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// Copyright The OpenTelemetry Authors
// SPDX-License-Identifier: Apache-2.0
#pragma once
/*
OPENTELEMETRY_HAVE_BUILTIN&OPENTELEMETRY_HAVE_FEATURE
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
Note: Use this macro to avoid an extra level of #ifdef __has_builtin check.
*/
#if !defined(OPENTELEMETRY_HAVE_BUILTIN)
# ifdef __has_builtin
# define OPENTELEMETRY_HAVE_BUILTIN(x) __has_builtin(x)
# else
# define OPENTELEMETRY_HAVE_BUILTIN(x) 0
# endif
#endif
#if !defined(OPENTELEMETRY_HAVE_FEATURE)
# ifdef __has_feature
# define OPENTELEMETRY_HAVE_FEATURE(f) __has_feature(f)
# else
# define OPENTELEMETRY_HAVE_FEATURE(f) 0
# endif
#endif
/*
has feature
OPENTELEMETRY_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.
*/
#if !defined(OPENTELEMETRY_HAVE_ATTRIBUTE)
# ifdef __has_attribute
# define OPENTELEMETRY_HAVE_ATTRIBUTE(x) __has_attribute(x)
# else
# define OPENTELEMETRY_HAVE_ATTRIBUTE(x) 0
# endif
#endif
/*
OPENTELEMETRY_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
find `__has_cpp_attribute`, will evaluate to 0.
*/
#if !defined(OPENTELEMETRY_HAVE_CPP_ATTRIBUTE)
# if defined(__cplusplus) && defined(__has_cpp_attribute)
// NOTE: requiring __cplusplus above should not be necessary, but
# define OPENTELEMETRY_HAVE_CPP_ATTRIBUTE(x) __has_cpp_attribute(x)
# else
# define OPENTELEMETRY_HAVE_CPP_ATTRIBUTE(x) 0
# endif
#endif
/*
Expected usage pattern:
if OPENTELEMETRY_LIKELY_CONDITION (ptr != nullptr)
{
do_something_likely();
} else {
do_something_unlikely();
}
This pattern works with gcc/clang and __builtin_expect(),
as well as with C++20.
It is unclear if __builtin_expect() will be deprecated
in favor of C++20 [[likely]] or not.
OPENTELEMETRY_LIKELY_CONDITION is preferred over OPENTELEMETRY_LIKELY,
to be revisited when C++20 is required.
*/
#if !defined(OPENTELEMETRY_LIKELY_CONDITION) && defined(__cplusplus)
// Only use likely with C++20
# if __cplusplus >= 202002L
// GCC 9 has likely attribute but do not support declare it at the beginning of statement
# if defined(__has_cpp_attribute) && (defined(__clang__) || !defined(__GNUC__) || __GNUC__ > 9)
# if __has_cpp_attribute(likely)
# define OPENTELEMETRY_LIKELY_CONDITION(C) (C) [[likely]]
# endif
# endif
# endif
#endif
#if !defined(OPENTELEMETRY_LIKELY_CONDITION) && (defined(__clang__) || defined(__GNUC__))
// Only use if supported by the compiler
# define OPENTELEMETRY_LIKELY_CONDITION(C) (__builtin_expect(!!(C), true))
#endif
#ifndef OPENTELEMETRY_LIKELY_CONDITION
// Do not use likely annotations
# define OPENTELEMETRY_LIKELY_CONDITION(C) (C)
#endif
#if !defined(OPENTELEMETRY_UNLIKELY_CONDITION) && defined(__cplusplus)
// Only use unlikely with C++20
# if __cplusplus >= 202002L
// GCC 9 has unlikely attribute but do not support declare it at the beginning of statement
# if defined(__has_cpp_attribute) && (defined(__clang__) || !defined(__GNUC__) || __GNUC__ > 9)
# if __has_cpp_attribute(unlikely)
# define OPENTELEMETRY_UNLIKELY_CONDITION(C) (C) [[unlikely]]
# endif
# endif
# endif
#endif
#if !defined(OPENTELEMETRY_UNLIKELY_CONDITION) && (defined(__clang__) || defined(__GNUC__))
// Only use if supported by the compiler
# define OPENTELEMETRY_UNLIKELY_CONDITION(C) (__builtin_expect(!!(C), false))
#endif
#ifndef OPENTELEMETRY_UNLIKELY_CONDITION
// Do not use unlikely annotations
# define OPENTELEMETRY_UNLIKELY_CONDITION(C) (C)
#endif
/*
Expected usage pattern:
if (ptr != nullptr)
OPENTELEMETRY_LIKELY
{
do_something_likely();
} else {
do_something_unlikely();
}
This pattern works starting with C++20.
Please use OPENTELEMETRY_LIKELY_CONDITION instead for now.
*/
#if !defined(OPENTELEMETRY_LIKELY) && defined(__cplusplus)
// Only use likely with C++20
# if __cplusplus >= 202002L
// GCC 9 has likely attribute but do not support declare it at the beginning of statement
# if defined(__has_cpp_attribute) && (defined(__clang__) || !defined(__GNUC__) || __GNUC__ > 9)
# if __has_cpp_attribute(likely)
# define OPENTELEMETRY_LIKELY [[likely]]
# endif
# endif
# endif
#endif
#ifndef OPENTELEMETRY_LIKELY
# define OPENTELEMETRY_LIKELY
#endif
#if !defined(OPENTELEMETRY_UNLIKELY) && defined(__cplusplus)
// Only use unlikely with C++20
# if __cplusplus >= 202002L
// GCC 9 has unlikely attribute but do not support declare it at the beginning of statement
# if defined(__has_cpp_attribute) && (defined(__clang__) || !defined(__GNUC__) || __GNUC__ > 9)
# if __has_cpp_attribute(unlikely)
# define OPENTELEMETRY_UNLIKELY [[unlikely]]
# endif
# endif
# endif
#endif
#ifndef OPENTELEMETRY_UNLIKELY
# define OPENTELEMETRY_UNLIKELY
#endif
/// \brief Declare variable as maybe unused
/// usage:
/// OPENTