTE_SECTION_STOP(name) (reinterpret_cast<void *>(0))
#endif // ABSL_ATTRIBUTE_SECTION
// ABSL_ATTRIBUTE_STACK_ALIGN_FOR_OLD_LIBC
//
// Support for aligning the stack on 32-bit x86.
#if ABSL_HAVE_ATTRIBUTE(force_align_arg_pointer) || \
(defined(__GNUC__) && !defined(__clang__))
#if defined(__i386__)
#define ABSL_ATTRIBUTE_STACK_ALIGN_FOR_OLD_LIBC \
__attribute__((force_align_arg_pointer))
#define ABSL_REQUIRE_STACK_ALIGN_TRAMPOLINE (0)
#elif defined(__x86_64__)
#define ABSL_REQUIRE_STACK_ALIGN_TRAMPOLINE (1)
#define ABSL_ATTRIBUTE_STACK_ALIGN_FOR_OLD_LIBC
#else // !__i386__ && !__x86_64
#define ABSL_REQUIRE_STACK_ALIGN_TRAMPOLINE (0)
#define ABSL_ATTRIBUTE_STACK_ALIGN_FOR_OLD_LIBC
#endif // __i386__
#else
#define ABSL_ATTRIBUTE_STACK_ALIGN_FOR_OLD_LIBC
#define ABSL_REQUIRE_STACK_ALIGN_TRAMPOLINE (0)
#endif
// ABSL_MUST_USE_RESULT
//
// Tells the compiler to warn about unused results.
//
// For code or headers that are assured to only build with C++17 and up, prefer
// just using the standard `[[nodiscard]]` directly over this macro.
//
// When annotating a function, it must appear as the first part of the
// declaration or definition. The compiler will warn if the return value from
// such a function is unused:
//
// ABSL_MUST_USE_RESULT Sprocket* AllocateSprocket();
// AllocateSprocket(); // Triggers a warning.
//
// When annotating a class, it is equivalent to annotating every function which
// returns an instance.
//
// class ABSL_MUST_USE_RESULT Sprocket {};
// Sprocket(); // Triggers a warning.
//
// Sprocket MakeSprocket();
// MakeSprocket(); // Triggers a warning.
//
// Note that references and pointers are not instances:
//
// Sprocket* SprocketPointer();
// SprocketPointer(); // Does *not* trigger a warning.
//
// ABSL_MUST_USE_RESULT allows using cast-to-void to suppress the unused result
// warning. For that, warn_unused_result is used only for clang but not for gcc.
// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66425
//
// Note: past advice was to place the macro after the argument list.
//
// TODO(b/176172494): Use ABSL_HAVE_CPP_ATTRIBUTE(nodiscard) when all code is
// compliant with the stricter [[nodiscard]].
#if defined(__clang__) && ABSL_HAVE_ATTRIBUTE(warn_unused_result)
#define ABSL_MUST_USE_RESULT __attribute__((warn_unused_result))
#else
#define ABSL_MUST_USE_RESULT
#endif
// ABSL_ATTRIBUTE_HOT, ABSL_ATTRIBUTE_COLD
//
// Tells GCC that a function is hot or cold. GCC can use this information to
// improve static analysis, i.e. a conditional branch to a cold function
// is likely to be not-taken.
// This annotation is used for function declarations.
//
// Example:
//
// int foo() ABSL_ATTRIBUTE_HOT;
#if ABSL_HAVE_ATTRIBUTE(hot) || (defined(__GNUC__) && !defined(__clang__))
#define ABSL_ATTRIBUTE_HOT __attribute__((hot))
#else
#define ABSL_ATTRIBUTE_HOT
#endif
#if ABSL_HAVE_ATTRIBUTE(cold) || (defined(__GNUC__) && !defined(__clang__))
#define ABSL_ATTRIBUTE_COLD __attribute__((cold))
#else
#define ABSL_ATTRIBUTE_COLD
#endif
// ABSL_XRAY_ALWAYS_INSTRUMENT, ABSL_XRAY_NEVER_INSTRUMENT, ABSL_XRAY_LOG_ARGS
//
// We define the ABSL_XRAY_ALWAYS_INSTRUMENT and ABSL_XRAY_NEVER_INSTRUMENT
// macro used as an attribute to mark functions that must always or never be
// instrumented by XRay. Currently, this is only supported in Clang/LLVM.
//
// For reference on the LLVM XRay instrumentation, see
// http://llvm.org/docs/XRay.html.
//
// A function with the XRAY_ALWAYS_INSTRUMENT macro attribute in its declaration
// will always get the XRay instrumentation sleds. These sleds may introduce
// some binary size and runtime overhead and must be used sparingly.
//
// These attributes only take effect when the following conditions are met:
//
// * The file/target is built in at least C++11 mode, with a Clang compiler
// that supports XRay attributes.
// * The file/target is built with the -fxray-instrument flag set for the
// Clang/LLVM compiler.
// * The function is defined in the translation unit (the compiler honors the
// attribute in either the definition or the declaration, and must match).
//
// There are cases when, even when building with XRay instrumentation, users
// might want to control specifically which functions are instrumented for a
// particular build using special-case lists provided to the compiler. These
// special case lists are provided to Clang via the
// -fxray-always-instrument=... and -fxray-never-instrument=... flags. The
// attributes in source take precedence over these special-case lists.
//
// To disable the XRay attributes at build-time, users may define
// ABSL_NO_XRAY_ATTRIBUTES. Do NOT define ABSL_NO_XRAY_ATTRIBUTES on specific
// packages/targets, as this may lead to conflicting definitions of functions at
// link-time.
//
// XRay isn't currently supported on Android:
// https://github.com/android/ndk/issues/368
#if ABSL_HAVE_CPP_ATTRIBUTE(clang::xray_always_instrument) && \
!defined(ABSL_NO_XRAY_ATTRIBUTES) && !defined(__ANDROID__)
#define ABSL_XRAY_ALWAYS_INSTRUMENT [[clang::xray_always_instrument]]
#define ABSL_XRAY_NEVER_INSTRUMENT [[clang::xray_never_instrument]]
#if ABSL_HAVE_CPP_ATTRIBUTE(clang::xray_log_args)
#define ABSL_XRAY_LOG_ARGS(N) \
[[clang::xray_always_instrument, clang::xray_log_args(N)]]
#else
#define ABSL_XRAY_LOG_ARGS(N) [[clang::xray_always_instrument]]
#endif
#else
#define ABSL_XRAY_ALWAYS_INSTRUMENT
#define ABSL_XRAY_NEVER_INSTRUMENT
#define ABSL_XRAY_LOG_ARGS(N)
#endif
// ABSL_ATTRIBUTE_REINITIALIZES
//
// Indicates that a member function reinitializes the entire object to a known
// state, independent of the previous state of the object.
//
// The clang-tidy check bugprone-use-after-move allows member functions marked
// with this attribute to be called on objects that have been moved from;
// without the attribute, this would result in a use-after-move warning.
#if ABSL_HAVE_CPP_ATTRIBUTE(clang::reinitializes)
#define ABSL_ATTRIBUTE_REINITIALIZES [[clang::reinitializes]]
#else
#define ABSL_ATTRIBUTE_REINITIALIZES
#endif
// -----------------------------------------------------------------------------
// Variable Attributes
// -----------------------------------------------------------------------------
// ABSL_ATTRIBUTE_UNUSED
//
// Prevents the compiler from complaining about variables that appear unused.
//
// For code or headers that are assured to only build with C++17 and up, prefer
// just using the standard '[[maybe_unused]]' directly over this macro.
//
// Due to differences in positioning requirements between the old, compiler
// specific __attribute__ syntax and the now standard [[maybe_unused]], this
// macro does not attempt to take advantage of '[[maybe_unused]]'.
#if ABSL_HAVE_ATTRIBUTE(unused) || (defined(__GNUC__) && !defined(__clang__))
#undef ABSL_ATTRIBUTE_UNUSED
#define ABSL_ATTRIBUTE_UNUSED __attribute__((__unused__))
#else
#define ABSL_ATTRIBUTE_UNUSED
#endif
// ABSL_ATTRIBUTE_INITIAL_EXEC
//
// Tells the compiler to use "initial-exec" mode for a thread-local variable.
// See http://people.redhat.com/drepper/tls.pdf for the gory details.
#if ABSL_HAVE_ATTRIBUTE(tls_model) || (defined(__GNUC__) && !defined(__clang__))
#define ABSL_ATTRIBUTE_INITIAL_EXEC __attribute__((tls_model("initial-exec")))
#else
#define ABSL_ATTRIBUTE_INITIAL_EXEC
#endif
// ABSL_ATTRIBUTE_PACKED
//
// Instructs the compiler not to use natural alignment for a tagged data
// structure, but instead to reduce its alignment to 1.
//
// Therefore, DO NOT APPLY THIS ATTRIBUTE TO STRUCTS CONTAINING ATOMICS. Doing
// so can cause atomic variables to be mis-aligned and silently violate
// atomicity on x86.
//
// This attribute can either be applied to members of a structure or to a
// structure in its entirety. Applying this attribute (judiciously) to a
// structure in its entirety to optimize the memory footprint of very
// commonly-used structs is fine. Do not apply this attribute to a structure in
// its entirety if the purpose is to control the offsets of the members in the
// structure. Instead, apply this attribute only to structure members that need
// it.
//
// When applying ABSL_ATTRIBUTE_PACKED only to specific structure members the
// natural alignment of structure members not annotated is preserved. Aligned
// member accesses are faster than non-aligned member accesses even if the
// targeted microprocessor supports non-aligned accesses.
#if ABSL_HAVE_ATTRIBUTE(packed) || (defined(__GNUC__) && !defined(__clang__))
#define ABSL_ATTRIBUTE_PACKED __attribute__((__packed__))
#else
#define ABSL_ATTRIBUTE_PACKED
#endif
// ABSL_ATTRIBUTE_FUNC_ALIGN
//
// Tells the compiler to align the function start at least to certain
// alignment boundary
#if ABSL_HAVE_ATTRIBUTE(aligned) || (defined(__GNUC__) && !defined(__clang__))
#define ABSL_ATTRIBUTE_FUNC_ALIGN(bytes) __attribute__((aligned(bytes)))
#else
#define ABSL_ATTRIBUTE_FUNC_ALIGN(bytes)
#endif
// ABSL_FALLTHROUGH_INTENDED
//
// Annotates implicit fall-through between switch labels, allowing a case to
// indicate intentional fallthrough and turn off warnings about any lack of a
// `break` statement. The ABSL_FALLTHROUGH_INTENDED macro should be followed by
// a semicolon and can be used in most places where `break` can, provided that
// no statements exist between it and the next switch label.
//
// Example:
//
// switch (x) {
// case 40:
// case 41:
// if (truth_is_out_there) {
// ++x;
// ABSL_FALLTHROUGH_INTENDED; // Use instead of/along with annotations
// // in comments
// } else {
// return x;
// }
// case 42:
// ...
//
// Notes: When supported, GCC and Clang can issue a warning on switch labels
// with unannotated fallthrough using the warning `-Wimplicit-fallthrough`. See
// clang documentation on language extensions for details:
// https://clang.llvm.org/docs/AttributeReference.html#fallthrough-clang-fallthrough
//
// When used with unsupported compilers, the ABSL_FALLTHROUGH_INTENDED macro has
// no effect on diagnostics. In any case this macro has no effect on runtime
// behavior and performance of code.
#ifdef ABSL_FALLTHROUGH_INTENDED
#error "ABSL_FALLTHROUGH_INTENDED should not be defined."
#elif ABSL_HAVE_CPP_ATTRIBUTE(fallthrough)
#define ABSL_FALLTHROUGH_INTENDED [[fallthrough]]
#elif ABSL_HAVE_CPP_ATTRIBUTE(clang::fallthrough)
#define ABSL_FALLTHROUGH_INTENDED [[clang::fallthrough]]
#elif ABSL_HAVE_CPP_ATTRIBUTE(gnu::fallthrough)
#define ABSL_FALLTHROUGH_INTENDED [[gnu::fallthrough]]
#else
#define ABSL_FALLTHROUGH_INTENDED \
do { \
} while (0)
#endif
// ABSL_DEPRECATED()
//
// Marks a deprecated class, struct, enum, function, method and variable
// declarations. The macro argument is used as a custom diagnostic message (e.g.
// suggestion of a better alternative).
//
// For code or headers that are assured to only build with C++14 and up, prefer
// just using the standard `[[deprecated("message")]]` directly over this macro.
//
// Examples:
//
// class ABSL_DEPRECATED("Use Bar instead") Foo {...};
//
// ABSL_DEPRECATED("Use Baz() instead") void Bar() {...}
//
// template <typename T>
// ABSL_DEPRECATED("Use DoThat() instead")
// void DoThis();
//
// enum FooEnum {
// kBar ABSL_DEPRECATED("Use kBaz instead"),
// };
//
// Every usage of a deprecated entity will trigger a warning when compiled with
// GCC/Clang's `-Wdeprecated-declarations` option. Google's production toolchain
// turns this warning off by default, instead relying on clang-tidy to report
// new uses of deprecated code.
#if ABSL_HAVE_ATTRIBUTE(deprecated)
#define ABSL_DEPRECATED(message) __attribute__((deprecated(message)))
#else
#define ABSL_DEPRECATED(message)
#endif
// When deprecating Abseil code, it is sometimes necessary to turn off the
// warning within Abseil, until the deprecated code is actually removed. The
// deprecated code can be surrounded with these directives to achieve that
// result.
//
// class ABSL_DEPRECATED("Use Bar instead") Foo;
//
// ABSL_INTERNAL_DISABLE_DEPRECATED_DECLARATION_WARNING
// Baz ComputeBazFromFoo(Foo f);
// ABSL_INTERNAL_RESTORE_DEPRECATED_DECLARATION_WARNING
#if defined(__GNUC__) || defined(__clang__)
// Clang also supports these GCC pragmas.
#define ABSL_INTERNAL_DISABLE_DEPRECATED_DECLARATION_WARNING \
_Pragma("GCC diagnostic push") \
_Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
#define ABSL_INTERNAL_RESTORE_DEPRECATED_DECLARATION_WARNING \
_Pragma("GCC diagnostic pop")
#else
#define ABSL_INTERNAL_DISABLE_DEPRECATED_DECLARATION_WARNING
#define ABSL_INTERNAL_RESTORE_DEPRECATED_DECLARATION_WARNING
#endif // defined(__GNUC__) || defined(__clang__)
// ABSL_CONST_INIT
//
// A variable declaration annotated with the `ABSL_CONST_INIT` attribute will
// not compile (on supported platforms) unless the variable has a constant
// initializer. This is useful for variables with static and thread storage
// duration, because it guarantees that they will not suffer from the so-called
// "static init order fiasco".
//
// This attribute must be placed on the initializing declaration of the
// variable. Some compilers will give a -Wmissing-constinit warning when this
// attribute is placed on some other declaration but missing from the
// initializing declaration.
//
// In some cases (notably with thread_local variables), `ABSL_CONST_INIT` can
// also be used in a non-initializing declaration to tell the compiler that a
// variable is already initialized, reducing overhead that would otherwise be
// incurred by a hidden guard variable. Thus annotating all declarations with
// this attribute is recommended to potentially enhance optimization.
//
// Example:
//
// class MyClass {
// public:
// ABSL_CONST_INIT static MyType my_var;
// };
//
// ABSL_CONST_INIT MyType MyClass::my_var = MakeMyType(...);
//
// For code or headers that are assured to only build with C++20 and up, prefer
// just using the standard `constinit` keyword directly over this macro.
//
// Note that this attribute is redundant if the variable is declared constexpr.
#if defined(__cpp_constinit) && __cpp_constinit >= 201907L
#define ABSL_CONST_INIT constinit
#elif ABSL_HAVE_CPP_ATTRIBUTE(clang::require_constant_initialization)
#define ABSL_CONST_INIT [[clang::require_constant_initialization]]
#else
#define ABSL_CONST_INIT
#endif
// ABSL_ATTRIBUTE_PURE_FUNCTION
//
// ABSL_ATTRIBUTE_PURE_FUNCTION is used to annotate declarations of "pure"
// functions. A function is pure if its return value is only a function of its
// arguments. The pure attribute prohibits a function from modifying the state
// of the program that is observable by means other than inspecting the
// function's return value. Declaring such functions with the pure attribute
// allows the compiler to avoid emitting some calls in repeated invocations of
// the function with the same argument values.
//
// Example:
//
// ABSL_ATTRIBUTE_PURE_FUNCTION std::string FormatTime(Time t);
#if ABSL_HAVE_CPP_ATTRIBUTE(gnu::pure)
#define ABSL_ATTRIBUTE_PURE_FUNCTION [[gnu::pure]]
#elif ABSL_HAVE_ATTRIBUTE(pure)
#define ABSL_ATTRIBUTE_PURE_FUNCTION __attribute__((pure))
#else
// If the attribute isn't defined, we'll fallback to ABSL_MUST_USE_RESULT since
// pure functions are useless if its return is ignored.
#define ABSL_ATTRIBUTE_PURE_FUNCTION ABSL_MUST_USE_RESULT
#endif
// ABSL_ATTRIBUTE_CONST_FUNCTION
//
// ABSL_ATTRIBUTE_CONST_FUNCTION is used to annotate declarations of "const"
// functions. A const function is similar to a pure function, with one
// exception: Pure functions may return value that depend on a non-volatile
// object that isn't provided as a function argument, while the const function
// is guaranteed to return the same result given the same arguments.
//
// Example:
//
// ABSL_ATTRIBUTE_CONST_FUNCTION int64_t ToInt64Milliseconds(Duration d);
#if defined(_MSC_VER) && !defined(__clang__)
// Put the MSVC case first since MSVC seems to parse const as a C++ keyword.
#define ABSL_ATTRIBUTE_CONST_FUNCTION ABSL_ATTRIBUTE_PURE_FUNCTION
#elif ABSL_HAVE_CPP_ATTRIBUTE(gnu::const)
#define ABSL_ATTRIBUTE_CONST_FUNCTION [[gnu::const]]
#elif ABSL_HAVE_ATTRIBUTE(const)
#define ABSL_ATTRIBUTE_CONST_FUNCTION __attribute__((const))
#else
// Since const functions are more restrictive pure function, we'll fallback to a
// pure function if the const attribute is not handled.
#define ABSL_ATTRIBUTE_CONST_FUNCTION ABSL_ATTRIBUTE_PURE_FUNCTION
#endif
// ABSL_ATTRIBUTE_LIFETIME_BOUND indicates that a resource owned by a function
// parameter or implicit object parameter is retained by the return value of the
// annotated function (or, for a parameter of a constructor, in the value of the
// constructed object). This attribute causes warnings to be produced if a
// temporary object does not live long enough.
//
// When applied to a reference parameter, the referenced object is assumed to be
// retained by the return value of the function. When applied to a non-reference
// parameter (for example, a pointer or a class type), all temporaries
// referenced by the parameter are assumed to be retained by the return value of
// the function.
//
// See also the upstream documentation:
// https://clang.llvm.org/docs/AttributeReference.html#lifetimebound
#if ABSL_HAVE_CPP_ATTRIBUTE(clang::lifetimebound)
#define ABSL_ATTRIBUTE_LIFETIME_BOUND [[clang::lifetimebound]]
#elif ABSL_HAVE_ATTRIBUTE(lifetimebound)
#define ABSL_ATTRIBUTE_LIFETIME_BOUND __attribute__((lifetimebound))
#else
#define ABSL_ATTRIBUTE_LIFETIME_BOUND
#endif
// ABSL_ATTRIBUTE_TRIVIAL_ABI
// Indicates that a type is "trivially relocatable" -- meaning it can be
// relocated without invoking the constructor/destructor, using a form of move
// elision.
//
// From a memory safety point of view, putting aside destructor ordering, it's
// safe to apply ABSL_ATTRIBUTE_TRIVIAL_ABI if an object's location
// can change over the course of its lifetime: if a constructor can be run one
// place, and then the object magically teleports to another place where some
// methods are run, and then the object teleports to yet another place where it
// is destroyed. This is notably not true for self-referential types, where the
// move-constructor must keep the self-reference up to date. If the type changed
// location without invoking the move constructor, it would have a dangling
// self-reference.
//
// The use of this teleporting machinery means that the number of paired
// move/destroy operations can change, and so it is a bad idea to apply this to
// a type meant to count the number of moves.
//
// Warning: applying this can, rarely, break callers. Objects passed by value
// will be destroyed at the end of the call, instead of the end of the
// full-expression containing the call. In addition, it changes the ABI
// of functions accepting this type by value (e.g. to pass in registers).
//
// See also the upstream documentation:
// https://clang.llvm.org/docs/AttributeReference.html#trivial-abi
//
// b/321691395 - This is currently disabled in open-source builds since
// compiler support differs. If system libraries compiled with GCC are mixed
// with libraries compiled with Clang, types will have different ideas about
// their ABI, leading to hard to debug crashes.
#define ABSL_ATTRIBUTE_TRIVIAL_ABI
// ABSL_ATTRIBUTE_NO_UNIQUE_ADDRESS
//
// Indicates a data member can be optimized to occupy no space (if it is empty)
// and/or its tail padding can be used for other members.
//
// For code that is assured to only build with C++20 or later, prefer using
// the standard attribute `[[no_unique_address]]` directly instead of this
// macro.
//
// https://devblogs.microsoft.com/cppblog/msvc-cpp20-and-the-std-cpp20-switch/#c20-no_unique_address
// Current versions of MSVC have disabled `[[no_unique_address]]` since it
// breaks ABI compatibility, but offers `[[msvc::no_unique_address]]` for
// situations when it can be assured that it is desired. Since Abseil does not
// claim ABI compatibility in mixed builds, we can offer it unconditionally.
#if defined(_MSC_VER) && _MSC_VER >= 1929
#define ABSL_ATTRIBUTE_NO_UNIQUE_ADDRESS [[msvc::no_unique_address]]
#elif ABSL_HAVE_CPP_ATTRIBUTE(no_unique_address)
#define ABSL_ATTRIBUTE_NO_UNIQUE_ADDRESS [[no_unique_address]]
#else
#define ABSL_ATTRIBUTE_NO_UNIQUE_ADDRESS
#endif
#endif // ABSL_BASE_ATTRIBUTES_H_

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// 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: call_once.h
// -----------------------------------------------------------------------------
//
// This header file provides an Abseil version of `std::call_once` for invoking
// a given function at most once, across all threads. This Abseil version is
// faster than the C++11 version and incorporates the C++17 argument-passing
// fix, so that (for example) non-const references may be passed to the invoked
// function.
#ifndef ABSL_BASE_CALL_ONCE_H_
#define ABSL_BASE_CALL_ONCE_H_
#include <algorithm>
#include <atomic>
#include <cstdint>
#include <type_traits>
#include <utility>
#include "absl/base/internal/invoke.h"
#include "absl/base/internal/low_level_scheduling.h"
#include "absl/base/internal/raw_logging.h"
#include "absl/base/internal/scheduling_mode.h"
#include "absl/base/internal/spinlock_wait.h"
#include "absl/base/macros.h"
#include "absl/base/nullability.h"
#include "absl/base/optimization.h"
#include "absl/base/port.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
class once_flag;
namespace base_internal {
absl::Nonnull<std::atomic<uint32_t>*> ControlWord(
absl::Nonnull<absl::once_flag*> flag);
} // namespace base_internal
// call_once()
//
// For all invocations using a given `once_flag`, invokes a given `fn` exactly
// once across all threads. The first call to `call_once()` with a particular
// `once_flag` argument (that does not throw an exception) will run the
// specified function with the provided `args`; other calls with the same
// `once_flag` argument will not run the function, but will wait
// for the provided function to finish running (if it is still running).
//
// This mechanism provides a safe, simple, and fast mechanism for one-time
// initialization in a multi-threaded process.
//
// Example:
//
// class MyInitClass {
// public:
// ...
// mutable absl::once_flag once_;
//
// MyInitClass* init() const {
// absl::call_once(once_, &MyInitClass::Init, this);
// return ptr_;
// }
//
template <typename Callable, typename... Args>
void call_once(absl::once_flag& flag, Callable&& fn, Args&&... args);
// once_flag
//
// Objects of this type are used to distinguish calls to `call_once()` and
// ensure the provided function is only invoked once across all threads. This
// type is not copyable or movable. However, it has a `constexpr`
// constructor, and is safe to use as a namespace-scoped global variable.
class once_flag {
public:
constexpr once_flag() : control_(0) {}
once_flag(const once_flag&) = delete;
once_flag& operator=(const once_flag&) = delete;
private:
friend absl::Nonnull<std::atomic<uint32_t>*> base_internal::ControlWord(
absl::Nonnull<once_flag*> flag);
std::atomic<uint32_t> control_;
};
//------------------------------------------------------------------------------
// End of public interfaces.
// Implementation details follow.
//------------------------------------------------------------------------------
namespace base_internal {
// Like call_once, but uses KERNEL_ONLY scheduling. Intended to be used to
// initialize entities used by the scheduler implementation.
template <typename Callable, typename... Args>
void LowLevelCallOnce(absl::Nonnull<absl::once_flag*> flag, Callable&& fn,
Args&&... args);
// Disables scheduling while on stack when scheduling mode is non-cooperative.
// No effect for cooperative scheduling modes.
class SchedulingHelper {
public:
explicit SchedulingHelper(base_internal::SchedulingMode mode) : mode_(mode) {
if (mode_ == base_internal::SCHEDULE_KERNEL_ONLY) {
guard_result_ = base_internal::SchedulingGuard::DisableRescheduling();
}
}
~SchedulingHelper() {
if (mode_ == base_internal::SCHEDULE_KERNEL_ONLY) {
base_internal::SchedulingGuard::EnableRescheduling(guard_result_);
}
}
private:
base_internal::SchedulingMode mode_;
bool guard_result_ = false;
};
// Bit patterns for call_once state machine values. Internal implementation
// detail, not for use by clients.
//
// The bit patterns are arbitrarily chosen from unlikely values, to aid in
// debugging. However, kOnceInit must be 0, so that a zero-initialized
// once_flag will be valid for immediate use.
enum {
kOnceInit = 0,
kOnceRunning = 0x65C2937B,
kOnceWaiter = 0x05A308D2,
// A very small constant is chosen for kOnceDone so that it fit in a single
// compare with immediate instruction for most common ISAs. This is verified
// for x86, POWER and ARM.
kOnceDone = 221, // Random Number
};
template <typename Callable, typename... Args>
ABSL_ATTRIBUTE_NOINLINE void CallOnceImpl(
absl::Nonnull<std::atomic<uint32_t>*> control,
base_internal::SchedulingMode scheduling_mode, Callable&& fn,
Args&&... args) {
#ifndef NDEBUG
{
uint32_t old_control = control->load(std::memory_order_relaxed);
if (old_control != kOnceInit &&
old_control != kOnceRunning &&
old_control != kOnceWaiter &&
old_control != kOnceDone) {
ABSL_RAW_LOG(FATAL, "Unexpected value for control word: 0x%lx",
static_cast<unsigned long>(old_control)); // NOLINT
}
}
#endif // NDEBUG
static const base_internal::SpinLockWaitTransition trans[] = {
{kOnceInit, kOnceRunning, true},
{kOnceRunning, kOnceWaiter, false},
{kOnceDone, kOnceDone, true}};
// Must do this before potentially modifying control word's state.
base_internal::SchedulingHelper maybe_disable_scheduling(scheduling_mode);
// Short circuit the simplest case to avoid procedure call overhead.
// The base_internal::SpinLockWait() call returns either kOnceInit or
// kOnceDone. If it returns kOnceDone, it must have loaded the control word
// with std::memory_order_acquire and seen a value of kOnceDone.
uint32_t old_control = kOnceInit;
if (control->compare_exchange_strong(old_control, kOnceRunning,
std::memory_order_relaxed) ||
base_internal::SpinLockWait(control, ABSL_ARRAYSIZE(trans), trans,
scheduling_mode) == kOnceInit) {
base_internal::invoke(std::forward<Callable>(fn),
std::forward<Args>(args)...);
old_control =
control->exchange(base_internal::kOnceDone, std::memory_order_release);
if (old_control == base_internal::kOnceWaiter) {
base_internal::SpinLockWake(control, true);
}
} // else *control is already kOnceDone
}
inline absl::Nonnull<std::atomic<uint32_t>*> ControlWord(
absl::Nonnull<once_flag*> flag) {
return &flag->control_;
}
template <typename Callable, typename... Args>
void LowLevelCallOnce(absl::Nonnull<absl::once_flag*> flag, Callable&& fn,
Args&&... args) {
std::atomic<uint32_t>* once = base_internal::ControlWord(flag);
uint32_t s = once->load(std::memory_order_acquire);
if (ABSL_PREDICT_FALSE(s != base_internal::kOnceDone)) {
base_internal::CallOnceImpl(once, base_internal::SCHEDULE_KERNEL_ONLY,
std::forward<Callable>(fn),
std::forward<Args>(args)...);
}
}
} // namespace base_internal
template <typename Callable, typename... Args>
void call_once(absl::once_flag& flag, Callable&& fn, Args&&... args) {
std::atomic<uint32_t>* once = base_internal::ControlWord(&flag);
uint32_t s = once->load(std::memory_order_acquire);
if (ABSL_PREDICT_FALSE(s != base_internal::kOnceDone)) {
base_internal::CallOnceImpl(
once, base_internal::SCHEDULE_COOPERATIVE_AND_KERNEL,
std::forward<Callable>(fn), std::forward<Args>(args)...);
}
}
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_CALL_ONCE_H_

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//
// 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: casts.h
// -----------------------------------------------------------------------------
//
// This header file defines casting templates to fit use cases not covered by
// the standard casts provided in the C++ standard. As with all cast operations,
// use these with caution and only if alternatives do not exist.
#ifndef ABSL_BASE_CASTS_H_
#define ABSL_BASE_CASTS_H_
#include <cstring>
#include <memory>
#include <type_traits>
#include <utility>
#if defined(__cpp_lib_bit_cast) && __cpp_lib_bit_cast >= 201806L
#include <bit> // For std::bit_cast.
#endif // defined(__cpp_lib_bit_cast) && __cpp_lib_bit_cast >= 201806L
#include "absl/base/internal/identity.h"
#include "absl/base/macros.h"
#include "absl/meta/type_traits.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
// implicit_cast()
//
// Performs an implicit conversion between types following the language
// rules for implicit conversion; if an implicit conversion is otherwise
// allowed by the language in the given context, this function performs such an
// implicit conversion.
//
// Example:
//
// // If the context allows implicit conversion:
// From from;
// To to = from;
//
// // Such code can be replaced by:
// implicit_cast<To>(from);
//
// An `implicit_cast()` may also be used to annotate numeric type conversions
// that, although safe, may produce compiler warnings (such as `long` to `int`).
// Additionally, an `implicit_cast()` is also useful within return statements to
// indicate a specific implicit conversion is being undertaken.
//
// Example:
//
// return implicit_cast<double>(size_in_bytes) / capacity_;
//
// Annotating code with `implicit_cast()` allows you to explicitly select
// particular overloads and template instantiations, while providing a safer
// cast than `reinterpret_cast()` or `static_cast()`.
//
// Additionally, an `implicit_cast()` can be used to allow upcasting within a
// type hierarchy where incorrect use of `static_cast()` could accidentally
// allow downcasting.
//
// Finally, an `implicit_cast()` can be used to perform implicit conversions
// from unrelated types that otherwise couldn't be implicitly cast directly;
// C++ will normally only implicitly cast "one step" in such conversions.
//
// That is, if C is a type which can be implicitly converted to B, with B being
// a type that can be implicitly converted to A, an `implicit_cast()` can be
// used to convert C to B (which the compiler can then implicitly convert to A
// using language rules).
//
// Example:
//
// // Assume an object C is convertible to B, which is implicitly convertible
// // to A
// A a = implicit_cast<B>(C);
//
// Such implicit cast chaining may be useful within template logic.
template <typename To>
constexpr To implicit_cast(typename absl::internal::type_identity_t<To> to) {
return to;
}
// bit_cast()
//
// Creates a value of the new type `Dest` whose representation is the same as
// that of the argument, which is of (deduced) type `Source` (a "bitwise cast";
// every bit in the value representation of the result is equal to the
// corresponding bit in the object representation of the source). Source and
// destination types must be of the same size, and both types must be trivially
// copyable.
//
// As with most casts, use with caution. A `bit_cast()` might be needed when you
// need to treat a value as the value of some other type, for example, to access
// the individual bits of an object which are not normally accessible through
// the object's type, such as for working with the binary representation of a
// floating point value:
//
// float f = 3.14159265358979;
// int i = bit_cast<int>(f);
// // i = 0x40490fdb
//
// Reinterpreting and accessing a value directly as a different type (as shown
// below) usually results in undefined behavior.
//
// Example:
//
// // WRONG
// float f = 3.14159265358979;
// int i = reinterpret_cast<int&>(f); // Wrong
// int j = *reinterpret_cast<int*>(&f); // Equally wrong
// int k = *bit_cast<int*>(&f); // Equally wrong
//
// Reinterpret-casting results in undefined behavior according to the ISO C++
// specification, section [basic.lval]. Roughly, this section says: if an object
// in memory has one type, and a program accesses it with a different type, the
// result is undefined behavior for most "different type".
//
// Using bit_cast on a pointer and then dereferencing it is no better than using
// reinterpret_cast. You should only use bit_cast on the value itself.
//
// Such casting results in type punning: holding an object in memory of one type
// and reading its bits back using a different type. A `bit_cast()` avoids this
// issue by copying the object representation to a new value, which avoids
// introducing this undefined behavior (since the original value is never
// accessed in the wrong way).
//
// The requirements of `absl::bit_cast` are more strict than that of
// `std::bit_cast` unless compiler support is available. Specifically, without
// compiler support, this implementation also requires `Dest` to be
// default-constructible. In C++20, `absl::bit_cast` is replaced by
// `std::bit_cast`.
#if defined(__cpp_lib_bit_cast) && __cpp_lib_bit_cast >= 201806L
using std::bit_cast;
#else // defined(__cpp_lib_bit_cast) && __cpp_lib_bit_cast >= 201806L
template <
typename Dest, typename Source,
typename std::enable_if<sizeof(Dest) == sizeof(Source) &&
std::is_trivially_copyable<Source>::value &&
std::is_trivially_copyable<Dest>::value
#if !ABSL_HAVE_BUILTIN(__builtin_bit_cast)
&& std::is_default_constructible<Dest>::value
#endif // !ABSL_HAVE_BUILTIN(__builtin_bit_cast)
,
int>::type = 0>
#if ABSL_HAVE_BUILTIN(__builtin_bit_cast)
inline constexpr Dest bit_cast(const Source& source) {
return __builtin_bit_cast(Dest, source);
}
#else // ABSL_HAVE_BUILTIN(__builtin_bit_cast)
inline Dest bit_cast(const Source& source) {
Dest dest;
memcpy(static_cast<void*>(std::addressof(dest)),
static_cast<const void*>(std::addressof(source)), sizeof(dest));
return dest;
}
#endif // ABSL_HAVE_BUILTIN(__builtin_bit_cast)
#endif // defined(__cpp_lib_bit_cast) && __cpp_lib_bit_cast >= 201806L
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_CASTS_H_

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@@ -0,0 +1,1004 @@
//
// 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
// ABSL_INTERNAL_CPLUSPLUS_LANG
//
// MSVC does not set the value of __cplusplus correctly, but instead uses
// _MSVC_LANG as a stand-in.
// https://docs.microsoft.com/en-us/cpp/preprocessor/predefined-macros
//
// However, there are reports that MSVC even sets _MSVC_LANG incorrectly at
// times, for example:
// https://github.com/microsoft/vscode-cpptools/issues/1770
// https://reviews.llvm.org/D70996
//
// For this reason, this symbol is considered INTERNAL and code outside of
// Abseil must not use it.
#if defined(_MSVC_LANG)
#define ABSL_INTERNAL_CPLUSPLUS_LANG _MSVC_LANG
#elif defined(__cplusplus)
#define ABSL_INTERNAL_CPLUSPLUS_LANG __cplusplus
#endif
#if defined(ABSL_INTERNAL_CPLUSPLUS_LANG) && \
ABSL_INTERNAL_CPLUSPLUS_LANG >= 202002L
// Include library feature test macros.
#include <version>
#endif
#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"
// Abseil long-term support (LTS) releases will define
// `ABSL_LTS_RELEASE_VERSION` to the integer representing the date string of the
// LTS release version, and will define `ABSL_LTS_RELEASE_PATCH_LEVEL` to the
// integer representing the patch-level for that release.
//
// For example, for LTS release version "20300401.2", this would give us
// ABSL_LTS_RELEASE_VERSION == 20300401 && ABSL_LTS_RELEASE_PATCH_LEVEL == 2
//
// These symbols will not be defined in non-LTS code.
//
// Abseil recommends that clients live-at-head. Therefore, if you are using
// these symbols to assert a minimum version requirement, we recommend you do it
// as
//
// #if defined(ABSL_LTS_RELEASE_VERSION) && ABSL_LTS_RELEASE_VERSION < 20300401
// #error Project foo requires Abseil LTS version >= 20300401
// #endif
//
// The `defined(ABSL_LTS_RELEASE_VERSION)` part of the check excludes
// live-at-head clients from the minimum version assertion.
//
// See https://abseil.io/about/releases for more information on Abseil release
// management.
//
// LTS releases can be obtained from
// https://github.com/abseil/abseil-cpp/releases.
#define ABSL_LTS_RELEASE_VERSION 20240116
#define ABSL_LTS_RELEASE_PATCH_LEVEL 1
// 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
#define ABSL_INTERNAL_C_SYMBOL(x) x
#elif ABSL_OPTION_USE_INLINE_NAMESPACE == 1
#define ABSL_NAMESPACE_BEGIN \
inline namespace ABSL_OPTION_INLINE_NAMESPACE_NAME {
#define ABSL_NAMESPACE_END }
#define ABSL_INTERNAL_C_SYMBOL_HELPER_2(x, v) x##_##v
#define ABSL_INTERNAL_C_SYMBOL_HELPER_1(x, v) \
ABSL_INTERNAL_C_SYMBOL_HELPER_2(x, v)
#define ABSL_INTERNAL_C_SYMBOL(x) \
ABSL_INTERNAL_C_SYMBOL_HELPER_1(x, ABSL_OPTION_INLINE_NAMESPACE_NAME)
#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
#ifdef __has_feature
#define ABSL_HAVE_FEATURE(f) __has_feature(f)
#else
#define ABSL_HAVE_FEATURE(f) 0
#endif
// Portable check for GCC minimum version:
// https://gcc.gnu.org/onlinedocs/cpp/Common-Predefined-Macros.html
#if defined(__GNUC__) && defined(__GNUC_MINOR__)
#define ABSL_INTERNAL_HAVE_MIN_GNUC_VERSION(x, y) \
(__GNUC__ > (x) || __GNUC__ == (x) && __GNUC_MINOR__ >= (y))
#else
#define ABSL_INTERNAL_HAVE_MIN_GNUC_VERSION(x, y) 0
#endif
#if defined(__clang__) && defined(__clang_major__) && defined(__clang_minor__)
#define ABSL_INTERNAL_HAVE_MIN_CLANG_VERSION(x, y) \
(__clang_major__ > (x) || __clang_major__ == (x) && __clang_minor__ >= (y))
#else
#define ABSL_INTERNAL_HAVE_MIN_CLANG_VERSION(x, y) 0
#endif
// ABSL_HAVE_TLS is defined to 1 when __thread should be supported.
// We assume __thread is supported on Linux or Asylo 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(__ASYLO__)) && \
(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.
#ifdef ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE
#error ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE cannot be directly set
#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.
#ifdef ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE
#error ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE cannot be directly set
#else
#define ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE 1
#endif
// ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE
//
// Checks whether `std::is_trivially_copy_assignable<T>` is supported.
#ifdef ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE
#error ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE cannot be directly set
#else
#define ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE 1
#endif
// ABSL_HAVE_STD_IS_TRIVIALLY_COPYABLE
//
// Checks whether `std::is_trivially_copyable<T>` is supported.
#ifdef ABSL_HAVE_STD_IS_TRIVIALLY_COPYABLE
#error ABSL_HAVE_STD_IS_TRIVIALLY_COPYABLE cannot be directly set
#define ABSL_HAVE_STD_IS_TRIVIALLY_COPYABLE 1
#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 ABSL_HAVE_FEATURE unreliable there.
//
#if ABSL_HAVE_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__)
// 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 ABSL_INTERNAL_HAVE_MIN_CLANG_VERSION(3, 6)
// Clang >= 3.6
#if ABSL_HAVE_FEATURE(cxx_exceptions)
#define ABSL_HAVE_EXCEPTIONS 1
#endif // ABSL_HAVE_FEATURE(cxx_exceptions)
#elif defined(__clang__)
// Clang < 3.6
// http://releases.llvm.org/3.6.0/tools/clang/docs/ReleaseNotes.html#the-exceptions-macro
#if defined(__EXCEPTIONS) && ABSL_HAVE_FEATURE(cxx_exceptions)
#define ABSL_HAVE_EXCEPTIONS 1
#endif // defined(__EXCEPTIONS) && ABSL_HAVE_FEATURE(cxx_exceptions)
// Handle remaining special cases and default to exceptions being supported.
#elif !(defined(__GNUC__) && (__GNUC__ < 5) && !defined(__EXCEPTIONS)) && \
!(ABSL_INTERNAL_HAVE_MIN_GNUC_VERSION(5, 0) && \
!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 (Emscripten) __EMSCRIPTEN__
// 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(_AIX) || defined(__ros__) || defined(__native_client__) || \
defined(__asmjs__) || defined(__EMSCRIPTEN__) || defined(__Fuchsia__) || \
defined(__sun) || defined(__ASYLO__) || defined(__myriad2__) || \
defined(__HAIKU__) || defined(__OpenBSD__) || defined(__NetBSD__) || \
defined(__QNX__) || defined(__VXWORKS__) || defined(__hexagon__)
#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(_AIX) || defined(__ros__) || defined(__OpenBSD__) || \
defined(__NetBSD__) || defined(__VXWORKS__)
#define ABSL_HAVE_PTHREAD_GETSCHEDPARAM 1
#endif
// ABSL_HAVE_SCHED_GETCPU
//
// Checks whether sched_getcpu is available.
#ifdef ABSL_HAVE_SCHED_GETCPU
#error ABSL_HAVE_SCHED_GETCPU cannot be directly set
#elif defined(__linux__)
#define ABSL_HAVE_SCHED_GETCPU 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__) || \
defined(__VXWORKS__)
#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__) || defined(__VXWORKS__)
#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(__wasi__)
// WASI doesn't support signals
#elif defined(__Fuchsia__)
// Signals don't exist on fuchsia.
#elif defined(__native_client__)
// Signals don't exist on hexagon/QuRT
#elif defined(__hexagon__)
#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 < 12 don't support <any>, <optional>, or <variant>
// because the libc++ shared library shipped on the system doesn't have the
// requisite exported symbols. 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. The set of versions has been
// modified a few times, via
// https://github.com/llvm/llvm-project/commit/7fb40e1569dd66292b647f4501b85517e9247953
// and
// https://github.com/llvm/llvm-project/commit/0bc451e7e137c4ccadcd3377250874f641ca514a
// The second has the actually correct versions, thus, is what we copy here.
#if defined(__APPLE__) && \
((defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && \
__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 101300) || \
(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__ < 50000) || \
(defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && \
__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 120000))
#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.
#ifdef ABSL_HAVE_STD_ANY
#error "ABSL_HAVE_STD_ANY cannot be directly set."
#elif defined(__cpp_lib_any) && __cpp_lib_any >= 201606L
#define ABSL_HAVE_STD_ANY 1
#elif defined(ABSL_INTERNAL_CPLUSPLUS_LANG) && \
ABSL_INTERNAL_CPLUSPLUS_LANG >= 201703L && \
!ABSL_INTERNAL_APPLE_CXX17_TYPES_UNAVAILABLE
#define ABSL_HAVE_STD_ANY 1
#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."
#elif defined(__cpp_lib_optional) && __cpp_lib_optional >= 202106L
#define ABSL_HAVE_STD_OPTIONAL 1
#elif defined(ABSL_INTERNAL_CPLUSPLUS_LANG) && \
ABSL_INTERNAL_CPLUSPLUS_LANG >= 201703L && \
!ABSL_INTERNAL_APPLE_CXX17_TYPES_UNAVAILABLE
#define ABSL_HAVE_STD_OPTIONAL 1
#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."
#elif defined(__cpp_lib_variant) && __cpp_lib_variant >= 201606L
#define ABSL_HAVE_STD_VARIANT 1
#elif defined(ABSL_INTERNAL_CPLUSPLUS_LANG) && \
ABSL_INTERNAL_CPLUSPLUS_LANG >= 201703L && \
!ABSL_INTERNAL_APPLE_CXX17_TYPES_UNAVAILABLE
#define ABSL_HAVE_STD_VARIANT 1
#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."
#elif defined(__cpp_lib_string_view) && __cpp_lib_string_view >= 201606L
#define ABSL_HAVE_STD_STRING_VIEW 1
#elif defined(ABSL_INTERNAL_CPLUSPLUS_LANG) && \
ABSL_INTERNAL_CPLUSPLUS_LANG >= 201703L
#define ABSL_HAVE_STD_STRING_VIEW 1
#endif
// ABSL_HAVE_STD_ORDERING
//
// Checks whether C++20 std::{partial,weak,strong}_ordering are available.
//
// __cpp_lib_three_way_comparison is missing on libc++
// (https://github.com/llvm/llvm-project/issues/73953) so treat it as defined
// when building in C++20 mode.
#ifdef ABSL_HAVE_STD_ORDERING
#error "ABSL_HAVE_STD_ORDERING cannot be directly set."
#elif (defined(__cpp_lib_three_way_comparison) && \
__cpp_lib_three_way_comparison >= 201907L) || \
(defined(ABSL_INTERNAL_CPLUSPLUS_LANG) && \
ABSL_INTERNAL_CPLUSPLUS_LANG >= 202002L)
#define ABSL_HAVE_STD_ORDERING 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
// ABSL_USES_STD_ORDERING
//
// Indicates whether absl::{partial,weak,strong}_ordering are aliases for the
// std:: ordering types.
#if !defined(ABSL_OPTION_USE_STD_ORDERING)
#error options.h is misconfigured.
#elif ABSL_OPTION_USE_STD_ORDERING == 0 || \
(ABSL_OPTION_USE_STD_ORDERING == 2 && !defined(ABSL_HAVE_STD_ORDERING))
#undef ABSL_USES_STD_ORDERING
#elif ABSL_OPTION_USE_STD_ORDERING == 1 || \
(ABSL_OPTION_USE_STD_ORDERING == 2 && defined(ABSL_HAVE_STD_ORDERING))
#define ABSL_USES_STD_ORDERING 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
// 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)
#if defined(_MSC_VER)
#if defined(ABSL_BUILD_TEST_DLL)
#define ABSL_TEST_DLL __declspec(dllexport)
#elif defined(ABSL_CONSUME_TEST_DLL)
#define ABSL_TEST_DLL __declspec(dllimport)
#else
#define ABSL_TEST_DLL
#endif
#else
#define ABSL_TEST_DLL
#endif // defined(_MSC_VER)
// ABSL_HAVE_MEMORY_SANITIZER
//
// MemorySanitizer (MSan) is a detector of uninitialized reads. It consists of
// a compiler instrumentation module and a run-time library.
#ifdef ABSL_HAVE_MEMORY_SANITIZER
#error "ABSL_HAVE_MEMORY_SANITIZER cannot be directly set."
#elif !defined(__native_client__) && ABSL_HAVE_FEATURE(memory_sanitizer)
#define ABSL_HAVE_MEMORY_SANITIZER 1
#endif
// ABSL_HAVE_THREAD_SANITIZER
//
// ThreadSanitizer (TSan) is a fast data race detector.
#ifdef ABSL_HAVE_THREAD_SANITIZER
#error "ABSL_HAVE_THREAD_SANITIZER cannot be directly set."
#elif defined(__SANITIZE_THREAD__)
#define ABSL_HAVE_THREAD_SANITIZER 1
#elif ABSL_HAVE_FEATURE(thread_sanitizer)
#define ABSL_HAVE_THREAD_SANITIZER 1
#endif
// ABSL_HAVE_ADDRESS_SANITIZER
//
// AddressSanitizer (ASan) is a fast memory error detector.
#ifdef ABSL_HAVE_ADDRESS_SANITIZER
#error "ABSL_HAVE_ADDRESS_SANITIZER cannot be directly set."
#elif defined(__SANITIZE_ADDRESS__)
#define ABSL_HAVE_ADDRESS_SANITIZER 1
#elif ABSL_HAVE_FEATURE(address_sanitizer)
#define ABSL_HAVE_ADDRESS_SANITIZER 1
#endif
// ABSL_HAVE_HWADDRESS_SANITIZER
//
// Hardware-Assisted AddressSanitizer (or HWASAN) is even faster than asan
// memory error detector which can use CPU features like ARM TBI, Intel LAM or
// AMD UAI.
#ifdef ABSL_HAVE_HWADDRESS_SANITIZER
#error "ABSL_HAVE_HWADDRESS_SANITIZER cannot be directly set."
#elif defined(__SANITIZE_HWADDRESS__)
#define ABSL_HAVE_HWADDRESS_SANITIZER 1
#elif ABSL_HAVE_FEATURE(hwaddress_sanitizer)
#define ABSL_HAVE_HWADDRESS_SANITIZER 1
#endif
// ABSL_HAVE_DATAFLOW_SANITIZER
//
// Dataflow Sanitizer (or DFSAN) is a generalised dynamic data flow analysis.
#ifdef ABSL_HAVE_DATAFLOW_SANITIZER
#error "ABSL_HAVE_DATAFLOW_SANITIZER cannot be directly set."
#elif defined(DATAFLOW_SANITIZER)
// GCC provides no method for detecting the presence of the standalone
// DataFlowSanitizer (-fsanitize=dataflow), so GCC users of -fsanitize=dataflow
// should also use -DDATAFLOW_SANITIZER.
#define ABSL_HAVE_DATAFLOW_SANITIZER 1
#elif ABSL_HAVE_FEATURE(dataflow_sanitizer)
#define ABSL_HAVE_DATAFLOW_SANITIZER 1
#endif
// ABSL_HAVE_LEAK_SANITIZER
//
// LeakSanitizer (or lsan) is a detector of memory leaks.
// https://clang.llvm.org/docs/LeakSanitizer.html
// https://github.com/google/sanitizers/wiki/AddressSanitizerLeakSanitizer
//
// The macro ABSL_HAVE_LEAK_SANITIZER can be used to detect at compile-time
// whether the LeakSanitizer is potentially available. However, just because the
// LeakSanitizer is available does not mean it is active. Use the
// always-available run-time interface in //absl/debugging/leak_check.h for
// interacting with LeakSanitizer.
#ifdef ABSL_HAVE_LEAK_SANITIZER
#error "ABSL_HAVE_LEAK_SANITIZER cannot be directly set."
#elif defined(LEAK_SANITIZER)
// GCC provides no method for detecting the presence of the standalone
// LeakSanitizer (-fsanitize=leak), so GCC users of -fsanitize=leak should also
// use -DLEAK_SANITIZER.
#define ABSL_HAVE_LEAK_SANITIZER 1
// Clang standalone LeakSanitizer (-fsanitize=leak)
#elif ABSL_HAVE_FEATURE(leak_sanitizer)
#define ABSL_HAVE_LEAK_SANITIZER 1
#elif defined(ABSL_HAVE_ADDRESS_SANITIZER)
// GCC or Clang using the LeakSanitizer integrated into AddressSanitizer.
#define ABSL_HAVE_LEAK_SANITIZER 1
#endif
// ABSL_HAVE_CLASS_TEMPLATE_ARGUMENT_DEDUCTION
//
// Class template argument deduction is a language feature added in C++17.
#ifdef ABSL_HAVE_CLASS_TEMPLATE_ARGUMENT_DEDUCTION
#error "ABSL_HAVE_CLASS_TEMPLATE_ARGUMENT_DEDUCTION cannot be directly set."
#elif defined(__cpp_deduction_guides)
#define ABSL_HAVE_CLASS_TEMPLATE_ARGUMENT_DEDUCTION 1
#endif
// ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
//
// Prior to C++17, static constexpr variables defined in classes required a
// separate definition outside of the class body, for example:
//
// class Foo {
// static constexpr int kBar = 0;
// };
// constexpr int Foo::kBar;
//
// In C++17, these variables defined in classes are considered inline variables,
// and the extra declaration is redundant. Since some compilers warn on the
// extra declarations, ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL can be used
// conditionally ignore them:
//
// #ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
// constexpr int Foo::kBar;
// #endif
#if defined(ABSL_INTERNAL_CPLUSPLUS_LANG) && \
ABSL_INTERNAL_CPLUSPLUS_LANG < 201703L
#define ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL 1
#endif
// `ABSL_INTERNAL_HAS_RTTI` determines whether abseil is being compiled with
// RTTI support.
#ifdef ABSL_INTERNAL_HAS_RTTI
#error ABSL_INTERNAL_HAS_RTTI cannot be directly set
#elif ABSL_HAVE_FEATURE(cxx_rtti)
#define ABSL_INTERNAL_HAS_RTTI 1
#elif defined(__GNUC__) && defined(__GXX_RTTI)
#define ABSL_INTERNAL_HAS_RTTI 1
#elif defined(_MSC_VER) && defined(_CPPRTTI)
#define ABSL_INTERNAL_HAS_RTTI 1
#elif !defined(__GNUC__) && !defined(_MSC_VER)
// Unknown compiler, default to RTTI
#define ABSL_INTERNAL_HAS_RTTI 1
#endif
// `ABSL_INTERNAL_HAS_CXA_DEMANGLE` determines whether `abi::__cxa_demangle` is
// available.
#ifdef ABSL_INTERNAL_HAS_CXA_DEMANGLE
#error ABSL_INTERNAL_HAS_CXA_DEMANGLE cannot be directly set
#elif defined(OS_ANDROID) && (defined(__i386__) || defined(__x86_64__))
#define ABSL_INTERNAL_HAS_CXA_DEMANGLE 0
#elif defined(__GNUC__) && defined(__GNUC_MINOR__) && \
(__GNUC__ >= 4 || (__GNUC__ >= 3 && __GNUC_MINOR__ >= 4)) && \
!defined(__mips__)
#define ABSL_INTERNAL_HAS_CXA_DEMANGLE 1
#elif defined(__clang__) && !defined(_MSC_VER)
#define ABSL_INTERNAL_HAS_CXA_DEMANGLE 1
#endif
// ABSL_INTERNAL_HAVE_SSE is used for compile-time detection of SSE support.
// See https://gcc.gnu.org/onlinedocs/gcc/x86-Options.html for an overview of
// which architectures support the various x86 instruction sets.
#ifdef ABSL_INTERNAL_HAVE_SSE
#error ABSL_INTERNAL_HAVE_SSE cannot be directly set
#elif defined(__SSE__)
#define ABSL_INTERNAL_HAVE_SSE 1
#elif (defined(_M_X64) || (defined(_M_IX86_FP) && _M_IX86_FP >= 1)) && \
!defined(_M_ARM64EC)
// MSVC only defines _M_IX86_FP for x86 32-bit code, and _M_IX86_FP >= 1
// indicates that at least SSE was targeted with the /arch:SSE option.
// All x86-64 processors support SSE, so support can be assumed.
// https://docs.microsoft.com/en-us/cpp/preprocessor/predefined-macros
#define ABSL_INTERNAL_HAVE_SSE 1
#endif
// ABSL_INTERNAL_HAVE_SSE2 is used for compile-time detection of SSE2 support.
// See https://gcc.gnu.org/onlinedocs/gcc/x86-Options.html for an overview of
// which architectures support the various x86 instruction sets.
#ifdef ABSL_INTERNAL_HAVE_SSE2
#error ABSL_INTERNAL_HAVE_SSE2 cannot be directly set
#elif defined(__SSE2__)
#define ABSL_INTERNAL_HAVE_SSE2 1
#elif (defined(_M_X64) || (defined(_M_IX86_FP) && _M_IX86_FP >= 2)) && \
!defined(_M_ARM64EC)
// MSVC only defines _M_IX86_FP for x86 32-bit code, and _M_IX86_FP >= 2
// indicates that at least SSE2 was targeted with the /arch:SSE2 option.
// All x86-64 processors support SSE2, so support can be assumed.
// https://docs.microsoft.com/en-us/cpp/preprocessor/predefined-macros
#define ABSL_INTERNAL_HAVE_SSE2 1
#endif
// ABSL_INTERNAL_HAVE_SSSE3 is used for compile-time detection of SSSE3 support.
// See https://gcc.gnu.org/onlinedocs/gcc/x86-Options.html for an overview of
// which architectures support the various x86 instruction sets.
//
// MSVC does not have a mode that targets SSSE3 at compile-time. To use SSSE3
// with MSVC requires either assuming that the code will only every run on CPUs
// that support SSSE3, otherwise __cpuid() can be used to detect support at
// runtime and fallback to a non-SSSE3 implementation when SSSE3 is unsupported
// by the CPU.
#ifdef ABSL_INTERNAL_HAVE_SSSE3
#error ABSL_INTERNAL_HAVE_SSSE3 cannot be directly set
#elif defined(__SSSE3__)
#define ABSL_INTERNAL_HAVE_SSSE3 1
#endif
// ABSL_INTERNAL_HAVE_ARM_NEON is used for compile-time detection of NEON (ARM
// SIMD).
//
// If __CUDA_ARCH__ is defined, then we are compiling CUDA code in device mode.
// In device mode, NEON intrinsics are not available, regardless of host
// platform.
// https://llvm.org/docs/CompileCudaWithLLVM.html#detecting-clang-vs-nvcc-from-code
#ifdef ABSL_INTERNAL_HAVE_ARM_NEON
#error ABSL_INTERNAL_HAVE_ARM_NEON cannot be directly set
#elif defined(__ARM_NEON) && !defined(__CUDA_ARCH__)
#define ABSL_INTERNAL_HAVE_ARM_NEON 1
#endif
// ABSL_HAVE_CONSTANT_EVALUATED is used for compile-time detection of
// constant evaluation support through `absl::is_constant_evaluated`.
#ifdef ABSL_HAVE_CONSTANT_EVALUATED
#error ABSL_HAVE_CONSTANT_EVALUATED cannot be directly set
#endif
#ifdef __cpp_lib_is_constant_evaluated
#define ABSL_HAVE_CONSTANT_EVALUATED 1
#elif ABSL_HAVE_BUILTIN(__builtin_is_constant_evaluated)
#define ABSL_HAVE_CONSTANT_EVALUATED 1
#endif
// ABSL_INTERNAL_EMSCRIPTEN_VERSION combines Emscripten's three version macros
// into an integer that can be compared against.
#ifdef ABSL_INTERNAL_EMSCRIPTEN_VERSION
#error ABSL_INTERNAL_EMSCRIPTEN_VERSION cannot be directly set
#endif
#ifdef __EMSCRIPTEN__
#include <emscripten/version.h>
#ifdef __EMSCRIPTEN_major__
#if __EMSCRIPTEN_minor__ >= 1000
#error __EMSCRIPTEN_minor__ is too big to fit in ABSL_INTERNAL_EMSCRIPTEN_VERSION
#endif
#if __EMSCRIPTEN_tiny__ >= 1000
#error __EMSCRIPTEN_tiny__ is too big to fit in ABSL_INTERNAL_EMSCRIPTEN_VERSION
#endif
#define ABSL_INTERNAL_EMSCRIPTEN_VERSION \
((__EMSCRIPTEN_major__) * 1000000 + (__EMSCRIPTEN_minor__) * 1000 + \
(__EMSCRIPTEN_tiny__))
#endif
#endif
#endif // ABSL_BASE_CONFIG_H_

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// 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.
//
// -----------------------------------------------------------------------------
// kConstInit
// -----------------------------------------------------------------------------
//
// A constructor tag used to mark an object as safe for use as a global
// variable, avoiding the usual lifetime issues that can affect globals.
#ifndef ABSL_BASE_CONST_INIT_H_
#define ABSL_BASE_CONST_INIT_H_
#include "absl/base/config.h"
// In general, objects with static storage duration (such as global variables)
// can trigger tricky object lifetime situations. Attempting to access them
// from the constructors or destructors of other global objects can result in
// undefined behavior, unless their constructors and destructors are designed
// with this issue in mind.
//
// The normal way to deal with this issue in C++11 is to use constant
// initialization and trivial destructors.
//
// Constant initialization is guaranteed to occur before any other code
// executes. Constructors that are declared 'constexpr' are eligible for
// constant initialization. You can annotate a variable declaration with the
// ABSL_CONST_INIT macro to express this intent. For compilers that support
// it, this annotation will cause a compilation error for declarations that
// aren't subject to constant initialization (perhaps because a runtime value
// was passed as a constructor argument).
//
// On program shutdown, lifetime issues can be avoided on global objects by
// ensuring that they contain trivial destructors. A class has a trivial
// destructor unless it has a user-defined destructor, a virtual method or base
// class, or a data member or base class with a non-trivial destructor of its
// own. Objects with static storage duration and a trivial destructor are not
// cleaned up on program shutdown, and are thus safe to access from other code
// running during shutdown.
//
// For a few core Abseil classes, we make a best effort to allow for safe global
// instances, even though these classes have non-trivial destructors. These
// objects can be created with the absl::kConstInit tag. For example:
// ABSL_CONST_INIT absl::Mutex global_mutex(absl::kConstInit);
//
// The line above declares a global variable of type absl::Mutex which can be
// accessed at any point during startup or shutdown. global_mutex's destructor
// will still run, but will not invalidate the object. Note that C++ specifies
// that accessing an object after its destructor has run results in undefined
// behavior, but this pattern works on the toolchains we support.
//
// The absl::kConstInit tag should only be used to define objects with static
// or thread_local storage duration.
namespace absl {
ABSL_NAMESPACE_BEGIN
enum ConstInitType {
kConstInit,
};
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_CONST_INIT_H_

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// 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.
// This file defines dynamic annotations for use with dynamic analysis tool
// such as valgrind, PIN, etc.
//
// Dynamic annotation is a source code annotation that affects the generated
// code (that is, the annotation is not a comment). Each such annotation is
// attached to a particular instruction and/or to a particular object (address)
// in the program.
//
// The annotations that should be used by users are macros in all upper-case
// (e.g., ABSL_ANNOTATE_THREAD_NAME).
//
// Actual implementation of these macros may differ depending on the dynamic
// analysis tool being used.
//
// This file supports the following configurations:
// - Dynamic Annotations enabled (with static thread-safety warnings disabled).
// In this case, macros expand to functions implemented by Thread Sanitizer,
// when building with TSan. When not provided an external implementation,
// dynamic_annotations.cc provides no-op implementations.
//
// - Static Clang thread-safety warnings enabled.
// When building with a Clang compiler that supports thread-safety warnings,
// a subset of annotations can be statically-checked at compile-time. We
// expand these macros to static-inline functions that can be analyzed for
// thread-safety, but afterwards elided when building the final binary.
//
// - All annotations are disabled.
// If neither Dynamic Annotations nor Clang thread-safety warnings are
// enabled, then all annotation-macros expand to empty.
#ifndef ABSL_BASE_DYNAMIC_ANNOTATIONS_H_
#define ABSL_BASE_DYNAMIC_ANNOTATIONS_H_
#include <stddef.h>
#include <stdint.h>
#include "absl/base/attributes.h"
#include "absl/base/config.h"
#ifdef __cplusplus
#include "absl/base/macros.h"
#endif
#ifdef ABSL_HAVE_HWADDRESS_SANITIZER
#include <sanitizer/hwasan_interface.h>
#endif
// TODO(rogeeff): Remove after the backward compatibility period.
#include "absl/base/internal/dynamic_annotations.h" // IWYU pragma: export
// -------------------------------------------------------------------------
// Decide which features are enabled.
#ifdef ABSL_HAVE_THREAD_SANITIZER
#define ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED 1
#define ABSL_INTERNAL_READS_ANNOTATIONS_ENABLED 1
#define ABSL_INTERNAL_WRITES_ANNOTATIONS_ENABLED 1
#define ABSL_INTERNAL_ANNOTALYSIS_ENABLED 0
#define ABSL_INTERNAL_READS_WRITES_ANNOTATIONS_ENABLED 1
#else
#define ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED 0
#define ABSL_INTERNAL_READS_ANNOTATIONS_ENABLED 0
#define ABSL_INTERNAL_WRITES_ANNOTATIONS_ENABLED 0
// Clang provides limited support for static thread-safety analysis through a
// feature called Annotalysis. We configure macro-definitions according to
// whether Annotalysis support is available. When running in opt-mode, GCC
// will issue a warning, if these attributes are compiled. Only include them
// when compiling using Clang.
#if defined(__clang__)
#define ABSL_INTERNAL_ANNOTALYSIS_ENABLED 1
#if !defined(SWIG)
#define ABSL_INTERNAL_IGNORE_READS_ATTRIBUTE_ENABLED 1
#endif
#else
#define ABSL_INTERNAL_ANNOTALYSIS_ENABLED 0
#endif
// Read/write annotations are enabled in Annotalysis mode; disabled otherwise.
#define ABSL_INTERNAL_READS_WRITES_ANNOTATIONS_ENABLED \
ABSL_INTERNAL_ANNOTALYSIS_ENABLED
#endif // ABSL_HAVE_THREAD_SANITIZER
#ifdef __cplusplus
#define ABSL_INTERNAL_BEGIN_EXTERN_C extern "C" {
#define ABSL_INTERNAL_END_EXTERN_C } // extern "C"
#define ABSL_INTERNAL_GLOBAL_SCOPED(F) ::F
#define ABSL_INTERNAL_STATIC_INLINE inline
#else
#define ABSL_INTERNAL_BEGIN_EXTERN_C // empty
#define ABSL_INTERNAL_END_EXTERN_C // empty
#define ABSL_INTERNAL_GLOBAL_SCOPED(F) F
#define ABSL_INTERNAL_STATIC_INLINE static inline
#endif
// -------------------------------------------------------------------------
// Define race annotations.
#if ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED == 1
// Some of the symbols used in this section (e.g. AnnotateBenignRaceSized) are
// defined by the compiler-based sanitizer implementation, not by the Abseil
// library. Therefore they do not use ABSL_INTERNAL_C_SYMBOL.
// -------------------------------------------------------------
// Annotations that suppress errors. It is usually better to express the
// program's synchronization using the other annotations, but these can be used
// when all else fails.
// Report that we may have a benign race at `pointer`, with size
// "sizeof(*(pointer))". `pointer` must be a non-void* pointer. Insert at the
// point where `pointer` has been allocated, preferably close to the point
// where the race happens. See also ABSL_ANNOTATE_BENIGN_RACE_STATIC.
#define ABSL_ANNOTATE_BENIGN_RACE(pointer, description) \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateBenignRaceSized) \
(__FILE__, __LINE__, pointer, sizeof(*(pointer)), description)
// Same as ABSL_ANNOTATE_BENIGN_RACE(`address`, `description`), but applies to
// the memory range [`address`, `address`+`size`).
#define ABSL_ANNOTATE_BENIGN_RACE_SIZED(address, size, description) \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateBenignRaceSized) \
(__FILE__, __LINE__, address, size, description)
// Enable (`enable`!=0) or disable (`enable`==0) race detection for all threads.
// This annotation could be useful if you want to skip expensive race analysis
// during some period of program execution, e.g. during initialization.
#define ABSL_ANNOTATE_ENABLE_RACE_DETECTION(enable) \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateEnableRaceDetection) \
(__FILE__, __LINE__, enable)
// -------------------------------------------------------------
// Annotations useful for debugging.
// Report the current thread `name` to a race detector.
#define ABSL_ANNOTATE_THREAD_NAME(name) \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateThreadName)(__FILE__, __LINE__, name)
// -------------------------------------------------------------
// Annotations useful when implementing locks. They are not normally needed by
// modules that merely use locks. The `lock` argument is a pointer to the lock
// object.
// Report that a lock has been created at address `lock`.
#define ABSL_ANNOTATE_RWLOCK_CREATE(lock) \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateRWLockCreate)(__FILE__, __LINE__, lock)
// Report that a linker initialized lock has been created at address `lock`.
#ifdef ABSL_HAVE_THREAD_SANITIZER
#define ABSL_ANNOTATE_RWLOCK_CREATE_STATIC(lock) \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateRWLockCreateStatic) \
(__FILE__, __LINE__, lock)
#else
#define ABSL_ANNOTATE_RWLOCK_CREATE_STATIC(lock) \
ABSL_ANNOTATE_RWLOCK_CREATE(lock)
#endif
// Report that the lock at address `lock` is about to be destroyed.
#define ABSL_ANNOTATE_RWLOCK_DESTROY(lock) \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateRWLockDestroy)(__FILE__, __LINE__, lock)
// Report that the lock at address `lock` has been acquired.
// `is_w`=1 for writer lock, `is_w`=0 for reader lock.
#define ABSL_ANNOTATE_RWLOCK_ACQUIRED(lock, is_w) \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateRWLockAcquired) \
(__FILE__, __LINE__, lock, is_w)
// Report that the lock at address `lock` is about to be released.
// `is_w`=1 for writer lock, `is_w`=0 for reader lock.
#define ABSL_ANNOTATE_RWLOCK_RELEASED(lock, is_w) \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateRWLockReleased) \
(__FILE__, __LINE__, lock, is_w)
// Apply ABSL_ANNOTATE_BENIGN_RACE_SIZED to a static variable `static_var`.
#define ABSL_ANNOTATE_BENIGN_RACE_STATIC(static_var, description) \
namespace { \
class static_var##_annotator { \
public: \
static_var##_annotator() { \
ABSL_ANNOTATE_BENIGN_RACE_SIZED(&static_var, sizeof(static_var), \
#static_var ": " description); \
} \
}; \
static static_var##_annotator the##static_var##_annotator; \
} // namespace
// Function prototypes of annotations provided by the compiler-based sanitizer
// implementation.
ABSL_INTERNAL_BEGIN_EXTERN_C
void AnnotateRWLockCreate(const char* file, int line,
const volatile void* lock);
void AnnotateRWLockCreateStatic(const char* file, int line,
const volatile void* lock);
void AnnotateRWLockDestroy(const char* file, int line,
const volatile void* lock);
void AnnotateRWLockAcquired(const char* file, int line,
const volatile void* lock, long is_w); // NOLINT
void AnnotateRWLockReleased(const char* file, int line,
const volatile void* lock, long is_w); // NOLINT
void AnnotateBenignRace(const char* file, int line,
const volatile void* address, const char* description);
void AnnotateBenignRaceSized(const char* file, int line,
const volatile void* address, size_t size,
const char* description);
void AnnotateThreadName(const char* file, int line, const char* name);
void AnnotateEnableRaceDetection(const char* file, int line, int enable);
ABSL_INTERNAL_END_EXTERN_C
#else // ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED == 0
#define ABSL_ANNOTATE_RWLOCK_CREATE(lock) // empty
#define ABSL_ANNOTATE_RWLOCK_CREATE_STATIC(lock) // empty
#define ABSL_ANNOTATE_RWLOCK_DESTROY(lock) // empty
#define ABSL_ANNOTATE_RWLOCK_ACQUIRED(lock, is_w) // empty
#define ABSL_ANNOTATE_RWLOCK_RELEASED(lock, is_w) // empty
#define ABSL_ANNOTATE_BENIGN_RACE(address, description) // empty
#define ABSL_ANNOTATE_BENIGN_RACE_SIZED(address, size, description) // empty
#define ABSL_ANNOTATE_THREAD_NAME(name) // empty
#define ABSL_ANNOTATE_ENABLE_RACE_DETECTION(enable) // empty
#define ABSL_ANNOTATE_BENIGN_RACE_STATIC(static_var, description) // empty
#endif // ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED
// -------------------------------------------------------------------------
// Define memory annotations.
#ifdef ABSL_HAVE_MEMORY_SANITIZER
#include <sanitizer/msan_interface.h>
#define ABSL_ANNOTATE_MEMORY_IS_INITIALIZED(address, size) \
__msan_unpoison(address, size)
#define ABSL_ANNOTATE_MEMORY_IS_UNINITIALIZED(address, size) \
__msan_allocated_memory(address, size)
#else // !defined(ABSL_HAVE_MEMORY_SANITIZER)
// TODO(rogeeff): remove this branch
#ifdef ABSL_HAVE_THREAD_SANITIZER
#define ABSL_ANNOTATE_MEMORY_IS_INITIALIZED(address, size) \
do { \
(void)(address); \
(void)(size); \
} while (0)
#define ABSL_ANNOTATE_MEMORY_IS_UNINITIALIZED(address, size) \
do { \
(void)(address); \
(void)(size); \
} while (0)
#else
#define ABSL_ANNOTATE_MEMORY_IS_INITIALIZED(address, size) // empty
#define ABSL_ANNOTATE_MEMORY_IS_UNINITIALIZED(address, size) // empty
#endif
#endif // ABSL_HAVE_MEMORY_SANITIZER
// -------------------------------------------------------------------------
// Define IGNORE_READS_BEGIN/_END attributes.
#if defined(ABSL_INTERNAL_IGNORE_READS_ATTRIBUTE_ENABLED)
#define ABSL_INTERNAL_IGNORE_READS_BEGIN_ATTRIBUTE \
__attribute((exclusive_lock_function("*")))
#define ABSL_INTERNAL_IGNORE_READS_END_ATTRIBUTE \
__attribute((unlock_function("*")))
#else // !defined(ABSL_INTERNAL_IGNORE_READS_ATTRIBUTE_ENABLED)
#define ABSL_INTERNAL_IGNORE_READS_BEGIN_ATTRIBUTE // empty
#define ABSL_INTERNAL_IGNORE_READS_END_ATTRIBUTE // empty
#endif // defined(ABSL_INTERNAL_IGNORE_READS_ATTRIBUTE_ENABLED)
// -------------------------------------------------------------------------
// Define IGNORE_READS_BEGIN/_END annotations.
#if ABSL_INTERNAL_READS_ANNOTATIONS_ENABLED == 1
// Some of the symbols used in this section (e.g. AnnotateIgnoreReadsBegin) are
// defined by the compiler-based implementation, not by the Abseil
// library. Therefore they do not use ABSL_INTERNAL_C_SYMBOL.
// Request the analysis tool to ignore all reads in the current thread until
// ABSL_ANNOTATE_IGNORE_READS_END is called. Useful to ignore intentional racey
// reads, while still checking other reads and all writes.
// See also ABSL_ANNOTATE_UNPROTECTED_READ.
#define ABSL_ANNOTATE_IGNORE_READS_BEGIN() \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateIgnoreReadsBegin) \
(__FILE__, __LINE__)
// Stop ignoring reads.
#define ABSL_ANNOTATE_IGNORE_READS_END() \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateIgnoreReadsEnd) \
(__FILE__, __LINE__)
// Function prototypes of annotations provided by the compiler-based sanitizer
// implementation.
ABSL_INTERNAL_BEGIN_EXTERN_C
void AnnotateIgnoreReadsBegin(const char* file, int line)
ABSL_INTERNAL_IGNORE_READS_BEGIN_ATTRIBUTE;
void AnnotateIgnoreReadsEnd(const char* file,
int line) ABSL_INTERNAL_IGNORE_READS_END_ATTRIBUTE;
ABSL_INTERNAL_END_EXTERN_C
#elif defined(ABSL_INTERNAL_ANNOTALYSIS_ENABLED)
// When Annotalysis is enabled without Dynamic Annotations, the use of
// static-inline functions allows the annotations to be read at compile-time,
// while still letting the compiler elide the functions from the final build.
//
// TODO(delesley) -- The exclusive lock here ignores writes as well, but
// allows IGNORE_READS_AND_WRITES to work properly.
#define ABSL_ANNOTATE_IGNORE_READS_BEGIN() \
ABSL_INTERNAL_GLOBAL_SCOPED( \
ABSL_INTERNAL_C_SYMBOL(AbslInternalAnnotateIgnoreReadsBegin)) \
()
#define ABSL_ANNOTATE_IGNORE_READS_END() \
ABSL_INTERNAL_GLOBAL_SCOPED( \
ABSL_INTERNAL_C_SYMBOL(AbslInternalAnnotateIgnoreReadsEnd)) \
()
ABSL_INTERNAL_STATIC_INLINE void ABSL_INTERNAL_C_SYMBOL(
AbslInternalAnnotateIgnoreReadsBegin)()
ABSL_INTERNAL_IGNORE_READS_BEGIN_ATTRIBUTE {}
ABSL_INTERNAL_STATIC_INLINE void ABSL_INTERNAL_C_SYMBOL(
AbslInternalAnnotateIgnoreReadsEnd)()
ABSL_INTERNAL_IGNORE_READS_END_ATTRIBUTE {}
#else
#define ABSL_ANNOTATE_IGNORE_READS_BEGIN() // empty
#define ABSL_ANNOTATE_IGNORE_READS_END() // empty
#endif
// -------------------------------------------------------------------------
// Define IGNORE_WRITES_BEGIN/_END annotations.
#if ABSL_INTERNAL_WRITES_ANNOTATIONS_ENABLED == 1
// Similar to ABSL_ANNOTATE_IGNORE_READS_BEGIN, but ignore writes instead.
#define ABSL_ANNOTATE_IGNORE_WRITES_BEGIN() \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateIgnoreWritesBegin)(__FILE__, __LINE__)
// Stop ignoring writes.
#define ABSL_ANNOTATE_IGNORE_WRITES_END() \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateIgnoreWritesEnd)(__FILE__, __LINE__)
// Function prototypes of annotations provided by the compiler-based sanitizer
// implementation.
ABSL_INTERNAL_BEGIN_EXTERN_C
void AnnotateIgnoreWritesBegin(const char* file, int line);
void AnnotateIgnoreWritesEnd(const char* file, int line);
ABSL_INTERNAL_END_EXTERN_C
#else
#define ABSL_ANNOTATE_IGNORE_WRITES_BEGIN() // empty
#define ABSL_ANNOTATE_IGNORE_WRITES_END() // empty
#endif
// -------------------------------------------------------------------------
// Define the ABSL_ANNOTATE_IGNORE_READS_AND_WRITES_* annotations using the more
// primitive annotations defined above.
//
// Instead of doing
// ABSL_ANNOTATE_IGNORE_READS_BEGIN();
// ... = x;
// ABSL_ANNOTATE_IGNORE_READS_END();
// one can use
// ... = ABSL_ANNOTATE_UNPROTECTED_READ(x);
#if defined(ABSL_INTERNAL_READS_WRITES_ANNOTATIONS_ENABLED)
// Start ignoring all memory accesses (both reads and writes).
#define ABSL_ANNOTATE_IGNORE_READS_AND_WRITES_BEGIN() \
do { \
ABSL_ANNOTATE_IGNORE_READS_BEGIN(); \
ABSL_ANNOTATE_IGNORE_WRITES_BEGIN(); \
} while (0)
// Stop ignoring both reads and writes.
#define ABSL_ANNOTATE_IGNORE_READS_AND_WRITES_END() \
do { \
ABSL_ANNOTATE_IGNORE_WRITES_END(); \
ABSL_ANNOTATE_IGNORE_READS_END(); \
} while (0)
#ifdef __cplusplus
// ABSL_ANNOTATE_UNPROTECTED_READ is the preferred way to annotate racey reads.
#define ABSL_ANNOTATE_UNPROTECTED_READ(x) \
absl::base_internal::AnnotateUnprotectedRead(x)
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
template <typename T>
inline T AnnotateUnprotectedRead(const volatile T& x) { // NOLINT
ABSL_ANNOTATE_IGNORE_READS_BEGIN();
T res = x;
ABSL_ANNOTATE_IGNORE_READS_END();
return res;
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif
#else
#define ABSL_ANNOTATE_IGNORE_READS_AND_WRITES_BEGIN() // empty
#define ABSL_ANNOTATE_IGNORE_READS_AND_WRITES_END() // empty
#define ABSL_ANNOTATE_UNPROTECTED_READ(x) (x)
#endif
// -------------------------------------------------------------------------
// Address sanitizer annotations
#ifdef ABSL_HAVE_ADDRESS_SANITIZER
// Describe the current state of a contiguous container such as e.g.
// std::vector or std::string. For more details see
// sanitizer/common_interface_defs.h, which is provided by the compiler.
#include <sanitizer/common_interface_defs.h>
#define ABSL_ANNOTATE_CONTIGUOUS_CONTAINER(beg, end, old_mid, new_mid) \
__sanitizer_annotate_contiguous_container(beg, end, old_mid, new_mid)
#define ABSL_ADDRESS_SANITIZER_REDZONE(name) \
struct { \
alignas(8) char x[8]; \
} name
#else
#define ABSL_ANNOTATE_CONTIGUOUS_CONTAINER(beg, end, old_mid, new_mid) // empty
#define ABSL_ADDRESS_SANITIZER_REDZONE(name) static_assert(true, "")
#endif // ABSL_HAVE_ADDRESS_SANITIZER
// -------------------------------------------------------------------------
// HWAddress sanitizer annotations
#ifdef __cplusplus
namespace absl {
#ifdef ABSL_HAVE_HWADDRESS_SANITIZER
// Under HWASAN changes the tag of the pointer.
template <typename T>
T* HwasanTagPointer(T* ptr, uintptr_t tag) {
return reinterpret_cast<T*>(__hwasan_tag_pointer(ptr, tag));
}
#else
template <typename T>
T* HwasanTagPointer(T* ptr, uintptr_t) {
return ptr;
}
#endif
} // namespace absl
#endif
// -------------------------------------------------------------------------
// Undefine the macros intended only for this file.
#undef ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED
#undef ABSL_INTERNAL_READS_ANNOTATIONS_ENABLED
#undef ABSL_INTERNAL_WRITES_ANNOTATIONS_ENABLED
#undef ABSL_INTERNAL_ANNOTALYSIS_ENABLED
#undef ABSL_INTERNAL_READS_WRITES_ANNOTATIONS_ENABLED
#undef ABSL_INTERNAL_BEGIN_EXTERN_C
#undef ABSL_INTERNAL_END_EXTERN_C
#undef ABSL_INTERNAL_STATIC_INLINE
#endif // ABSL_BASE_DYNAMIC_ANNOTATIONS_H_

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// 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.
#ifndef ABSL_BASE_INTERNAL_ATOMIC_HOOK_H_
#define ABSL_BASE_INTERNAL_ATOMIC_HOOK_H_
#include <atomic>
#include <cassert>
#include <cstdint>
#include <utility>
#include "absl/base/attributes.h"
#include "absl/base/config.h"
#if defined(_MSC_VER) && !defined(__clang__)
#define ABSL_HAVE_WORKING_CONSTEXPR_STATIC_INIT 0
#else
#define ABSL_HAVE_WORKING_CONSTEXPR_STATIC_INIT 1
#endif
#if defined(_MSC_VER)
#define ABSL_HAVE_WORKING_ATOMIC_POINTER 0
#else
#define ABSL_HAVE_WORKING_ATOMIC_POINTER 1
#endif
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
template <typename T>
class AtomicHook;
// To workaround AtomicHook not being constant-initializable on some platforms,
// prefer to annotate instances with `ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES`
// instead of `ABSL_CONST_INIT`.
#if ABSL_HAVE_WORKING_CONSTEXPR_STATIC_INIT
#define ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES ABSL_CONST_INIT
#else
#define ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES
#endif
// `AtomicHook` is a helper class, templatized on a raw function pointer type,
// for implementing Abseil customization hooks. It is a callable object that
// dispatches to the registered hook. Objects of type `AtomicHook` must have
// static or thread storage duration.
//
// A default constructed object performs a no-op (and returns a default
// constructed object) if no hook has been registered.
//
// Hooks can be pre-registered via constant initialization, for example:
//
// ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES static AtomicHook<void(*)()>
// my_hook(DefaultAction);
//
// and then changed at runtime via a call to `Store()`.
//
// Reads and writes guarantee memory_order_acquire/memory_order_release
// semantics.
template <typename ReturnType, typename... Args>
class AtomicHook<ReturnType (*)(Args...)> {
public:
using FnPtr = ReturnType (*)(Args...);
// Constructs an object that by default performs a no-op (and
// returns a default constructed object) when no hook as been registered.
constexpr AtomicHook() : AtomicHook(DummyFunction) {}
// Constructs an object that by default dispatches to/returns the
// pre-registered default_fn when no hook has been registered at runtime.
#if ABSL_HAVE_WORKING_ATOMIC_POINTER && ABSL_HAVE_WORKING_CONSTEXPR_STATIC_INIT
explicit constexpr AtomicHook(FnPtr default_fn)
: hook_(default_fn), default_fn_(default_fn) {}
#elif ABSL_HAVE_WORKING_CONSTEXPR_STATIC_INIT
explicit constexpr AtomicHook(FnPtr default_fn)
: hook_(kUninitialized), default_fn_(default_fn) {}
#else
// As of January 2020, on all known versions of MSVC this constructor runs in
// the global constructor sequence. If `Store()` is called by a dynamic
// initializer, we want to preserve the value, even if this constructor runs
// after the call to `Store()`. If not, `hook_` will be
// zero-initialized by the linker and we have no need to set it.
// https://developercommunity.visualstudio.com/content/problem/336946/class-with-constexpr-constructor-not-using-static.html
explicit constexpr AtomicHook(FnPtr default_fn)
: /* hook_(deliberately omitted), */ default_fn_(default_fn) {
static_assert(kUninitialized == 0, "here we rely on zero-initialization");
}
#endif
// Stores the provided function pointer as the value for this hook.
//
// This is intended to be called once. Multiple calls are legal only if the
// same function pointer is provided for each call. The store is implemented
// as a memory_order_release operation, and read accesses are implemented as
// memory_order_acquire.
void Store(FnPtr fn) {
bool success = DoStore(fn);
static_cast<void>(success);
assert(success);
}
// Invokes the registered callback. If no callback has yet been registered, a
// default-constructed object of the appropriate type is returned instead.
template <typename... CallArgs>
ReturnType operator()(CallArgs&&... args) const {
return DoLoad()(std::forward<CallArgs>(args)...);
}
// Returns the registered callback, or nullptr if none has been registered.
// Useful if client code needs to conditionalize behavior based on whether a
// callback was registered.
//
// Note that atomic_hook.Load()() and atomic_hook() have different semantics:
// operator()() will perform a no-op if no callback was registered, while
// Load()() will dereference a null function pointer. Prefer operator()() to
// Load()() unless you must conditionalize behavior on whether a hook was
// registered.
FnPtr Load() const {
FnPtr ptr = DoLoad();
return (ptr == DummyFunction) ? nullptr : ptr;
}
private:
static ReturnType DummyFunction(Args...) {
return ReturnType();
}
// Current versions of MSVC (as of September 2017) have a broken
// implementation of std::atomic<T*>: Its constructor attempts to do the
// equivalent of a reinterpret_cast in a constexpr context, which is not
// allowed.
//
// This causes an issue when building with LLVM under Windows. To avoid this,
// we use a less-efficient, intptr_t-based implementation on Windows.
#if ABSL_HAVE_WORKING_ATOMIC_POINTER
// Return the stored value, or DummyFunction if no value has been stored.
FnPtr DoLoad() const { return hook_.load(std::memory_order_acquire); }
// Store the given value. Returns false if a different value was already
// stored to this object.
bool DoStore(FnPtr fn) {
assert(fn);
FnPtr expected = default_fn_;
const bool store_succeeded = hook_.compare_exchange_strong(
expected, fn, std::memory_order_acq_rel, std::memory_order_acquire);
const bool same_value_already_stored = (expected == fn);
return store_succeeded || same_value_already_stored;
}
std::atomic<FnPtr> hook_;
#else // !ABSL_HAVE_WORKING_ATOMIC_POINTER
// Use a sentinel value unlikely to be the address of an actual function.
static constexpr intptr_t kUninitialized = 0;
static_assert(sizeof(intptr_t) >= sizeof(FnPtr),
"intptr_t can't contain a function pointer");
FnPtr DoLoad() const {
const intptr_t value = hook_.load(std::memory_order_acquire);
if (value == kUninitialized) {
return default_fn_;
}
return reinterpret_cast<FnPtr>(value);
}
bool DoStore(FnPtr fn) {
assert(fn);
const auto value = reinterpret_cast<intptr_t>(fn);
intptr_t expected = kUninitialized;
const bool store_succeeded = hook_.compare_exchange_strong(
expected, value, std::memory_order_acq_rel, std::memory_order_acquire);
const bool same_value_already_stored = (expected == value);
return store_succeeded || same_value_already_stored;
}
std::atomic<intptr_t> hook_;
#endif
const FnPtr default_fn_;
};
#undef ABSL_HAVE_WORKING_ATOMIC_POINTER
#undef ABSL_HAVE_WORKING_CONSTEXPR_STATIC_INIT
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_ATOMIC_HOOK_H_

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// 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.
// The implementation of CycleClock::Frequency.
//
// NOTE: only i386 and x86_64 have been well tested.
// PPC, sparc, alpha, and ia64 are based on
// http://peter.kuscsik.com/wordpress/?p=14
// with modifications by m3b. See also
// https://setisvn.ssl.berkeley.edu/svn/lib/fftw-3.0.1/kernel/cycle.h
#include "absl/base/internal/cycleclock.h"
#include <atomic>
#include <chrono> // NOLINT(build/c++11)
#include "absl/base/attributes.h"
#include "absl/base/config.h"
#include "absl/base/internal/unscaledcycleclock.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
#if ABSL_USE_UNSCALED_CYCLECLOCK
#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
constexpr int32_t CycleClock::kShift;
constexpr double CycleClock::kFrequencyScale;
#endif
ABSL_CONST_INIT std::atomic<CycleClockSourceFunc>
CycleClock::cycle_clock_source_{nullptr};
void CycleClockSource::Register(CycleClockSourceFunc source) {
// Corresponds to the load(std::memory_order_acquire) in LoadCycleClockSource.
CycleClock::cycle_clock_source_.store(source, std::memory_order_release);
}
#ifdef _WIN32
int64_t CycleClock::Now() {
auto fn = LoadCycleClockSource();
if (fn == nullptr) {
return base_internal::UnscaledCycleClock::Now() >> kShift;
}
return fn() >> kShift;
}
#endif
#else
int64_t CycleClock::Now() {
return std::chrono::duration_cast<std::chrono::nanoseconds>(
std::chrono::steady_clock::now().time_since_epoch())
.count();
}
double CycleClock::Frequency() {
return 1e9;
}
#endif
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl

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//
// 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: cycleclock.h
// -----------------------------------------------------------------------------
//
// This header file defines a `CycleClock`, which yields the value and frequency
// of a cycle counter that increments at a rate that is approximately constant.
//
// NOTE:
//
// The cycle counter frequency is not necessarily related to the core clock
// frequency and should not be treated as such. That is, `CycleClock` cycles are
// not necessarily "CPU cycles" and code should not rely on that behavior, even
// if experimentally observed.
//
// An arbitrary offset may have been added to the counter at power on.
//
// On some platforms, the rate and offset of the counter may differ
// slightly when read from different CPUs of a multiprocessor. Usually,
// we try to ensure that the operating system adjusts values periodically
// so that values agree approximately. If you need stronger guarantees,
// consider using alternate interfaces.
//
// The CPU is not required to maintain the ordering of a cycle counter read
// with respect to surrounding instructions.
#ifndef ABSL_BASE_INTERNAL_CYCLECLOCK_H_
#define ABSL_BASE_INTERNAL_CYCLECLOCK_H_
#include <atomic>
#include <cstdint>
#include "absl/base/attributes.h"
#include "absl/base/config.h"
#include "absl/base/internal/cycleclock_config.h"
#include "absl/base/internal/unscaledcycleclock.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
using CycleClockSourceFunc = int64_t (*)();
// -----------------------------------------------------------------------------
// CycleClock
// -----------------------------------------------------------------------------
class CycleClock {
public:
// CycleClock::Now()
//
// Returns the value of a cycle counter that counts at a rate that is
// approximately constant.
static int64_t Now();
// CycleClock::Frequency()
//
// Returns the amount by which `CycleClock::Now()` increases per second. Note
// that this value may not necessarily match the core CPU clock frequency.
static double Frequency();
private:
#if ABSL_USE_UNSCALED_CYCLECLOCK
static CycleClockSourceFunc LoadCycleClockSource();
static constexpr int32_t kShift = kCycleClockShift;
static constexpr double kFrequencyScale = kCycleClockFrequencyScale;
ABSL_CONST_INIT static std::atomic<CycleClockSourceFunc> cycle_clock_source_;
#endif // ABSL_USE_UNSCALED_CYCLECLOC
CycleClock() = delete; // no instances
CycleClock(const CycleClock&) = delete;
CycleClock& operator=(const CycleClock&) = delete;
friend class CycleClockSource;
};
class CycleClockSource {
private:
// CycleClockSource::Register()
//
// Register a function that provides an alternate source for the unscaled CPU
// cycle count value. The source function must be async signal safe, must not
// call CycleClock::Now(), and must have a frequency that matches that of the
// unscaled clock used by CycleClock. A nullptr value resets CycleClock to use
// the default source.
static void Register(CycleClockSourceFunc source);
};
#if ABSL_USE_UNSCALED_CYCLECLOCK
inline CycleClockSourceFunc CycleClock::LoadCycleClockSource() {
#if !defined(__x86_64__)
// Optimize for the common case (no callback) by first doing a relaxed load;
// this is significantly faster on non-x86 platforms.
if (cycle_clock_source_.load(std::memory_order_relaxed) == nullptr) {
return nullptr;
}
#endif // !defined(__x86_64__)
// This corresponds to the store(std::memory_order_release) in
// CycleClockSource::Register, and makes sure that any updates made prior to
// registering the callback are visible to this thread before the callback
// is invoked.
return cycle_clock_source_.load(std::memory_order_acquire);
}
// Accessing globals in inlined code in Window DLLs is problematic.
#ifndef _WIN32
inline int64_t CycleClock::Now() {
auto fn = LoadCycleClockSource();
if (fn == nullptr) {
return base_internal::UnscaledCycleClock::Now() >> kShift;
}
return fn() >> kShift;
}
#endif
inline double CycleClock::Frequency() {
return kFrequencyScale * base_internal::UnscaledCycleClock::Frequency();
}
#endif // ABSL_USE_UNSCALED_CYCLECLOCK
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_CYCLECLOCK_H_

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// Copyright 2022 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.
#ifndef ABSL_BASE_INTERNAL_CYCLECLOCK_CONFIG_H_
#define ABSL_BASE_INTERNAL_CYCLECLOCK_CONFIG_H_
#include <cstdint>
#include "absl/base/config.h"
#include "absl/base/internal/inline_variable.h"
#include "absl/base/internal/unscaledcycleclock_config.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
#if ABSL_USE_UNSCALED_CYCLECLOCK
#ifdef NDEBUG
#ifdef ABSL_INTERNAL_UNSCALED_CYCLECLOCK_FREQUENCY_IS_CPU_FREQUENCY
// Not debug mode and the UnscaledCycleClock frequency is the CPU
// frequency. Scale the CycleClock to prevent overflow if someone
// tries to represent the time as cycles since the Unix epoch.
ABSL_INTERNAL_INLINE_CONSTEXPR(int32_t, kCycleClockShift, 1);
#else
// Not debug mode and the UnscaledCycleClock isn't operating at the
// raw CPU frequency. There is no need to do any scaling, so don't
// needlessly sacrifice precision.
ABSL_INTERNAL_INLINE_CONSTEXPR(int32_t, kCycleClockShift, 0);
#endif
#else // NDEBUG
// In debug mode use a different shift to discourage depending on a
// particular shift value.
ABSL_INTERNAL_INLINE_CONSTEXPR(int32_t, kCycleClockShift, 2);
#endif // NDEBUG
ABSL_INTERNAL_INLINE_CONSTEXPR(double, kCycleClockFrequencyScale,
1.0 / (1 << kCycleClockShift));
#endif // ABSL_USE_UNSCALED_CYCLECLOC
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_CYCLECLOCK_CONFIG_H_

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// 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.
//
// Functions for directly invoking mmap() via syscall, avoiding the case where
// mmap() has been locally overridden.
#ifndef ABSL_BASE_INTERNAL_DIRECT_MMAP_H_
#define ABSL_BASE_INTERNAL_DIRECT_MMAP_H_
#include "absl/base/config.h"
#ifdef ABSL_HAVE_MMAP
#include <sys/mman.h>
#ifdef __linux__
#include <sys/types.h>
#ifdef __BIONIC__
#include <sys/syscall.h>
#else
#include <syscall.h>
#endif
#include <linux/unistd.h>
#include <unistd.h>
#include <cerrno>
#include <cstdarg>
#include <cstdint>
#ifdef __mips__
// Include definitions of the ABI currently in use.
#if defined(__BIONIC__) || !defined(__GLIBC__)
// Android doesn't have sgidefs.h, but does have asm/sgidefs.h, which has the
// definitions we need.
#include <asm/sgidefs.h>
#else
#include <sgidefs.h>
#endif // __BIONIC__ || !__GLIBC__
#endif // __mips__
// SYS_mmap and SYS_munmap are not defined in Android.
#ifdef __BIONIC__
extern "C" void* __mmap2(void*, size_t, int, int, int, size_t);
#if defined(__NR_mmap) && !defined(SYS_mmap)
#define SYS_mmap __NR_mmap
#endif
#ifndef SYS_munmap
#define SYS_munmap __NR_munmap
#endif
#endif // __BIONIC__
#if defined(__NR_mmap2) && !defined(SYS_mmap2)
#define SYS_mmap2 __NR_mmap2
#endif
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
// Platform specific logic extracted from
// https://chromium.googlesource.com/linux-syscall-support/+/master/linux_syscall_support.h
inline void* DirectMmap(void* start, size_t length, int prot, int flags, int fd,
off_t offset) noexcept {
#if defined(__i386__) || defined(__ARM_ARCH_3__) || defined(__ARM_EABI__) || \
defined(__m68k__) || defined(__sh__) || \
(defined(__hppa__) && !defined(__LP64__)) || \
(defined(__mips__) && _MIPS_SIM == _MIPS_SIM_ABI32) || \
(defined(__PPC__) && !defined(__PPC64__)) || \
(defined(__riscv) && __riscv_xlen == 32) || \
(defined(__s390__) && !defined(__s390x__)) || \
(defined(__sparc__) && !defined(__arch64__))
// On these architectures, implement mmap with mmap2.
static int pagesize = 0;
if (pagesize == 0) {
#if defined(__wasm__) || defined(__asmjs__)
pagesize = getpagesize();
#else
pagesize = sysconf(_SC_PAGESIZE);
#endif
}
if (offset < 0 || offset % pagesize != 0) {
errno = EINVAL;
return MAP_FAILED;
}
#ifdef __BIONIC__
// SYS_mmap2 has problems on Android API level <= 16.
// Workaround by invoking __mmap2() instead.
return __mmap2(start, length, prot, flags, fd,
static_cast<size_t>(offset / pagesize));
#else
return reinterpret_cast<void*>(
syscall(SYS_mmap2, start, length, prot, flags, fd,
static_cast<unsigned long>(offset / pagesize))); // NOLINT
#endif
#elif defined(__s390x__)
// On s390x, mmap() arguments are passed in memory.
unsigned long buf[6] = {reinterpret_cast<unsigned long>(start), // NOLINT
static_cast<unsigned long>(length), // NOLINT
static_cast<unsigned long>(prot), // NOLINT
static_cast<unsigned long>(flags), // NOLINT
static_cast<unsigned long>(fd), // NOLINT
static_cast<unsigned long>(offset)}; // NOLINT
return reinterpret_cast<void*>(syscall(SYS_mmap, buf));
#elif defined(__x86_64__)
// The x32 ABI has 32 bit longs, but the syscall interface is 64 bit.
// We need to explicitly cast to an unsigned 64 bit type to avoid implicit
// sign extension. We can't cast pointers directly because those are
// 32 bits, and gcc will dump ugly warnings about casting from a pointer
// to an integer of a different size. We also need to make sure __off64_t
// isn't truncated to 32-bits under x32.
#define MMAP_SYSCALL_ARG(x) ((uint64_t)(uintptr_t)(x))
return reinterpret_cast<void*>(
syscall(SYS_mmap, MMAP_SYSCALL_ARG(start), MMAP_SYSCALL_ARG(length),
MMAP_SYSCALL_ARG(prot), MMAP_SYSCALL_ARG(flags),
MMAP_SYSCALL_ARG(fd), static_cast<uint64_t>(offset)));
#undef MMAP_SYSCALL_ARG
#else // Remaining 64-bit aritectures.
static_assert(sizeof(unsigned long) == 8, "Platform is not 64-bit");
return reinterpret_cast<void*>(
syscall(SYS_mmap, start, length, prot, flags, fd, offset));
#endif
}
inline int DirectMunmap(void* start, size_t length) {
return static_cast<int>(syscall(SYS_munmap, start, length));
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#else // !__linux__
// For non-linux platforms where we have mmap, just dispatch directly to the
// actual mmap()/munmap() methods.
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
inline void* DirectMmap(void* start, size_t length, int prot, int flags, int fd,
off_t offset) {
return mmap(start, length, prot, flags, fd, offset);
}
inline int DirectMunmap(void* start, size_t length) {
return munmap(start, length);
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // __linux__
#endif // ABSL_HAVE_MMAP
#endif // ABSL_BASE_INTERNAL_DIRECT_MMAP_H_

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// 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.
// This file defines dynamic annotations for use with dynamic analysis tool
// such as valgrind, PIN, etc.
//
// Dynamic annotation is a source code annotation that affects the generated
// code (that is, the annotation is not a comment). Each such annotation is
// attached to a particular instruction and/or to a particular object (address)
// in the program.
//
// The annotations that should be used by users are macros in all upper-case
// (e.g., ANNOTATE_THREAD_NAME).
//
// Actual implementation of these macros may differ depending on the dynamic
// analysis tool being used.
//
// This file supports the following configurations:
// - Dynamic Annotations enabled (with static thread-safety warnings disabled).
// In this case, macros expand to functions implemented by Thread Sanitizer,
// when building with TSan. When not provided an external implementation,
// dynamic_annotations.cc provides no-op implementations.
//
// - Static Clang thread-safety warnings enabled.
// When building with a Clang compiler that supports thread-safety warnings,
// a subset of annotations can be statically-checked at compile-time. We
// expand these macros to static-inline functions that can be analyzed for
// thread-safety, but afterwards elided when building the final binary.
//
// - All annotations are disabled.
// If neither Dynamic Annotations nor Clang thread-safety warnings are
// enabled, then all annotation-macros expand to empty.
#ifndef ABSL_BASE_INTERNAL_DYNAMIC_ANNOTATIONS_H_
#define ABSL_BASE_INTERNAL_DYNAMIC_ANNOTATIONS_H_
#include <stddef.h>
#include "absl/base/config.h"
// -------------------------------------------------------------------------
// Decide which features are enabled
#ifndef DYNAMIC_ANNOTATIONS_ENABLED
#define DYNAMIC_ANNOTATIONS_ENABLED 0
#endif
#if defined(__clang__) && !defined(SWIG)
#define ABSL_INTERNAL_IGNORE_READS_ATTRIBUTE_ENABLED 1
#endif
#if DYNAMIC_ANNOTATIONS_ENABLED != 0
#define ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED 1
#define ABSL_INTERNAL_READS_ANNOTATIONS_ENABLED 1
#define ABSL_INTERNAL_WRITES_ANNOTATIONS_ENABLED 1
#define ABSL_INTERNAL_ANNOTALYSIS_ENABLED 0
#define ABSL_INTERNAL_READS_WRITES_ANNOTATIONS_ENABLED 1
#else
#define ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED 0
#define ABSL_INTERNAL_READS_ANNOTATIONS_ENABLED 0
#define ABSL_INTERNAL_WRITES_ANNOTATIONS_ENABLED 0
// Clang provides limited support for static thread-safety analysis through a
// feature called Annotalysis. We configure macro-definitions according to
// whether Annotalysis support is available. When running in opt-mode, GCC
// will issue a warning, if these attributes are compiled. Only include them
// when compiling using Clang.
// ANNOTALYSIS_ENABLED == 1 when IGNORE_READ_ATTRIBUTE_ENABLED == 1
#define ABSL_INTERNAL_ANNOTALYSIS_ENABLED \
defined(ABSL_INTERNAL_IGNORE_READS_ATTRIBUTE_ENABLED)
// Read/write annotations are enabled in Annotalysis mode; disabled otherwise.
#define ABSL_INTERNAL_READS_WRITES_ANNOTATIONS_ENABLED \
ABSL_INTERNAL_ANNOTALYSIS_ENABLED
#endif
// Memory annotations are also made available to LLVM's Memory Sanitizer
#if defined(ABSL_HAVE_MEMORY_SANITIZER) && !defined(__native_client__)
#define ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED 1
#endif
#ifndef ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED
#define ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED 0
#endif
#ifdef __cplusplus
#define ABSL_INTERNAL_BEGIN_EXTERN_C extern "C" {
#define ABSL_INTERNAL_END_EXTERN_C } // extern "C"
#define ABSL_INTERNAL_GLOBAL_SCOPED(F) ::F
#define ABSL_INTERNAL_STATIC_INLINE inline
#else
#define ABSL_INTERNAL_BEGIN_EXTERN_C // empty
#define ABSL_INTERNAL_END_EXTERN_C // empty
#define ABSL_INTERNAL_GLOBAL_SCOPED(F) F
#define ABSL_INTERNAL_STATIC_INLINE static inline
#endif
// -------------------------------------------------------------------------
// Define race annotations.
#if ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED == 1
// -------------------------------------------------------------
// Annotations that suppress errors. It is usually better to express the
// program's synchronization using the other annotations, but these can be used
// when all else fails.
// Report that we may have a benign race at `pointer`, with size
// "sizeof(*(pointer))". `pointer` must be a non-void* pointer. Insert at the
// point where `pointer` has been allocated, preferably close to the point
// where the race happens. See also ANNOTATE_BENIGN_RACE_STATIC.
#define ANNOTATE_BENIGN_RACE(pointer, description) \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateBenignRaceSized) \
(__FILE__, __LINE__, pointer, sizeof(*(pointer)), description)
// Same as ANNOTATE_BENIGN_RACE(`address`, `description`), but applies to
// the memory range [`address`, `address`+`size`).
#define ANNOTATE_BENIGN_RACE_SIZED(address, size, description) \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateBenignRaceSized) \
(__FILE__, __LINE__, address, size, description)
// Enable (`enable`!=0) or disable (`enable`==0) race detection for all threads.
// This annotation could be useful if you want to skip expensive race analysis
// during some period of program execution, e.g. during initialization.
#define ANNOTATE_ENABLE_RACE_DETECTION(enable) \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateEnableRaceDetection) \
(__FILE__, __LINE__, enable)
// -------------------------------------------------------------
// Annotations useful for debugging.
// Report the current thread `name` to a race detector.
#define ANNOTATE_THREAD_NAME(name) \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateThreadName)(__FILE__, __LINE__, name)
// -------------------------------------------------------------
// Annotations useful when implementing locks. They are not normally needed by
// modules that merely use locks. The `lock` argument is a pointer to the lock
// object.
// Report that a lock has been created at address `lock`.
#define ANNOTATE_RWLOCK_CREATE(lock) \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateRWLockCreate)(__FILE__, __LINE__, lock)
// Report that a linker initialized lock has been created at address `lock`.
#ifdef ABSL_HAVE_THREAD_SANITIZER
#define ANNOTATE_RWLOCK_CREATE_STATIC(lock) \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateRWLockCreateStatic) \
(__FILE__, __LINE__, lock)
#else
#define ANNOTATE_RWLOCK_CREATE_STATIC(lock) ANNOTATE_RWLOCK_CREATE(lock)
#endif
// Report that the lock at address `lock` is about to be destroyed.
#define ANNOTATE_RWLOCK_DESTROY(lock) \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateRWLockDestroy)(__FILE__, __LINE__, lock)
// Report that the lock at address `lock` has been acquired.
// `is_w`=1 for writer lock, `is_w`=0 for reader lock.
#define ANNOTATE_RWLOCK_ACQUIRED(lock, is_w) \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateRWLockAcquired) \
(__FILE__, __LINE__, lock, is_w)
// Report that the lock at address `lock` is about to be released.
// `is_w`=1 for writer lock, `is_w`=0 for reader lock.
#define ANNOTATE_RWLOCK_RELEASED(lock, is_w) \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateRWLockReleased) \
(__FILE__, __LINE__, lock, is_w)
// Apply ANNOTATE_BENIGN_RACE_SIZED to a static variable `static_var`.
#define ANNOTATE_BENIGN_RACE_STATIC(static_var, description) \
namespace { \
class static_var##_annotator { \
public: \
static_var##_annotator() { \
ANNOTATE_BENIGN_RACE_SIZED(&static_var, sizeof(static_var), \
#static_var ": " description); \
} \
}; \
static static_var##_annotator the##static_var##_annotator; \
} // namespace
#else // ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED == 0
#define ANNOTATE_RWLOCK_CREATE(lock) // empty
#define ANNOTATE_RWLOCK_CREATE_STATIC(lock) // empty
#define ANNOTATE_RWLOCK_DESTROY(lock) // empty
#define ANNOTATE_RWLOCK_ACQUIRED(lock, is_w) // empty
#define ANNOTATE_RWLOCK_RELEASED(lock, is_w) // empty
#define ANNOTATE_BENIGN_RACE(address, description) // empty
#define ANNOTATE_BENIGN_RACE_SIZED(address, size, description) // empty
#define ANNOTATE_THREAD_NAME(name) // empty
#define ANNOTATE_ENABLE_RACE_DETECTION(enable) // empty
#define ANNOTATE_BENIGN_RACE_STATIC(static_var, description) // empty
#endif // ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED
// -------------------------------------------------------------------------
// Define memory annotations.
#if ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED == 1
#include <sanitizer/msan_interface.h>
#define ANNOTATE_MEMORY_IS_INITIALIZED(address, size) \
__msan_unpoison(address, size)
#define ANNOTATE_MEMORY_IS_UNINITIALIZED(address, size) \
__msan_allocated_memory(address, size)
#else // ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED == 0
#if DYNAMIC_ANNOTATIONS_ENABLED == 1
#define ANNOTATE_MEMORY_IS_INITIALIZED(address, size) \
do { \
(void)(address); \
(void)(size); \
} while (0)
#define ANNOTATE_MEMORY_IS_UNINITIALIZED(address, size) \
do { \
(void)(address); \
(void)(size); \
} while (0)
#else
#define ANNOTATE_MEMORY_IS_INITIALIZED(address, size) // empty
#define ANNOTATE_MEMORY_IS_UNINITIALIZED(address, size) // empty
#endif
#endif // ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED
// -------------------------------------------------------------------------
// Define IGNORE_READS_BEGIN/_END attributes.
#if defined(ABSL_INTERNAL_IGNORE_READS_ATTRIBUTE_ENABLED)
#define ABSL_INTERNAL_IGNORE_READS_BEGIN_ATTRIBUTE \
__attribute((exclusive_lock_function("*")))
#define ABSL_INTERNAL_IGNORE_READS_END_ATTRIBUTE \
__attribute((unlock_function("*")))
#else // !defined(ABSL_INTERNAL_IGNORE_READS_ATTRIBUTE_ENABLED)
#define ABSL_INTERNAL_IGNORE_READS_BEGIN_ATTRIBUTE // empty
#define ABSL_INTERNAL_IGNORE_READS_END_ATTRIBUTE // empty
#endif // defined(ABSL_INTERNAL_IGNORE_READS_ATTRIBUTE_ENABLED)
// -------------------------------------------------------------------------
// Define IGNORE_READS_BEGIN/_END annotations.
#if ABSL_INTERNAL_READS_ANNOTATIONS_ENABLED == 1
// Request the analysis tool to ignore all reads in the current thread until
// ANNOTATE_IGNORE_READS_END is called. Useful to ignore intentional racey
// reads, while still checking other reads and all writes.
// See also ANNOTATE_UNPROTECTED_READ.
#define ANNOTATE_IGNORE_READS_BEGIN() \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateIgnoreReadsBegin)(__FILE__, __LINE__)
// Stop ignoring reads.
#define ANNOTATE_IGNORE_READS_END() \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateIgnoreReadsEnd)(__FILE__, __LINE__)
#elif defined(ABSL_INTERNAL_ANNOTALYSIS_ENABLED)
// When Annotalysis is enabled without Dynamic Annotations, the use of
// static-inline functions allows the annotations to be read at compile-time,
// while still letting the compiler elide the functions from the final build.
//
// TODO(delesley) -- The exclusive lock here ignores writes as well, but
// allows IGNORE_READS_AND_WRITES to work properly.
#define ANNOTATE_IGNORE_READS_BEGIN() \
ABSL_INTERNAL_GLOBAL_SCOPED(AbslInternalAnnotateIgnoreReadsBegin)()
#define ANNOTATE_IGNORE_READS_END() \
ABSL_INTERNAL_GLOBAL_SCOPED(AbslInternalAnnotateIgnoreReadsEnd)()
#else
#define ANNOTATE_IGNORE_READS_BEGIN() // empty
#define ANNOTATE_IGNORE_READS_END() // empty
#endif
// -------------------------------------------------------------------------
// Define IGNORE_WRITES_BEGIN/_END annotations.
#if ABSL_INTERNAL_WRITES_ANNOTATIONS_ENABLED == 1
// Similar to ANNOTATE_IGNORE_READS_BEGIN, but ignore writes instead.
#define ANNOTATE_IGNORE_WRITES_BEGIN() \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateIgnoreWritesBegin)(__FILE__, __LINE__)
// Stop ignoring writes.
#define ANNOTATE_IGNORE_WRITES_END() \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateIgnoreWritesEnd)(__FILE__, __LINE__)
#else
#define ANNOTATE_IGNORE_WRITES_BEGIN() // empty
#define ANNOTATE_IGNORE_WRITES_END() // empty
#endif
// -------------------------------------------------------------------------
// Define the ANNOTATE_IGNORE_READS_AND_WRITES_* annotations using the more
// primitive annotations defined above.
//
// Instead of doing
// ANNOTATE_IGNORE_READS_BEGIN();
// ... = x;
// ANNOTATE_IGNORE_READS_END();
// one can use
// ... = ANNOTATE_UNPROTECTED_READ(x);
#if defined(ABSL_INTERNAL_READS_WRITES_ANNOTATIONS_ENABLED)
// Start ignoring all memory accesses (both reads and writes).
#define ANNOTATE_IGNORE_READS_AND_WRITES_BEGIN() \
do { \
ANNOTATE_IGNORE_READS_BEGIN(); \
ANNOTATE_IGNORE_WRITES_BEGIN(); \
} while (0)
// Stop ignoring both reads and writes.
#define ANNOTATE_IGNORE_READS_AND_WRITES_END() \
do { \
ANNOTATE_IGNORE_WRITES_END(); \
ANNOTATE_IGNORE_READS_END(); \
} while (0)
#ifdef __cplusplus
// ANNOTATE_UNPROTECTED_READ is the preferred way to annotate racey reads.
#define ANNOTATE_UNPROTECTED_READ(x) \
absl::base_internal::AnnotateUnprotectedRead(x)
#endif
#else
#define ANNOTATE_IGNORE_READS_AND_WRITES_BEGIN() // empty
#define ANNOTATE_IGNORE_READS_AND_WRITES_END() // empty
#define ANNOTATE_UNPROTECTED_READ(x) (x)
#endif
// -------------------------------------------------------------------------
// Address sanitizer annotations
#ifdef ABSL_HAVE_ADDRESS_SANITIZER
// Describe the current state of a contiguous container such as e.g.
// std::vector or std::string. For more details see
// sanitizer/common_interface_defs.h, which is provided by the compiler.
#include <sanitizer/common_interface_defs.h>
#define ANNOTATE_CONTIGUOUS_CONTAINER(beg, end, old_mid, new_mid) \
__sanitizer_annotate_contiguous_container(beg, end, old_mid, new_mid)
#define ADDRESS_SANITIZER_REDZONE(name) \
struct { \
char x[8] __attribute__((aligned(8))); \
} name
#else
#define ANNOTATE_CONTIGUOUS_CONTAINER(beg, end, old_mid, new_mid)
#define ADDRESS_SANITIZER_REDZONE(name) static_assert(true, "")
#endif // ABSL_HAVE_ADDRESS_SANITIZER
// -------------------------------------------------------------------------
// Undefine the macros intended only for this file.
#undef ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED
#undef ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED
#undef ABSL_INTERNAL_READS_ANNOTATIONS_ENABLED
#undef ABSL_INTERNAL_WRITES_ANNOTATIONS_ENABLED
#undef ABSL_INTERNAL_ANNOTALYSIS_ENABLED
#undef ABSL_INTERNAL_READS_WRITES_ANNOTATIONS_ENABLED
#undef ABSL_INTERNAL_BEGIN_EXTERN_C
#undef ABSL_INTERNAL_END_EXTERN_C
#undef ABSL_INTERNAL_STATIC_INLINE
#endif // ABSL_BASE_INTERNAL_DYNAMIC_ANNOTATIONS_H_

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// 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.
//
#ifndef ABSL_BASE_INTERNAL_ENDIAN_H_
#define ABSL_BASE_INTERNAL_ENDIAN_H_
#include <cstdint>
#include <cstdlib>
#include "absl/base/casts.h"
#include "absl/base/config.h"
#include "absl/base/internal/unaligned_access.h"
#include "absl/base/nullability.h"
#include "absl/base/port.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
inline uint64_t gbswap_64(uint64_t host_int) {
#if ABSL_HAVE_BUILTIN(__builtin_bswap64) || defined(__GNUC__)
return __builtin_bswap64(host_int);
#elif defined(_MSC_VER)
return _byteswap_uint64(host_int);
#else
return (((host_int & uint64_t{0xFF}) << 56) |
((host_int & uint64_t{0xFF00}) << 40) |
((host_int & uint64_t{0xFF0000}) << 24) |
((host_int & uint64_t{0xFF000000}) << 8) |
((host_int & uint64_t{0xFF00000000}) >> 8) |
((host_int & uint64_t{0xFF0000000000}) >> 24) |
((host_int & uint64_t{0xFF000000000000}) >> 40) |
((host_int & uint64_t{0xFF00000000000000}) >> 56));
#endif
}
inline uint32_t gbswap_32(uint32_t host_int) {
#if ABSL_HAVE_BUILTIN(__builtin_bswap32) || defined(__GNUC__)
return __builtin_bswap32(host_int);
#elif defined(_MSC_VER)
return _byteswap_ulong(host_int);
#else
return (((host_int & uint32_t{0xFF}) << 24) |
((host_int & uint32_t{0xFF00}) << 8) |
((host_int & uint32_t{0xFF0000}) >> 8) |
((host_int & uint32_t{0xFF000000}) >> 24));
#endif
}
inline uint16_t gbswap_16(uint16_t host_int) {
#if ABSL_HAVE_BUILTIN(__builtin_bswap16) || defined(__GNUC__)
return __builtin_bswap16(host_int);
#elif defined(_MSC_VER)
return _byteswap_ushort(host_int);
#else
return (((host_int & uint16_t{0xFF}) << 8) |
((host_int & uint16_t{0xFF00}) >> 8));
#endif
}
#ifdef ABSL_IS_LITTLE_ENDIAN
// Portable definitions for htonl (host-to-network) and friends on little-endian
// architectures.
inline uint16_t ghtons(uint16_t x) { return gbswap_16(x); }
inline uint32_t ghtonl(uint32_t x) { return gbswap_32(x); }
inline uint64_t ghtonll(uint64_t x) { return gbswap_64(x); }
#elif defined ABSL_IS_BIG_ENDIAN
// Portable definitions for htonl (host-to-network) etc on big-endian
// architectures. These definitions are simpler since the host byte order is the
// same as network byte order.
inline uint16_t ghtons(uint16_t x) { return x; }
inline uint32_t ghtonl(uint32_t x) { return x; }
inline uint64_t ghtonll(uint64_t x) { return x; }
#else
#error \
"Unsupported byte order: Either ABSL_IS_BIG_ENDIAN or " \
"ABSL_IS_LITTLE_ENDIAN must be defined"
#endif // byte order
inline uint16_t gntohs(uint16_t x) { return ghtons(x); }
inline uint32_t gntohl(uint32_t x) { return ghtonl(x); }
inline uint64_t gntohll(uint64_t x) { return ghtonll(x); }
// Utilities to convert numbers between the current hosts's native byte
// order and little-endian byte order
//
// Load/Store methods are alignment safe
namespace little_endian {
// Conversion functions.
#ifdef ABSL_IS_LITTLE_ENDIAN
inline uint16_t FromHost16(uint16_t x) { return x; }
inline uint16_t ToHost16(uint16_t x) { return x; }
inline uint32_t FromHost32(uint32_t x) { return x; }
inline uint32_t ToHost32(uint32_t x) { return x; }
inline uint64_t FromHost64(uint64_t x) { return x; }
inline uint64_t ToHost64(uint64_t x) { return x; }
inline constexpr bool IsLittleEndian() { return true; }
#elif defined ABSL_IS_BIG_ENDIAN
inline uint16_t FromHost16(uint16_t x) { return gbswap_16(x); }
inline uint16_t ToHost16(uint16_t x) { return gbswap_16(x); }
inline uint32_t FromHost32(uint32_t x) { return gbswap_32(x); }
inline uint32_t ToHost32(uint32_t x) { return gbswap_32(x); }
inline uint64_t FromHost64(uint64_t x) { return gbswap_64(x); }
inline uint64_t ToHost64(uint64_t x) { return gbswap_64(x); }
inline constexpr bool IsLittleEndian() { return false; }
#endif /* ENDIAN */
inline uint8_t FromHost(uint8_t x) { return x; }
inline uint16_t FromHost(uint16_t x) { return FromHost16(x); }
inline uint32_t FromHost(uint32_t x) { return FromHost32(x); }
inline uint64_t FromHost(uint64_t x) { return FromHost64(x); }
inline uint8_t ToHost(uint8_t x) { return x; }
inline uint16_t ToHost(uint16_t x) { return ToHost16(x); }
inline uint32_t ToHost(uint32_t x) { return ToHost32(x); }
inline uint64_t ToHost(uint64_t x) { return ToHost64(x); }
inline int8_t FromHost(int8_t x) { return x; }
inline int16_t FromHost(int16_t x) {
return bit_cast<int16_t>(FromHost16(bit_cast<uint16_t>(x)));
}
inline int32_t FromHost(int32_t x) {
return bit_cast<int32_t>(FromHost32(bit_cast<uint32_t>(x)));
}
inline int64_t FromHost(int64_t x) {
return bit_cast<int64_t>(FromHost64(bit_cast<uint64_t>(x)));
}
inline int8_t ToHost(int8_t x) { return x; }
inline int16_t ToHost(int16_t x) {
return bit_cast<int16_t>(ToHost16(bit_cast<uint16_t>(x)));
}
inline int32_t ToHost(int32_t x) {
return bit_cast<int32_t>(ToHost32(bit_cast<uint32_t>(x)));
}
inline int64_t ToHost(int64_t x) {
return bit_cast<int64_t>(ToHost64(bit_cast<uint64_t>(x)));
}
// Functions to do unaligned loads and stores in little-endian order.
inline uint16_t Load16(absl::Nonnull<const void *> p) {
return ToHost16(ABSL_INTERNAL_UNALIGNED_LOAD16(p));
}
inline void Store16(absl::Nonnull<void *> p, uint16_t v) {
ABSL_INTERNAL_UNALIGNED_STORE16(p, FromHost16(v));
}
inline uint32_t Load32(absl::Nonnull<const void *> p) {
return ToHost32(ABSL_INTERNAL_UNALIGNED_LOAD32(p));
}
inline void Store32(absl::Nonnull<void *> p, uint32_t v) {
ABSL_INTERNAL_UNALIGNED_STORE32(p, FromHost32(v));
}
inline uint64_t Load64(absl::Nonnull<const void *> p) {
return ToHost64(ABSL_INTERNAL_UNALIGNED_LOAD64(p));
}
inline void Store64(absl::Nonnull<void *> p, uint64_t v) {
ABSL_INTERNAL_UNALIGNED_STORE64(p, FromHost64(v));
}
} // namespace little_endian
// Utilities to convert numbers between the current hosts's native byte
// order and big-endian byte order (same as network byte order)
//
// Load/Store methods are alignment safe
namespace big_endian {
#ifdef ABSL_IS_LITTLE_ENDIAN
inline uint16_t FromHost16(uint16_t x) { return gbswap_16(x); }
inline uint16_t ToHost16(uint16_t x) { return gbswap_16(x); }
inline uint32_t FromHost32(uint32_t x) { return gbswap_32(x); }
inline uint32_t ToHost32(uint32_t x) { return gbswap_32(x); }
inline uint64_t FromHost64(uint64_t x) { return gbswap_64(x); }
inline uint64_t ToHost64(uint64_t x) { return gbswap_64(x); }
inline constexpr bool IsLittleEndian() { return true; }
#elif defined ABSL_IS_BIG_ENDIAN
inline uint16_t FromHost16(uint16_t x) { return x; }
inline uint16_t ToHost16(uint16_t x) { return x; }
inline uint32_t FromHost32(uint32_t x) { return x; }
inline uint32_t ToHost32(uint32_t x) { return x; }
inline uint64_t FromHost64(uint64_t x) { return x; }
inline uint64_t ToHost64(uint64_t x) { return x; }
inline constexpr bool IsLittleEndian() { return false; }
#endif /* ENDIAN */
inline uint8_t FromHost(uint8_t x) { return x; }
inline uint16_t FromHost(uint16_t x) { return FromHost16(x); }
inline uint32_t FromHost(uint32_t x) { return FromHost32(x); }
inline uint64_t FromHost(uint64_t x) { return FromHost64(x); }
inline uint8_t ToHost(uint8_t x) { return x; }
inline uint16_t ToHost(uint16_t x) { return ToHost16(x); }
inline uint32_t ToHost(uint32_t x) { return ToHost32(x); }
inline uint64_t ToHost(uint64_t x) { return ToHost64(x); }
inline int8_t FromHost(int8_t x) { return x; }
inline int16_t FromHost(int16_t x) {
return bit_cast<int16_t>(FromHost16(bit_cast<uint16_t>(x)));
}
inline int32_t FromHost(int32_t x) {
return bit_cast<int32_t>(FromHost32(bit_cast<uint32_t>(x)));
}
inline int64_t FromHost(int64_t x) {
return bit_cast<int64_t>(FromHost64(bit_cast<uint64_t>(x)));
}
inline int8_t ToHost(int8_t x) { return x; }
inline int16_t ToHost(int16_t x) {
return bit_cast<int16_t>(ToHost16(bit_cast<uint16_t>(x)));
}
inline int32_t ToHost(int32_t x) {
return bit_cast<int32_t>(ToHost32(bit_cast<uint32_t>(x)));
}
inline int64_t ToHost(int64_t x) {
return bit_cast<int64_t>(ToHost64(bit_cast<uint64_t>(x)));
}
// Functions to do unaligned loads and stores in big-endian order.
inline uint16_t Load16(absl::Nonnull<const void *> p) {
return ToHost16(ABSL_INTERNAL_UNALIGNED_LOAD16(p));
}
inline void Store16(absl::Nonnull<void *> p, uint16_t v) {
ABSL_INTERNAL_UNALIGNED_STORE16(p, FromHost16(v));
}
inline uint32_t Load32(absl::Nonnull<const void *> p) {
return ToHost32(ABSL_INTERNAL_UNALIGNED_LOAD32(p));
}
inline void Store32(absl::Nonnull<void *>p, uint32_t v) {
ABSL_INTERNAL_UNALIGNED_STORE32(p, FromHost32(v));
}
inline uint64_t Load64(absl::Nonnull<const void *> p) {
return ToHost64(ABSL_INTERNAL_UNALIGNED_LOAD64(p));
}
inline void Store64(absl::Nonnull<void *> p, uint64_t v) {
ABSL_INTERNAL_UNALIGNED_STORE64(p, FromHost64(v));
}
} // namespace big_endian
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_ENDIAN_H_

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// 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.
#ifndef ABSL_BASE_INTERNAL_ERRNO_SAVER_H_
#define ABSL_BASE_INTERNAL_ERRNO_SAVER_H_
#include <cerrno>
#include "absl/base/config.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
// `ErrnoSaver` captures the value of `errno` upon construction and restores it
// upon deletion. It is used in low-level code and must be super fast. Do not
// add instrumentation, even in debug modes.
class ErrnoSaver {
public:
ErrnoSaver() : saved_errno_(errno) {}
~ErrnoSaver() { errno = saved_errno_; }
int operator()() const { return saved_errno_; }
private:
const int saved_errno_;
};
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_ERRNO_SAVER_H_

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//
// Copyright 2020 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.
//
#ifndef ABSL_BASE_INTERNAL_FAST_TYPE_ID_H_
#define ABSL_BASE_INTERNAL_FAST_TYPE_ID_H_
#include "absl/base/config.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
template <typename Type>
struct FastTypeTag {
constexpr static char dummy_var = 0;
};
#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
template <typename Type>
constexpr char FastTypeTag<Type>::dummy_var;
#endif
// FastTypeId<Type>() evaluates at compile/link-time to a unique pointer for the
// passed-in type. These are meant to be good match for keys into maps or
// straight up comparisons.
using FastTypeIdType = const void*;
template <typename Type>
constexpr inline FastTypeIdType FastTypeId() {
return &FastTypeTag<Type>::dummy_var;
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_FAST_TYPE_ID_H_

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// Copyright 2018 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.
#ifndef ABSL_BASE_INTERNAL_HIDE_PTR_H_
#define ABSL_BASE_INTERNAL_HIDE_PTR_H_
#include <cstdint>
#include "absl/base/config.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
// Arbitrary value with high bits set. Xor'ing with it is unlikely
// to map one valid pointer to another valid pointer.
constexpr uintptr_t HideMask() {
return (uintptr_t{0xF03A5F7BU} << (sizeof(uintptr_t) - 4) * 8) | 0xF03A5F7BU;
}
// Hide a pointer from the leak checker. For internal use only.
// Differs from absl::IgnoreLeak(ptr) in that absl::IgnoreLeak(ptr) causes ptr
// and all objects reachable from ptr to be ignored by the leak checker.
template <class T>
inline uintptr_t HidePtr(T* ptr) {
return reinterpret_cast<uintptr_t>(ptr) ^ HideMask();
}
// Return a pointer that has been hidden from the leak checker.
// For internal use only.
template <class T>
inline T* UnhidePtr(uintptr_t hidden) {
return reinterpret_cast<T*>(hidden ^ HideMask());
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_HIDE_PTR_H_

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// 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.
//
#ifndef ABSL_BASE_INTERNAL_IDENTITY_H_
#define ABSL_BASE_INTERNAL_IDENTITY_H_
#include "absl/base/config.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace internal {
// This is a back-fill of C++20's `std::type_identity`.
template <typename T>
struct type_identity {
typedef T type;
};
// This is a back-fill of C++20's `std::type_identity_t`.
template <typename T>
using type_identity_t = typename type_identity<T>::type;
} // namespace internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_IDENTITY_H_

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// 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.
#ifndef ABSL_BASE_INTERNAL_INLINE_VARIABLE_H_
#define ABSL_BASE_INTERNAL_INLINE_VARIABLE_H_
#include <type_traits>
#include "absl/base/internal/identity.h"
// File:
// This file define a macro that allows the creation of or emulation of C++17
// inline variables based on whether or not the feature is supported.
////////////////////////////////////////////////////////////////////////////////
// Macro: ABSL_INTERNAL_INLINE_CONSTEXPR(type, name, init)
//
// Description:
// Expands to the equivalent of an inline constexpr instance of the specified
// `type` and `name`, initialized to the value `init`. If the compiler being
// used is detected as supporting actual inline variables as a language
// feature, then the macro expands to an actual inline variable definition.
//
// Requires:
// `type` is a type that is usable in an extern variable declaration.
//
// Requires: `name` is a valid identifier
//
// Requires:
// `init` is an expression that can be used in the following definition:
// constexpr type name = init;
//
// Usage:
//
// // Equivalent to: `inline constexpr size_t variant_npos = -1;`
// ABSL_INTERNAL_INLINE_CONSTEXPR(size_t, variant_npos, -1);
//
// Differences in implementation:
// For a direct, language-level inline variable, decltype(name) will be the
// type that was specified along with const qualification, whereas for
// emulated inline variables, decltype(name) may be different (in practice
// it will likely be a reference type).
////////////////////////////////////////////////////////////////////////////////
#ifdef __cpp_inline_variables
// Clang's -Wmissing-variable-declarations option erroneously warned that
// inline constexpr objects need to be pre-declared. This has now been fixed,
// but we will need to support this workaround for people building with older
// versions of clang.
//
// Bug: https://bugs.llvm.org/show_bug.cgi?id=35862
//
// Note:
// type_identity_t is used here so that the const and name are in the
// appropriate place for pointer types, reference types, function pointer
// types, etc..
#if defined(__clang__)
#define ABSL_INTERNAL_EXTERN_DECL(type, name) \
extern const ::absl::internal::type_identity_t<type> name;
#else // Otherwise, just define the macro to do nothing.
#define ABSL_INTERNAL_EXTERN_DECL(type, name)
#endif // defined(__clang__)
// See above comment at top of file for details.
#define ABSL_INTERNAL_INLINE_CONSTEXPR(type, name, init) \
ABSL_INTERNAL_EXTERN_DECL(type, name) \
inline constexpr ::absl::internal::type_identity_t<type> name = init
#else
// See above comment at top of file for details.
//
// Note:
// type_identity_t is used here so that the const and name are in the
// appropriate place for pointer types, reference types, function pointer
// types, etc..
#define ABSL_INTERNAL_INLINE_CONSTEXPR(var_type, name, init) \
template <class /*AbslInternalDummy*/ = void> \
struct AbslInternalInlineVariableHolder##name { \
static constexpr ::absl::internal::type_identity_t<var_type> kInstance = \
init; \
}; \
\
template <class AbslInternalDummy> \
constexpr ::absl::internal::type_identity_t<var_type> \
AbslInternalInlineVariableHolder##name<AbslInternalDummy>::kInstance; \
\
static constexpr const ::absl::internal::type_identity_t<var_type>& \
name = /* NOLINT */ \
AbslInternalInlineVariableHolder##name<>::kInstance; \
static_assert(sizeof(void (*)(decltype(name))) != 0, \
"Silence unused variable warnings.")
#endif // __cpp_inline_variables
#endif // ABSL_BASE_INTERNAL_INLINE_VARIABLE_H_

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// 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.
//
// absl::base_internal::invoke(f, args...) is an implementation of
// INVOKE(f, args...) from section [func.require] of the C++ standard.
// When compiled as C++17 and later versions, it is implemented as an alias of
// std::invoke.
//
// [func.require]
// Define INVOKE (f, t1, t2, ..., tN) as follows:
// 1. (t1.*f)(t2, ..., tN) when f is a pointer to a member function of a class T
// and t1 is an object of type T or a reference to an object of type T or a
// reference to an object of a type derived from T;
// 2. ((*t1).*f)(t2, ..., tN) when f is a pointer to a member function of a
// class T and t1 is not one of the types described in the previous item;
// 3. t1.*f when N == 1 and f is a pointer to member data of a class T and t1 is
// an object of type T or a reference to an object of type T or a reference
// to an object of a type derived from T;
// 4. (*t1).*f when N == 1 and f is a pointer to member data of a class T and t1
// is not one of the types described in the previous item;
// 5. f(t1, t2, ..., tN) in all other cases.
//
// The implementation is SFINAE-friendly: substitution failure within invoke()
// isn't an error.
#ifndef ABSL_BASE_INTERNAL_INVOKE_H_
#define ABSL_BASE_INTERNAL_INVOKE_H_
#include "absl/base/config.h"
#if ABSL_INTERNAL_CPLUSPLUS_LANG >= 201703L
#include <functional>
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
using std::invoke;
using std::invoke_result_t;
using std::is_invocable_r;
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#else // ABSL_INTERNAL_CPLUSPLUS_LANG >= 201703L
#include <algorithm>
#include <type_traits>
#include <utility>
#include "absl/meta/type_traits.h"
// The following code is internal implementation detail. See the comment at the
// top of this file for the API documentation.
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
// The five classes below each implement one of the clauses from the definition
// of INVOKE. The inner class template Accept<F, Args...> checks whether the
// clause is applicable; static function template Invoke(f, args...) does the
// invocation.
//
// By separating the clause selection logic from invocation we make sure that
// Invoke() does exactly what the standard says.
template <typename Derived>
struct StrippedAccept {
template <typename... Args>
struct Accept : Derived::template AcceptImpl<typename std::remove_cv<
typename std::remove_reference<Args>::type>::type...> {};
};
// (t1.*f)(t2, ..., tN) when f is a pointer to a member function of a class T
// and t1 is an object of type T or a reference to an object of type T or a
// reference to an object of a type derived from T.
struct MemFunAndRef : StrippedAccept<MemFunAndRef> {
template <typename... Args>
struct AcceptImpl : std::false_type {};
template <typename MemFunType, typename C, typename Obj, typename... Args>
struct AcceptImpl<MemFunType C::*, Obj, Args...>
: std::integral_constant<bool, std::is_base_of<C, Obj>::value &&
absl::is_function<MemFunType>::value> {
};
template <typename MemFun, typename Obj, typename... Args>
static decltype((std::declval<Obj>().*
std::declval<MemFun>())(std::declval<Args>()...))
Invoke(MemFun&& mem_fun, Obj&& obj, Args&&... args) {
// Ignore bogus GCC warnings on this line.
// See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101436 for similar example.
#if ABSL_INTERNAL_HAVE_MIN_GNUC_VERSION(11, 0)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Warray-bounds"
#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
#endif
return (std::forward<Obj>(obj).*
std::forward<MemFun>(mem_fun))(std::forward<Args>(args)...);
#if ABSL_INTERNAL_HAVE_MIN_GNUC_VERSION(11, 0)
#pragma GCC diagnostic pop
#endif
}
};
// ((*t1).*f)(t2, ..., tN) when f is a pointer to a member function of a
// class T and t1 is not one of the types described in the previous item.
struct MemFunAndPtr : StrippedAccept<MemFunAndPtr> {
template <typename... Args>
struct AcceptImpl : std::false_type {};
template <typename MemFunType, typename C, typename Ptr, typename... Args>
struct AcceptImpl<MemFunType C::*, Ptr, Args...>
: std::integral_constant<bool, !std::is_base_of<C, Ptr>::value &&
absl::is_function<MemFunType>::value> {
};
template <typename MemFun, typename Ptr, typename... Args>
static decltype(((*std::declval<Ptr>()).*
std::declval<MemFun>())(std::declval<Args>()...))
Invoke(MemFun&& mem_fun, Ptr&& ptr, Args&&... args) {
return ((*std::forward<Ptr>(ptr)).*
std::forward<MemFun>(mem_fun))(std::forward<Args>(args)...);
}
};
// t1.*f when N == 1 and f is a pointer to member data of a class T and t1 is
// an object of type T or a reference to an object of type T or a reference
// to an object of a type derived from T.
struct DataMemAndRef : StrippedAccept<DataMemAndRef> {
template <typename... Args>
struct AcceptImpl : std::false_type {};
template <typename R, typename C, typename Obj>
struct AcceptImpl<R C::*, Obj>
: std::integral_constant<bool, std::is_base_of<C, Obj>::value &&
!absl::is_function<R>::value> {};
template <typename DataMem, typename Ref>
static decltype(std::declval<Ref>().*std::declval<DataMem>()) Invoke(
DataMem&& data_mem, Ref&& ref) {
return std::forward<Ref>(ref).*std::forward<DataMem>(data_mem);
}
};
// (*t1).*f when N == 1 and f is a pointer to member data of a class T and t1
// is not one of the types described in the previous item.
struct DataMemAndPtr : StrippedAccept<DataMemAndPtr> {
template <typename... Args>
struct AcceptImpl : std::false_type {};
template <typename R, typename C, typename Ptr>
struct AcceptImpl<R C::*, Ptr>
: std::integral_constant<bool, !std::is_base_of<C, Ptr>::value &&
!absl::is_function<R>::value> {};
template <typename DataMem, typename Ptr>
static decltype((*std::declval<Ptr>()).*std::declval<DataMem>()) Invoke(
DataMem&& data_mem, Ptr&& ptr) {
return (*std::forward<Ptr>(ptr)).*std::forward<DataMem>(data_mem);
}
};
// f(t1, t2, ..., tN) in all other cases.
struct Callable {
// Callable doesn't have Accept because it's the last clause that gets picked
// when none of the previous clauses are applicable.
template <typename F, typename... Args>
static decltype(std::declval<F>()(std::declval<Args>()...)) Invoke(
F&& f, Args&&... args) {
return std::forward<F>(f)(std::forward<Args>(args)...);
}
};
// Resolves to the first matching clause.
template <typename... Args>
struct Invoker {
typedef typename std::conditional<
MemFunAndRef::Accept<Args...>::value, MemFunAndRef,
typename std::conditional<
MemFunAndPtr::Accept<Args...>::value, MemFunAndPtr,
typename std::conditional<
DataMemAndRef::Accept<Args...>::value, DataMemAndRef,
typename std::conditional<DataMemAndPtr::Accept<Args...>::value,
DataMemAndPtr, Callable>::type>::type>::
type>::type type;
};
// The result type of Invoke<F, Args...>.
template <typename F, typename... Args>
using invoke_result_t = decltype(Invoker<F, Args...>::type::Invoke(
std::declval<F>(), std::declval<Args>()...));
// Invoke(f, args...) is an implementation of INVOKE(f, args...) from section
// [func.require] of the C++ standard.
template <typename F, typename... Args>
invoke_result_t<F, Args...> invoke(F&& f, Args&&... args) {
return Invoker<F, Args...>::type::Invoke(std::forward<F>(f),
std::forward<Args>(args)...);
}
template <typename AlwaysVoid, typename, typename, typename...>
struct IsInvocableRImpl : std::false_type {};
template <typename R, typename F, typename... Args>
struct IsInvocableRImpl<
absl::void_t<absl::base_internal::invoke_result_t<F, Args...> >, R, F,
Args...>
: std::integral_constant<
bool,
std::is_convertible<absl::base_internal::invoke_result_t<F, Args...>,
R>::value ||
std::is_void<R>::value> {};
// Type trait whose member `value` is true if invoking `F` with `Args` is valid,
// and either the return type is convertible to `R`, or `R` is void.
// C++11-compatible version of `std::is_invocable_r`.
template <typename R, typename F, typename... Args>
using is_invocable_r = IsInvocableRImpl<void, R, F, Args...>;
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_INTERNAL_CPLUSPLUS_LANG >= 201703L
#endif // ABSL_BASE_INTERNAL_INVOKE_H_

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@@ -0,0 +1,631 @@
// 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.
// A low-level allocator that can be used by other low-level
// modules without introducing dependency cycles.
// This allocator is slow and wasteful of memory;
// it should not be used when performance is key.
#include "absl/base/internal/low_level_alloc.h"
#include <type_traits>
#include "absl/base/call_once.h"
#include "absl/base/config.h"
#include "absl/base/internal/direct_mmap.h"
#include "absl/base/internal/scheduling_mode.h"
#include "absl/base/macros.h"
#include "absl/base/thread_annotations.h"
// LowLevelAlloc requires that the platform support low-level
// allocation of virtual memory. Platforms lacking this cannot use
// LowLevelAlloc.
#ifndef ABSL_LOW_LEVEL_ALLOC_MISSING
#ifndef _WIN32
#include <pthread.h>
#include <signal.h>
#include <sys/mman.h>
#include <unistd.h>
#else
#include <windows.h>
#endif
#ifdef __linux__
#include <sys/prctl.h>
#endif
#include <string.h>
#include <algorithm>
#include <atomic>
#include <cerrno>
#include <cstddef>
#include <new> // for placement-new
#include "absl/base/dynamic_annotations.h"
#include "absl/base/internal/raw_logging.h"
#include "absl/base/internal/spinlock.h"
#if defined(MAP_ANON) && !defined(MAP_ANONYMOUS)
#define MAP_ANONYMOUS MAP_ANON
#endif
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
// A first-fit allocator with amortized logarithmic free() time.
// ---------------------------------------------------------------------------
static const int kMaxLevel = 30;
namespace {
// This struct describes one allocated block, or one free block.
struct AllocList {
struct Header {
// Size of entire region, including this field. Must be
// first. Valid in both allocated and unallocated blocks.
uintptr_t size;
// kMagicAllocated or kMagicUnallocated xor this.
uintptr_t magic;
// Pointer to parent arena.
LowLevelAlloc::Arena *arena;
// Aligns regions to 0 mod 2*sizeof(void*).
void *dummy_for_alignment;
} header;
// Next two fields: in unallocated blocks: freelist skiplist data
// in allocated blocks: overlaps with client data
// Levels in skiplist used.
int levels;
// Actually has levels elements. The AllocList node may not have room
// for all kMaxLevel entries. See max_fit in LLA_SkiplistLevels().
AllocList *next[kMaxLevel];
};
} // namespace
// ---------------------------------------------------------------------------
// A trivial skiplist implementation. This is used to keep the freelist
// in address order while taking only logarithmic time per insert and delete.
// An integer approximation of log2(size/base)
// Requires size >= base.
static int IntLog2(size_t size, size_t base) {
int result = 0;
for (size_t i = size; i > base; i >>= 1) { // i == floor(size/2**result)
result++;
}
// floor(size / 2**result) <= base < floor(size / 2**(result-1))
// => log2(size/(base+1)) <= result < 1+log2(size/base)
// => result ~= log2(size/base)
return result;
}
// Return a random integer n: p(n)=1/(2**n) if 1 <= n; p(n)=0 if n < 1.
static int Random(uint32_t *state) {
uint32_t r = *state;
int result = 1;
while ((((r = r * 1103515245 + 12345) >> 30) & 1) == 0) {
result++;
}
*state = r;
return result;
}
// Return a number of skiplist levels for a node of size bytes, where
// base is the minimum node size. Compute level=log2(size / base)+n
// where n is 1 if random is false and otherwise a random number generated with
// the standard distribution for a skiplist: See Random() above.
// Bigger nodes tend to have more skiplist levels due to the log2(size / base)
// term, so first-fit searches touch fewer nodes. "level" is clipped so
// level<kMaxLevel and next[level-1] will fit in the node.
// 0 < LLA_SkiplistLevels(x,y,false) <= LLA_SkiplistLevels(x,y,true) < kMaxLevel
static int LLA_SkiplistLevels(size_t size, size_t base, uint32_t *random) {
// max_fit is the maximum number of levels that will fit in a node for the
// given size. We can't return more than max_fit, no matter what the
// random number generator says.
size_t max_fit = (size - offsetof(AllocList, next)) / sizeof(AllocList *);
int level = IntLog2(size, base) + (random != nullptr ? Random(random) : 1);
if (static_cast<size_t>(level) > max_fit) level = static_cast<int>(max_fit);
if (level > kMaxLevel - 1) level = kMaxLevel - 1;
ABSL_RAW_CHECK(level >= 1, "block not big enough for even one level");
return level;
}
// Return "atleast", the first element of AllocList *head s.t. *atleast >= *e.
// For 0 <= i < head->levels, set prev[i] to "no_greater", where no_greater
// points to the last element at level i in the AllocList less than *e, or is
// head if no such element exists.
static AllocList *LLA_SkiplistSearch(AllocList *head, AllocList *e,
AllocList **prev) {
AllocList *p = head;
for (int level = head->levels - 1; level >= 0; level--) {
for (AllocList *n; (n = p->next[level]) != nullptr && n < e; p = n) {
}
prev[level] = p;
}
return (head->levels == 0) ? nullptr : prev[0]->next[0];
}
// Insert element *e into AllocList *head. Set prev[] as LLA_SkiplistSearch.
// Requires that e->levels be previously set by the caller (using
// LLA_SkiplistLevels())
static void LLA_SkiplistInsert(AllocList *head, AllocList *e,
AllocList **prev) {
LLA_SkiplistSearch(head, e, prev);
for (; head->levels < e->levels; head->levels++) { // extend prev pointers
prev[head->levels] = head; // to all *e's levels
}
for (int i = 0; i != e->levels; i++) { // add element to list
e->next[i] = prev[i]->next[i];
prev[i]->next[i] = e;
}
}
// Remove element *e from AllocList *head. Set prev[] as LLA_SkiplistSearch().
// Requires that e->levels be previous set by the caller (using
// LLA_SkiplistLevels())
static void LLA_SkiplistDelete(AllocList *head, AllocList *e,
AllocList **prev) {
AllocList *found = LLA_SkiplistSearch(head, e, prev);
ABSL_RAW_CHECK(e == found, "element not in freelist");
for (int i = 0; i != e->levels && prev[i]->next[i] == e; i++) {
prev[i]->next[i] = e->next[i];
}
while (head->levels > 0 && head->next[head->levels - 1] == nullptr) {
head->levels--; // reduce head->levels if level unused
}
}
// ---------------------------------------------------------------------------
// Arena implementation
// Metadata for an LowLevelAlloc arena instance.
struct LowLevelAlloc::Arena {
// Constructs an arena with the given LowLevelAlloc flags.
explicit Arena(uint32_t flags_value);
base_internal::SpinLock mu;
// Head of free list, sorted by address
AllocList freelist ABSL_GUARDED_BY(mu);
// Count of allocated blocks
int32_t allocation_count ABSL_GUARDED_BY(mu);
// flags passed to NewArena
const uint32_t flags;
// Result of sysconf(_SC_PAGESIZE)
const size_t pagesize;
// Lowest power of two >= max(16, sizeof(AllocList))
const size_t round_up;
// Smallest allocation block size
const size_t min_size;
// PRNG state
uint32_t random ABSL_GUARDED_BY(mu);
};
namespace {
// Static storage space for the lazily-constructed, default global arena
// instances. We require this space because the whole point of LowLevelAlloc
// is to avoid relying on malloc/new.
alignas(LowLevelAlloc::Arena) unsigned char default_arena_storage[sizeof(
LowLevelAlloc::Arena)];
alignas(LowLevelAlloc::Arena) unsigned char unhooked_arena_storage[sizeof(
LowLevelAlloc::Arena)];
#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
alignas(
LowLevelAlloc::Arena) unsigned char unhooked_async_sig_safe_arena_storage
[sizeof(LowLevelAlloc::Arena)];
#endif
// We must use LowLevelCallOnce here to construct the global arenas, rather than
// using function-level statics, to avoid recursively invoking the scheduler.
absl::once_flag create_globals_once;
void CreateGlobalArenas() {
new (&default_arena_storage)
LowLevelAlloc::Arena(LowLevelAlloc::kCallMallocHook);
new (&unhooked_arena_storage) LowLevelAlloc::Arena(0);
#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
new (&unhooked_async_sig_safe_arena_storage)
LowLevelAlloc::Arena(LowLevelAlloc::kAsyncSignalSafe);
#endif
}
// Returns a global arena that does not call into hooks. Used by NewArena()
// when kCallMallocHook is not set.
LowLevelAlloc::Arena *UnhookedArena() {
base_internal::LowLevelCallOnce(&create_globals_once, CreateGlobalArenas);
return reinterpret_cast<LowLevelAlloc::Arena *>(&unhooked_arena_storage);
}
#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
// Returns a global arena that is async-signal safe. Used by NewArena() when
// kAsyncSignalSafe is set.
LowLevelAlloc::Arena *UnhookedAsyncSigSafeArena() {
base_internal::LowLevelCallOnce(&create_globals_once, CreateGlobalArenas);
return reinterpret_cast<LowLevelAlloc::Arena *>(
&unhooked_async_sig_safe_arena_storage);
}
#endif
} // namespace
// Returns the default arena, as used by LowLevelAlloc::Alloc() and friends.
LowLevelAlloc::Arena *LowLevelAlloc::DefaultArena() {
base_internal::LowLevelCallOnce(&create_globals_once, CreateGlobalArenas);
return reinterpret_cast<LowLevelAlloc::Arena *>(&default_arena_storage);
}
// magic numbers to identify allocated and unallocated blocks
static const uintptr_t kMagicAllocated = 0x4c833e95U;
static const uintptr_t kMagicUnallocated = ~kMagicAllocated;
namespace {
class ABSL_SCOPED_LOCKABLE ArenaLock {
public:
explicit ArenaLock(LowLevelAlloc::Arena *arena)
ABSL_EXCLUSIVE_LOCK_FUNCTION(arena->mu)
: arena_(arena) {
#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
if ((arena->flags & LowLevelAlloc::kAsyncSignalSafe) != 0) {
sigset_t all;
sigfillset(&all);
mask_valid_ = pthread_sigmask(SIG_BLOCK, &all, &mask_) == 0;
}
#endif
arena_->mu.Lock();
}
~ArenaLock() { ABSL_RAW_CHECK(left_, "haven't left Arena region"); }
void Leave() ABSL_UNLOCK_FUNCTION() {
arena_->mu.Unlock();
#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
if (mask_valid_) {
const int err = pthread_sigmask(SIG_SETMASK, &mask_, nullptr);
if (err != 0) {
ABSL_RAW_LOG(FATAL, "pthread_sigmask failed: %d", err);
}
}
#endif
left_ = true;
}
private:
bool left_ = false; // whether left region
#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
bool mask_valid_ = false;
sigset_t mask_; // old mask of blocked signals
#endif
LowLevelAlloc::Arena *arena_;
ArenaLock(const ArenaLock &) = delete;
ArenaLock &operator=(const ArenaLock &) = delete;
};
} // namespace
// create an appropriate magic number for an object at "ptr"
// "magic" should be kMagicAllocated or kMagicUnallocated
inline static uintptr_t Magic(uintptr_t magic, AllocList::Header *ptr) {
return magic ^ reinterpret_cast<uintptr_t>(ptr);
}
namespace {
size_t GetPageSize() {
#ifdef _WIN32
SYSTEM_INFO system_info;
GetSystemInfo(&system_info);
return std::max(system_info.dwPageSize, system_info.dwAllocationGranularity);
#elif defined(__wasm__) || defined(__asmjs__) || defined(__hexagon__)
return getpagesize();
#else
return static_cast<size_t>(sysconf(_SC_PAGESIZE));
#endif
}
size_t RoundedUpBlockSize() {
// Round up block sizes to a power of two close to the header size.
size_t round_up = 16;
while (round_up < sizeof(AllocList::Header)) {
round_up += round_up;
}
return round_up;
}
} // namespace
LowLevelAlloc::Arena::Arena(uint32_t flags_value)
: mu(base_internal::SCHEDULE_KERNEL_ONLY),
allocation_count(0),
flags(flags_value),
pagesize(GetPageSize()),
round_up(RoundedUpBlockSize()),
min_size(2 * round_up),
random(0) {
freelist.header.size = 0;
freelist.header.magic = Magic(kMagicUnallocated, &freelist.header);
freelist.header.arena = this;
freelist.levels = 0;
memset(freelist.next, 0, sizeof(freelist.next));
}
// L < meta_data_arena->mu
LowLevelAlloc::Arena *LowLevelAlloc::NewArena(uint32_t flags) {
Arena *meta_data_arena = DefaultArena();
#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
if ((flags & LowLevelAlloc::kAsyncSignalSafe) != 0) {
meta_data_arena = UnhookedAsyncSigSafeArena();
} else // NOLINT(readability/braces)
#endif
if ((flags & LowLevelAlloc::kCallMallocHook) == 0) {
meta_data_arena = UnhookedArena();
}
Arena *result =
new (AllocWithArena(sizeof(*result), meta_data_arena)) Arena(flags);
return result;
}
// L < arena->mu, L < arena->arena->mu
bool LowLevelAlloc::DeleteArena(Arena *arena) {
ABSL_RAW_CHECK(
arena != nullptr && arena != DefaultArena() && arena != UnhookedArena(),
"may not delete default arena");
ArenaLock section(arena);
if (arena->allocation_count != 0) {
section.Leave();
return false;
}
while (arena->freelist.next[0] != nullptr) {
AllocList *region = arena->freelist.next[0];
size_t size = region->header.size;
arena->freelist.next[0] = region->next[0];
ABSL_RAW_CHECK(
region->header.magic == Magic(kMagicUnallocated, &region->header),
"bad magic number in DeleteArena()");
ABSL_RAW_CHECK(region->header.arena == arena,
"bad arena pointer in DeleteArena()");
ABSL_RAW_CHECK(size % arena->pagesize == 0,
"empty arena has non-page-aligned block size");
ABSL_RAW_CHECK(reinterpret_cast<uintptr_t>(region) % arena->pagesize == 0,
"empty arena has non-page-aligned block");
int munmap_result;
#ifdef _WIN32
munmap_result = VirtualFree(region, 0, MEM_RELEASE);
ABSL_RAW_CHECK(munmap_result != 0,
"LowLevelAlloc::DeleteArena: VitualFree failed");
#else
#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
if ((arena->flags & LowLevelAlloc::kAsyncSignalSafe) == 0) {
munmap_result = munmap(region, size);
} else {
munmap_result = base_internal::DirectMunmap(region, size);
}
#else
munmap_result = munmap(region, size);
#endif // ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
if (munmap_result != 0) {
ABSL_RAW_LOG(FATAL, "LowLevelAlloc::DeleteArena: munmap failed: %d",
errno);
}
#endif // _WIN32
}
section.Leave();
arena->~Arena();
Free(arena);
return true;
}
// ---------------------------------------------------------------------------
// Addition, checking for overflow. The intent is to die if an external client
// manages to push through a request that would cause arithmetic to fail.
static inline uintptr_t CheckedAdd(uintptr_t a, uintptr_t b) {
uintptr_t sum = a + b;
ABSL_RAW_CHECK(sum >= a, "LowLevelAlloc arithmetic overflow");
return sum;
}
// Return value rounded up to next multiple of align.
// align must be a power of two.
static inline uintptr_t RoundUp(uintptr_t addr, uintptr_t align) {
return CheckedAdd(addr, align - 1) & ~(align - 1);
}
// Equivalent to "return prev->next[i]" but with sanity checking
// that the freelist is in the correct order, that it
// consists of regions marked "unallocated", and that no two regions
// are adjacent in memory (they should have been coalesced).
// L >= arena->mu
static AllocList *Next(int i, AllocList *prev, LowLevelAlloc::Arena *arena) {
ABSL_RAW_CHECK(i < prev->levels, "too few levels in Next()");
AllocList *next = prev->next[i];
if (next != nullptr) {
ABSL_RAW_CHECK(
next->header.magic == Magic(kMagicUnallocated, &next->header),
"bad magic number in Next()");
ABSL_RAW_CHECK(next->header.arena == arena, "bad arena pointer in Next()");
if (prev != &arena->freelist) {
ABSL_RAW_CHECK(prev < next, "unordered freelist");
ABSL_RAW_CHECK(reinterpret_cast<char *>(prev) + prev->header.size <
reinterpret_cast<char *>(next),
"malformed freelist");
}
}
return next;
}
// Coalesce list item "a" with its successor if they are adjacent.
static void Coalesce(AllocList *a) {
AllocList *n = a->next[0];
if (n != nullptr && reinterpret_cast<char *>(a) + a->header.size ==
reinterpret_cast<char *>(n)) {
LowLevelAlloc::Arena *arena = a->header.arena;
a->header.size += n->header.size;
n->header.magic = 0;
n->header.arena = nullptr;
AllocList *prev[kMaxLevel];
LLA_SkiplistDelete(&arena->freelist, n, prev);
LLA_SkiplistDelete(&arena->freelist, a, prev);
a->levels =
LLA_SkiplistLevels(a->header.size, arena->min_size, &arena->random);
LLA_SkiplistInsert(&arena->freelist, a, prev);
}
}
// Adds block at location "v" to the free list
// L >= arena->mu
static void AddToFreelist(void *v, LowLevelAlloc::Arena *arena) {
AllocList *f = reinterpret_cast<AllocList *>(reinterpret_cast<char *>(v) -
sizeof(f->header));
ABSL_RAW_CHECK(f->header.magic == Magic(kMagicAllocated, &f->header),
"bad magic number in AddToFreelist()");
ABSL_RAW_CHECK(f->header.arena == arena,
"bad arena pointer in AddToFreelist()");
f->levels =
LLA_SkiplistLevels(f->header.size, arena->min_size, &arena->random);
AllocList *prev[kMaxLevel];
LLA_SkiplistInsert(&arena->freelist, f, prev);
f->header.magic = Magic(kMagicUnallocated, &f->header);
Coalesce(f); // maybe coalesce with successor
Coalesce(prev[0]); // maybe coalesce with predecessor
}
// Frees storage allocated by LowLevelAlloc::Alloc().
// L < arena->mu
void LowLevelAlloc::Free(void *v) {
if (v != nullptr) {
AllocList *f = reinterpret_cast<AllocList *>(reinterpret_cast<char *>(v) -
sizeof(f->header));
LowLevelAlloc::Arena *arena = f->header.arena;
ArenaLock section(arena);
AddToFreelist(v, arena);
ABSL_RAW_CHECK(arena->allocation_count > 0, "nothing in arena to free");
arena->allocation_count--;
section.Leave();
}
}
// allocates and returns a block of size bytes, to be freed with Free()
// L < arena->mu
static void *DoAllocWithArena(size_t request, LowLevelAlloc::Arena *arena) {
void *result = nullptr;
if (request != 0) {
AllocList *s; // will point to region that satisfies request
ArenaLock section(arena);
// round up with header
size_t req_rnd =
RoundUp(CheckedAdd(request, sizeof(s->header)), arena->round_up);
for (;;) { // loop until we find a suitable region
// find the minimum levels that a block of this size must have
int i = LLA_SkiplistLevels(req_rnd, arena->min_size, nullptr) - 1;
if (i < arena->freelist.levels) { // potential blocks exist
AllocList *before = &arena->freelist; // predecessor of s
while ((s = Next(i, before, arena)) != nullptr &&
s->header.size < req_rnd) {
before = s;
}
if (s != nullptr) { // we found a region
break;
}
}
// we unlock before mmap() both because mmap() may call a callback hook,
// and because it may be slow.
arena->mu.Unlock();
// mmap generous 64K chunks to decrease
// the chances/impact of fragmentation:
size_t new_pages_size = RoundUp(req_rnd, arena->pagesize * 16);
void *new_pages;
#ifdef _WIN32
new_pages = VirtualAlloc(nullptr, new_pages_size,
MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
ABSL_RAW_CHECK(new_pages != nullptr, "VirtualAlloc failed");
#else
#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
if ((arena->flags & LowLevelAlloc::kAsyncSignalSafe) != 0) {
new_pages = base_internal::DirectMmap(nullptr, new_pages_size,
PROT_WRITE|PROT_READ, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
} else {
new_pages = mmap(nullptr, new_pages_size, PROT_WRITE | PROT_READ,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
}
#else
new_pages = mmap(nullptr, new_pages_size, PROT_WRITE | PROT_READ,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
#endif // ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
if (new_pages == MAP_FAILED) {
ABSL_RAW_LOG(FATAL, "mmap error: %d", errno);
}
#ifdef __linux__
#if defined(PR_SET_VMA) && defined(PR_SET_VMA_ANON_NAME)
// Attempt to name the allocated address range in /proc/$PID/smaps on
// Linux.
//
// This invocation of prctl() may fail if the Linux kernel was not
// configured with the CONFIG_ANON_VMA_NAME option. This is OK since
// the naming of arenas is primarily a debugging aid.
prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, new_pages, new_pages_size,
"absl");
#endif
#endif // __linux__
#endif // _WIN32
arena->mu.Lock();
s = reinterpret_cast<AllocList *>(new_pages);
s->header.size = new_pages_size;
// Pretend the block is allocated; call AddToFreelist() to free it.
s->header.magic = Magic(kMagicAllocated, &s->header);
s->header.arena = arena;
AddToFreelist(&s->levels, arena); // insert new region into free list
}
AllocList *prev[kMaxLevel];
LLA_SkiplistDelete(&arena->freelist, s, prev); // remove from free list
// s points to the first free region that's big enough
if (CheckedAdd(req_rnd, arena->min_size) <= s->header.size) {
// big enough to split
AllocList *n =
reinterpret_cast<AllocList *>(req_rnd + reinterpret_cast<char *>(s));
n->header.size = s->header.size - req_rnd;
n->header.magic = Magic(kMagicAllocated, &n->header);
n->header.arena = arena;
s->header.size = req_rnd;
AddToFreelist(&n->levels, arena);
}
s->header.magic = Magic(kMagicAllocated, &s->header);
ABSL_RAW_CHECK(s->header.arena == arena, "");
arena->allocation_count++;
section.Leave();
result = &s->levels;
}
ABSL_ANNOTATE_MEMORY_IS_UNINITIALIZED(result, request);
return result;
}
void *LowLevelAlloc::Alloc(size_t request) {
void *result = DoAllocWithArena(request, DefaultArena());
return result;
}
void *LowLevelAlloc::AllocWithArena(size_t request, Arena *arena) {
ABSL_RAW_CHECK(arena != nullptr, "must pass a valid arena");
void *result = DoAllocWithArena(request, arena);
return result;
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_LOW_LEVEL_ALLOC_MISSING

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// 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.
//
#ifndef ABSL_BASE_INTERNAL_LOW_LEVEL_ALLOC_H_
#define ABSL_BASE_INTERNAL_LOW_LEVEL_ALLOC_H_
// A simple thread-safe memory allocator that does not depend on
// mutexes or thread-specific data. It is intended to be used
// sparingly, and only when malloc() would introduce an unwanted
// dependency, such as inside the heap-checker, or the Mutex
// implementation.
// IWYU pragma: private, include "base/low_level_alloc.h"
#include <sys/types.h>
#include <cstdint>
#include "absl/base/attributes.h"
#include "absl/base/config.h"
// LowLevelAlloc requires that the platform support low-level
// allocation of virtual memory. Platforms lacking this cannot use
// LowLevelAlloc.
#ifdef ABSL_LOW_LEVEL_ALLOC_MISSING
#error ABSL_LOW_LEVEL_ALLOC_MISSING cannot be directly set
#elif !defined(ABSL_HAVE_MMAP) && !defined(_WIN32)
#define ABSL_LOW_LEVEL_ALLOC_MISSING 1
#endif
// Using LowLevelAlloc with kAsyncSignalSafe isn't supported on Windows or
// asm.js / WebAssembly.
// See https://kripken.github.io/emscripten-site/docs/porting/pthreads.html
// for more information.
#ifdef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
#error ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING cannot be directly set
#elif defined(_WIN32) || defined(__asmjs__) || defined(__wasm__) || \
defined(__hexagon__)
#define ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING 1
#endif
#include <cstddef>
#include "absl/base/port.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
class LowLevelAlloc {
public:
struct Arena; // an arena from which memory may be allocated
// Returns a pointer to a block of at least "request" bytes
// that have been newly allocated from the specific arena.
// for Alloc() call the DefaultArena() is used.
// Returns 0 if passed request==0.
// Does not return 0 under other circumstances; it crashes if memory
// is not available.
static void *Alloc(size_t request) ABSL_ATTRIBUTE_SECTION(malloc_hook);
static void *AllocWithArena(size_t request, Arena *arena)
ABSL_ATTRIBUTE_SECTION(malloc_hook);
// Deallocates a region of memory that was previously allocated with
// Alloc(). Does nothing if passed 0. "s" must be either 0,
// or must have been returned from a call to Alloc() and not yet passed to
// Free() since that call to Alloc(). The space is returned to the arena
// from which it was allocated.
static void Free(void *s) ABSL_ATTRIBUTE_SECTION(malloc_hook);
// ABSL_ATTRIBUTE_SECTION(malloc_hook) for Alloc* and Free
// are to put all callers of MallocHook::Invoke* in this module
// into special section,
// so that MallocHook::GetCallerStackTrace can function accurately.
// Create a new arena.
// The root metadata for the new arena is allocated in the
// meta_data_arena; the DefaultArena() can be passed for meta_data_arena.
// These values may be ored into flags:
enum {
// Report calls to Alloc() and Free() via the MallocHook interface.
// Set in the DefaultArena.
kCallMallocHook = 0x0001,
#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
// Make calls to Alloc(), Free() be async-signal-safe. Not set in
// DefaultArena(). Not supported on all platforms.
kAsyncSignalSafe = 0x0002,
#endif
};
// Construct a new arena. The allocation of the underlying metadata honors
// the provided flags. For example, the call NewArena(kAsyncSignalSafe)
// is itself async-signal-safe, as well as generatating an arena that provides
// async-signal-safe Alloc/Free.
static Arena *NewArena(uint32_t flags);
// Destroys an arena allocated by NewArena and returns true,
// provided no allocated blocks remain in the arena.
// If allocated blocks remain in the arena, does nothing and
// returns false.
// It is illegal to attempt to destroy the DefaultArena().
static bool DeleteArena(Arena *arena);
// The default arena that always exists.
static Arena *DefaultArena();
private:
LowLevelAlloc(); // no instances
};
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_LOW_LEVEL_ALLOC_H_

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// 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.
//
// Core interfaces and definitions used by by low-level interfaces such as
// SpinLock.
#ifndef ABSL_BASE_INTERNAL_LOW_LEVEL_SCHEDULING_H_
#define ABSL_BASE_INTERNAL_LOW_LEVEL_SCHEDULING_H_
#include "absl/base/internal/raw_logging.h"
#include "absl/base/internal/scheduling_mode.h"
#include "absl/base/macros.h"
// The following two declarations exist so SchedulingGuard may friend them with
// the appropriate language linkage. These callbacks allow libc internals, such
// as function level statics, to schedule cooperatively when locking.
extern "C" bool __google_disable_rescheduling(void);
extern "C" void __google_enable_rescheduling(bool disable_result);
namespace absl {
ABSL_NAMESPACE_BEGIN
class CondVar;
class Mutex;
namespace synchronization_internal {
int MutexDelay(int32_t c, int mode);
} // namespace synchronization_internal
namespace base_internal {
class SchedulingHelper; // To allow use of SchedulingGuard.
class SpinLock; // To allow use of SchedulingGuard.
// SchedulingGuard
// Provides guard semantics that may be used to disable cooperative rescheduling
// of the calling thread within specific program blocks. This is used to
// protect resources (e.g. low-level SpinLocks or Domain code) that cooperative
// scheduling depends on.
//
// Domain implementations capable of rescheduling in reaction to involuntary
// kernel thread actions (e.g blocking due to a pagefault or syscall) must
// guarantee that an annotated thread is not allowed to (cooperatively)
// reschedule until the annotated region is complete.
//
// It is an error to attempt to use a cooperatively scheduled resource (e.g.
// Mutex) within a rescheduling-disabled region.
//
// All methods are async-signal safe.
class SchedulingGuard {
public:
// Returns true iff the calling thread may be cooperatively rescheduled.
static bool ReschedulingIsAllowed();
SchedulingGuard(const SchedulingGuard&) = delete;
SchedulingGuard& operator=(const SchedulingGuard&) = delete;
private:
// Disable cooperative rescheduling of the calling thread. It may still
// initiate scheduling operations (e.g. wake-ups), however, it may not itself
// reschedule. Nestable. The returned result is opaque, clients should not
// attempt to interpret it.
// REQUIRES: Result must be passed to a pairing EnableScheduling().
static bool DisableRescheduling();
// Marks the end of a rescheduling disabled region, previously started by
// DisableRescheduling().
// REQUIRES: Pairs with innermost call (and result) of DisableRescheduling().
static void EnableRescheduling(bool disable_result);
// A scoped helper for {Disable, Enable}Rescheduling().
// REQUIRES: destructor must run in same thread as constructor.
struct ScopedDisable {
ScopedDisable() { disabled = SchedulingGuard::DisableRescheduling(); }
~ScopedDisable() { SchedulingGuard::EnableRescheduling(disabled); }
bool disabled;
};
// A scoped helper to enable rescheduling temporarily.
// REQUIRES: destructor must run in same thread as constructor.
class ScopedEnable {
public:
ScopedEnable();
~ScopedEnable();
private:
int scheduling_disabled_depth_;
};
// Access to SchedulingGuard is explicitly permitted.
friend class absl::CondVar;
friend class absl::Mutex;
friend class SchedulingHelper;
friend class SpinLock;
friend int absl::synchronization_internal::MutexDelay(int32_t c, int mode);
};
//------------------------------------------------------------------------------
// End of public interfaces.
//------------------------------------------------------------------------------
inline bool SchedulingGuard::ReschedulingIsAllowed() {
return false;
}
inline bool SchedulingGuard::DisableRescheduling() {
return false;
}
inline void SchedulingGuard::EnableRescheduling(bool /* disable_result */) {
return;
}
inline SchedulingGuard::ScopedEnable::ScopedEnable()
: scheduling_disabled_depth_(0) {}
inline SchedulingGuard::ScopedEnable::~ScopedEnable() {
ABSL_RAW_CHECK(scheduling_disabled_depth_ == 0, "disable unused warning");
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_LOW_LEVEL_SCHEDULING_H_

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// Copyright 2023 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.
#ifndef ABSL_BASE_INTERNAL_NULLABILITY_IMPL_H_
#define ABSL_BASE_INTERNAL_NULLABILITY_IMPL_H_
#include <memory>
#include <type_traits>
#include "absl/base/attributes.h"
#include "absl/meta/type_traits.h"
namespace absl {
namespace nullability_internal {
// `IsNullabilityCompatible` checks whether its first argument is a class
// explicitly tagged as supporting nullability annotations. The tag is the type
// declaration `absl_nullability_compatible`.
template <typename, typename = void>
struct IsNullabilityCompatible : std::false_type {};
template <typename T>
struct IsNullabilityCompatible<
T, absl::void_t<typename T::absl_nullability_compatible>> : std::true_type {
};
template <typename T>
constexpr bool IsSupportedType = IsNullabilityCompatible<T>::value;
template <typename T>
constexpr bool IsSupportedType<T*> = true;
template <typename T, typename U>
constexpr bool IsSupportedType<T U::*> = true;
template <typename T, typename... Deleter>
constexpr bool IsSupportedType<std::unique_ptr<T, Deleter...>> = true;
template <typename T>
constexpr bool IsSupportedType<std::shared_ptr<T>> = true;
template <typename T>
struct EnableNullable {
static_assert(nullability_internal::IsSupportedType<std::remove_cv_t<T>>,
"Template argument must be a raw or supported smart pointer "
"type. See absl/base/nullability.h.");
using type = T;
};
template <typename T>
struct EnableNonnull {
static_assert(nullability_internal::IsSupportedType<std::remove_cv_t<T>>,
"Template argument must be a raw or supported smart pointer "
"type. See absl/base/nullability.h.");
using type = T;
};
template <typename T>
struct EnableNullabilityUnknown {
static_assert(nullability_internal::IsSupportedType<std::remove_cv_t<T>>,
"Template argument must be a raw or supported smart pointer "
"type. See absl/base/nullability.h.");
using type = T;
};
// Note: we do not apply Clang nullability attributes (e.g. _Nullable). These
// only support raw pointers, and conditionally enabling them only for raw
// pointers inhibits template arg deduction. Ideally, they would support all
// pointer-like types.
template <typename T, typename = typename EnableNullable<T>::type>
using NullableImpl
#if ABSL_HAVE_CPP_ATTRIBUTE(clang::annotate)
[[clang::annotate("Nullable")]]
#endif
= T;
template <typename T, typename = typename EnableNonnull<T>::type>
using NonnullImpl
#if ABSL_HAVE_CPP_ATTRIBUTE(clang::annotate)
[[clang::annotate("Nonnull")]]
#endif
= T;
template <typename T, typename = typename EnableNullabilityUnknown<T>::type>
using NullabilityUnknownImpl
#if ABSL_HAVE_CPP_ATTRIBUTE(clang::annotate)
[[clang::annotate("Nullability_Unspecified")]]
#endif
= T;
} // namespace nullability_internal
} // namespace absl
#endif // ABSL_BASE_INTERNAL_NULLABILITY_IMPL_H_

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// 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.
#ifndef ABSL_BASE_INTERNAL_PER_THREAD_TLS_H_
#define ABSL_BASE_INTERNAL_PER_THREAD_TLS_H_
// This header defines two macros:
//
// If the platform supports thread-local storage:
//
// * ABSL_PER_THREAD_TLS_KEYWORD is the C keyword needed to declare a
// thread-local variable
// * ABSL_PER_THREAD_TLS is 1
//
// Otherwise:
//
// * ABSL_PER_THREAD_TLS_KEYWORD is empty
// * ABSL_PER_THREAD_TLS is 0
//
// Microsoft C supports thread-local storage.
// GCC supports it if the appropriate version of glibc is available,
// which the programmer can indicate by defining ABSL_HAVE_TLS
#include "absl/base/port.h" // For ABSL_HAVE_TLS
#if defined(ABSL_PER_THREAD_TLS)
#error ABSL_PER_THREAD_TLS cannot be directly set
#elif defined(ABSL_PER_THREAD_TLS_KEYWORD)
#error ABSL_PER_THREAD_TLS_KEYWORD cannot be directly set
#elif defined(ABSL_HAVE_TLS)
#define ABSL_PER_THREAD_TLS_KEYWORD __thread
#define ABSL_PER_THREAD_TLS 1
#elif defined(_MSC_VER)
#define ABSL_PER_THREAD_TLS_KEYWORD __declspec(thread)
#define ABSL_PER_THREAD_TLS 1
#else
#define ABSL_PER_THREAD_TLS_KEYWORD
#define ABSL_PER_THREAD_TLS 0
#endif
#endif // ABSL_BASE_INTERNAL_PER_THREAD_TLS_H_

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// 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.
#ifndef ABSL_BASE_INTERNAL_PRETTY_FUNCTION_H_
#define ABSL_BASE_INTERNAL_PRETTY_FUNCTION_H_
// ABSL_PRETTY_FUNCTION
//
// In C++11, __func__ gives the undecorated name of the current function. That
// is, "main", not "int main()". Various compilers give extra macros to get the
// decorated function name, including return type and arguments, to
// differentiate between overload sets. ABSL_PRETTY_FUNCTION is a portable
// version of these macros which forwards to the correct macro on each compiler.
#if defined(_MSC_VER)
#define ABSL_PRETTY_FUNCTION __FUNCSIG__
#elif defined(__GNUC__)
#define ABSL_PRETTY_FUNCTION __PRETTY_FUNCTION__
#else
#error "Unsupported compiler"
#endif
#endif // ABSL_BASE_INTERNAL_PRETTY_FUNCTION_H_

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// 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.
#include "absl/base/internal/raw_logging.h"
#include <cstdarg>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <string>
#ifdef __EMSCRIPTEN__
#include <emscripten/console.h>
#endif
#include "absl/base/attributes.h"
#include "absl/base/config.h"
#include "absl/base/internal/atomic_hook.h"
#include "absl/base/internal/errno_saver.h"
#include "absl/base/log_severity.h"
// We know how to perform low-level writes to stderr in POSIX and Windows. For
// these platforms, we define the token ABSL_LOW_LEVEL_WRITE_SUPPORTED.
// Much of raw_logging.cc becomes a no-op when we can't output messages,
// although a FATAL ABSL_RAW_LOG message will still abort the process.
// ABSL_HAVE_POSIX_WRITE is defined when the platform provides posix write()
// (as from unistd.h)
//
// This preprocessor token is also defined in raw_io.cc. If you need to copy
// this, consider moving both to config.h instead.
#if defined(__linux__) || defined(__APPLE__) || defined(__FreeBSD__) || \
defined(__hexagon__) || defined(__Fuchsia__) || \
defined(__native_client__) || defined(__OpenBSD__) || \
defined(__EMSCRIPTEN__) || defined(__ASYLO__)
#include <unistd.h>
#define ABSL_HAVE_POSIX_WRITE 1
#define ABSL_LOW_LEVEL_WRITE_SUPPORTED 1
#else
#undef ABSL_HAVE_POSIX_WRITE
#endif
// ABSL_HAVE_SYSCALL_WRITE is defined when the platform provides the syscall
// syscall(SYS_write, /*int*/ fd, /*char* */ buf, /*size_t*/ len);
// for low level operations that want to avoid libc.
#if (defined(__linux__) || defined(__FreeBSD__)) && !defined(__ANDROID__)
#include <sys/syscall.h>
#define ABSL_HAVE_SYSCALL_WRITE 1
#define ABSL_LOW_LEVEL_WRITE_SUPPORTED 1
#else
#undef ABSL_HAVE_SYSCALL_WRITE
#endif
#ifdef _WIN32
#include <io.h>
#define ABSL_HAVE_RAW_IO 1
#define ABSL_LOW_LEVEL_WRITE_SUPPORTED 1
#else
#undef ABSL_HAVE_RAW_IO
#endif
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace raw_log_internal {
namespace {
// TODO(gfalcon): We want raw-logging to work on as many platforms as possible.
// Explicitly `#error` out when not `ABSL_LOW_LEVEL_WRITE_SUPPORTED`, except for
// a selected set of platforms for which we expect not to be able to raw log.
#ifdef ABSL_LOW_LEVEL_WRITE_SUPPORTED
constexpr char kTruncated[] = " ... (message truncated)\n";
// sprintf the format to the buffer, adjusting *buf and *size to reflect the
// consumed bytes, and return whether the message fit without truncation. If
// truncation occurred, if possible leave room in the buffer for the message
// kTruncated[].
bool VADoRawLog(char** buf, int* size, const char* format, va_list ap)
ABSL_PRINTF_ATTRIBUTE(3, 0);
bool VADoRawLog(char** buf, int* size, const char* format, va_list ap) {
if (*size < 0) return false;
int n = vsnprintf(*buf, static_cast<size_t>(*size), format, ap);
bool result = true;
if (n < 0 || n > *size) {
result = false;
if (static_cast<size_t>(*size) > sizeof(kTruncated)) {
n = *size - static_cast<int>(sizeof(kTruncated));
} else {
n = 0; // no room for truncation message
}
}
*size -= n;
*buf += n;
return result;
}
#endif // ABSL_LOW_LEVEL_WRITE_SUPPORTED
constexpr int kLogBufSize = 3000;
// CAVEAT: vsnprintf called from *DoRawLog below has some (exotic) code paths
// that invoke malloc() and getenv() that might acquire some locks.
// Helper for RawLog below.
// *DoRawLog writes to *buf of *size and move them past the written portion.
// It returns true iff there was no overflow or error.
bool DoRawLog(char** buf, int* size, const char* format, ...)
ABSL_PRINTF_ATTRIBUTE(3, 4);
bool DoRawLog(char** buf, int* size, const char* format, ...) {
if (*size < 0) return false;
va_list ap;
va_start(ap, format);
int n = vsnprintf(*buf, static_cast<size_t>(*size), format, ap);
va_end(ap);
if (n < 0 || n > *size) return false;
*size -= n;
*buf += n;
return true;
}
bool DefaultLogFilterAndPrefix(absl::LogSeverity, const char* file, int line,
char** buf, int* buf_size) {
DoRawLog(buf, buf_size, "[%s : %d] RAW: ", file, line);
return true;
}
ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES
absl::base_internal::AtomicHook<LogFilterAndPrefixHook>
log_filter_and_prefix_hook(DefaultLogFilterAndPrefix);
ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES
absl::base_internal::AtomicHook<AbortHook> abort_hook;
void RawLogVA(absl::LogSeverity severity, const char* file, int line,
const char* format, va_list ap) ABSL_PRINTF_ATTRIBUTE(4, 0);
void RawLogVA(absl::LogSeverity severity, const char* file, int line,
const char* format, va_list ap) {
char buffer[kLogBufSize];
char* buf = buffer;
int size = sizeof(buffer);
#ifdef ABSL_LOW_LEVEL_WRITE_SUPPORTED
bool enabled = true;
#else
bool enabled = false;
#endif
#ifdef ABSL_MIN_LOG_LEVEL
if (severity < static_cast<absl::LogSeverity>(ABSL_MIN_LOG_LEVEL) &&
severity < absl::LogSeverity::kFatal) {
enabled = false;
}
#endif
enabled = log_filter_and_prefix_hook(severity, file, line, &buf, &size);
const char* const prefix_end = buf;
#ifdef ABSL_LOW_LEVEL_WRITE_SUPPORTED
if (enabled) {
bool no_chop = VADoRawLog(&buf, &size, format, ap);
if (no_chop) {
DoRawLog(&buf, &size, "\n");
} else {
DoRawLog(&buf, &size, "%s", kTruncated);
}
AsyncSignalSafeWriteError(buffer, strlen(buffer));
}
#else
static_cast<void>(format);
static_cast<void>(ap);
static_cast<void>(enabled);
#endif
// Abort the process after logging a FATAL message, even if the output itself
// was suppressed.
if (severity == absl::LogSeverity::kFatal) {
abort_hook(file, line, buffer, prefix_end, buffer + kLogBufSize);
abort();
}
}
// Non-formatting version of RawLog().
//
// TODO(gfalcon): When string_view no longer depends on base, change this
// interface to take its message as a string_view instead.
void DefaultInternalLog(absl::LogSeverity severity, const char* file, int line,
const std::string& message) {
RawLog(severity, file, line, "%.*s", static_cast<int>(message.size()),
message.data());
}
} // namespace
void AsyncSignalSafeWriteError(const char* s, size_t len) {
if (!len) return;
absl::base_internal::ErrnoSaver errno_saver;
#if defined(__EMSCRIPTEN__)
// In WebAssembly, bypass filesystem emulation via fwrite.
if (s[len - 1] == '\n') {
// Skip a trailing newline character as emscripten_errn adds one itself.
len--;
}
// emscripten_errn was introduced in 3.1.41 but broken in standalone mode
// until 3.1.43.
#if ABSL_INTERNAL_EMSCRIPTEN_VERSION >= 3001043
emscripten_errn(s, len);
#else
char buf[kLogBufSize];
if (len >= kLogBufSize) {
len = kLogBufSize - 1;
constexpr size_t trunc_len = sizeof(kTruncated) - 2;
memcpy(buf + len - trunc_len, kTruncated, trunc_len);
buf[len] = '\0';
len -= trunc_len;
} else {
buf[len] = '\0';
}
memcpy(buf, s, len);
_emscripten_err(buf);
#endif
#elif defined(ABSL_HAVE_SYSCALL_WRITE)
// We prefer calling write via `syscall` to minimize the risk of libc doing
// something "helpful".
syscall(SYS_write, STDERR_FILENO, s, len);
#elif defined(ABSL_HAVE_POSIX_WRITE)
write(STDERR_FILENO, s, len);
#elif defined(ABSL_HAVE_RAW_IO)
_write(/* stderr */ 2, s, static_cast<unsigned>(len));
#else
// stderr logging unsupported on this platform
(void)s;
(void)len;
#endif
}
void RawLog(absl::LogSeverity severity, const char* file, int line,
const char* format, ...) {
va_list ap;
va_start(ap, format);
RawLogVA(severity, file, line, format, ap);
va_end(ap);
}
bool RawLoggingFullySupported() {
#ifdef ABSL_LOW_LEVEL_WRITE_SUPPORTED
return true;
#else // !ABSL_LOW_LEVEL_WRITE_SUPPORTED
return false;
#endif // !ABSL_LOW_LEVEL_WRITE_SUPPORTED
}
ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES ABSL_DLL
absl::base_internal::AtomicHook<InternalLogFunction>
internal_log_function(DefaultInternalLog);
void RegisterLogFilterAndPrefixHook(LogFilterAndPrefixHook func) {
log_filter_and_prefix_hook.Store(func);
}
void RegisterAbortHook(AbortHook func) { abort_hook.Store(func); }
void RegisterInternalLogFunction(InternalLogFunction func) {
internal_log_function.Store(func);
}
} // namespace raw_log_internal
ABSL_NAMESPACE_END
} // namespace absl

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// 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.
//
// Thread-safe logging routines that do not allocate any memory or
// acquire any locks, and can therefore be used by low-level memory
// allocation, synchronization, and signal-handling code.
#ifndef ABSL_BASE_INTERNAL_RAW_LOGGING_H_
#define ABSL_BASE_INTERNAL_RAW_LOGGING_H_
#include <string>
#include "absl/base/attributes.h"
#include "absl/base/config.h"
#include "absl/base/internal/atomic_hook.h"
#include "absl/base/log_severity.h"
#include "absl/base/macros.h"
#include "absl/base/optimization.h"
#include "absl/base/port.h"
// This is similar to LOG(severity) << format..., but
// * it is to be used ONLY by low-level modules that can't use normal LOG()
// * it is designed to be a low-level logger that does not allocate any
// memory and does not need any locks, hence:
// * it logs straight and ONLY to STDERR w/o buffering
// * it uses an explicit printf-format and arguments list
// * it will silently chop off really long message strings
// Usage example:
// ABSL_RAW_LOG(ERROR, "Failed foo with %i: %s", status, error);
// This will print an almost standard log line like this to stderr only:
// E0821 211317 file.cc:123] RAW: Failed foo with 22: bad_file
#define ABSL_RAW_LOG(severity, ...) \
do { \
constexpr const char* absl_raw_log_internal_basename = \
::absl::raw_log_internal::Basename(__FILE__, sizeof(__FILE__) - 1); \
::absl::raw_log_internal::RawLog(ABSL_RAW_LOG_INTERNAL_##severity, \
absl_raw_log_internal_basename, __LINE__, \
__VA_ARGS__); \
ABSL_RAW_LOG_INTERNAL_MAYBE_UNREACHABLE_##severity; \
} while (0)
// Similar to CHECK(condition) << message, but for low-level modules:
// we use only ABSL_RAW_LOG that does not allocate memory.
// We do not want to provide args list here to encourage this usage:
// if (!cond) ABSL_RAW_LOG(FATAL, "foo ...", hard_to_compute_args);
// so that the args are not computed when not needed.
#define ABSL_RAW_CHECK(condition, message) \
do { \
if (ABSL_PREDICT_FALSE(!(condition))) { \
ABSL_RAW_LOG(FATAL, "Check %s failed: %s", #condition, message); \
} \
} while (0)
// ABSL_INTERNAL_LOG and ABSL_INTERNAL_CHECK work like the RAW variants above,
// except that if the richer log library is linked into the binary, we dispatch
// to that instead. This is potentially useful for internal logging and
// assertions, where we are using RAW_LOG neither for its async-signal-safety
// nor for its non-allocating nature, but rather because raw logging has very
// few other dependencies.
//
// The API is a subset of the above: each macro only takes two arguments. Use
// StrCat if you need to build a richer message.
#define ABSL_INTERNAL_LOG(severity, message) \
do { \
constexpr const char* absl_raw_log_internal_filename = __FILE__; \
::absl::raw_log_internal::internal_log_function( \
ABSL_RAW_LOG_INTERNAL_##severity, absl_raw_log_internal_filename, \
__LINE__, message); \
ABSL_RAW_LOG_INTERNAL_MAYBE_UNREACHABLE_##severity; \
} while (0)
#define ABSL_INTERNAL_CHECK(condition, message) \
do { \
if (ABSL_PREDICT_FALSE(!(condition))) { \
std::string death_message = "Check " #condition " failed: "; \
death_message += std::string(message); \
ABSL_INTERNAL_LOG(FATAL, death_message); \
} \
} while (0)
#ifndef NDEBUG
#define ABSL_RAW_DLOG(severity, ...) ABSL_RAW_LOG(severity, __VA_ARGS__)
#define ABSL_RAW_DCHECK(condition, message) ABSL_RAW_CHECK(condition, message)
#else // NDEBUG
#define ABSL_RAW_DLOG(severity, ...) \
while (false) ABSL_RAW_LOG(severity, __VA_ARGS__)
#define ABSL_RAW_DCHECK(condition, message) \
while (false) ABSL_RAW_CHECK(condition, message)
#endif // NDEBUG
#define ABSL_RAW_LOG_INTERNAL_INFO ::absl::LogSeverity::kInfo
#define ABSL_RAW_LOG_INTERNAL_WARNING ::absl::LogSeverity::kWarning
#define ABSL_RAW_LOG_INTERNAL_ERROR ::absl::LogSeverity::kError
#define ABSL_RAW_LOG_INTERNAL_FATAL ::absl::LogSeverity::kFatal
#define ABSL_RAW_LOG_INTERNAL_DFATAL ::absl::kLogDebugFatal
#define ABSL_RAW_LOG_INTERNAL_LEVEL(severity) \
::absl::NormalizeLogSeverity(severity)
#define ABSL_RAW_LOG_INTERNAL_MAYBE_UNREACHABLE_INFO
#define ABSL_RAW_LOG_INTERNAL_MAYBE_UNREACHABLE_WARNING
#define ABSL_RAW_LOG_INTERNAL_MAYBE_UNREACHABLE_ERROR
#define ABSL_RAW_LOG_INTERNAL_MAYBE_UNREACHABLE_FATAL ABSL_UNREACHABLE()
#define ABSL_RAW_LOG_INTERNAL_MAYBE_UNREACHABLE_DFATAL
#define ABSL_RAW_LOG_INTERNAL_MAYBE_UNREACHABLE_LEVEL(severity)
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace raw_log_internal {
// Helper function to implement ABSL_RAW_LOG
// Logs format... at "severity" level, reporting it
// as called from file:line.
// This does not allocate memory or acquire locks.
void RawLog(absl::LogSeverity severity, const char* file, int line,
const char* format, ...) ABSL_PRINTF_ATTRIBUTE(4, 5);
// Writes the provided buffer directly to stderr, in a signal-safe, low-level
// manner. Preserves errno.
void AsyncSignalSafeWriteError(const char* s, size_t len);
// compile-time function to get the "base" filename, that is, the part of
// a filename after the last "/" or "\" path separator. The search starts at
// the end of the string; the second parameter is the length of the string.
constexpr const char* Basename(const char* fname, int offset) {
return offset == 0 || fname[offset - 1] == '/' || fname[offset - 1] == '\\'
? fname + offset
: Basename(fname, offset - 1);
}
// For testing only.
// Returns true if raw logging is fully supported. When it is not
// fully supported, no messages will be emitted, but a log at FATAL
// severity will cause an abort.
//
// TODO(gfalcon): Come up with a better name for this method.
bool RawLoggingFullySupported();
// Function type for a raw_log customization hook for suppressing messages
// by severity, and for writing custom prefixes on non-suppressed messages.
//
// The installed hook is called for every raw log invocation. The message will
// be logged to stderr only if the hook returns true. FATAL errors will cause
// the process to abort, even if writing to stderr is suppressed. The hook is
// also provided with an output buffer, where it can write a custom log message
// prefix.
//
// The raw_log system does not allocate memory or grab locks. User-provided
// hooks must avoid these operations, and must not throw exceptions.
//
// 'severity' is the severity level of the message being written.
// 'file' and 'line' are the file and line number where the ABSL_RAW_LOG macro
// was located.
// 'buf' and 'buf_size' are pointers to the buffer and buffer size. If the
// hook writes a prefix, it must increment *buf and decrement *buf_size
// accordingly.
using LogFilterAndPrefixHook = bool (*)(absl::LogSeverity severity,
const char* file, int line, char** buf,
int* buf_size);
// Function type for a raw_log customization hook called to abort a process
// when a FATAL message is logged. If the provided AbortHook() returns, the
// logging system will call abort().
//
// 'file' and 'line' are the file and line number where the ABSL_RAW_LOG macro
// was located.
// The NUL-terminated logged message lives in the buffer between 'buf_start'
// and 'buf_end'. 'prefix_end' points to the first non-prefix character of the
// buffer (as written by the LogFilterAndPrefixHook.)
//
// The lifetime of the filename and message buffers will not end while the
// process remains alive.
using AbortHook = void (*)(const char* file, int line, const char* buf_start,
const char* prefix_end, const char* buf_end);
// Internal logging function for ABSL_INTERNAL_LOG to dispatch to.
//
// TODO(gfalcon): When string_view no longer depends on base, change this
// interface to take its message as a string_view instead.
using InternalLogFunction = void (*)(absl::LogSeverity severity,
const char* file, int line,
const std::string& message);
ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES ABSL_DLL extern base_internal::AtomicHook<
InternalLogFunction>
internal_log_function;
// Registers hooks of the above types. Only a single hook of each type may be
// registered. It is an error to call these functions multiple times with
// different input arguments.
//
// These functions are safe to call at any point during initialization; they do
// not block or malloc, and are async-signal safe.
void RegisterLogFilterAndPrefixHook(LogFilterAndPrefixHook func);
void RegisterAbortHook(AbortHook func);
void RegisterInternalLogFunction(InternalLogFunction func);
} // namespace raw_log_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_RAW_LOGGING_H_

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// 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.
//
// Core interfaces and definitions used by by low-level interfaces such as
// SpinLock.
#ifndef ABSL_BASE_INTERNAL_SCHEDULING_MODE_H_
#define ABSL_BASE_INTERNAL_SCHEDULING_MODE_H_
#include "absl/base/config.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
// Used to describe how a thread may be scheduled. Typically associated with
// the declaration of a resource supporting synchronized access.
//
// SCHEDULE_COOPERATIVE_AND_KERNEL:
// Specifies that when waiting, a cooperative thread (e.g. a Fiber) may
// reschedule (using base::scheduling semantics); allowing other cooperative
// threads to proceed.
//
// SCHEDULE_KERNEL_ONLY: (Also described as "non-cooperative")
// Specifies that no cooperative scheduling semantics may be used, even if the
// current thread is itself cooperatively scheduled. This means that
// cooperative threads will NOT allow other cooperative threads to execute in
// their place while waiting for a resource of this type. Host operating system
// semantics (e.g. a futex) may still be used.
//
// When optional, clients should strongly prefer SCHEDULE_COOPERATIVE_AND_KERNEL
// by default. SCHEDULE_KERNEL_ONLY should only be used for resources on which
// base::scheduling (e.g. the implementation of a Scheduler) may depend.
//
// NOTE: Cooperative resources may not be nested below non-cooperative ones.
// This means that it is invalid to to acquire a SCHEDULE_COOPERATIVE_AND_KERNEL
// resource if a SCHEDULE_KERNEL_ONLY resource is already held.
enum SchedulingMode {
SCHEDULE_KERNEL_ONLY = 0, // Allow scheduling only the host OS.
SCHEDULE_COOPERATIVE_AND_KERNEL, // Also allow cooperative scheduling.
};
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_SCHEDULING_MODE_H_

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// 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.
#include "absl/base/internal/spinlock.h"
#include <algorithm>
#include <atomic>
#include <limits>
#include "absl/base/attributes.h"
#include "absl/base/config.h"
#include "absl/base/internal/atomic_hook.h"
#include "absl/base/internal/cycleclock.h"
#include "absl/base/internal/spinlock_wait.h"
#include "absl/base/internal/sysinfo.h" /* For NumCPUs() */
#include "absl/base/call_once.h"
// Description of lock-word:
// 31..00: [............................3][2][1][0]
//
// [0]: kSpinLockHeld
// [1]: kSpinLockCooperative
// [2]: kSpinLockDisabledScheduling
// [31..3]: ONLY kSpinLockSleeper OR
// Wait time in cycles >> PROFILE_TIMESTAMP_SHIFT
//
// Detailed descriptions:
//
// Bit [0]: The lock is considered held iff kSpinLockHeld is set.
//
// Bit [1]: Eligible waiters (e.g. Fibers) may co-operatively reschedule when
// contended iff kSpinLockCooperative is set.
//
// Bit [2]: This bit is exclusive from bit [1]. It is used only by a
// non-cooperative lock. When set, indicates that scheduling was
// successfully disabled when the lock was acquired. May be unset,
// even if non-cooperative, if a ThreadIdentity did not yet exist at
// time of acquisition.
//
// Bit [3]: If this is the only upper bit ([31..3]) set then this lock was
// acquired without contention, however, at least one waiter exists.
//
// Otherwise, bits [31..3] represent the time spent by the current lock
// holder to acquire the lock. There may be outstanding waiter(s).
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES static base_internal::AtomicHook<void (*)(
const void *lock, int64_t wait_cycles)>
submit_profile_data;
void RegisterSpinLockProfiler(void (*fn)(const void *contendedlock,
int64_t wait_cycles)) {
submit_profile_data.Store(fn);
}
#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
// Static member variable definitions.
constexpr uint32_t SpinLock::kSpinLockHeld;
constexpr uint32_t SpinLock::kSpinLockCooperative;
constexpr uint32_t SpinLock::kSpinLockDisabledScheduling;
constexpr uint32_t SpinLock::kSpinLockSleeper;
constexpr uint32_t SpinLock::kWaitTimeMask;
#endif
// Uncommon constructors.
SpinLock::SpinLock(base_internal::SchedulingMode mode)
: lockword_(IsCooperative(mode) ? kSpinLockCooperative : 0) {
ABSL_TSAN_MUTEX_CREATE(this, __tsan_mutex_not_static);
}
// Monitor the lock to see if its value changes within some time period
// (adaptive_spin_count loop iterations). The last value read from the lock
// is returned from the method.
uint32_t SpinLock::SpinLoop() {
// We are already in the slow path of SpinLock, initialize the
// adaptive_spin_count here.
ABSL_CONST_INIT static absl::once_flag init_adaptive_spin_count;
ABSL_CONST_INIT static int adaptive_spin_count = 0;
base_internal::LowLevelCallOnce(&init_adaptive_spin_count, []() {
adaptive_spin_count = base_internal::NumCPUs() > 1 ? 1000 : 1;
});
int c = adaptive_spin_count;
uint32_t lock_value;
do {
lock_value = lockword_.load(std::memory_order_relaxed);
} while ((lock_value & kSpinLockHeld) != 0 && --c > 0);
return lock_value;
}
void SpinLock::SlowLock() {
uint32_t lock_value = SpinLoop();
lock_value = TryLockInternal(lock_value, 0);
if ((lock_value & kSpinLockHeld) == 0) {
return;
}
base_internal::SchedulingMode scheduling_mode;
if ((lock_value & kSpinLockCooperative) != 0) {
scheduling_mode = base_internal::SCHEDULE_COOPERATIVE_AND_KERNEL;
} else {
scheduling_mode = base_internal::SCHEDULE_KERNEL_ONLY;
}
// The lock was not obtained initially, so this thread needs to wait for
// it. Record the current timestamp in the local variable wait_start_time
// so the total wait time can be stored in the lockword once this thread
// obtains the lock.
int64_t wait_start_time = CycleClock::Now();
uint32_t wait_cycles = 0;
int lock_wait_call_count = 0;
while ((lock_value & kSpinLockHeld) != 0) {
// If the lock is currently held, but not marked as having a sleeper, mark
// it as having a sleeper.
if ((lock_value & kWaitTimeMask) == 0) {
// Here, just "mark" that the thread is going to sleep. Don't store the
// lock wait time in the lock -- the lock word stores the amount of time
// that the current holder waited before acquiring the lock, not the wait
// time of any thread currently waiting to acquire it.
if (lockword_.compare_exchange_strong(
lock_value, lock_value | kSpinLockSleeper,
std::memory_order_relaxed, std::memory_order_relaxed)) {
// Successfully transitioned to kSpinLockSleeper. Pass
// kSpinLockSleeper to the SpinLockWait routine to properly indicate
// the last lock_value observed.
lock_value |= kSpinLockSleeper;
} else if ((lock_value & kSpinLockHeld) == 0) {
// Lock is free again, so try and acquire it before sleeping. The
// new lock state will be the number of cycles this thread waited if
// this thread obtains the lock.
lock_value = TryLockInternal(lock_value, wait_cycles);
continue; // Skip the delay at the end of the loop.
} else if ((lock_value & kWaitTimeMask) == 0) {
// The lock is still held, without a waiter being marked, but something
// else about the lock word changed, causing our CAS to fail. For
// example, a new lock holder may have acquired the lock with
// kSpinLockDisabledScheduling set, whereas the previous holder had not
// set that flag. In this case, attempt again to mark ourselves as a
// waiter.
continue;
}
}
// SpinLockDelay() calls into fiber scheduler, we need to see
// synchronization there to avoid false positives.
ABSL_TSAN_MUTEX_PRE_DIVERT(this, 0);
// Wait for an OS specific delay.
base_internal::SpinLockDelay(&lockword_, lock_value, ++lock_wait_call_count,
scheduling_mode);
ABSL_TSAN_MUTEX_POST_DIVERT(this, 0);
// Spin again after returning from the wait routine to give this thread
// some chance of obtaining the lock.
lock_value = SpinLoop();
wait_cycles = EncodeWaitCycles(wait_start_time, CycleClock::Now());
lock_value = TryLockInternal(lock_value, wait_cycles);
}
}
void SpinLock::SlowUnlock(uint32_t lock_value) {
base_internal::SpinLockWake(&lockword_,
false); // wake waiter if necessary
// If our acquisition was contended, collect contentionz profile info. We
// reserve a unitary wait time to represent that a waiter exists without our
// own acquisition having been contended.
if ((lock_value & kWaitTimeMask) != kSpinLockSleeper) {
const int64_t wait_cycles = DecodeWaitCycles(lock_value);
ABSL_TSAN_MUTEX_PRE_DIVERT(this, 0);
submit_profile_data(this, wait_cycles);
ABSL_TSAN_MUTEX_POST_DIVERT(this, 0);
}
}
// We use the upper 29 bits of the lock word to store the time spent waiting to
// acquire this lock. This is reported by contentionz profiling. Since the
// lower bits of the cycle counter wrap very quickly on high-frequency
// processors we divide to reduce the granularity to 2^kProfileTimestampShift
// sized units. On a 4Ghz machine this will lose track of wait times greater
// than (2^29/4 Ghz)*128 =~ 17.2 seconds. Such waits should be extremely rare.
static constexpr int kProfileTimestampShift = 7;
// We currently reserve the lower 3 bits.
static constexpr int kLockwordReservedShift = 3;
uint32_t SpinLock::EncodeWaitCycles(int64_t wait_start_time,
int64_t wait_end_time) {
static const int64_t kMaxWaitTime =
std::numeric_limits<uint32_t>::max() >> kLockwordReservedShift;
int64_t scaled_wait_time =
(wait_end_time - wait_start_time) >> kProfileTimestampShift;
// Return a representation of the time spent waiting that can be stored in
// the lock word's upper bits.
uint32_t clamped = static_cast<uint32_t>(
std::min(scaled_wait_time, kMaxWaitTime) << kLockwordReservedShift);
if (clamped == 0) {
return kSpinLockSleeper; // Just wake waiters, but don't record contention.
}
// Bump up value if necessary to avoid returning kSpinLockSleeper.
const uint32_t kMinWaitTime =
kSpinLockSleeper + (1 << kLockwordReservedShift);
if (clamped == kSpinLockSleeper) {
return kMinWaitTime;
}
return clamped;
}
int64_t SpinLock::DecodeWaitCycles(uint32_t lock_value) {
// Cast to uint32_t first to ensure bits [63:32] are cleared.
const int64_t scaled_wait_time =
static_cast<uint32_t>(lock_value & kWaitTimeMask);
return scaled_wait_time << (kProfileTimestampShift - kLockwordReservedShift);
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl

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//
// 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.
//
// Most users requiring mutual exclusion should use Mutex.
// SpinLock is provided for use in two situations:
// - for use by Abseil internal code that Mutex itself depends on
// - for async signal safety (see below)
// SpinLock with a base_internal::SchedulingMode::SCHEDULE_KERNEL_ONLY is async
// signal safe. If a spinlock is used within a signal handler, all code that
// acquires the lock must ensure that the signal cannot arrive while they are
// holding the lock. Typically, this is done by blocking the signal.
//
// Threads waiting on a SpinLock may be woken in an arbitrary order.
#ifndef ABSL_BASE_INTERNAL_SPINLOCK_H_
#define ABSL_BASE_INTERNAL_SPINLOCK_H_
#include <atomic>
#include <cstdint>
#include "absl/base/attributes.h"
#include "absl/base/const_init.h"
#include "absl/base/dynamic_annotations.h"
#include "absl/base/internal/low_level_scheduling.h"
#include "absl/base/internal/raw_logging.h"
#include "absl/base/internal/scheduling_mode.h"
#include "absl/base/internal/tsan_mutex_interface.h"
#include "absl/base/thread_annotations.h"
namespace tcmalloc {
namespace tcmalloc_internal {
class AllocationGuardSpinLockHolder;
} // namespace tcmalloc_internal
} // namespace tcmalloc
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
class ABSL_LOCKABLE SpinLock {
public:
SpinLock() : lockword_(kSpinLockCooperative) {
ABSL_TSAN_MUTEX_CREATE(this, __tsan_mutex_not_static);
}
// Constructors that allow non-cooperative spinlocks to be created for use
// inside thread schedulers. Normal clients should not use these.
explicit SpinLock(base_internal::SchedulingMode mode);
// Constructor for global SpinLock instances. See absl/base/const_init.h.
constexpr SpinLock(absl::ConstInitType, base_internal::SchedulingMode mode)
: lockword_(IsCooperative(mode) ? kSpinLockCooperative : 0) {}
// For global SpinLock instances prefer trivial destructor when possible.
// Default but non-trivial destructor in some build configurations causes an
// extra static initializer.
#ifdef ABSL_INTERNAL_HAVE_TSAN_INTERFACE
~SpinLock() { ABSL_TSAN_MUTEX_DESTROY(this, __tsan_mutex_not_static); }
#else
~SpinLock() = default;
#endif
// Acquire this SpinLock.
inline void Lock() ABSL_EXCLUSIVE_LOCK_FUNCTION() {
ABSL_TSAN_MUTEX_PRE_LOCK(this, 0);
if (!TryLockImpl()) {
SlowLock();
}
ABSL_TSAN_MUTEX_POST_LOCK(this, 0, 0);
}
// Try to acquire this SpinLock without blocking and return true if the
// acquisition was successful. If the lock was not acquired, false is
// returned. If this SpinLock is free at the time of the call, TryLock
// will return true with high probability.
inline bool TryLock() ABSL_EXCLUSIVE_TRYLOCK_FUNCTION(true) {
ABSL_TSAN_MUTEX_PRE_LOCK(this, __tsan_mutex_try_lock);
bool res = TryLockImpl();
ABSL_TSAN_MUTEX_POST_LOCK(
this, __tsan_mutex_try_lock | (res ? 0 : __tsan_mutex_try_lock_failed),
0);
return res;
}
// Release this SpinLock, which must be held by the calling thread.
inline void Unlock() ABSL_UNLOCK_FUNCTION() {
ABSL_TSAN_MUTEX_PRE_UNLOCK(this, 0);
uint32_t lock_value = lockword_.load(std::memory_order_relaxed);
lock_value = lockword_.exchange(lock_value & kSpinLockCooperative,
std::memory_order_release);
if ((lock_value & kSpinLockDisabledScheduling) != 0) {
base_internal::SchedulingGuard::EnableRescheduling(true);
}
if ((lock_value & kWaitTimeMask) != 0) {
// Collect contentionz profile info, and speed the wakeup of any waiter.
// The wait_cycles value indicates how long this thread spent waiting
// for the lock.
SlowUnlock(lock_value);
}
ABSL_TSAN_MUTEX_POST_UNLOCK(this, 0);
}
// Determine if the lock is held. When the lock is held by the invoking
// thread, true will always be returned. Intended to be used as
// CHECK(lock.IsHeld()).
inline bool IsHeld() const {
return (lockword_.load(std::memory_order_relaxed) & kSpinLockHeld) != 0;
}
// Return immediately if this thread holds the SpinLock exclusively.
// Otherwise, report an error by crashing with a diagnostic.
inline void AssertHeld() const ABSL_ASSERT_EXCLUSIVE_LOCK() {
if (!IsHeld()) {
ABSL_RAW_LOG(FATAL, "thread should hold the lock on SpinLock");
}
}
protected:
// These should not be exported except for testing.
// Store number of cycles between wait_start_time and wait_end_time in a
// lock value.
static uint32_t EncodeWaitCycles(int64_t wait_start_time,
int64_t wait_end_time);
// Extract number of wait cycles in a lock value.
static int64_t DecodeWaitCycles(uint32_t lock_value);
// Provide access to protected method above. Use for testing only.
friend struct SpinLockTest;
friend class tcmalloc::tcmalloc_internal::AllocationGuardSpinLockHolder;
private:
// lockword_ is used to store the following:
//
// bit[0] encodes whether a lock is being held.
// bit[1] encodes whether a lock uses cooperative scheduling.
// bit[2] encodes whether the current lock holder disabled scheduling when
// acquiring the lock. Only set when kSpinLockHeld is also set.
// bit[3:31] encodes time a lock spent on waiting as a 29-bit unsigned int.
// This is set by the lock holder to indicate how long it waited on
// the lock before eventually acquiring it. The number of cycles is
// encoded as a 29-bit unsigned int, or in the case that the current
// holder did not wait but another waiter is queued, the LSB
// (kSpinLockSleeper) is set. The implementation does not explicitly
// track the number of queued waiters beyond this. It must always be
// assumed that waiters may exist if the current holder was required to
// queue.
//
// Invariant: if the lock is not held, the value is either 0 or
// kSpinLockCooperative.
static constexpr uint32_t kSpinLockHeld = 1;
static constexpr uint32_t kSpinLockCooperative = 2;
static constexpr uint32_t kSpinLockDisabledScheduling = 4;
static constexpr uint32_t kSpinLockSleeper = 8;
// Includes kSpinLockSleeper.
static constexpr uint32_t kWaitTimeMask =
~(kSpinLockHeld | kSpinLockCooperative | kSpinLockDisabledScheduling);
// Returns true if the provided scheduling mode is cooperative.
static constexpr bool IsCooperative(
base_internal::SchedulingMode scheduling_mode) {
return scheduling_mode == base_internal::SCHEDULE_COOPERATIVE_AND_KERNEL;
}
bool IsCooperative() const {
return lockword_.load(std::memory_order_relaxed) & kSpinLockCooperative;
}
uint32_t TryLockInternal(uint32_t lock_value, uint32_t wait_cycles);
void SlowLock() ABSL_ATTRIBUTE_COLD;
void SlowUnlock(uint32_t lock_value) ABSL_ATTRIBUTE_COLD;
uint32_t SpinLoop();
inline bool TryLockImpl() {
uint32_t lock_value = lockword_.load(std::memory_order_relaxed);
return (TryLockInternal(lock_value, 0) & kSpinLockHeld) == 0;
}
std::atomic<uint32_t> lockword_;
SpinLock(const SpinLock&) = delete;
SpinLock& operator=(const SpinLock&) = delete;
};
// Corresponding locker object that arranges to acquire a spinlock for
// the duration of a C++ scope.
class ABSL_SCOPED_LOCKABLE SpinLockHolder {
public:
inline explicit SpinLockHolder(SpinLock* l) ABSL_EXCLUSIVE_LOCK_FUNCTION(l)
: lock_(l) {
l->Lock();
}
inline ~SpinLockHolder() ABSL_UNLOCK_FUNCTION() { lock_->Unlock(); }
SpinLockHolder(const SpinLockHolder&) = delete;
SpinLockHolder& operator=(const SpinLockHolder&) = delete;
private:
SpinLock* lock_;
};
// Register a hook for profiling support.
//
// The function pointer registered here will be called whenever a spinlock is
// contended. The callback is given an opaque handle to the contended spinlock
// and the number of wait cycles. This is thread-safe, but only a single
// profiler can be registered. It is an error to call this function multiple
// times with different arguments.
void RegisterSpinLockProfiler(void (*fn)(const void* lock,
int64_t wait_cycles));
//------------------------------------------------------------------------------
// Public interface ends here.
//------------------------------------------------------------------------------
// If (result & kSpinLockHeld) == 0, then *this was successfully locked.
// Otherwise, returns last observed value for lockword_.
inline uint32_t SpinLock::TryLockInternal(uint32_t lock_value,
uint32_t wait_cycles) {
if ((lock_value & kSpinLockHeld) != 0) {
return lock_value;
}
uint32_t sched_disabled_bit = 0;
if ((lock_value & kSpinLockCooperative) == 0) {
// For non-cooperative locks we must make sure we mark ourselves as
// non-reschedulable before we attempt to CompareAndSwap.
if (base_internal::SchedulingGuard::DisableRescheduling()) {
sched_disabled_bit = kSpinLockDisabledScheduling;
}
}
if (!lockword_.compare_exchange_strong(
lock_value,
kSpinLockHeld | lock_value | wait_cycles | sched_disabled_bit,
std::memory_order_acquire, std::memory_order_relaxed)) {
base_internal::SchedulingGuard::EnableRescheduling(sched_disabled_bit != 0);
}
return lock_value;
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_SPINLOCK_H_

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// 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.
//
// This file is an Akaros-specific part of spinlock_wait.cc
#include <atomic>
#include "absl/base/internal/scheduling_mode.h"
extern "C" {
ABSL_ATTRIBUTE_WEAK void ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockDelay)(
std::atomic<uint32_t>* /* lock_word */, uint32_t /* value */,
int /* loop */, absl::base_internal::SchedulingMode /* mode */) {
// In Akaros, one must take care not to call anything that could cause a
// malloc(), a blocking system call, or a uthread_yield() while holding a
// spinlock. Our callers assume will not call into libraries or other
// arbitrary code.
}
ABSL_ATTRIBUTE_WEAK void ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockWake)(
std::atomic<uint32_t>* /* lock_word */, bool /* all */) {}
} // extern "C"

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// Copyright 2018 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.
//
// This file is a Linux-specific part of spinlock_wait.cc
#include <linux/futex.h>
#include <sys/syscall.h>
#include <unistd.h>
#include <atomic>
#include <climits>
#include <cstdint>
#include <ctime>
#include "absl/base/attributes.h"
#include "absl/base/internal/errno_saver.h"
// The SpinLock lockword is `std::atomic<uint32_t>`. Here we assert that
// `std::atomic<uint32_t>` is bitwise equivalent of the `int` expected
// by SYS_futex. We also assume that reads/writes done to the lockword
// by SYS_futex have rational semantics with regard to the
// std::atomic<> API. C++ provides no guarantees of these assumptions,
// but they are believed to hold in practice.
static_assert(sizeof(std::atomic<uint32_t>) == sizeof(int),
"SpinLock lockword has the wrong size for a futex");
// Some Android headers are missing these definitions even though they
// support these futex operations.
#ifdef __BIONIC__
#ifndef SYS_futex
#define SYS_futex __NR_futex
#endif
#ifndef FUTEX_PRIVATE_FLAG
#define FUTEX_PRIVATE_FLAG 128
#endif
#endif
#if defined(__NR_futex_time64) && !defined(SYS_futex_time64)
#define SYS_futex_time64 __NR_futex_time64
#endif
#if defined(SYS_futex_time64) && !defined(SYS_futex)
#define SYS_futex SYS_futex_time64
#endif
extern "C" {
ABSL_ATTRIBUTE_WEAK void ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockDelay)(
std::atomic<uint32_t> *w, uint32_t value, int,
absl::base_internal::SchedulingMode) {
absl::base_internal::ErrnoSaver errno_saver;
syscall(SYS_futex, w, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, value, nullptr);
}
ABSL_ATTRIBUTE_WEAK void ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockWake)(
std::atomic<uint32_t> *w, bool all) {
syscall(SYS_futex, w, FUTEX_WAKE | FUTEX_PRIVATE_FLAG, all ? INT_MAX : 1, 0);
}
} // extern "C"

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// 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.
//
// This file is a Posix-specific part of spinlock_wait.cc
#include <sched.h>
#include <atomic>
#include <ctime>
#include "absl/base/internal/errno_saver.h"
#include "absl/base/internal/scheduling_mode.h"
#include "absl/base/port.h"
extern "C" {
ABSL_ATTRIBUTE_WEAK void ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockDelay)(
std::atomic<uint32_t>* /* lock_word */, uint32_t /* value */, int loop,
absl::base_internal::SchedulingMode /* mode */) {
absl::base_internal::ErrnoSaver errno_saver;
if (loop == 0) {
} else if (loop == 1) {
sched_yield();
} else {
struct timespec tm;
tm.tv_sec = 0;
tm.tv_nsec = absl::base_internal::SpinLockSuggestedDelayNS(loop);
nanosleep(&tm, nullptr);
}
}
ABSL_ATTRIBUTE_WEAK void ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockWake)(
std::atomic<uint32_t>* /* lock_word */, bool /* all */) {}
} // extern "C"

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// 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.
// The OS-specific header included below must provide two calls:
// AbslInternalSpinLockDelay() and AbslInternalSpinLockWake().
// See spinlock_wait.h for the specs.
#include <atomic>
#include <cstdint>
#include "absl/base/internal/spinlock_wait.h"
#if defined(_WIN32)
#include "absl/base/internal/spinlock_win32.inc"
#elif defined(__linux__)
#include "absl/base/internal/spinlock_linux.inc"
#elif defined(__akaros__)
#include "absl/base/internal/spinlock_akaros.inc"
#else
#include "absl/base/internal/spinlock_posix.inc"
#endif
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
// See spinlock_wait.h for spec.
uint32_t SpinLockWait(std::atomic<uint32_t> *w, int n,
const SpinLockWaitTransition trans[],
base_internal::SchedulingMode scheduling_mode) {
int loop = 0;
for (;;) {
uint32_t v = w->load(std::memory_order_acquire);
int i;
for (i = 0; i != n && v != trans[i].from; i++) {
}
if (i == n) {
SpinLockDelay(w, v, ++loop, scheduling_mode); // no matching transition
} else if (trans[i].to == v || // null transition
w->compare_exchange_strong(v, trans[i].to,
std::memory_order_acquire,
std::memory_order_relaxed)) {
if (trans[i].done) return v;
}
}
}
static std::atomic<uint64_t> delay_rand;
// Return a suggested delay in nanoseconds for iteration number "loop"
int SpinLockSuggestedDelayNS(int loop) {
// Weak pseudo-random number generator to get some spread between threads
// when many are spinning.
uint64_t r = delay_rand.load(std::memory_order_relaxed);
r = 0x5deece66dLL * r + 0xb; // numbers from nrand48()
delay_rand.store(r, std::memory_order_relaxed);
if (loop < 0 || loop > 32) { // limit loop to 0..32
loop = 32;
}
const int kMinDelay = 128 << 10; // 128us
// Double delay every 8 iterations, up to 16x (2ms).
int delay = kMinDelay << (loop / 8);
// Randomize in delay..2*delay range, for resulting 128us..4ms range.
return delay | ((delay - 1) & static_cast<int>(r));
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl

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// 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.
#ifndef ABSL_BASE_INTERNAL_SPINLOCK_WAIT_H_
#define ABSL_BASE_INTERNAL_SPINLOCK_WAIT_H_
// Operations to make atomic transitions on a word, and to allow
// waiting for those transitions to become possible.
#include <stdint.h>
#include <atomic>
#include "absl/base/internal/scheduling_mode.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
// SpinLockWait() waits until it can perform one of several transitions from
// "from" to "to". It returns when it performs a transition where done==true.
struct SpinLockWaitTransition {
uint32_t from;
uint32_t to;
bool done;
};
// Wait until *w can transition from trans[i].from to trans[i].to for some i
// satisfying 0<=i<n && trans[i].done, atomically make the transition,
// then return the old value of *w. Make any other atomic transitions
// where !trans[i].done, but continue waiting.
//
// Wakeups for threads blocked on SpinLockWait do not respect priorities.
uint32_t SpinLockWait(std::atomic<uint32_t> *w, int n,
const SpinLockWaitTransition trans[],
SchedulingMode scheduling_mode);
// If possible, wake some thread that has called SpinLockDelay(w, ...). If `all`
// is true, wake all such threads. On some systems, this may be a no-op; on
// those systems, threads calling SpinLockDelay() will always wake eventually
// even if SpinLockWake() is never called.
void SpinLockWake(std::atomic<uint32_t> *w, bool all);
// Wait for an appropriate spin delay on iteration "loop" of a
// spin loop on location *w, whose previously observed value was "value".
// SpinLockDelay() may do nothing, may yield the CPU, may sleep a clock tick,
// or may wait for a call to SpinLockWake(w).
void SpinLockDelay(std::atomic<uint32_t> *w, uint32_t value, int loop,
base_internal::SchedulingMode scheduling_mode);
// Helper used by AbslInternalSpinLockDelay.
// Returns a suggested delay in nanoseconds for iteration number "loop".
int SpinLockSuggestedDelayNS(int loop);
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
// In some build configurations we pass --detect-odr-violations to the
// gold linker. This causes it to flag weak symbol overrides as ODR
// violations. Because ODR only applies to C++ and not C,
// --detect-odr-violations ignores symbols not mangled with C++ names.
// By changing our extension points to be extern "C", we dodge this
// check.
extern "C" {
void ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockWake)(std::atomic<uint32_t> *w,
bool all);
void ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockDelay)(
std::atomic<uint32_t> *w, uint32_t value, int loop,
absl::base_internal::SchedulingMode scheduling_mode);
}
inline void absl::base_internal::SpinLockWake(std::atomic<uint32_t> *w,
bool all) {
ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockWake)(w, all);
}
inline void absl::base_internal::SpinLockDelay(
std::atomic<uint32_t> *w, uint32_t value, int loop,
absl::base_internal::SchedulingMode scheduling_mode) {
ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockDelay)
(w, value, loop, scheduling_mode);
}
#endif // ABSL_BASE_INTERNAL_SPINLOCK_WAIT_H_

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// 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.
//
// This file is a Win32-specific part of spinlock_wait.cc
#include <windows.h>
#include <atomic>
#include "absl/base/internal/scheduling_mode.h"
extern "C" {
void ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockDelay)(
std::atomic<uint32_t>* /* lock_word */, uint32_t /* value */, int loop,
absl::base_internal::SchedulingMode /* mode */) {
if (loop == 0) {
} else if (loop == 1) {
Sleep(0);
} else {
// SpinLockSuggestedDelayNS() always returns a positive integer, so this
// static_cast is safe.
Sleep(static_cast<DWORD>(
absl::base_internal::SpinLockSuggestedDelayNS(loop) / 1000000));
}
}
void ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockWake)(
std::atomic<uint32_t>* /* lock_word */, bool /* all */) {}
} // extern "C"

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// Copyright 2020 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.
#include "absl/base/internal/strerror.h"
#include <array>
#include <cerrno>
#include <cstddef>
#include <cstdio>
#include <cstring>
#include <string>
#include <type_traits>
#include "absl/base/internal/errno_saver.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
namespace {
const char* StrErrorAdaptor(int errnum, char* buf, size_t buflen) {
#if defined(_WIN32)
int rc = strerror_s(buf, buflen, errnum);
buf[buflen - 1] = '\0'; // guarantee NUL termination
if (rc == 0 && strncmp(buf, "Unknown error", buflen) == 0) *buf = '\0';
return buf;
#else
// The type of `ret` is platform-specific; both of these branches must compile
// either way but only one will execute on any given platform:
auto ret = strerror_r(errnum, buf, buflen);
if (std::is_same<decltype(ret), int>::value) {
// XSI `strerror_r`; `ret` is `int`:
if (ret) *buf = '\0';
return buf;
} else {
// GNU `strerror_r`; `ret` is `char *`:
return reinterpret_cast<const char*>(ret);
}
#endif
}
std::string StrErrorInternal(int errnum) {
char buf[100];
const char* str = StrErrorAdaptor(errnum, buf, sizeof buf);
if (*str == '\0') {
snprintf(buf, sizeof buf, "Unknown error %d", errnum);
str = buf;
}
return str;
}
// kSysNerr is the number of errors from a recent glibc. `StrError()` falls back
// to `StrErrorAdaptor()` if the value is larger than this.
constexpr int kSysNerr = 135;
std::array<std::string, kSysNerr>* NewStrErrorTable() {
auto* table = new std::array<std::string, kSysNerr>;
for (size_t i = 0; i < table->size(); ++i) {
(*table)[i] = StrErrorInternal(static_cast<int>(i));
}
return table;
}
} // namespace
std::string StrError(int errnum) {
absl::base_internal::ErrnoSaver errno_saver;
static const auto* table = NewStrErrorTable();
if (errnum >= 0 && static_cast<size_t>(errnum) < table->size()) {
return (*table)[static_cast<size_t>(errnum)];
}
return StrErrorInternal(errnum);
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl

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// Copyright 2020 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.
#ifndef ABSL_BASE_INTERNAL_STRERROR_H_
#define ABSL_BASE_INTERNAL_STRERROR_H_
#include <string>
#include "absl/base/config.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
// A portable and thread-safe alternative to C89's `strerror`.
//
// The C89 specification of `strerror` is not suitable for use in a
// multi-threaded application as the returned string may be changed by calls to
// `strerror` from another thread. The many non-stdlib alternatives differ
// enough in their names, availability, and semantics to justify this wrapper
// around them. `errno` will not be modified by a call to `absl::StrError`.
std::string StrError(int errnum);
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_STRERROR_H_

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// 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.
#include "absl/base/internal/sysinfo.h"
#include "absl/base/attributes.h"
#ifdef _WIN32
#include <windows.h>
#else
#include <fcntl.h>
#include <pthread.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#endif
#ifdef __linux__
#include <sys/syscall.h>
#endif
#if defined(__APPLE__) || defined(__FreeBSD__)
#include <sys/sysctl.h>
#endif
#ifdef __FreeBSD__
#include <pthread_np.h>
#endif
#ifdef __NetBSD__
#include <lwp.h>
#endif
#if defined(__myriad2__)
#include <rtems.h>
#endif
#include <string.h>
#include <cassert>
#include <cerrno>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <ctime>
#include <limits>
#include <thread> // NOLINT(build/c++11)
#include <utility>
#include <vector>
#include "absl/base/call_once.h"
#include "absl/base/config.h"
#include "absl/base/internal/raw_logging.h"
#include "absl/base/internal/spinlock.h"
#include "absl/base/internal/unscaledcycleclock.h"
#include "absl/base/thread_annotations.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
namespace {
#if defined(_WIN32)
// Returns number of bits set in `bitMask`
DWORD Win32CountSetBits(ULONG_PTR bitMask) {
for (DWORD bitSetCount = 0; ; ++bitSetCount) {
if (bitMask == 0) return bitSetCount;
bitMask &= bitMask - 1;
}
}
// Returns the number of logical CPUs using GetLogicalProcessorInformation(), or
// 0 if the number of processors is not available or can not be computed.
// https://docs.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-getlogicalprocessorinformation
int Win32NumCPUs() {
#pragma comment(lib, "kernel32.lib")
using Info = SYSTEM_LOGICAL_PROCESSOR_INFORMATION;
DWORD info_size = sizeof(Info);
Info* info(static_cast<Info*>(malloc(info_size)));
if (info == nullptr) return 0;
bool success = GetLogicalProcessorInformation(info, &info_size);
if (!success && GetLastError() == ERROR_INSUFFICIENT_BUFFER) {
free(info);
info = static_cast<Info*>(malloc(info_size));
if (info == nullptr) return 0;
success = GetLogicalProcessorInformation(info, &info_size);
}
DWORD logicalProcessorCount = 0;
if (success) {
Info* ptr = info;
DWORD byteOffset = 0;
while (byteOffset + sizeof(Info) <= info_size) {
switch (ptr->Relationship) {
case RelationProcessorCore:
logicalProcessorCount += Win32CountSetBits(ptr->ProcessorMask);
break;
case RelationNumaNode:
case RelationCache:
case RelationProcessorPackage:
// Ignore other entries
break;
default:
// Ignore unknown entries
break;
}
byteOffset += sizeof(Info);
ptr++;
}
}
free(info);
return static_cast<int>(logicalProcessorCount);
}
#endif
} // namespace
static int GetNumCPUs() {
#if defined(__myriad2__)
return 1;
#elif defined(_WIN32)
const int hardware_concurrency = Win32NumCPUs();
return hardware_concurrency ? hardware_concurrency : 1;
#elif defined(_AIX)
return sysconf(_SC_NPROCESSORS_ONLN);
#else
// Other possibilities:
// - Read /sys/devices/system/cpu/online and use cpumask_parse()
// - sysconf(_SC_NPROCESSORS_ONLN)
return static_cast<int>(std::thread::hardware_concurrency());
#endif
}
#if defined(_WIN32)
static double GetNominalCPUFrequency() {
#if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_APP) && \
!WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
// UWP apps don't have access to the registry and currently don't provide an
// API informing about CPU nominal frequency.
return 1.0;
#else
#pragma comment(lib, "advapi32.lib") // For Reg* functions.
HKEY key;
// Use the Reg* functions rather than the SH functions because shlwapi.dll
// pulls in gdi32.dll which makes process destruction much more costly.
if (RegOpenKeyExA(HKEY_LOCAL_MACHINE,
"HARDWARE\\DESCRIPTION\\System\\CentralProcessor\\0", 0,
KEY_READ, &key) == ERROR_SUCCESS) {
DWORD type = 0;
DWORD data = 0;
DWORD data_size = sizeof(data);
auto result = RegQueryValueExA(key, "~MHz", nullptr, &type,
reinterpret_cast<LPBYTE>(&data), &data_size);
RegCloseKey(key);
if (result == ERROR_SUCCESS && type == REG_DWORD &&
data_size == sizeof(data)) {
return data * 1e6; // Value is MHz.
}
}
return 1.0;
#endif // WINAPI_PARTITION_APP && !WINAPI_PARTITION_DESKTOP
}
#elif defined(CTL_HW) && defined(HW_CPU_FREQ)
static double GetNominalCPUFrequency() {
unsigned freq;
size_t size = sizeof(freq);
int mib[2] = {CTL_HW, HW_CPU_FREQ};
if (sysctl(mib, 2, &freq, &size, nullptr, 0) == 0) {
return static_cast<double>(freq);
}
return 1.0;
}
#else
// Helper function for reading a long from a file. Returns true if successful
// and the memory location pointed to by value is set to the value read.
static bool ReadLongFromFile(const char *file, long *value) {
bool ret = false;
#if defined(_POSIX_C_SOURCE)
const int file_mode = (O_RDONLY | O_CLOEXEC);
#else
const int file_mode = O_RDONLY;
#endif
int fd = open(file, file_mode);
if (fd != -1) {
char line[1024];
char *err;
memset(line, '\0', sizeof(line));
ssize_t len;
do {
len = read(fd, line, sizeof(line) - 1);
} while (len < 0 && errno == EINTR);
if (len <= 0) {
ret = false;
} else {
const long temp_value = strtol(line, &err, 10);
if (line[0] != '\0' && (*err == '\n' || *err == '\0')) {
*value = temp_value;
ret = true;
}
}
close(fd);
}
return ret;
}
#if defined(ABSL_INTERNAL_UNSCALED_CYCLECLOCK_FREQUENCY_IS_CPU_FREQUENCY)
// Reads a monotonic time source and returns a value in
// nanoseconds. The returned value uses an arbitrary epoch, not the
// Unix epoch.
static int64_t ReadMonotonicClockNanos() {
struct timespec t;
#ifdef CLOCK_MONOTONIC_RAW
int rc = clock_gettime(CLOCK_MONOTONIC_RAW, &t);
#else
int rc = clock_gettime(CLOCK_MONOTONIC, &t);
#endif
if (rc != 0) {
ABSL_INTERNAL_LOG(
FATAL, "clock_gettime() failed: (" + std::to_string(errno) + ")");
}
return int64_t{t.tv_sec} * 1000000000 + t.tv_nsec;
}
class UnscaledCycleClockWrapperForInitializeFrequency {
public:
static int64_t Now() { return base_internal::UnscaledCycleClock::Now(); }
};
struct TimeTscPair {
int64_t time; // From ReadMonotonicClockNanos().
int64_t tsc; // From UnscaledCycleClock::Now().
};
// Returns a pair of values (monotonic kernel time, TSC ticks) that
// approximately correspond to each other. This is accomplished by
// doing several reads and picking the reading with the lowest
// latency. This approach is used to minimize the probability that
// our thread was preempted between clock reads.
static TimeTscPair GetTimeTscPair() {
int64_t best_latency = std::numeric_limits<int64_t>::max();
TimeTscPair best;
for (int i = 0; i < 10; ++i) {
int64_t t0 = ReadMonotonicClockNanos();
int64_t tsc = UnscaledCycleClockWrapperForInitializeFrequency::Now();
int64_t t1 = ReadMonotonicClockNanos();
int64_t latency = t1 - t0;
if (latency < best_latency) {
best_latency = latency;
best.time = t0;
best.tsc = tsc;
}
}
return best;
}
// Measures and returns the TSC frequency by taking a pair of
// measurements approximately `sleep_nanoseconds` apart.
static double MeasureTscFrequencyWithSleep(int sleep_nanoseconds) {
auto t0 = GetTimeTscPair();
struct timespec ts;
ts.tv_sec = 0;
ts.tv_nsec = sleep_nanoseconds;
while (nanosleep(&ts, &ts) != 0 && errno == EINTR) {}
auto t1 = GetTimeTscPair();
double elapsed_ticks = t1.tsc - t0.tsc;
double elapsed_time = (t1.time - t0.time) * 1e-9;
return elapsed_ticks / elapsed_time;
}
// Measures and returns the TSC frequency by calling
// MeasureTscFrequencyWithSleep(), doubling the sleep interval until the
// frequency measurement stabilizes.
static double MeasureTscFrequency() {
double last_measurement = -1.0;
int sleep_nanoseconds = 1000000; // 1 millisecond.
for (int i = 0; i < 8; ++i) {
double measurement = MeasureTscFrequencyWithSleep(sleep_nanoseconds);
if (measurement * 0.99 < last_measurement &&
last_measurement < measurement * 1.01) {
// Use the current measurement if it is within 1% of the
// previous measurement.
return measurement;
}
last_measurement = measurement;
sleep_nanoseconds *= 2;
}
return last_measurement;
}
#endif // ABSL_INTERNAL_UNSCALED_CYCLECLOCK_FREQUENCY_IS_CPU_FREQUENCY
static double GetNominalCPUFrequency() {
long freq = 0;
// Google's production kernel has a patch to export the TSC
// frequency through sysfs. If the kernel is exporting the TSC
// frequency use that. There are issues where cpuinfo_max_freq
// cannot be relied on because the BIOS may be exporting an invalid
// p-state (on x86) or p-states may be used to put the processor in
// a new mode (turbo mode). Essentially, those frequencies cannot
// always be relied upon. The same reasons apply to /proc/cpuinfo as
// well.
if (ReadLongFromFile("/sys/devices/system/cpu/cpu0/tsc_freq_khz", &freq)) {
return freq * 1e3; // Value is kHz.
}
#if defined(ABSL_INTERNAL_UNSCALED_CYCLECLOCK_FREQUENCY_IS_CPU_FREQUENCY)
// On these platforms, the TSC frequency is the nominal CPU
// frequency. But without having the kernel export it directly
// though /sys/devices/system/cpu/cpu0/tsc_freq_khz, there is no
// other way to reliably get the TSC frequency, so we have to
// measure it ourselves. Some CPUs abuse cpuinfo_max_freq by
// exporting "fake" frequencies for implementing new features. For
// example, Intel's turbo mode is enabled by exposing a p-state
// value with a higher frequency than that of the real TSC
// rate. Because of this, we prefer to measure the TSC rate
// ourselves on i386 and x86-64.
return MeasureTscFrequency();
#else
// If CPU scaling is in effect, we want to use the *maximum*
// frequency, not whatever CPU speed some random processor happens
// to be using now.
if (ReadLongFromFile("/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq",
&freq)) {
return freq * 1e3; // Value is kHz.
}
return 1.0;
#endif // !ABSL_INTERNAL_UNSCALED_CYCLECLOCK_FREQUENCY_IS_CPU_FREQUENCY
}
#endif
ABSL_CONST_INIT static once_flag init_num_cpus_once;
ABSL_CONST_INIT static int num_cpus = 0;
// NumCPUs() may be called before main() and before malloc is properly
// initialized, therefore this must not allocate memory.
int NumCPUs() {
base_internal::LowLevelCallOnce(
&init_num_cpus_once, []() { num_cpus = GetNumCPUs(); });
return num_cpus;
}
// A default frequency of 0.0 might be dangerous if it is used in division.
ABSL_CONST_INIT static once_flag init_nominal_cpu_frequency_once;
ABSL_CONST_INIT static double nominal_cpu_frequency = 1.0;
// NominalCPUFrequency() may be called before main() and before malloc is
// properly initialized, therefore this must not allocate memory.
double NominalCPUFrequency() {
base_internal::LowLevelCallOnce(
&init_nominal_cpu_frequency_once,
[]() { nominal_cpu_frequency = GetNominalCPUFrequency(); });
return nominal_cpu_frequency;
}
#if defined(_WIN32)
pid_t GetTID() {
return pid_t{GetCurrentThreadId()};
}
#elif defined(__linux__)
#ifndef SYS_gettid
#define SYS_gettid __NR_gettid
#endif
pid_t GetTID() {
return static_cast<pid_t>(syscall(SYS_gettid));
}
#elif defined(__akaros__)
pid_t GetTID() {
// Akaros has a concept of "vcore context", which is the state the program
// is forced into when we need to make a user-level scheduling decision, or
// run a signal handler. This is analogous to the interrupt context that a
// CPU might enter if it encounters some kind of exception.
//
// There is no current thread context in vcore context, but we need to give
// a reasonable answer if asked for a thread ID (e.g., in a signal handler).
// Thread 0 always exists, so if we are in vcore context, we return that.
//
// Otherwise, we know (since we are using pthreads) that the uthread struct
// current_uthread is pointing to is the first element of a
// struct pthread_tcb, so we extract and return the thread ID from that.
//
// TODO(dcross): Akaros anticipates moving the thread ID to the uthread
// structure at some point. We should modify this code to remove the cast
// when that happens.
if (in_vcore_context())
return 0;
return reinterpret_cast<struct pthread_tcb *>(current_uthread)->id;
}
#elif defined(__myriad2__)
pid_t GetTID() {
uint32_t tid;
rtems_task_ident(RTEMS_SELF, 0, &tid);
return tid;
}
#elif defined(__APPLE__)
pid_t GetTID() {
uint64_t tid;
// `nullptr` here implies this thread. This only fails if the specified
// thread is invalid or the pointer-to-tid is null, so we needn't worry about
// it.
pthread_threadid_np(nullptr, &tid);
return static_cast<pid_t>(tid);
}
#elif defined(__FreeBSD__)
pid_t GetTID() { return static_cast<pid_t>(pthread_getthreadid_np()); }
#elif defined(__OpenBSD__)
pid_t GetTID() { return getthrid(); }
#elif defined(__NetBSD__)
pid_t GetTID() { return static_cast<pid_t>(_lwp_self()); }
#elif defined(__native_client__)
pid_t GetTID() {
auto* thread = pthread_self();
static_assert(sizeof(pid_t) == sizeof(thread),
"In NaCL int expected to be the same size as a pointer");
return reinterpret_cast<pid_t>(thread);
}
#else
// Fallback implementation of `GetTID` using `pthread_self`.
pid_t GetTID() {
// `pthread_t` need not be arithmetic per POSIX; platforms where it isn't
// should be handled above.
return static_cast<pid_t>(pthread_self());
}
#endif
// GetCachedTID() caches the thread ID in thread-local storage (which is a
// userspace construct) to avoid unnecessary system calls. Without this caching,
// it can take roughly 98ns, while it takes roughly 1ns with this caching.
pid_t GetCachedTID() {
#ifdef ABSL_HAVE_THREAD_LOCAL
static thread_local pid_t thread_id = GetTID();
return thread_id;
#else
return GetTID();
#endif // ABSL_HAVE_THREAD_LOCAL
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl

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// 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.
//
// This file includes routines to find out characteristics
// of the machine a program is running on. It is undoubtedly
// system-dependent.
// Functions listed here that accept a pid_t as an argument act on the
// current process if the pid_t argument is 0
// All functions here are thread-hostile due to file caching unless
// commented otherwise.
#ifndef ABSL_BASE_INTERNAL_SYSINFO_H_
#define ABSL_BASE_INTERNAL_SYSINFO_H_
#ifndef _WIN32
#include <sys/types.h>
#endif
#include <cstdint>
#include "absl/base/config.h"
#include "absl/base/port.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
// Nominal core processor cycles per second of each processor. This is _not_
// necessarily the frequency of the CycleClock counter (see cycleclock.h)
// Thread-safe.
double NominalCPUFrequency();
// Number of logical processors (hyperthreads) in system. Thread-safe.
int NumCPUs();
// Return the thread id of the current thread, as told by the system.
// No two currently-live threads implemented by the OS shall have the same ID.
// Thread ids of exited threads may be reused. Multiple user-level threads
// may have the same thread ID if multiplexed on the same OS thread.
//
// On Linux, you may send a signal to the resulting ID with kill(). However,
// it is recommended for portability that you use pthread_kill() instead.
#ifdef _WIN32
// On Windows, process id and thread id are of the same type according to the
// return types of GetProcessId() and GetThreadId() are both DWORD, an unsigned
// 32-bit type.
using pid_t = uint32_t;
#endif
pid_t GetTID();
// Like GetTID(), but caches the result in thread-local storage in order
// to avoid unnecessary system calls. Note that there are some cases where
// one must call through to GetTID directly, which is why this exists as a
// separate function. For example, GetCachedTID() is not safe to call in
// an asynchronous signal-handling context nor right after a call to fork().
pid_t GetCachedTID();
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_SYSINFO_H_

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// 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.
#include "absl/base/internal/thread_identity.h"
#if !defined(_WIN32) || defined(__MINGW32__)
#include <pthread.h>
#ifndef __wasi__
// WASI does not provide this header, either way we disable use
// of signals with it below.
#include <signal.h>
#endif
#endif
#include <atomic>
#include <cassert>
#include <memory>
#include "absl/base/attributes.h"
#include "absl/base/call_once.h"
#include "absl/base/internal/raw_logging.h"
#include "absl/base/internal/spinlock.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
#if ABSL_THREAD_IDENTITY_MODE != ABSL_THREAD_IDENTITY_MODE_USE_CPP11
namespace {
// Used to co-ordinate one-time creation of our pthread_key
absl::once_flag init_thread_identity_key_once;
pthread_key_t thread_identity_pthread_key;
std::atomic<bool> pthread_key_initialized(false);
void AllocateThreadIdentityKey(ThreadIdentityReclaimerFunction reclaimer) {
pthread_key_create(&thread_identity_pthread_key, reclaimer);
pthread_key_initialized.store(true, std::memory_order_release);
}
} // namespace
#endif
#if ABSL_THREAD_IDENTITY_MODE == ABSL_THREAD_IDENTITY_MODE_USE_TLS || \
ABSL_THREAD_IDENTITY_MODE == ABSL_THREAD_IDENTITY_MODE_USE_CPP11
// The actual TLS storage for a thread's currently associated ThreadIdentity.
// This is referenced by inline accessors in the header.
// "protected" visibility ensures that if multiple instances of Abseil code
// exist within a process (via dlopen() or similar), references to
// thread_identity_ptr from each instance of the code will refer to
// *different* instances of this ptr.
// Apple platforms have the visibility attribute, but issue a compile warning
// that protected visibility is unsupported.
ABSL_CONST_INIT // Must come before __attribute__((visibility("protected")))
#if ABSL_HAVE_ATTRIBUTE(visibility) && !defined(__APPLE__)
__attribute__((visibility("protected")))
#endif // ABSL_HAVE_ATTRIBUTE(visibility) && !defined(__APPLE__)
#if ABSL_PER_THREAD_TLS
// Prefer __thread to thread_local as benchmarks indicate it is a bit
// faster.
ABSL_PER_THREAD_TLS_KEYWORD ThreadIdentity* thread_identity_ptr = nullptr;
#elif defined(ABSL_HAVE_THREAD_LOCAL)
thread_local ThreadIdentity* thread_identity_ptr = nullptr;
#endif // ABSL_PER_THREAD_TLS
#endif // TLS or CPP11
void SetCurrentThreadIdentity(ThreadIdentity* identity,
ThreadIdentityReclaimerFunction reclaimer) {
assert(CurrentThreadIdentityIfPresent() == nullptr);
// Associate our destructor.
// NOTE: This call to pthread_setspecific is currently the only immovable
// barrier to CurrentThreadIdentity() always being async signal safe.
#if ABSL_THREAD_IDENTITY_MODE == ABSL_THREAD_IDENTITY_MODE_USE_POSIX_SETSPECIFIC
// NOTE: Not async-safe. But can be open-coded.
absl::call_once(init_thread_identity_key_once, AllocateThreadIdentityKey,
reclaimer);
#if defined(__wasi__) || defined(__EMSCRIPTEN__) || defined(__MINGW32__) || \
defined(__hexagon__)
// Emscripten, WASI and MinGW pthread implementations does not support
// signals. See
// https://kripken.github.io/emscripten-site/docs/porting/pthreads.html for
// more information.
pthread_setspecific(thread_identity_pthread_key,
reinterpret_cast<void*>(identity));
#else
// We must mask signals around the call to setspecific as with current glibc,
// a concurrent getspecific (needed for GetCurrentThreadIdentityIfPresent())
// may zero our value.
//
// While not officially async-signal safe, getspecific within a signal handler
// is otherwise OK.
sigset_t all_signals;
sigset_t curr_signals;
sigfillset(&all_signals);
pthread_sigmask(SIG_SETMASK, &all_signals, &curr_signals);
pthread_setspecific(thread_identity_pthread_key,
reinterpret_cast<void*>(identity));
pthread_sigmask(SIG_SETMASK, &curr_signals, nullptr);
#endif // !__EMSCRIPTEN__ && !__MINGW32__
#elif ABSL_THREAD_IDENTITY_MODE == ABSL_THREAD_IDENTITY_MODE_USE_TLS
// NOTE: Not async-safe. But can be open-coded.
absl::call_once(init_thread_identity_key_once, AllocateThreadIdentityKey,
reclaimer);
pthread_setspecific(thread_identity_pthread_key,
reinterpret_cast<void*>(identity));
thread_identity_ptr = identity;
#elif ABSL_THREAD_IDENTITY_MODE == ABSL_THREAD_IDENTITY_MODE_USE_CPP11
thread_local std::unique_ptr<ThreadIdentity, ThreadIdentityReclaimerFunction>
holder(identity, reclaimer);
thread_identity_ptr = identity;
#else
#error Unimplemented ABSL_THREAD_IDENTITY_MODE
#endif
}
#if ABSL_THREAD_IDENTITY_MODE == ABSL_THREAD_IDENTITY_MODE_USE_TLS || \
ABSL_THREAD_IDENTITY_MODE == ABSL_THREAD_IDENTITY_MODE_USE_CPP11
// Please see the comment on `CurrentThreadIdentityIfPresent` in
// thread_identity.h. When we cannot expose thread_local variables in
// headers, we opt for the correct-but-slower option of not inlining this
// function.
#ifndef ABSL_INTERNAL_INLINE_CURRENT_THREAD_IDENTITY_IF_PRESENT
ThreadIdentity* CurrentThreadIdentityIfPresent() { return thread_identity_ptr; }
#endif
#endif
void ClearCurrentThreadIdentity() {
#if ABSL_THREAD_IDENTITY_MODE == ABSL_THREAD_IDENTITY_MODE_USE_TLS || \
ABSL_THREAD_IDENTITY_MODE == ABSL_THREAD_IDENTITY_MODE_USE_CPP11
thread_identity_ptr = nullptr;
#elif ABSL_THREAD_IDENTITY_MODE == \
ABSL_THREAD_IDENTITY_MODE_USE_POSIX_SETSPECIFIC
// pthread_setspecific expected to clear value on destruction
assert(CurrentThreadIdentityIfPresent() == nullptr);
#endif
}
#if ABSL_THREAD_IDENTITY_MODE == ABSL_THREAD_IDENTITY_MODE_USE_POSIX_SETSPECIFIC
ThreadIdentity* CurrentThreadIdentityIfPresent() {
bool initialized = pthread_key_initialized.load(std::memory_order_acquire);
if (!initialized) {
return nullptr;
}
return reinterpret_cast<ThreadIdentity*>(
pthread_getspecific(thread_identity_pthread_key));
}
#endif
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl

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// 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.
//
// Each active thread has an ThreadIdentity that may represent the thread in
// various level interfaces. ThreadIdentity objects are never deallocated.
// When a thread terminates, its ThreadIdentity object may be reused for a
// thread created later.
#ifndef ABSL_BASE_INTERNAL_THREAD_IDENTITY_H_
#define ABSL_BASE_INTERNAL_THREAD_IDENTITY_H_
#ifndef _WIN32
#include <pthread.h>
// Defines __GOOGLE_GRTE_VERSION__ (via glibc-specific features.h) when
// supported.
#include <unistd.h>
#endif
#include <atomic>
#include <cstdint>
#include "absl/base/config.h"
#include "absl/base/internal/per_thread_tls.h"
#include "absl/base/optimization.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
struct SynchLocksHeld;
struct SynchWaitParams;
namespace base_internal {
class SpinLock;
struct ThreadIdentity;
// Used by the implementation of absl::Mutex and absl::CondVar.
struct PerThreadSynch {
// The internal representation of absl::Mutex and absl::CondVar rely
// on the alignment of PerThreadSynch. Both store the address of the
// PerThreadSynch in the high-order bits of their internal state,
// which means the low kLowZeroBits of the address of PerThreadSynch
// must be zero.
static constexpr int kLowZeroBits = 8;
static constexpr int kAlignment = 1 << kLowZeroBits;
// Returns the associated ThreadIdentity.
// This can be implemented as a cast because we guarantee
// PerThreadSynch is the first element of ThreadIdentity.
ThreadIdentity* thread_identity() {
return reinterpret_cast<ThreadIdentity*>(this);
}
PerThreadSynch* next; // Circular waiter queue; initialized to 0.
PerThreadSynch* skip; // If non-zero, all entries in Mutex queue
// up to and including "skip" have same
// condition as this, and will be woken later
bool may_skip; // if false while on mutex queue, a mutex unlocker
// is using this PerThreadSynch as a terminator. Its
// skip field must not be filled in because the loop
// might then skip over the terminator.
bool wake; // This thread is to be woken from a Mutex.
// If "x" is on a waiter list for a mutex, "x->cond_waiter" is true iff the
// waiter is waiting on the mutex as part of a CV Wait or Mutex Await.
//
// The value of "x->cond_waiter" is meaningless if "x" is not on a
// Mutex waiter list.
bool cond_waiter;
bool maybe_unlocking; // Valid at head of Mutex waiter queue;
// true if UnlockSlow could be searching
// for a waiter to wake. Used for an optimization
// in Enqueue(). true is always a valid value.
// Can be reset to false when the unlocker or any
// writer releases the lock, or a reader fully
// releases the lock. It may not be set to false
// by a reader that decrements the count to
// non-zero. protected by mutex spinlock
bool suppress_fatal_errors; // If true, try to proceed even in the face
// of broken invariants. This is used within
// fatal signal handlers to improve the
// chances of debug logging information being
// output successfully.
int priority; // Priority of thread (updated every so often).
// State values:
// kAvailable: This PerThreadSynch is available.
// kQueued: This PerThreadSynch is unavailable, it's currently queued on a
// Mutex or CondVar waistlist.
//
// Transitions from kQueued to kAvailable require a release
// barrier. This is needed as a waiter may use "state" to
// independently observe that it's no longer queued.
//
// Transitions from kAvailable to kQueued require no barrier, they
// are externally ordered by the Mutex.
enum State { kAvailable, kQueued };
std::atomic<State> state;
// The wait parameters of the current wait. waitp is null if the
// thread is not waiting. Transitions from null to non-null must
// occur before the enqueue commit point (state = kQueued in
// Enqueue() and CondVarEnqueue()). Transitions from non-null to
// null must occur after the wait is finished (state = kAvailable in
// Mutex::Block() and CondVar::WaitCommon()). This field may be
// changed only by the thread that describes this PerThreadSynch. A
// special case is Fer(), which calls Enqueue() on another thread,
// but with an identical SynchWaitParams pointer, thus leaving the
// pointer unchanged.
SynchWaitParams* waitp;
intptr_t readers; // Number of readers in mutex.
// When priority will next be read (cycles).
int64_t next_priority_read_cycles;
// Locks held; used during deadlock detection.
// Allocated in Synch_GetAllLocks() and freed in ReclaimThreadIdentity().
SynchLocksHeld* all_locks;
};
// The instances of this class are allocated in NewThreadIdentity() with an
// alignment of PerThreadSynch::kAlignment.
//
// NOTE: The layout of fields in this structure is critical, please do not
// add, remove, or modify the field placements without fully auditing the
// layout.
struct ThreadIdentity {
// Must be the first member. The Mutex implementation requires that
// the PerThreadSynch object associated with each thread is
// PerThreadSynch::kAlignment aligned. We provide this alignment on
// ThreadIdentity itself.
PerThreadSynch per_thread_synch;
// Private: Reserved for absl::synchronization_internal::Waiter.
struct WaiterState {
alignas(void*) char data[256];
} waiter_state;
// Used by PerThreadSem::{Get,Set}ThreadBlockedCounter().
std::atomic<int>* blocked_count_ptr;
// The following variables are mostly read/written just by the
// thread itself. The only exception is that these are read by
// a ticker thread as a hint.
std::atomic<int> ticker; // Tick counter, incremented once per second.
std::atomic<int> wait_start; // Ticker value when thread started waiting.
std::atomic<bool> is_idle; // Has thread become idle yet?
ThreadIdentity* next;
};
// Returns the ThreadIdentity object representing the calling thread; guaranteed
// to be unique for its lifetime. The returned object will remain valid for the
// program's lifetime; although it may be re-assigned to a subsequent thread.
// If one does not exist, return nullptr instead.
//
// Does not malloc(*), and is async-signal safe.
// [*] Technically pthread_setspecific() does malloc on first use; however this
// is handled internally within tcmalloc's initialization already. Note that
// darwin does *not* use tcmalloc, so this can catch you if using MallocHooks
// on Apple platforms. Whatever function is calling your MallocHooks will need
// to watch for recursion on Apple platforms.
//
// New ThreadIdentity objects can be constructed and associated with a thread
// by calling GetOrCreateCurrentThreadIdentity() in per-thread-sem.h.
ThreadIdentity* CurrentThreadIdentityIfPresent();
using ThreadIdentityReclaimerFunction = void (*)(void*);
// Sets the current thread identity to the given value. 'reclaimer' is a
// pointer to the global function for cleaning up instances on thread
// destruction.
void SetCurrentThreadIdentity(ThreadIdentity* identity,
ThreadIdentityReclaimerFunction reclaimer);
// Removes the currently associated ThreadIdentity from the running thread.
// This must be called from inside the ThreadIdentityReclaimerFunction, and only
// from that function.
void ClearCurrentThreadIdentity();
// May be chosen at compile time via: -DABSL_FORCE_THREAD_IDENTITY_MODE=<mode
// index>
#ifdef ABSL_THREAD_IDENTITY_MODE_USE_POSIX_SETSPECIFIC
#error ABSL_THREAD_IDENTITY_MODE_USE_POSIX_SETSPECIFIC cannot be directly set
#else
#define ABSL_THREAD_IDENTITY_MODE_USE_POSIX_SETSPECIFIC 0
#endif
#ifdef ABSL_THREAD_IDENTITY_MODE_USE_TLS
#error ABSL_THREAD_IDENTITY_MODE_USE_TLS cannot be directly set
#else
#define ABSL_THREAD_IDENTITY_MODE_USE_TLS 1
#endif
#ifdef ABSL_THREAD_IDENTITY_MODE_USE_CPP11
#error ABSL_THREAD_IDENTITY_MODE_USE_CPP11 cannot be directly set
#else
#define ABSL_THREAD_IDENTITY_MODE_USE_CPP11 2
#endif
#ifdef ABSL_THREAD_IDENTITY_MODE
#error ABSL_THREAD_IDENTITY_MODE cannot be directly set
#elif defined(ABSL_FORCE_THREAD_IDENTITY_MODE)
#define ABSL_THREAD_IDENTITY_MODE ABSL_FORCE_THREAD_IDENTITY_MODE
#elif defined(_WIN32) && !defined(__MINGW32__)
#define ABSL_THREAD_IDENTITY_MODE ABSL_THREAD_IDENTITY_MODE_USE_CPP11
#elif defined(__APPLE__) && defined(ABSL_HAVE_THREAD_LOCAL)
#define ABSL_THREAD_IDENTITY_MODE ABSL_THREAD_IDENTITY_MODE_USE_CPP11
#elif ABSL_PER_THREAD_TLS && defined(__GOOGLE_GRTE_VERSION__) && \
(__GOOGLE_GRTE_VERSION__ >= 20140228L)
// Support for async-safe TLS was specifically added in GRTEv4. It's not
// present in the upstream eglibc.
// Note: Current default for production systems.
#define ABSL_THREAD_IDENTITY_MODE ABSL_THREAD_IDENTITY_MODE_USE_TLS
#else
#define ABSL_THREAD_IDENTITY_MODE \
ABSL_THREAD_IDENTITY_MODE_USE_POSIX_SETSPECIFIC
#endif
#if ABSL_THREAD_IDENTITY_MODE == ABSL_THREAD_IDENTITY_MODE_USE_TLS || \
ABSL_THREAD_IDENTITY_MODE == ABSL_THREAD_IDENTITY_MODE_USE_CPP11
#if ABSL_PER_THREAD_TLS
ABSL_CONST_INIT extern ABSL_PER_THREAD_TLS_KEYWORD ThreadIdentity*
thread_identity_ptr;
#elif defined(ABSL_HAVE_THREAD_LOCAL)
ABSL_CONST_INIT extern thread_local ThreadIdentity* thread_identity_ptr;
#else
#error Thread-local storage not detected on this platform
#endif
// thread_local variables cannot be in headers exposed by DLLs or in certain
// build configurations on Apple platforms. However, it is important for
// performance reasons in general that `CurrentThreadIdentityIfPresent` be
// inlined. In the other cases we opt to have the function not be inlined. Note
// that `CurrentThreadIdentityIfPresent` is declared above so we can exclude
// this entire inline definition.
#if !defined(__APPLE__) && !defined(ABSL_BUILD_DLL) && \
!defined(ABSL_CONSUME_DLL)
#define ABSL_INTERNAL_INLINE_CURRENT_THREAD_IDENTITY_IF_PRESENT 1
#endif
#ifdef ABSL_INTERNAL_INLINE_CURRENT_THREAD_IDENTITY_IF_PRESENT
inline ThreadIdentity* CurrentThreadIdentityIfPresent() {
return thread_identity_ptr;
}
#endif
#elif ABSL_THREAD_IDENTITY_MODE != \
ABSL_THREAD_IDENTITY_MODE_USE_POSIX_SETSPECIFIC
#error Unknown ABSL_THREAD_IDENTITY_MODE
#endif
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_THREAD_IDENTITY_H_

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// 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.
#include "absl/base/internal/throw_delegate.h"
#include <cstdlib>
#include <functional>
#include <new>
#include <stdexcept>
#include "absl/base/config.h"
#include "absl/base/internal/raw_logging.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
// NOTE: The exception types, like `std::logic_error`, do not exist on all
// platforms. (For example, the Android NDK does not have them.)
// Therefore, their use must be guarded by `#ifdef` or equivalent.
void ThrowStdLogicError(const std::string& what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::logic_error(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg.c_str());
std::abort();
#endif
}
void ThrowStdLogicError(const char* what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::logic_error(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg);
std::abort();
#endif
}
void ThrowStdInvalidArgument(const std::string& what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::invalid_argument(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg.c_str());
std::abort();
#endif
}
void ThrowStdInvalidArgument(const char* what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::invalid_argument(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg);
std::abort();
#endif
}
void ThrowStdDomainError(const std::string& what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::domain_error(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg.c_str());
std::abort();
#endif
}
void ThrowStdDomainError(const char* what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::domain_error(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg);
std::abort();
#endif
}
void ThrowStdLengthError(const std::string& what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::length_error(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg.c_str());
std::abort();
#endif
}
void ThrowStdLengthError(const char* what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::length_error(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg);
std::abort();
#endif
}
void ThrowStdOutOfRange(const std::string& what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::out_of_range(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg.c_str());
std::abort();
#endif
}
void ThrowStdOutOfRange(const char* what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::out_of_range(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg);
std::abort();
#endif
}
void ThrowStdRuntimeError(const std::string& what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::runtime_error(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg.c_str());
std::abort();
#endif
}
void ThrowStdRuntimeError(const char* what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::runtime_error(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg);
std::abort();
#endif
}
void ThrowStdRangeError(const std::string& what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::range_error(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg.c_str());
std::abort();
#endif
}
void ThrowStdRangeError(const char* what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::range_error(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg);
std::abort();
#endif
}
void ThrowStdOverflowError(const std::string& what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::overflow_error(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg.c_str());
std::abort();
#endif
}
void ThrowStdOverflowError(const char* what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::overflow_error(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg);
std::abort();
#endif
}
void ThrowStdUnderflowError(const std::string& what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::underflow_error(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg.c_str());
std::abort();
#endif
}
void ThrowStdUnderflowError(const char* what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::underflow_error(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg);
std::abort();
#endif
}
void ThrowStdBadFunctionCall() {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::bad_function_call();
#else
std::abort();
#endif
}
void ThrowStdBadAlloc() {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::bad_alloc();
#else
std::abort();
#endif
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl

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//
// 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.
//
#ifndef ABSL_BASE_INTERNAL_THROW_DELEGATE_H_
#define ABSL_BASE_INTERNAL_THROW_DELEGATE_H_
#include <string>
#include "absl/base/config.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
// Helper functions that allow throwing exceptions consistently from anywhere.
// The main use case is for header-based libraries (eg templates), as they will
// be built by many different targets with their own compiler options.
// In particular, this will allow a safe way to throw exceptions even if the
// caller is compiled with -fno-exceptions. This is intended for implementing
// things like map<>::at(), which the standard documents as throwing an
// exception on error.
//
// Using other techniques like #if tricks could lead to ODR violations.
//
// You shouldn't use it unless you're writing code that you know will be built
// both with and without exceptions and you need to conform to an interface
// that uses exceptions.
[[noreturn]] void ThrowStdLogicError(const std::string& what_arg);
[[noreturn]] void ThrowStdLogicError(const char* what_arg);
[[noreturn]] void ThrowStdInvalidArgument(const std::string& what_arg);
[[noreturn]] void ThrowStdInvalidArgument(const char* what_arg);
[[noreturn]] void ThrowStdDomainError(const std::string& what_arg);
[[noreturn]] void ThrowStdDomainError(const char* what_arg);
[[noreturn]] void ThrowStdLengthError(const std::string& what_arg);
[[noreturn]] void ThrowStdLengthError(const char* what_arg);
[[noreturn]] void ThrowStdOutOfRange(const std::string& what_arg);
[[noreturn]] void ThrowStdOutOfRange(const char* what_arg);
[[noreturn]] void ThrowStdRuntimeError(const std::string& what_arg);
[[noreturn]] void ThrowStdRuntimeError(const char* what_arg);
[[noreturn]] void ThrowStdRangeError(const std::string& what_arg);
[[noreturn]] void ThrowStdRangeError(const char* what_arg);
[[noreturn]] void ThrowStdOverflowError(const std::string& what_arg);
[[noreturn]] void ThrowStdOverflowError(const char* what_arg);
[[noreturn]] void ThrowStdUnderflowError(const std::string& what_arg);
[[noreturn]] void ThrowStdUnderflowError(const char* what_arg);
[[noreturn]] void ThrowStdBadFunctionCall();
[[noreturn]] void ThrowStdBadAlloc();
// ThrowStdBadArrayNewLength() cannot be consistently supported because
// std::bad_array_new_length is missing in libstdc++ until 4.9.0.
// https://gcc.gnu.org/onlinedocs/gcc-4.8.3/libstdc++/api/a01379_source.html
// https://gcc.gnu.org/onlinedocs/gcc-4.9.0/libstdc++/api/a01327_source.html
// libcxx (as of 3.2) and msvc (as of 2015) both have it.
// [[noreturn]] void ThrowStdBadArrayNewLength();
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_THROW_DELEGATE_H_

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// 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.
//
// This file is intended solely for spinlock.h.
// It provides ThreadSanitizer annotations for custom mutexes.
// See <sanitizer/tsan_interface.h> for meaning of these annotations.
#ifndef ABSL_BASE_INTERNAL_TSAN_MUTEX_INTERFACE_H_
#define ABSL_BASE_INTERNAL_TSAN_MUTEX_INTERFACE_H_
#include "absl/base/config.h"
// ABSL_INTERNAL_HAVE_TSAN_INTERFACE
// Macro intended only for internal use.
//
// Checks whether LLVM Thread Sanitizer interfaces are available.
// First made available in LLVM 5.0 (Sep 2017).
#ifdef ABSL_INTERNAL_HAVE_TSAN_INTERFACE
#error "ABSL_INTERNAL_HAVE_TSAN_INTERFACE cannot be directly set."
#endif
#if defined(ABSL_HAVE_THREAD_SANITIZER) && defined(__has_include)
#if __has_include(<sanitizer/tsan_interface.h>)
#define ABSL_INTERNAL_HAVE_TSAN_INTERFACE 1
#endif
#endif
#ifdef ABSL_INTERNAL_HAVE_TSAN_INTERFACE
#include <sanitizer/tsan_interface.h>
#define ABSL_TSAN_MUTEX_CREATE __tsan_mutex_create
#define ABSL_TSAN_MUTEX_DESTROY __tsan_mutex_destroy
#define ABSL_TSAN_MUTEX_PRE_LOCK __tsan_mutex_pre_lock
#define ABSL_TSAN_MUTEX_POST_LOCK __tsan_mutex_post_lock
#define ABSL_TSAN_MUTEX_PRE_UNLOCK __tsan_mutex_pre_unlock
#define ABSL_TSAN_MUTEX_POST_UNLOCK __tsan_mutex_post_unlock
#define ABSL_TSAN_MUTEX_PRE_SIGNAL __tsan_mutex_pre_signal
#define ABSL_TSAN_MUTEX_POST_SIGNAL __tsan_mutex_post_signal
#define ABSL_TSAN_MUTEX_PRE_DIVERT __tsan_mutex_pre_divert
#define ABSL_TSAN_MUTEX_POST_DIVERT __tsan_mutex_post_divert
#else
#define ABSL_TSAN_MUTEX_CREATE(...)
#define ABSL_TSAN_MUTEX_DESTROY(...)
#define ABSL_TSAN_MUTEX_PRE_LOCK(...)
#define ABSL_TSAN_MUTEX_POST_LOCK(...)
#define ABSL_TSAN_MUTEX_PRE_UNLOCK(...)
#define ABSL_TSAN_MUTEX_POST_UNLOCK(...)
#define ABSL_TSAN_MUTEX_PRE_SIGNAL(...)
#define ABSL_TSAN_MUTEX_POST_SIGNAL(...)
#define ABSL_TSAN_MUTEX_PRE_DIVERT(...)
#define ABSL_TSAN_MUTEX_POST_DIVERT(...)
#endif
#endif // ABSL_BASE_INTERNAL_TSAN_MUTEX_INTERFACE_H_

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//
// 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.
//
#ifndef ABSL_BASE_INTERNAL_UNALIGNED_ACCESS_H_
#define ABSL_BASE_INTERNAL_UNALIGNED_ACCESS_H_
#include <string.h>
#include <cstdint>
#include "absl/base/attributes.h"
#include "absl/base/config.h"
#include "absl/base/nullability.h"
// unaligned APIs
// Portable handling of unaligned loads, stores, and copies.
// The unaligned API is C++ only. The declarations use C++ features
// (namespaces, inline) which are absent or incompatible in C.
#if defined(__cplusplus)
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
inline uint16_t UnalignedLoad16(absl::Nonnull<const void *> p) {
uint16_t t;
memcpy(&t, p, sizeof t);
return t;
}
inline uint32_t UnalignedLoad32(absl::Nonnull<const void *> p) {
uint32_t t;
memcpy(&t, p, sizeof t);
return t;
}
inline uint64_t UnalignedLoad64(absl::Nonnull<const void *> p) {
uint64_t t;
memcpy(&t, p, sizeof t);
return t;
}
inline void UnalignedStore16(absl::Nonnull<void *> p, uint16_t v) {
memcpy(p, &v, sizeof v);
}
inline void UnalignedStore32(absl::Nonnull<void *> p, uint32_t v) {
memcpy(p, &v, sizeof v);
}
inline void UnalignedStore64(absl::Nonnull<void *> p, uint64_t v) {
memcpy(p, &v, sizeof v);
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#define ABSL_INTERNAL_UNALIGNED_LOAD16(_p) \
(absl::base_internal::UnalignedLoad16(_p))
#define ABSL_INTERNAL_UNALIGNED_LOAD32(_p) \
(absl::base_internal::UnalignedLoad32(_p))
#define ABSL_INTERNAL_UNALIGNED_LOAD64(_p) \
(absl::base_internal::UnalignedLoad64(_p))
#define ABSL_INTERNAL_UNALIGNED_STORE16(_p, _val) \
(absl::base_internal::UnalignedStore16(_p, _val))
#define ABSL_INTERNAL_UNALIGNED_STORE32(_p, _val) \
(absl::base_internal::UnalignedStore32(_p, _val))
#define ABSL_INTERNAL_UNALIGNED_STORE64(_p, _val) \
(absl::base_internal::UnalignedStore64(_p, _val))
#endif // defined(__cplusplus), end of unaligned API
#endif // ABSL_BASE_INTERNAL_UNALIGNED_ACCESS_H_

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// 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.
#include "absl/base/internal/unscaledcycleclock.h"
#if ABSL_USE_UNSCALED_CYCLECLOCK
#if defined(_WIN32)
#include <intrin.h>
#endif
#if defined(__powerpc__) || defined(__ppc__)
#ifdef __GLIBC__
#include <sys/platform/ppc.h>
#elif defined(__FreeBSD__)
// clang-format off
// This order does actually matter =(.
#include <sys/types.h>
#include <sys/sysctl.h>
// clang-format on
#include "absl/base/call_once.h"
#endif
#endif
#include "absl/base/internal/sysinfo.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
#if defined(__i386__)
int64_t UnscaledCycleClock::Now() {
int64_t ret;
__asm__ volatile("rdtsc" : "=A"(ret));
return ret;
}
double UnscaledCycleClock::Frequency() {
return base_internal::NominalCPUFrequency();
}
#elif defined(__x86_64__)
double UnscaledCycleClock::Frequency() {
return base_internal::NominalCPUFrequency();
}
#elif defined(__powerpc__) || defined(__ppc__)
int64_t UnscaledCycleClock::Now() {
#ifdef __GLIBC__
return __ppc_get_timebase();
#else
#ifdef __powerpc64__
int64_t tbr;
asm volatile("mfspr %0, 268" : "=r"(tbr));
return tbr;
#else
int32_t tbu, tbl, tmp;
asm volatile(
"mftbu %[hi32]\n"
"mftb %[lo32]\n"
"mftbu %[tmp]\n"
"cmpw %[tmp],%[hi32]\n"
"bne $-16\n" // Retry on failure.
: [hi32] "=r"(tbu), [lo32] "=r"(tbl), [tmp] "=r"(tmp));
return (static_cast<int64_t>(tbu) << 32) | tbl;
#endif
#endif
}
double UnscaledCycleClock::Frequency() {
#ifdef __GLIBC__
return __ppc_get_timebase_freq();
#elif defined(_AIX)
// This is the same constant value as returned by
// __ppc_get_timebase_freq().
return static_cast<double>(512000000);
#elif defined(__FreeBSD__)
static once_flag init_timebase_frequency_once;
static double timebase_frequency = 0.0;
base_internal::LowLevelCallOnce(&init_timebase_frequency_once, [&]() {
size_t length = sizeof(timebase_frequency);
sysctlbyname("kern.timecounter.tc.timebase.frequency", &timebase_frequency,
&length, nullptr, 0);
});
return timebase_frequency;
#else
#error Must implement UnscaledCycleClock::Frequency()
#endif
}
#elif defined(__aarch64__)
// System timer of ARMv8 runs at a different frequency than the CPU's.
// The frequency is fixed, typically in the range 1-50MHz. It can be
// read at CNTFRQ special register. We assume the OS has set up
// the virtual timer properly.
int64_t UnscaledCycleClock::Now() {
int64_t virtual_timer_value;
asm volatile("mrs %0, cntvct_el0" : "=r"(virtual_timer_value));
return virtual_timer_value;
}
double UnscaledCycleClock::Frequency() {
uint64_t aarch64_timer_frequency;
asm volatile("mrs %0, cntfrq_el0" : "=r"(aarch64_timer_frequency));
return aarch64_timer_frequency;
}
#elif defined(__riscv)
int64_t UnscaledCycleClock::Now() {
int64_t virtual_timer_value;
asm volatile("rdcycle %0" : "=r"(virtual_timer_value));
return virtual_timer_value;
}
double UnscaledCycleClock::Frequency() {
return base_internal::NominalCPUFrequency();
}
#elif defined(_M_IX86) || defined(_M_X64)
#pragma intrinsic(__rdtsc)
int64_t UnscaledCycleClock::Now() { return __rdtsc(); }
double UnscaledCycleClock::Frequency() {
return base_internal::NominalCPUFrequency();
}
#endif
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_USE_UNSCALED_CYCLECLOCK

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// 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.
//
// UnscaledCycleClock
// An UnscaledCycleClock yields the value and frequency of a cycle counter
// that increments at a rate that is approximately constant.
// This class is for internal use only, you should consider using CycleClock
// instead.
//
// Notes:
// The cycle counter frequency is not necessarily the core clock frequency.
// That is, CycleCounter cycles are not necessarily "CPU cycles".
//
// An arbitrary offset may have been added to the counter at power on.
//
// On some platforms, the rate and offset of the counter may differ
// slightly when read from different CPUs of a multiprocessor. Usually,
// we try to ensure that the operating system adjusts values periodically
// so that values agree approximately. If you need stronger guarantees,
// consider using alternate interfaces.
//
// The CPU is not required to maintain the ordering of a cycle counter read
// with respect to surrounding instructions.
#ifndef ABSL_BASE_INTERNAL_UNSCALEDCYCLECLOCK_H_
#define ABSL_BASE_INTERNAL_UNSCALEDCYCLECLOCK_H_
#include <cstdint>
#if defined(__APPLE__)
#include <TargetConditionals.h>
#endif
#include "absl/base/config.h"
#include "absl/base/internal/unscaledcycleclock_config.h"
#if ABSL_USE_UNSCALED_CYCLECLOCK
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace time_internal {
class UnscaledCycleClockWrapperForGetCurrentTime;
} // namespace time_internal
namespace base_internal {
class CycleClock;
class UnscaledCycleClockWrapperForInitializeFrequency;
class UnscaledCycleClock {
private:
UnscaledCycleClock() = delete;
// Return the value of a cycle counter that counts at a rate that is
// approximately constant.
static int64_t Now();
// Return the how much UnscaledCycleClock::Now() increases per second.
// This is not necessarily the core CPU clock frequency.
// It may be the nominal value report by the kernel, rather than a measured
// value.
static double Frequency();
// Allowed users
friend class base_internal::CycleClock;
friend class time_internal::UnscaledCycleClockWrapperForGetCurrentTime;
friend class base_internal::UnscaledCycleClockWrapperForInitializeFrequency;
};
#if defined(__x86_64__)
inline int64_t UnscaledCycleClock::Now() {
uint64_t low, high;
__asm__ volatile("rdtsc" : "=a"(low), "=d"(high));
return static_cast<int64_t>((high << 32) | low);
}
#endif
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_USE_UNSCALED_CYCLECLOCK
#endif // ABSL_BASE_INTERNAL_UNSCALEDCYCLECLOCK_H_

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// Copyright 2022 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.
#ifndef ABSL_BASE_INTERNAL_UNSCALEDCYCLECLOCK_CONFIG_H_
#define ABSL_BASE_INTERNAL_UNSCALEDCYCLECLOCK_CONFIG_H_
#if defined(__APPLE__)
#include <TargetConditionals.h>
#endif
// The following platforms have an implementation of a hardware counter.
#if defined(__i386__) || defined(__x86_64__) || defined(__aarch64__) || \
defined(__powerpc__) || defined(__ppc__) || defined(__riscv) || \
defined(_M_IX86) || (defined(_M_X64) && !defined(_M_ARM64EC))
#define ABSL_HAVE_UNSCALED_CYCLECLOCK_IMPLEMENTATION 1
#else
#define ABSL_HAVE_UNSCALED_CYCLECLOCK_IMPLEMENTATION 0
#endif
// The following platforms often disable access to the hardware
// counter (through a sandbox) even if the underlying hardware has a
// usable counter. The CycleTimer interface also requires a *scaled*
// CycleClock that runs at atleast 1 MHz. We've found some Android
// ARM64 devices where this is not the case, so we disable it by
// default on Android ARM64.
#if defined(__native_client__) || (defined(__APPLE__)) || \
(defined(__ANDROID__) && defined(__aarch64__))
#define ABSL_USE_UNSCALED_CYCLECLOCK_DEFAULT 0
#else
#define ABSL_USE_UNSCALED_CYCLECLOCK_DEFAULT 1
#endif
// UnscaledCycleClock is an optional internal feature.
// Use "#if ABSL_USE_UNSCALED_CYCLECLOCK" to test for its presence.
// Can be overridden at compile-time via -DABSL_USE_UNSCALED_CYCLECLOCK=0|1
#if !defined(ABSL_USE_UNSCALED_CYCLECLOCK)
#define ABSL_USE_UNSCALED_CYCLECLOCK \
(ABSL_HAVE_UNSCALED_CYCLECLOCK_IMPLEMENTATION && \
ABSL_USE_UNSCALED_CYCLECLOCK_DEFAULT)
#endif
#if ABSL_USE_UNSCALED_CYCLECLOCK
// This macro can be used to test if UnscaledCycleClock::Frequency()
// is NominalCPUFrequency() on a particular platform.
#if (defined(__i386__) || defined(__x86_64__) || defined(__riscv) || \
defined(_M_IX86) || defined(_M_X64))
#define ABSL_INTERNAL_UNSCALED_CYCLECLOCK_FREQUENCY_IS_CPU_FREQUENCY
#endif
#endif
#endif // ABSL_BASE_INTERNAL_UNSCALEDCYCLECLOCK_CONFIG_H_

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// 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.
#include "absl/base/log_severity.h"
#include <ostream>
#include "absl/base/attributes.h"
#include "absl/base/config.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
std::ostream& operator<<(std::ostream& os, absl::LogSeverity s) {
if (s == absl::NormalizeLogSeverity(s)) return os << absl::LogSeverityName(s);
return os << "absl::LogSeverity(" << static_cast<int>(s) << ")";
}
std::ostream& operator<<(std::ostream& os, absl::LogSeverityAtLeast s) {
switch (s) {
case absl::LogSeverityAtLeast::kInfo:
case absl::LogSeverityAtLeast::kWarning:
case absl::LogSeverityAtLeast::kError:
case absl::LogSeverityAtLeast::kFatal:
return os << ">=" << static_cast<absl::LogSeverity>(s);
case absl::LogSeverityAtLeast::kInfinity:
return os << "INFINITY";
}
return os;
}
std::ostream& operator<<(std::ostream& os, absl::LogSeverityAtMost s) {
switch (s) {
case absl::LogSeverityAtMost::kInfo:
case absl::LogSeverityAtMost::kWarning:
case absl::LogSeverityAtMost::kError:
case absl::LogSeverityAtMost::kFatal:
return os << "<=" << static_cast<absl::LogSeverity>(s);
case absl::LogSeverityAtMost::kNegativeInfinity:
return os << "NEGATIVE_INFINITY";
}
return os;
}
ABSL_NAMESPACE_END
} // namespace absl

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// 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.
#ifndef ABSL_BASE_LOG_SEVERITY_H_
#define ABSL_BASE_LOG_SEVERITY_H_
#include <array>
#include <ostream>
#include "absl/base/attributes.h"
#include "absl/base/config.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
// absl::LogSeverity
//
// Four severity levels are defined. Logging APIs should terminate the program
// when a message is logged at severity `kFatal`; the other levels have no
// special semantics.
//
// Values other than the four defined levels (e.g. produced by `static_cast`)
// are valid, but their semantics when passed to a function, macro, or flag
// depend on the function, macro, or flag. The usual behavior is to normalize
// such values to a defined severity level, however in some cases values other
// than the defined levels are useful for comparison.
//
// Example:
//
// // Effectively disables all logging:
// SetMinLogLevel(static_cast<absl::LogSeverity>(100));
//
// Abseil flags may be defined with type `LogSeverity`. Dependency layering
// constraints require that the `AbslParseFlag()` overload be declared and
// defined in the flags library itself rather than here. The `AbslUnparseFlag()`
// overload is defined there as well for consistency.
//
// absl::LogSeverity Flag String Representation
//
// An `absl::LogSeverity` has a string representation used for parsing
// command-line flags based on the enumerator name (e.g. `kFatal`) or
// its unprefixed name (without the `k`) in any case-insensitive form. (E.g.
// "FATAL", "fatal" or "Fatal" are all valid.) Unparsing such flags produces an
// unprefixed string representation in all caps (e.g. "FATAL") or an integer.
//
// Additionally, the parser accepts arbitrary integers (as if the type were
// `int`).
//
// Examples:
//
// --my_log_level=kInfo
// --my_log_level=INFO
// --my_log_level=info
// --my_log_level=0
//
// `DFATAL` and `kLogDebugFatal` are similarly accepted.
//
// Unparsing a flag produces the same result as `absl::LogSeverityName()` for
// the standard levels and a base-ten integer otherwise.
enum class LogSeverity : int {
kInfo = 0,
kWarning = 1,
kError = 2,
kFatal = 3,
};
// LogSeverities()
//
// Returns an iterable of all standard `absl::LogSeverity` values, ordered from
// least to most severe.
constexpr std::array<absl::LogSeverity, 4> LogSeverities() {
return {{absl::LogSeverity::kInfo, absl::LogSeverity::kWarning,
absl::LogSeverity::kError, absl::LogSeverity::kFatal}};
}
// `absl::kLogDebugFatal` equals `absl::LogSeverity::kFatal` in debug builds
// (i.e. when `NDEBUG` is not defined) and `absl::LogSeverity::kError`
// otherwise. Avoid ODR-using this variable as it has internal linkage and thus
// distinct storage in different TUs.
#ifdef NDEBUG
static constexpr absl::LogSeverity kLogDebugFatal = absl::LogSeverity::kError;
#else
static constexpr absl::LogSeverity kLogDebugFatal = absl::LogSeverity::kFatal;
#endif
// LogSeverityName()
//
// Returns the all-caps string representation (e.g. "INFO") of the specified
// severity level if it is one of the standard levels and "UNKNOWN" otherwise.
constexpr const char* LogSeverityName(absl::LogSeverity s) {
switch (s) {
case absl::LogSeverity::kInfo: return "INFO";
case absl::LogSeverity::kWarning: return "WARNING";
case absl::LogSeverity::kError: return "ERROR";
case absl::LogSeverity::kFatal: return "FATAL";
}
return "UNKNOWN";
}
// NormalizeLogSeverity()
//
// Values less than `kInfo` normalize to `kInfo`; values greater than `kFatal`
// normalize to `kError` (**NOT** `kFatal`).
constexpr absl::LogSeverity NormalizeLogSeverity(absl::LogSeverity s) {
absl::LogSeverity n = s;
if (n < absl::LogSeverity::kInfo) n = absl::LogSeverity::kInfo;
if (n > absl::LogSeverity::kFatal) n = absl::LogSeverity::kError;
return n;
}
constexpr absl::LogSeverity NormalizeLogSeverity(int s) {
return absl::NormalizeLogSeverity(static_cast<absl::LogSeverity>(s));
}
// operator<<
//
// The exact representation of a streamed `absl::LogSeverity` is deliberately
// unspecified; do not rely on it.
std::ostream& operator<<(std::ostream& os, absl::LogSeverity s);
// Enums representing a lower bound for LogSeverity. APIs that only operate on
// messages of at least a certain level (for example, `SetMinLogLevel()`) use
// this type to specify that level. absl::LogSeverityAtLeast::kInfinity is
// a level above all threshold levels and therefore no log message will
// ever meet this threshold.
enum class LogSeverityAtLeast : int {
kInfo = static_cast<int>(absl::LogSeverity::kInfo),
kWarning = static_cast<int>(absl::LogSeverity::kWarning),
kError = static_cast<int>(absl::LogSeverity::kError),
kFatal = static_cast<int>(absl::LogSeverity::kFatal),
kInfinity = 1000,
};
std::ostream& operator<<(std::ostream& os, absl::LogSeverityAtLeast s);
// Enums representing an upper bound for LogSeverity. APIs that only operate on
// messages of at most a certain level (for example, buffer all messages at or
// below a certain level) use this type to specify that level.
// absl::LogSeverityAtMost::kNegativeInfinity is a level below all threshold
// levels and therefore will exclude all log messages.
enum class LogSeverityAtMost : int {
kNegativeInfinity = -1000,
kInfo = static_cast<int>(absl::LogSeverity::kInfo),
kWarning = static_cast<int>(absl::LogSeverity::kWarning),
kError = static_cast<int>(absl::LogSeverity::kError),
kFatal = static_cast<int>(absl::LogSeverity::kFatal),
};
std::ostream& operator<<(std::ostream& os, absl::LogSeverityAtMost s);
#define COMPOP(op1, op2, T) \
constexpr bool operator op1(absl::T lhs, absl::LogSeverity rhs) { \
return static_cast<absl::LogSeverity>(lhs) op1 rhs; \
} \
constexpr bool operator op2(absl::LogSeverity lhs, absl::T rhs) { \
return lhs op2 static_cast<absl::LogSeverity>(rhs); \
}
// Comparisons between `LogSeverity` and `LogSeverityAtLeast`/
// `LogSeverityAtMost` are only supported in one direction.
// Valid checks are:
// LogSeverity >= LogSeverityAtLeast
// LogSeverity < LogSeverityAtLeast
// LogSeverity <= LogSeverityAtMost
// LogSeverity > LogSeverityAtMost
COMPOP(>, <, LogSeverityAtLeast)
COMPOP(<=, >=, LogSeverityAtLeast)
COMPOP(<, >, LogSeverityAtMost)
COMPOP(>=, <=, LogSeverityAtMost)
#undef COMPOP
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_LOG_SEVERITY_H_

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//
// 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: macros.h
// -----------------------------------------------------------------------------
//
// This header file defines the set of language macros used within Abseil code.
// For the set of macros used to determine supported compilers and platforms,
// see absl/base/config.h instead.
//
// This code is compiled directly on many platforms, including client
// platforms like Windows, Mac, and embedded systems. Before making
// any changes here, make sure that you're not breaking any platforms.
#ifndef ABSL_BASE_MACROS_H_
#define ABSL_BASE_MACROS_H_
#include <cassert>
#include <cstddef>
#include "absl/base/attributes.h"
#include "absl/base/config.h"
#include "absl/base/optimization.h"
#include "absl/base/port.h"
// ABSL_ARRAYSIZE()
//
// Returns the number of elements in an array as a compile-time constant, which
// can be used in defining new arrays. If you use this macro on a pointer by
// mistake, you will get a compile-time error.
#define ABSL_ARRAYSIZE(array) \
(sizeof(::absl::macros_internal::ArraySizeHelper(array)))
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace macros_internal {
// Note: this internal template function declaration is used by ABSL_ARRAYSIZE.
// The function doesn't need a definition, as we only use its type.
template <typename T, size_t N>
auto ArraySizeHelper(const T (&array)[N]) -> char (&)[N];
} // namespace macros_internal
ABSL_NAMESPACE_END
} // namespace absl
// ABSL_BAD_CALL_IF()
//
// Used on a function overload to trap bad calls: any call that matches the
// overload will cause a compile-time error. This macro uses a clang-specific
// "enable_if" attribute, as described at
// https://clang.llvm.org/docs/AttributeReference.html#enable-if
//
// Overloads which use this macro should be bracketed by
// `#ifdef ABSL_BAD_CALL_IF`.
//
// Example:
//
// int isdigit(int c);
// #ifdef ABSL_BAD_CALL_IF
// int isdigit(int c)
// ABSL_BAD_CALL_IF(c <= -1 || c > 255,
// "'c' must have the value of an unsigned char or EOF");
// #endif // ABSL_BAD_CALL_IF
#if ABSL_HAVE_ATTRIBUTE(enable_if)
#define ABSL_BAD_CALL_IF(expr, msg) \
__attribute__((enable_if(expr, "Bad call trap"), unavailable(msg)))
#endif
// ABSL_ASSERT()
//
// In C++11, `assert` can't be used portably within constexpr functions.
// ABSL_ASSERT functions as a runtime assert but works in C++11 constexpr
// functions. Example:
//
// constexpr double Divide(double a, double b) {
// return ABSL_ASSERT(b != 0), a / b;
// }
//
// This macro is inspired by
// https://akrzemi1.wordpress.com/2017/05/18/asserts-in-constexpr-functions/
#if defined(NDEBUG)
#define ABSL_ASSERT(expr) \
(false ? static_cast<void>(expr) : static_cast<void>(0))
#else
#define ABSL_ASSERT(expr) \
(ABSL_PREDICT_TRUE((expr)) ? static_cast<void>(0) \
: [] { assert(false && #expr); }()) // NOLINT
#endif
// `ABSL_INTERNAL_HARDENING_ABORT()` controls how `ABSL_HARDENING_ASSERT()`
// aborts the program in release mode (when NDEBUG is defined). The
// implementation should abort the program as quickly as possible and ideally it
// should not be possible to ignore the abort request.
#define ABSL_INTERNAL_HARDENING_ABORT() \
do { \
ABSL_INTERNAL_IMMEDIATE_ABORT_IMPL(); \
ABSL_INTERNAL_UNREACHABLE_IMPL(); \
} while (false)
// ABSL_HARDENING_ASSERT()
//
// `ABSL_HARDENING_ASSERT()` is like `ABSL_ASSERT()`, but used to implement
// runtime assertions that should be enabled in hardened builds even when
// `NDEBUG` is defined.
//
// When `NDEBUG` is not defined, `ABSL_HARDENING_ASSERT()` is identical to
// `ABSL_ASSERT()`.
//
// See `ABSL_OPTION_HARDENED` in `absl/base/options.h` for more information on
// hardened mode.
#if ABSL_OPTION_HARDENED == 1 && defined(NDEBUG)
#define ABSL_HARDENING_ASSERT(expr) \
(ABSL_PREDICT_TRUE((expr)) ? static_cast<void>(0) \
: [] { ABSL_INTERNAL_HARDENING_ABORT(); }())
#else
#define ABSL_HARDENING_ASSERT(expr) ABSL_ASSERT(expr)
#endif
#ifdef ABSL_HAVE_EXCEPTIONS
#define ABSL_INTERNAL_TRY try
#define ABSL_INTERNAL_CATCH_ANY catch (...)
#define ABSL_INTERNAL_RETHROW do { throw; } while (false)
#else // ABSL_HAVE_EXCEPTIONS
#define ABSL_INTERNAL_TRY if (true)
#define ABSL_INTERNAL_CATCH_ANY else if (false)
#define ABSL_INTERNAL_RETHROW do {} while (false)
#endif // ABSL_HAVE_EXCEPTIONS
#endif // ABSL_BASE_MACROS_H_

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// Copyright 2023 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: no_destructor.h
// -----------------------------------------------------------------------------
//
// This header file defines the absl::NoDestructor<T> wrapper for defining a
// static type that does not need to be destructed upon program exit. Instead,
// such an object survives during program exit (and can be safely accessed at
// any time).
//
// Objects of such type, if constructed safely and under the right conditions,
// provide two main benefits over other alternatives:
//
// * Global objects not normally allowed due to concerns of destruction order
// (i.e. no "complex globals") can be safely allowed, provided that such
// objects can be constant initialized.
// * Function scope static objects can be optimized to avoid heap allocation,
// pointer chasing, and allow lazy construction.
//
// See below for complete details.
#ifndef ABSL_BASE_NO_DESTRUCTOR_H_
#define ABSL_BASE_NO_DESTRUCTOR_H_
#include <new>
#include <type_traits>
#include <utility>
#include "absl/base/config.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
// absl::NoDestructor<T>
//
// NoDestructor<T> is a wrapper around an object of type T that behaves as an
// object of type T but never calls T's destructor. NoDestructor<T> makes it
// safer and/or more efficient to use such objects in static storage contexts:
// as global or function scope static variables.
//
// An instance of absl::NoDestructor<T> has similar type semantics to an
// instance of T:
//
// * Constructs in the same manner as an object of type T through perfect
// forwarding.
// * Provides pointer/reference semantic access to the object of type T via
// `->`, `*`, and `get()`.
// (Note that `const NoDestructor<T>` works like a pointer to const `T`.)
//
// An object of type NoDestructor<T> should be defined in static storage:
// as either a global static object, or as a function scope static variable.
//
// Additionally, NoDestructor<T> provides the following benefits:
//
// * Never calls T's destructor for the object
// * If the object is a function-local static variable, the type can be
// lazily constructed.
//
// An object of type NoDestructor<T> is "trivially destructible" in the notion
// that its destructor is never run. Provided that an object of this type can be
// safely initialized and does not need to be cleaned up on program shutdown,
// NoDestructor<T> allows you to define global static variables, since Google's
// C++ style guide ban on such objects doesn't apply to objects that are
// trivially destructible.
//
// Usage as Global Static Variables
//
// NoDestructor<T> allows declaration of a global object with a non-trivial
// constructor in static storage without needing to add a destructor.
// However, such objects still need to worry about initialization order, so
// such objects should be const initialized:
//
// // Global or namespace scope.
// ABSL_CONST_INIT absl::NoDestructor<MyRegistry> reg{"foo", "bar", 8008};
//
// Note that if your object already has a trivial destructor, you don't need to
// use NoDestructor<T>.
//
// Usage as Function Scope Static Variables
//
// Function static objects will be lazily initialized within static storage:
//
// // Function scope.
// const std::string& MyString() {
// static const absl::NoDestructor<std::string> x("foo");
// return *x;
// }
//
// For function static variables, NoDestructor avoids heap allocation and can be
// inlined in static storage, resulting in exactly-once, thread-safe
// construction of an object, and very fast access thereafter (the cost is a few
// extra cycles).
//
// Using NoDestructor<T> in this manner is generally better than other patterns
// which require pointer chasing:
//
// // Prefer using absl::NoDestructor<T> instead for the static variable.
// const std::string& MyString() {
// static const std::string* x = new std::string("foo");
// return *x;
// }
//
template <typename T>
class NoDestructor {
public:
// Forwards arguments to the T's constructor: calls T(args...).
template <typename... Ts,
// Disable this overload when it might collide with copy/move.
typename std::enable_if<!std::is_same<void(std::decay_t<Ts>&...),
void(NoDestructor&)>::value,
int>::type = 0>
explicit constexpr NoDestructor(Ts&&... args)
: impl_(std::forward<Ts>(args)...) {}
// Forwards copy and move construction for T. Enables usage like this:
// static NoDestructor<std::array<string, 3>> x{{{"1", "2", "3"}}};
// static NoDestructor<std::vector<int>> x{{1, 2, 3}};
explicit constexpr NoDestructor(const T& x) : impl_(x) {}
explicit constexpr NoDestructor(T&& x)
: impl_(std::move(x)) {}
// No copying.
NoDestructor(const NoDestructor&) = delete;
NoDestructor& operator=(const NoDestructor&) = delete;
// Pretend to be a smart pointer to T with deep constness.
// Never returns a null pointer.
T& operator*() { return *get(); }
T* operator->() { return get(); }
T* get() { return impl_.get(); }
const T& operator*() const { return *get(); }
const T* operator->() const { return get(); }
const T* get() const { return impl_.get(); }
private:
class DirectImpl {
public:
template <typename... Args>
explicit constexpr DirectImpl(Args&&... args)
: value_(std::forward<Args>(args)...) {}
const T* get() const { return &value_; }
T* get() { return &value_; }
private:
T value_;
};
class PlacementImpl {
public:
template <typename... Args>
explicit PlacementImpl(Args&&... args) {
new (&space_) T(std::forward<Args>(args)...);
}
const T* get() const {
return Launder(reinterpret_cast<const T*>(&space_));
}
T* get() { return Launder(reinterpret_cast<T*>(&space_)); }
private:
template <typename P>
static P* Launder(P* p) {
#if defined(__cpp_lib_launder) && __cpp_lib_launder >= 201606L
return std::launder(p);
#elif ABSL_HAVE_BUILTIN(__builtin_launder)
return __builtin_launder(p);
#else
// When `std::launder` or equivalent are not available, we rely on
// undefined behavior, which works as intended on Abseil's officially
// supported platforms as of Q3 2023.
#if defined(__GNUC__) && !defined(__clang__)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wstrict-aliasing"
#endif
return p;
#if defined(__GNUC__) && !defined(__clang__)
#pragma GCC diagnostic pop
#endif
#endif
}
alignas(T) unsigned char space_[sizeof(T)];
};
// If the object is trivially destructible we use a member directly to avoid
// potential once-init runtime initialization. It somewhat defeats the
// purpose of NoDestructor in this case, but this makes the class more
// friendly to generic code.
std::conditional_t<std::is_trivially_destructible<T>::value, DirectImpl,
PlacementImpl>
impl_;
};
#ifdef ABSL_HAVE_CLASS_TEMPLATE_ARGUMENT_DEDUCTION
// Provide 'Class Template Argument Deduction': the type of NoDestructor's T
// will be the same type as the argument passed to NoDestructor's constructor.
template <typename T>
NoDestructor(T) -> NoDestructor<T>;
#endif // ABSL_HAVE_CLASS_TEMPLATE_ARGUMENT_DEDUCTION
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_NO_DESTRUCTOR_H_

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// Copyright 2023 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: nullability.h
// -----------------------------------------------------------------------------
//
// This header file defines a set of "templated annotations" for designating the
// expected nullability of pointers. These annotations allow you to designate
// pointers in one of three classification states:
//
// * "Non-null" (for pointers annotated `Nonnull<T>`), indicating that it is
// invalid for the given pointer to ever be null.
// * "Nullable" (for pointers annotated `Nullable<T>`), indicating that it is
// valid for the given pointer to be null.
// * "Unknown" (for pointers annotated `NullabilityUnknown<T>`), indicating
// that the given pointer has not been yet classified as either nullable or
// non-null. This is the default state of unannotated pointers.
//
// NOTE: unannotated pointers implicitly bear the annotation
// `NullabilityUnknown<T>`; you should rarely, if ever, see this annotation used
// in the codebase explicitly.
//
// -----------------------------------------------------------------------------
// Nullability and Contracts
// -----------------------------------------------------------------------------
//
// These nullability annotations allow you to more clearly specify contracts on
// software components by narrowing the *preconditions*, *postconditions*, and
// *invariants* of pointer state(s) in any given interface. It then depends on
// context who is responsible for fulfilling the annotation's requirements.
//
// For example, a function may receive a pointer argument. Designating that
// pointer argument as "non-null" tightens the precondition of the contract of
// that function. It is then the responsibility of anyone calling such a
// function to ensure that the passed pointer is not null.
//
// Similarly, a function may have a pointer as a return value. Designating that
// return value as "non-null" tightens the postcondition of the contract of that
// function. In this case, however, it is the responsibility of the function
// itself to ensure that the returned pointer is not null.
//
// Clearly defining these contracts allows providers (and consumers) of such
// pointers to have more confidence in their null state. If a function declares
// a return value as "non-null", for example, the caller should not need to
// check whether the returned value is `nullptr`; it can simply assume the
// pointer is valid.
//
// Of course most interfaces already have expectations on the nullability state
// of pointers, and these expectations are, in effect, a contract; often,
// however, those contracts are either poorly or partially specified, assumed,
// or misunderstood. These nullability annotations are designed to allow you to
// formalize those contracts within the codebase.
//
// -----------------------------------------------------------------------------
// Using Nullability Annotations
// -----------------------------------------------------------------------------
//
// It is important to note that these annotations are not distinct strong
// *types*. They are alias templates defined to be equal to the underlying
// pointer type. A pointer annotated `Nonnull<T*>`, for example, is simply a
// pointer of type `T*`. Each annotation acts as a form of documentation about
// the contract for the given pointer. Each annotation requires providers or
// consumers of these pointers across API boundaries to take appropriate steps
// when setting or using these pointers:
//
// * "Non-null" pointers should never be null. It is the responsibility of the
// provider of this pointer to ensure that the pointer may never be set to
// null. Consumers of such pointers can treat such pointers as non-null.
// * "Nullable" pointers may or may not be null. Consumers of such pointers
// should precede any usage of that pointer (e.g. a dereference operation)
// with a a `nullptr` check.
// * "Unknown" pointers may be either "non-null" or "nullable" but have not been
// definitively determined to be in either classification state. Providers of
// such pointers across API boundaries should determine -- over time -- to
// annotate the pointer in either of the above two states. Consumers of such
// pointers across an API boundary should continue to treat such pointers as
// they currently do.
//
// Example:
//
// // PaySalary() requires the passed pointer to an `Employee` to be non-null.
// void PaySalary(absl::Nonnull<Employee *> e) {
// pay(e->salary); // OK to dereference
// }
//
// // CompleteTransaction() guarantees the returned pointer to an `Account` to
// // be non-null.
// absl::Nonnull<Account *> balance CompleteTransaction(double fee) {
// ...
// }
//
// // Note that specifying a nullability annotation does not prevent someone
// // from violating the contract:
//
// Nullable<Employee *> find(Map& employees, std::string_view name);
//
// void g(Map& employees) {
// Employee *e = find(employees, "Pat");
// // `e` can now be null.
// PaySalary(e); // Violates contract, but compiles!
// }
//
// Nullability annotations, in other words, are useful for defining and
// narrowing contracts; *enforcement* of those contracts depends on use and any
// additional (static or dynamic analysis) tooling.
//
// NOTE: The "unknown" annotation state indicates that a pointer's contract has
// not yet been positively identified. The unknown state therefore acts as a
// form of documentation of your technical debt, and a codebase that adopts
// nullability annotations should aspire to annotate every pointer as either
// "non-null" or "nullable".
//
// -----------------------------------------------------------------------------
// Applicability of Nullability Annotations
// -----------------------------------------------------------------------------
//
// By default, nullability annotations are applicable to raw and smart
// pointers. User-defined types can indicate compatibility with nullability
// annotations by providing an `absl_nullability_compatible` nested type. The
// actual definition of this inner type is not relevant as it is used merely as
// a marker. It is common to use a using declaration of
// `absl_nullability_compatible` set to void.
//
// // Example:
// struct MyPtr {
// using absl_nullability_compatible = void;
// ...
// };
//
// DISCLAIMER:
// ===========================================================================
// These nullability annotations are primarily a human readable signal about the
// intended contract of the pointer. They are not *types* and do not currently
// provide any correctness guarantees. For example, a pointer annotated as
// `Nonnull<T*>` is *not guaranteed* to be non-null, and the compiler won't
// alert or prevent assignment of a `Nullable<T*>` to a `Nonnull<T*>`.
// ===========================================================================
#ifndef ABSL_BASE_NULLABILITY_H_
#define ABSL_BASE_NULLABILITY_H_
#include "absl/base/internal/nullability_impl.h"
namespace absl {
// absl::Nonnull
//
// The indicated pointer is never null. It is the responsibility of the provider
// of this pointer across an API boundary to ensure that the pointer is never be
// set to null. Consumers of this pointer across an API boundary may safely
// dereference the pointer.
//
// Example:
//
// // `employee` is designated as not null.
// void PaySalary(absl::Nonnull<Employee *> employee) {
// pay(*employee); // OK to dereference
// }
template <typename T>
using Nonnull = nullability_internal::NonnullImpl<T>;
// absl::Nullable
//
// The indicated pointer may, by design, be either null or non-null. Consumers
// of this pointer across an API boundary should perform a `nullptr` check
// before performing any operation using the pointer.
//
// Example:
//
// // `employee` may be null.
// void PaySalary(absl::Nullable<Employee *> employee) {
// if (employee != nullptr) {
// Pay(*employee); // OK to dereference
// }
// }
template <typename T>
using Nullable = nullability_internal::NullableImpl<T>;
// absl::NullabilityUnknown (default)
//
// The indicated pointer has not yet been determined to be definitively
// "non-null" or "nullable." Providers of such pointers across API boundaries
// should, over time, annotate such pointers as either "non-null" or "nullable."
// Consumers of these pointers across an API boundary should treat such pointers
// with the same caution they treat currently unannotated pointers. Most
// existing code will have "unknown" pointers, which should eventually be
// migrated into one of the above two nullability states: `Nonnull<T>` or
// `Nullable<T>`.
//
// NOTE: Because this annotation is the global default state, pointers without
// any annotation are assumed to have "unknown" semantics. This assumption is
// designed to minimize churn and reduce clutter within the codebase.
//
// Example:
//
// // `employee`s nullability state is unknown.
// void PaySalary(absl::NullabilityUnknown<Employee *> employee) {
// Pay(*employee); // Potentially dangerous. API provider should investigate.
// }
//
// Note that a pointer without an annotation, by default, is assumed to have the
// annotation `NullabilityUnknown`.
//
// // `employee`s nullability state is unknown.
// void PaySalary(Employee* employee) {
// Pay(*employee); // Potentially dangerous. API provider should investigate.
// }
template <typename T>
using NullabilityUnknown = nullability_internal::NullabilityUnknownImpl<T>;
} // namespace absl
#endif // ABSL_BASE_NULLABILITY_H_

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//
// 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: optimization.h
// -----------------------------------------------------------------------------
//
// This header file defines portable macros for performance optimization.
#ifndef ABSL_BASE_OPTIMIZATION_H_
#define ABSL_BASE_OPTIMIZATION_H_
#include <assert.h>
#include "absl/base/config.h"
#include "absl/base/options.h"
// ABSL_BLOCK_TAIL_CALL_OPTIMIZATION
//
// Instructs the compiler to avoid optimizing tail-call recursion. This macro is
// useful when you wish to preserve the existing function order within a stack
// trace for logging, debugging, or profiling purposes.
//
// Example:
//
// int f() {
// int result = g();
// ABSL_BLOCK_TAIL_CALL_OPTIMIZATION();
// return result;
// }
#if defined(__pnacl__)
#define ABSL_BLOCK_TAIL_CALL_OPTIMIZATION() if (volatile int x = 0) { (void)x; }
#elif defined(__clang__)
// Clang will not tail call given inline volatile assembly.
#define ABSL_BLOCK_TAIL_CALL_OPTIMIZATION() __asm__ __volatile__("")
#elif defined(__GNUC__)
// GCC will not tail call given inline volatile assembly.
#define ABSL_BLOCK_TAIL_CALL_OPTIMIZATION() __asm__ __volatile__("")
#elif defined(_MSC_VER)
#include <intrin.h>
// The __nop() intrinsic blocks the optimisation.
#define ABSL_BLOCK_TAIL_CALL_OPTIMIZATION() __nop()
#else
#define ABSL_BLOCK_TAIL_CALL_OPTIMIZATION() if (volatile int x = 0) { (void)x; }
#endif
// ABSL_CACHELINE_SIZE
//
// Explicitly defines the size of the L1 cache for purposes of alignment.
// Setting the cacheline size allows you to specify that certain objects be
// aligned on a cacheline boundary with `ABSL_CACHELINE_ALIGNED` declarations.
// (See below.)
//
// NOTE: this macro should be replaced with the following C++17 features, when
// those are generally available:
//
// * `std::hardware_constructive_interference_size`
// * `std::hardware_destructive_interference_size`
//
// See http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0154r1.html
// for more information.
#if defined(__GNUC__)
// Cache line alignment
#if defined(__i386__) || defined(__x86_64__)
#define ABSL_CACHELINE_SIZE 64
#elif defined(__powerpc64__)
#define ABSL_CACHELINE_SIZE 128
#elif defined(__aarch64__)
// We would need to read special register ctr_el0 to find out L1 dcache size.
// This value is a good estimate based on a real aarch64 machine.
#define ABSL_CACHELINE_SIZE 64
#elif defined(__arm__)
// Cache line sizes for ARM: These values are not strictly correct since
// cache line sizes depend on implementations, not architectures. There
// are even implementations with cache line sizes configurable at boot
// time.
#if defined(__ARM_ARCH_5T__)
#define ABSL_CACHELINE_SIZE 32
#elif defined(__ARM_ARCH_7A__)
#define ABSL_CACHELINE_SIZE 64
#endif
#endif
#endif
#ifndef ABSL_CACHELINE_SIZE
// A reasonable default guess. Note that overestimates tend to waste more
// space, while underestimates tend to waste more time.
#define ABSL_CACHELINE_SIZE 64
#endif
// ABSL_CACHELINE_ALIGNED
//
// Indicates that the declared object be cache aligned using
// `ABSL_CACHELINE_SIZE` (see above). Cacheline aligning objects allows you to
// load a set of related objects in the L1 cache for performance improvements.
// Cacheline aligning objects properly allows constructive memory sharing and
// prevents destructive (or "false") memory sharing.
//
// NOTE: callers should replace uses of this macro with `alignas()` using
// `std::hardware_constructive_interference_size` and/or
// `std::hardware_destructive_interference_size` when C++17 becomes available to
// them.
//
// See http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0154r1.html
// for more information.
//
// On some compilers, `ABSL_CACHELINE_ALIGNED` expands to an `__attribute__`
// or `__declspec` attribute. For compilers where this is not known to work,
// the macro expands to nothing.
//
// No further guarantees are made here. The result of applying the macro
// to variables and types is always implementation-defined.
//
// WARNING: It is easy to use this attribute incorrectly, even to the point
// of causing bugs that are difficult to diagnose, crash, etc. It does not
// of itself guarantee that objects are aligned to a cache line.
//
// NOTE: Some compilers are picky about the locations of annotations such as
// this attribute, so prefer to put it at the beginning of your declaration.
// For example,
//
// ABSL_CACHELINE_ALIGNED static Foo* foo = ...
//
// class ABSL_CACHELINE_ALIGNED Bar { ...
//
// Recommendations:
//
// 1) Consult compiler documentation; this comment is not kept in sync as
// toolchains evolve.
// 2) Verify your use has the intended effect. This often requires inspecting
// the generated machine code.
// 3) Prefer applying this attribute to individual variables. Avoid
// applying it to types. This tends to localize the effect.
#if defined(__clang__) || defined(__GNUC__)
#define ABSL_CACHELINE_ALIGNED __attribute__((aligned(ABSL_CACHELINE_SIZE)))
#elif defined(_MSC_VER)
#define ABSL_CACHELINE_ALIGNED __declspec(align(ABSL_CACHELINE_SIZE))
#else
#define ABSL_CACHELINE_ALIGNED
#endif
// ABSL_PREDICT_TRUE, ABSL_PREDICT_FALSE
//
// Enables the compiler to prioritize compilation using static analysis for
// likely paths within a boolean branch.
//
// Example:
//
// if (ABSL_PREDICT_TRUE(expression)) {
// return result; // Faster if more likely
// } else {
// return 0;
// }
//
// Compilers can use the information that a certain branch is not likely to be
// taken (for instance, a CHECK failure) to optimize for the common case in
// the absence of better information (ie. compiling gcc with `-fprofile-arcs`).
//
// Recommendation: Modern CPUs dynamically predict branch execution paths,
// typically with accuracy greater than 97%. As a result, annotating every
// branch in a codebase is likely counterproductive; however, annotating
// specific branches that are both hot and consistently mispredicted is likely
// to yield performance improvements.
#if ABSL_HAVE_BUILTIN(__builtin_expect) || \
(defined(__GNUC__) && !defined(__clang__))
#define ABSL_PREDICT_FALSE(x) (__builtin_expect(false || (x), false))
#define ABSL_PREDICT_TRUE(x) (__builtin_expect(false || (x), true))
#else
#define ABSL_PREDICT_FALSE(x) (x)
#define ABSL_PREDICT_TRUE(x) (x)
#endif
// `ABSL_INTERNAL_IMMEDIATE_ABORT_IMPL()` aborts the program in the fastest
// possible way, with no attempt at logging. One use is to implement hardening
// aborts with ABSL_OPTION_HARDENED. Since this is an internal symbol, it
// should not be used directly outside of Abseil.
#if ABSL_HAVE_BUILTIN(__builtin_trap) || \
(defined(__GNUC__) && !defined(__clang__))
#define ABSL_INTERNAL_IMMEDIATE_ABORT_IMPL() __builtin_trap()
#else
#define ABSL_INTERNAL_IMMEDIATE_ABORT_IMPL() abort()
#endif
// `ABSL_INTERNAL_UNREACHABLE_IMPL()` is the platform specific directive to
// indicate that a statement is unreachable, and to allow the compiler to
// optimize accordingly. Clients should use `ABSL_UNREACHABLE()`, which is
// defined below.
#if defined(__cpp_lib_unreachable) && __cpp_lib_unreachable >= 202202L
#define ABSL_INTERNAL_UNREACHABLE_IMPL() std::unreachable()
#elif defined(__GNUC__) || ABSL_HAVE_BUILTIN(__builtin_unreachable)
#define ABSL_INTERNAL_UNREACHABLE_IMPL() __builtin_unreachable()
#elif ABSL_HAVE_BUILTIN(__builtin_assume)
#define ABSL_INTERNAL_UNREACHABLE_IMPL() __builtin_assume(false)
#elif defined(_MSC_VER)
#define ABSL_INTERNAL_UNREACHABLE_IMPL() __assume(false)
#else
#define ABSL_INTERNAL_UNREACHABLE_IMPL()
#endif
// `ABSL_UNREACHABLE()` is an unreachable statement. A program which reaches
// one has undefined behavior, and the compiler may optimize accordingly.
#if ABSL_OPTION_HARDENED == 1 && defined(NDEBUG)
// Abort in hardened mode to avoid dangerous undefined behavior.
#define ABSL_UNREACHABLE() \
do { \
ABSL_INTERNAL_IMMEDIATE_ABORT_IMPL(); \
ABSL_INTERNAL_UNREACHABLE_IMPL(); \
} while (false)
#else
// The assert only fires in debug mode to aid in debugging.
// When NDEBUG is defined, reaching ABSL_UNREACHABLE() is undefined behavior.
#define ABSL_UNREACHABLE() \
do { \
/* NOLINTNEXTLINE: misc-static-assert */ \
assert(false && "ABSL_UNREACHABLE reached"); \
ABSL_INTERNAL_UNREACHABLE_IMPL(); \
} while (false)
#endif
// ABSL_ASSUME(cond)
//
// Informs the compiler that a condition is always true and that it can assume
// it to be true for optimization purposes.
//
// WARNING: If the condition is false, the program can produce undefined and
// potentially dangerous behavior.
//
// In !NDEBUG mode, the condition is checked with an assert().
//
// NOTE: The expression must not have side effects, as it may only be evaluated
// in some compilation modes and not others. Some compilers may issue a warning
// if the compiler cannot prove the expression has no side effects. For example,
// the expression should not use a function call since the compiler cannot prove
// that a function call does not have side effects.
//
// Example:
//
// int x = ...;
// ABSL_ASSUME(x >= 0);
// // The compiler can optimize the division to a simple right shift using the
// // assumption specified above.
// int y = x / 16;
//
#if !defined(NDEBUG)
#define ABSL_ASSUME(cond) assert(cond)
#elif ABSL_HAVE_BUILTIN(__builtin_assume)
#define ABSL_ASSUME(cond) __builtin_assume(cond)
#elif defined(_MSC_VER)
#define ABSL_ASSUME(cond) __assume(cond)
#elif defined(__cpp_lib_unreachable) && __cpp_lib_unreachable >= 202202L
#define ABSL_ASSUME(cond) \
do { \
if (!(cond)) std::unreachable(); \
} while (false)
#elif defined(__GNUC__) || ABSL_HAVE_BUILTIN(__builtin_unreachable)
#define ABSL_ASSUME(cond) \
do { \
if (!(cond)) __builtin_unreachable(); \
} while (false)
#else
#define ABSL_ASSUME(cond) \
do { \
static_cast<void>(false && (cond)); \
} while (false)
#endif
// ABSL_INTERNAL_UNIQUE_SMALL_NAME(cond)
// This macro forces small unique name on a static file level symbols like
// static local variables or static functions. This is intended to be used in
// macro definitions to optimize the cost of generated code. Do NOT use it on
// symbols exported from translation unit since it may cause a link time
// conflict.
//
// Example:
//
// #define MY_MACRO(txt)
// namespace {
// char VeryVeryLongVarName[] ABSL_INTERNAL_UNIQUE_SMALL_NAME() = txt;
// const char* VeryVeryLongFuncName() ABSL_INTERNAL_UNIQUE_SMALL_NAME();
// const char* VeryVeryLongFuncName() { return txt; }
// }
//
#if defined(__GNUC__)
#define ABSL_INTERNAL_UNIQUE_SMALL_NAME2(x) #x
#define ABSL_INTERNAL_UNIQUE_SMALL_NAME1(x) ABSL_INTERNAL_UNIQUE_SMALL_NAME2(x)
#define ABSL_INTERNAL_UNIQUE_SMALL_NAME() \
asm(ABSL_INTERNAL_UNIQUE_SMALL_NAME1(.absl.__COUNTER__))
#else
#define ABSL_INTERNAL_UNIQUE_SMALL_NAME()
#endif
#endif // ABSL_BASE_OPTIMIZATION_H_

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// Copyright 2019 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: options.h
// -----------------------------------------------------------------------------
//
// This file contains Abseil configuration options for setting specific
// implementations instead of letting Abseil determine which implementation to
// use at compile-time. Setting these options may be useful for package or build
// managers who wish to guarantee ABI stability within binary builds (which are
// otherwise difficult to enforce).
//
// *** IMPORTANT NOTICE FOR PACKAGE MANAGERS: It is important that
// maintainers of package managers who wish to package Abseil read and
// understand this file! ***
//
// Abseil contains a number of possible configuration endpoints, based on
// parameters such as the detected platform, language version, or command-line
// flags used to invoke the underlying binary. As is the case with all
// libraries, binaries which contain Abseil code must ensure that separate
// packages use the same compiled copy of Abseil to avoid a diamond dependency
// problem, which can occur if two packages built with different Abseil
// configuration settings are linked together. Diamond dependency problems in
// C++ may manifest as violations to the One Definition Rule (ODR) (resulting in
// linker errors), or undefined behavior (resulting in crashes).
//
// Diamond dependency problems can be avoided if all packages utilize the same
// exact version of Abseil. Building from source code with the same compilation
// parameters is the easiest way to avoid such dependency problems. However, for
// package managers who cannot control such compilation parameters, we are
// providing the file to allow you to inject ABI (Application Binary Interface)
// stability across builds. Settings options in this file will neither change
// API nor ABI, providing a stable copy of Abseil between packages.
//
// Care must be taken to keep options within these configurations isolated
// from any other dynamic settings, such as command-line flags which could alter
// these options. This file is provided specifically to help build and package
// managers provide a stable copy of Abseil within their libraries and binaries;
// other developers should not have need to alter the contents of this file.
//
// -----------------------------------------------------------------------------
// Usage
// -----------------------------------------------------------------------------
//
// For any particular package release, set the appropriate definitions within
// this file to whatever value makes the most sense for your package(s). Note
// that, by default, most of these options, at the moment, affect the
// implementation of types; future options may affect other implementation
// details.
//
// NOTE: the defaults within this file all assume that Abseil can select the
// proper Abseil implementation at compile-time, which will not be sufficient
// to guarantee ABI stability to package managers.
#ifndef ABSL_BASE_OPTIONS_H_
#define ABSL_BASE_OPTIONS_H_
// -----------------------------------------------------------------------------
// Type Compatibility Options
// -----------------------------------------------------------------------------
//
// ABSL_OPTION_USE_STD_ANY
//
// This option controls whether absl::any is implemented as an alias to
// std::any, or as an independent implementation.
//
// A value of 0 means to use Abseil's implementation. This requires only C++11
// support, and is expected to work on every toolchain we support.
//
// A value of 1 means to use an alias to std::any. This requires that all code
// using Abseil is built in C++17 mode or later.
//
// A value of 2 means to detect the C++ version being used to compile Abseil,
// and use an alias only if a working std::any is available. This option is
// useful when you are building your entire program, including all of its
// dependencies, from source. It should not be used otherwise -- for example,
// if you are distributing Abseil in a binary package manager -- since in
// mode 2, absl::any will name a different type, with a different mangled name
// and binary layout, depending on the compiler flags passed by the end user.
// For more info, see https://abseil.io/about/design/dropin-types.
//
// User code should not inspect this macro. To check in the preprocessor if
// absl::any is a typedef of std::any, use the feature macro ABSL_USES_STD_ANY.
#define ABSL_OPTION_USE_STD_ANY 2
// ABSL_OPTION_USE_STD_OPTIONAL
//
// This option controls whether absl::optional is implemented as an alias to
// std::optional, or as an independent implementation.
//
// A value of 0 means to use Abseil's implementation. This requires only C++11
// support, and is expected to work on every toolchain we support.
//
// A value of 1 means to use an alias to std::optional. This requires that all
// code using Abseil is built in C++17 mode or later.
//
// A value of 2 means to detect the C++ version being used to compile Abseil,
// and use an alias only if a working std::optional is available. This option
// is useful when you are building your program from source. It should not be
// used otherwise -- for example, if you are distributing Abseil in a binary
// package manager -- since in mode 2, absl::optional will name a different
// type, with a different mangled name and binary layout, depending on the
// compiler flags passed by the end user. For more info, see
// https://abseil.io/about/design/dropin-types.
// User code should not inspect this macro. To check in the preprocessor if
// absl::optional is a typedef of std::optional, use the feature macro
// ABSL_USES_STD_OPTIONAL.
#define ABSL_OPTION_USE_STD_OPTIONAL 2
// ABSL_OPTION_USE_STD_STRING_VIEW
//
// This option controls whether absl::string_view is implemented as an alias to
// std::string_view, or as an independent implementation.
//
// A value of 0 means to use Abseil's implementation. This requires only C++11
// support, and is expected to work on every toolchain we support.
//
// A value of 1 means to use an alias to std::string_view. This requires that
// all code using Abseil is built in C++17 mode or later.
//
// A value of 2 means to detect the C++ version being used to compile Abseil,
// and use an alias only if a working std::string_view is available. This
// option is useful when you are building your program from source. It should
// not be used otherwise -- for example, if you are distributing Abseil in a
// binary package manager -- since in mode 2, absl::string_view will name a
// different type, with a different mangled name and binary layout, depending on
// the compiler flags passed by the end user. For more info, see
// https://abseil.io/about/design/dropin-types.
//
// User code should not inspect this macro. To check in the preprocessor if
// absl::string_view is a typedef of std::string_view, use the feature macro
// ABSL_USES_STD_STRING_VIEW.
#define ABSL_OPTION_USE_STD_STRING_VIEW 2
// ABSL_OPTION_USE_STD_VARIANT
//
// This option controls whether absl::variant is implemented as an alias to
// std::variant, or as an independent implementation.
//
// A value of 0 means to use Abseil's implementation. This requires only C++11
// support, and is expected to work on every toolchain we support.
//
// A value of 1 means to use an alias to std::variant. This requires that all
// code using Abseil is built in C++17 mode or later.
//
// A value of 2 means to detect the C++ version being used to compile Abseil,
// and use an alias only if a working std::variant is available. This option
// is useful when you are building your program from source. It should not be
// used otherwise -- for example, if you are distributing Abseil in a binary
// package manager -- since in mode 2, absl::variant will name a different
// type, with a different mangled name and binary layout, depending on the
// compiler flags passed by the end user. For more info, see
// https://abseil.io/about/design/dropin-types.
//
// User code should not inspect this macro. To check in the preprocessor if
// absl::variant is a typedef of std::variant, use the feature macro
// ABSL_USES_STD_VARIANT.
#define ABSL_OPTION_USE_STD_VARIANT 2
// ABSL_OPTION_USE_STD_ORDERING
//
// This option controls whether absl::{partial,weak,strong}_ordering are
// implemented as aliases to the std:: ordering types, or as an independent
// implementation.
//
// A value of 0 means to use Abseil's implementation. This requires only C++11
// support, and is expected to work on every toolchain we support.
//
// A value of 1 means to use aliases. This requires that all code using Abseil
// is built in C++20 mode or later.
//
// A value of 2 means to detect the C++ version being used to compile Abseil,
// and use an alias only if working std:: ordering types are available. This
// option is useful when you are building your program from source. It should
// not be used otherwise -- for example, if you are distributing Abseil in a
// binary package manager -- since in mode 2, they will name different types,
// with different mangled names and binary layout, depending on the compiler
// flags passed by the end user. For more info, see
// https://abseil.io/about/design/dropin-types.
//
// User code should not inspect this macro. To check in the preprocessor if
// the ordering types are aliases of std:: ordering types, use the feature macro
// ABSL_USES_STD_ORDERING.
#define ABSL_OPTION_USE_STD_ORDERING 2
// ABSL_OPTION_USE_INLINE_NAMESPACE
// ABSL_OPTION_INLINE_NAMESPACE_NAME
//
// These options controls whether all entities in the absl namespace are
// contained within an inner inline namespace. This does not affect the
// user-visible API of Abseil, but it changes the mangled names of all symbols.
//
// This can be useful as a version tag if you are distributing Abseil in
// precompiled form. This will prevent a binary library build of Abseil with
// one inline namespace being used with headers configured with a different
// inline namespace name. Binary packagers are reminded that Abseil does not
// guarantee any ABI stability in Abseil, so any update of Abseil or
// configuration change in such a binary package should be combined with a
// new, unique value for the inline namespace name.
//
// A value of 0 means not to use inline namespaces.
//
// A value of 1 means to use an inline namespace with the given name inside
// namespace absl. If this is set, ABSL_OPTION_INLINE_NAMESPACE_NAME must also
// be changed to a new, unique identifier name. In particular "head" is not
// allowed.
#define ABSL_OPTION_USE_INLINE_NAMESPACE 1
#define ABSL_OPTION_INLINE_NAMESPACE_NAME lts_20240116
// ABSL_OPTION_HARDENED
//
// This option enables a "hardened" build in release mode (in this context,
// release mode is defined as a build where the `NDEBUG` macro is defined).
//
// A value of 0 means that "hardened" mode is not enabled.
//
// A value of 1 means that "hardened" mode is enabled.
//
// Hardened builds have additional security checks enabled when `NDEBUG` is
// defined. Defining `NDEBUG` is normally used to turn `assert()` macro into a
// no-op, as well as disabling other bespoke program consistency checks. By
// defining ABSL_OPTION_HARDENED to 1, a select set of checks remain enabled in
// release mode. These checks guard against programming errors that may lead to
// security vulnerabilities. In release mode, when one of these programming
// errors is encountered, the program will immediately abort, possibly without
// any attempt at logging.
//
// The checks enabled by this option are not free; they do incur runtime cost.
//
// The checks enabled by this option are always active when `NDEBUG` is not
// defined, even in the case when ABSL_OPTION_HARDENED is defined to 0. The
// checks enabled by this option may abort the program in a different way and
// log additional information when `NDEBUG` is not defined.
#define ABSL_OPTION_HARDENED 0
#endif // ABSL_BASE_OPTIONS_H_

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// 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: policy_checks.h
// -----------------------------------------------------------------------------
//
// This header enforces a minimum set of policies at build time, such as the
// supported compiler and library versions. Unsupported configurations are
// reported with `#error`. This enforcement is best effort, so successfully
// compiling this header does not guarantee a supported configuration.
#ifndef ABSL_BASE_POLICY_CHECKS_H_
#define ABSL_BASE_POLICY_CHECKS_H_
// Included for the __GLIBC_PREREQ macro used below.
#include <limits.h>
// Included for the _STLPORT_VERSION macro used below.
#if defined(__cplusplus)
#include <cstddef>
#endif
// -----------------------------------------------------------------------------
// Operating System Check
// -----------------------------------------------------------------------------
#if defined(__CYGWIN__)
#error "Cygwin is not supported."
#endif
// -----------------------------------------------------------------------------
// Toolchain Check
// -----------------------------------------------------------------------------
// We support Visual Studio 2019 (MSVC++ 16.0) and later.
// This minimum will go up.
#if defined(_MSC_VER) && _MSC_VER < 1920 && !defined(__clang__)
#error "This package requires Visual Studio 2019 (MSVC++ 16.0) or higher."
#endif
// We support GCC 7 and later.
// This minimum will go up.
#if defined(__GNUC__) && !defined(__clang__)
#if __GNUC__ < 7
#error "This package requires GCC 7 or higher."
#endif
#endif
// We support Apple Xcode clang 4.2.1 (version 421.11.65) and later.
// This corresponds to Apple Xcode version 4.5.
// This minimum will go up.
#if defined(__apple_build_version__) && __apple_build_version__ < 4211165
#error "This package requires __apple_build_version__ of 4211165 or higher."
#endif
// -----------------------------------------------------------------------------
// C++ Version Check
// -----------------------------------------------------------------------------
// Enforce C++14 as the minimum.
#if defined(_MSVC_LANG)
#if _MSVC_LANG < 201402L
#error "C++ versions less than C++14 are not supported."
#endif // _MSVC_LANG < 201402L
#elif defined(__cplusplus)
#if __cplusplus < 201402L
#error "C++ versions less than C++14 are not supported."
#endif // __cplusplus < 201402L
#endif
// -----------------------------------------------------------------------------
// Standard Library Check
// -----------------------------------------------------------------------------
#if defined(_STLPORT_VERSION)
#error "STLPort is not supported."
#endif
// -----------------------------------------------------------------------------
// `char` Size Check
// -----------------------------------------------------------------------------
// Abseil currently assumes CHAR_BIT == 8. If you would like to use Abseil on a
// platform where this is not the case, please provide us with the details about
// your platform so we can consider relaxing this requirement.
#if CHAR_BIT != 8
#error "Abseil assumes CHAR_BIT == 8."
#endif
// -----------------------------------------------------------------------------
// `int` Size Check
// -----------------------------------------------------------------------------
// Abseil currently assumes that an int is 4 bytes. If you would like to use
// Abseil on a platform where this is not the case, please provide us with the
// details about your platform so we can consider relaxing this requirement.
#if INT_MAX < 2147483647
#error "Abseil assumes that int is at least 4 bytes. "
#endif
#endif // ABSL_BASE_POLICY_CHECKS_H_

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// 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.
//
// This files is a forwarding header for other headers containing various
// portability macros and functions.
#ifndef ABSL_BASE_PORT_H_
#define ABSL_BASE_PORT_H_
#include "absl/base/attributes.h"
#include "absl/base/config.h"
#include "absl/base/optimization.h"
#endif // ABSL_BASE_PORT_H_

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// Copyright 2023 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: prefetch.h
// -----------------------------------------------------------------------------
//
// This header file defines prefetch functions to prefetch memory contents
// into the first level cache (L1) for the current CPU. The prefetch logic
// offered in this header is limited to prefetching first level cachelines
// only, and is aimed at relatively 'simple' prefetching logic.
//
#ifndef ABSL_BASE_PREFETCH_H_
#define ABSL_BASE_PREFETCH_H_
#include "absl/base/attributes.h"
#include "absl/base/config.h"
#if defined(ABSL_INTERNAL_HAVE_SSE)
#include <xmmintrin.h>
#endif
#if defined(_MSC_VER)
#include <intrin.h>
#if defined(ABSL_INTERNAL_HAVE_SSE)
#pragma intrinsic(_mm_prefetch)
#endif
#endif
namespace absl {
ABSL_NAMESPACE_BEGIN
// Moves data into the L1 cache before it is read, or "prefetches" it.
//
// The value of `addr` is the address of the memory to prefetch. If
// the target and compiler support it, data prefetch instructions are
// generated. If the prefetch is done some time before the memory is
// read, it may be in the cache by the time the read occurs.
//
// This method prefetches data with the highest degree of temporal locality;
// data is prefetched where possible into all levels of the cache.
//
// Incorrect or gratuitous use of this function can degrade performance.
// Use this function only when representative benchmarks show an improvement.
//
// Example:
//
// // Computes incremental checksum for `data`.
// int ComputeChecksum(int sum, absl::string_view data);
//
// // Computes cumulative checksum for all values in `data`
// int ComputeChecksum(absl::Span<const std::string> data) {
// int sum = 0;
// auto it = data.begin();
// auto pit = data.begin();
// auto end = data.end();
// for (int dist = 8; dist > 0 && pit != data.end(); --dist, ++pit) {
// absl::PrefetchToLocalCache(pit->data());
// }
// for (; pit != end; ++pit, ++it) {
// sum = ComputeChecksum(sum, *it);
// absl::PrefetchToLocalCache(pit->data());
// }
// for (; it != end; ++it) {
// sum = ComputeChecksum(sum, *it);
// }
// return sum;
// }
//
void PrefetchToLocalCache(const void* addr);
// Moves data into the L1 cache before it is read, or "prefetches" it.
//
// This function is identical to `PrefetchToLocalCache()` except that it has
// non-temporal locality: the fetched data should not be left in any of the
// cache tiers. This is useful for cases where the data is used only once /
// short term, for example, invoking a destructor on an object.
//
// Incorrect or gratuitous use of this function can degrade performance.
// Use this function only when representative benchmarks show an improvement.
//
// Example:
//
// template <typename Iterator>
// void DestroyPointers(Iterator begin, Iterator end) {
// size_t distance = std::min(8U, bars.size());
//
// int dist = 8;
// auto prefetch_it = begin;
// while (prefetch_it != end && --dist;) {
// absl::PrefetchToLocalCacheNta(*prefetch_it++);
// }
// while (prefetch_it != end) {
// delete *begin++;
// absl::PrefetchToLocalCacheNta(*prefetch_it++);
// }
// while (begin != end) {
// delete *begin++;
// }
// }
//
void PrefetchToLocalCacheNta(const void* addr);
// Moves data into the L1 cache with the intent to modify it.
//
// This function is similar to `PrefetchToLocalCache()` except that it
// prefetches cachelines with an 'intent to modify' This typically includes
// invalidating cache entries for this address in all other cache tiers, and an
// exclusive access intent.
//
// Incorrect or gratuitous use of this function can degrade performance. As this
// function can invalidate cached cachelines on other caches and computer cores,
// incorrect usage of this function can have an even greater negative impact
// than incorrect regular prefetches.
// Use this function only when representative benchmarks show an improvement.
//
// Example:
//
// void* Arena::Allocate(size_t size) {
// void* ptr = AllocateBlock(size);
// absl::PrefetchToLocalCacheForWrite(p);
// return ptr;
// }
//
void PrefetchToLocalCacheForWrite(const void* addr);
#if ABSL_HAVE_BUILTIN(__builtin_prefetch) || defined(__GNUC__)
#define ABSL_HAVE_PREFETCH 1
// See __builtin_prefetch:
// https://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html.
//
ABSL_ATTRIBUTE_ALWAYS_INLINE inline void PrefetchToLocalCache(
const void* addr) {
__builtin_prefetch(addr, 0, 3);
}
ABSL_ATTRIBUTE_ALWAYS_INLINE inline void PrefetchToLocalCacheNta(
const void* addr) {
__builtin_prefetch(addr, 0, 0);
}
ABSL_ATTRIBUTE_ALWAYS_INLINE inline void PrefetchToLocalCacheForWrite(
const void* addr) {
// [x86] gcc/clang don't generate PREFETCHW for __builtin_prefetch(.., 1)
// unless -march=broadwell or newer; this is not generally the default, so we
// manually emit prefetchw. PREFETCHW is recognized as a no-op on older Intel
// processors and has been present on AMD processors since the K6-2.
#if defined(__x86_64__) && !defined(__PRFCHW__)
asm("prefetchw %0" : : "m"(*reinterpret_cast<const char*>(addr)));
#else
__builtin_prefetch(addr, 1, 3);
#endif
}
#elif defined(ABSL_INTERNAL_HAVE_SSE)
#define ABSL_HAVE_PREFETCH 1
ABSL_ATTRIBUTE_ALWAYS_INLINE inline void PrefetchToLocalCache(
const void* addr) {
_mm_prefetch(reinterpret_cast<const char*>(addr), _MM_HINT_T0);
}
ABSL_ATTRIBUTE_ALWAYS_INLINE inline void PrefetchToLocalCacheNta(
const void* addr) {
_mm_prefetch(reinterpret_cast<const char*>(addr), _MM_HINT_NTA);
}
ABSL_ATTRIBUTE_ALWAYS_INLINE inline void PrefetchToLocalCacheForWrite(
const void* addr) {
#if defined(_MM_HINT_ET0)
_mm_prefetch(reinterpret_cast<const char*>(addr), _MM_HINT_ET0);
#elif !defined(_MSC_VER) && defined(__x86_64__)
// _MM_HINT_ET0 is not universally supported. As we commented further
// up, PREFETCHW is recognized as a no-op on older Intel processors
// and has been present on AMD processors since the K6-2. We have this
// disabled for MSVC compilers as this miscompiles on older MSVC compilers.
asm("prefetchw %0" : : "m"(*reinterpret_cast<const char*>(addr)));
#endif
}
#else
ABSL_ATTRIBUTE_ALWAYS_INLINE inline void PrefetchToLocalCache(
const void* addr) {}
ABSL_ATTRIBUTE_ALWAYS_INLINE inline void PrefetchToLocalCacheNta(
const void* addr) {}
ABSL_ATTRIBUTE_ALWAYS_INLINE inline void PrefetchToLocalCacheForWrite(
const void* addr) {}
#endif
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_PREFETCH_H_

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// 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: thread_annotations.h
// -----------------------------------------------------------------------------
//
// This header file contains macro definitions for thread safety annotations
// that allow developers to document the locking policies of multi-threaded
// code. The annotations can also help program analysis tools to identify
// potential thread safety issues.
//
// These annotations are implemented using compiler attributes. Using the macros
// defined here instead of raw attributes allow for portability and future
// compatibility.
//
// When referring to mutexes in the arguments of the attributes, you should
// use variable names or more complex expressions (e.g. my_object->mutex_)
// that evaluate to a concrete mutex object whenever possible. If the mutex
// you want to refer to is not in scope, you may use a member pointer
// (e.g. &MyClass::mutex_) to refer to a mutex in some (unknown) object.
#ifndef ABSL_BASE_THREAD_ANNOTATIONS_H_
#define ABSL_BASE_THREAD_ANNOTATIONS_H_
#include "absl/base/attributes.h"
#include "absl/base/config.h"
// ABSL_GUARDED_BY()
//
// Documents if a shared field or global variable needs to be protected by a
// mutex. ABSL_GUARDED_BY() allows the user to specify a particular mutex that
// should be held when accessing the annotated variable.
//
// Although this annotation (and ABSL_PT_GUARDED_BY, below) cannot be applied to
// local variables, a local variable and its associated mutex can often be
// combined into a small class or struct, thereby allowing the annotation.
//
// Example:
//
// class Foo {
// Mutex mu_;
// int p1_ ABSL_GUARDED_BY(mu_);
// ...
// };
#if ABSL_HAVE_ATTRIBUTE(guarded_by)
#define ABSL_GUARDED_BY(x) __attribute__((guarded_by(x)))
#else
#define ABSL_GUARDED_BY(x)
#endif
// ABSL_PT_GUARDED_BY()
//
// Documents if the memory location pointed to by a pointer should be guarded
// by a mutex when dereferencing the pointer.
//
// Example:
// class Foo {
// Mutex mu_;
// int *p1_ ABSL_PT_GUARDED_BY(mu_);
// ...
// };
//
// Note that a pointer variable to a shared memory location could itself be a
// shared variable.
//
// Example:
//
// // `q_`, guarded by `mu1_`, points to a shared memory location that is
// // guarded by `mu2_`:
// int *q_ ABSL_GUARDED_BY(mu1_) ABSL_PT_GUARDED_BY(mu2_);
#if ABSL_HAVE_ATTRIBUTE(pt_guarded_by)
#define ABSL_PT_GUARDED_BY(x) __attribute__((pt_guarded_by(x)))
#else
#define ABSL_PT_GUARDED_BY(x)
#endif
// ABSL_ACQUIRED_AFTER() / ABSL_ACQUIRED_BEFORE()
//
// Documents the acquisition order between locks that can be held
// simultaneously by a thread. For any two locks that need to be annotated
// to establish an acquisition order, only one of them needs the annotation.
// (i.e. You don't have to annotate both locks with both ABSL_ACQUIRED_AFTER
// and ABSL_ACQUIRED_BEFORE.)
//
// As with ABSL_GUARDED_BY, this is only applicable to mutexes that are shared
// fields or global variables.
//
// Example:
//
// Mutex m1_;
// Mutex m2_ ABSL_ACQUIRED_AFTER(m1_);
#if ABSL_HAVE_ATTRIBUTE(acquired_after)
#define ABSL_ACQUIRED_AFTER(...) __attribute__((acquired_after(__VA_ARGS__)))
#else
#define ABSL_ACQUIRED_AFTER(...)
#endif
#if ABSL_HAVE_ATTRIBUTE(acquired_before)
#define ABSL_ACQUIRED_BEFORE(...) __attribute__((acquired_before(__VA_ARGS__)))
#else
#define ABSL_ACQUIRED_BEFORE(...)
#endif
// ABSL_EXCLUSIVE_LOCKS_REQUIRED() / ABSL_SHARED_LOCKS_REQUIRED()
//
// Documents a function that expects a mutex to be held prior to entry.
// The mutex is expected to be held both on entry to, and exit from, the
// function.
//
// An exclusive lock allows read-write access to the guarded data member(s), and
// only one thread can acquire a lock exclusively at any one time. A shared lock
// allows read-only access, and any number of threads can acquire a shared lock
// concurrently.
//
// Generally, non-const methods should be annotated with
// ABSL_EXCLUSIVE_LOCKS_REQUIRED, while const methods should be annotated with
// ABSL_SHARED_LOCKS_REQUIRED.
//
// Example:
//
// Mutex mu1, mu2;
// int a ABSL_GUARDED_BY(mu1);
// int b ABSL_GUARDED_BY(mu2);
//
// void foo() ABSL_EXCLUSIVE_LOCKS_REQUIRED(mu1, mu2) { ... }
// void bar() const ABSL_SHARED_LOCKS_REQUIRED(mu1, mu2) { ... }
#if ABSL_HAVE_ATTRIBUTE(exclusive_locks_required)
#define ABSL_EXCLUSIVE_LOCKS_REQUIRED(...) \
__attribute__((exclusive_locks_required(__VA_ARGS__)))
#else
#define ABSL_EXCLUSIVE_LOCKS_REQUIRED(...)
#endif
#if ABSL_HAVE_ATTRIBUTE(shared_locks_required)
#define ABSL_SHARED_LOCKS_REQUIRED(...) \
__attribute__((shared_locks_required(__VA_ARGS__)))
#else
#define ABSL_SHARED_LOCKS_REQUIRED(...)
#endif
// ABSL_LOCKS_EXCLUDED()
//
// Documents the locks that cannot be held by callers of this function, as they
// might be acquired by this function (Abseil's `Mutex` locks are
// non-reentrant).
#if ABSL_HAVE_ATTRIBUTE(locks_excluded)
#define ABSL_LOCKS_EXCLUDED(...) __attribute__((locks_excluded(__VA_ARGS__)))
#else
#define ABSL_LOCKS_EXCLUDED(...)
#endif
// ABSL_LOCK_RETURNED()
//
// Documents a function that returns a mutex without acquiring it. For example,
// a public getter method that returns a pointer to a private mutex should
// be annotated with ABSL_LOCK_RETURNED.
#if ABSL_HAVE_ATTRIBUTE(lock_returned)
#define ABSL_LOCK_RETURNED(x) __attribute__((lock_returned(x)))
#else
#define ABSL_LOCK_RETURNED(x)
#endif
// ABSL_LOCKABLE
//
// Documents if a class/type is a lockable type (such as the `Mutex` class).
#if ABSL_HAVE_ATTRIBUTE(lockable)
#define ABSL_LOCKABLE __attribute__((lockable))
#else
#define ABSL_LOCKABLE
#endif
// ABSL_SCOPED_LOCKABLE
//
// Documents if a class does RAII locking (such as the `MutexLock` class).
// The constructor should use `LOCK_FUNCTION()` to specify the mutex that is
// acquired, and the destructor should use `UNLOCK_FUNCTION()` with no
// arguments; the analysis will assume that the destructor unlocks whatever the
// constructor locked.
#if ABSL_HAVE_ATTRIBUTE(scoped_lockable)
#define ABSL_SCOPED_LOCKABLE __attribute__((scoped_lockable))
#else
#define ABSL_SCOPED_LOCKABLE
#endif
// ABSL_EXCLUSIVE_LOCK_FUNCTION()
//
// Documents functions that acquire a lock in the body of a function, and do
// not release it.
#if ABSL_HAVE_ATTRIBUTE(exclusive_lock_function)
#define ABSL_EXCLUSIVE_LOCK_FUNCTION(...) \
__attribute__((exclusive_lock_function(__VA_ARGS__)))
#else
#define ABSL_EXCLUSIVE_LOCK_FUNCTION(...)
#endif
// ABSL_SHARED_LOCK_FUNCTION()
//
// Documents functions that acquire a shared (reader) lock in the body of a
// function, and do not release it.
#if ABSL_HAVE_ATTRIBUTE(shared_lock_function)
#define ABSL_SHARED_LOCK_FUNCTION(...) \
__attribute__((shared_lock_function(__VA_ARGS__)))
#else
#define ABSL_SHARED_LOCK_FUNCTION(...)
#endif
// ABSL_UNLOCK_FUNCTION()
//
// Documents functions that expect a lock to be held on entry to the function,
// and release it in the body of the function.
#if ABSL_HAVE_ATTRIBUTE(unlock_function)
#define ABSL_UNLOCK_FUNCTION(...) __attribute__((unlock_function(__VA_ARGS__)))
#else
#define ABSL_UNLOCK_FUNCTION(...)
#endif
// ABSL_EXCLUSIVE_TRYLOCK_FUNCTION() / ABSL_SHARED_TRYLOCK_FUNCTION()
//
// Documents functions that try to acquire a lock, and return success or failure
// (or a non-boolean value that can be interpreted as a boolean).
// The first argument should be `true` for functions that return `true` on
// success, or `false` for functions that return `false` on success. The second
// argument specifies the mutex that is locked on success. If unspecified, this
// mutex is assumed to be `this`.
#if ABSL_HAVE_ATTRIBUTE(exclusive_trylock_function)
#define ABSL_EXCLUSIVE_TRYLOCK_FUNCTION(...) \
__attribute__((exclusive_trylock_function(__VA_ARGS__)))
#else
#define ABSL_EXCLUSIVE_TRYLOCK_FUNCTION(...)
#endif
#if ABSL_HAVE_ATTRIBUTE(shared_trylock_function)
#define ABSL_SHARED_TRYLOCK_FUNCTION(...) \
__attribute__((shared_trylock_function(__VA_ARGS__)))
#else
#define ABSL_SHARED_TRYLOCK_FUNCTION(...)
#endif
// ABSL_ASSERT_EXCLUSIVE_LOCK() / ABSL_ASSERT_SHARED_LOCK()
//
// Documents functions that dynamically check to see if a lock is held, and fail
// if it is not held.
#if ABSL_HAVE_ATTRIBUTE(assert_exclusive_lock)
#define ABSL_ASSERT_EXCLUSIVE_LOCK(...) \
__attribute__((assert_exclusive_lock(__VA_ARGS__)))
#else
#define ABSL_ASSERT_EXCLUSIVE_LOCK(...)
#endif
#if ABSL_HAVE_ATTRIBUTE(assert_shared_lock)
#define ABSL_ASSERT_SHARED_LOCK(...) \
__attribute__((assert_shared_lock(__VA_ARGS__)))
#else
#define ABSL_ASSERT_SHARED_LOCK(...)
#endif
// ABSL_NO_THREAD_SAFETY_ANALYSIS
//
// Turns off thread safety checking within the body of a particular function.
// This annotation is used to mark functions that are known to be correct, but
// the locking behavior is more complicated than the analyzer can handle.
#if ABSL_HAVE_ATTRIBUTE(no_thread_safety_analysis)
#define ABSL_NO_THREAD_SAFETY_ANALYSIS \
__attribute__((no_thread_safety_analysis))
#else
#define ABSL_NO_THREAD_SAFETY_ANALYSIS
#endif
//------------------------------------------------------------------------------
// Tool-Supplied Annotations
//------------------------------------------------------------------------------
// ABSL_TS_UNCHECKED should be placed around lock expressions that are not valid
// C++ syntax, but which are present for documentation purposes. These
// annotations will be ignored by the analysis.
#define ABSL_TS_UNCHECKED(x) ""
// ABSL_TS_FIXME is used to mark lock expressions that are not valid C++ syntax.
// It is used by automated tools to mark and disable invalid expressions.
// The annotation should either be fixed, or changed to ABSL_TS_UNCHECKED.
#define ABSL_TS_FIXME(x) ""
// Like ABSL_NO_THREAD_SAFETY_ANALYSIS, this turns off checking within the body
// of a particular function. However, this attribute is used to mark functions
// that are incorrect and need to be fixed. It is used by automated tools to
// avoid breaking the build when the analysis is updated.
// Code owners are expected to eventually fix the routine.
#define ABSL_NO_THREAD_SAFETY_ANALYSIS_FIXME ABSL_NO_THREAD_SAFETY_ANALYSIS
// Similar to ABSL_NO_THREAD_SAFETY_ANALYSIS_FIXME, this macro marks a
// ABSL_GUARDED_BY annotation that needs to be fixed, because it is producing
// thread safety warning. It disables the ABSL_GUARDED_BY.
#define ABSL_GUARDED_BY_FIXME(x)
// Disables warnings for a single read operation. This can be used to avoid
// warnings when it is known that the read is not actually involved in a race,
// but the compiler cannot confirm that.
#define ABSL_TS_UNCHECKED_READ(x) absl::base_internal::ts_unchecked_read(x)
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
// Takes a reference to a guarded data member, and returns an unguarded
// reference.
// Do not use this function directly, use ABSL_TS_UNCHECKED_READ instead.
template <typename T>
inline const T& ts_unchecked_read(const T& v) ABSL_NO_THREAD_SAFETY_ANALYSIS {
return v;
}
template <typename T>
inline T& ts_unchecked_read(T& v) ABSL_NO_THREAD_SAFETY_ANALYSIS {
return v;
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_THREAD_ANNOTATIONS_H_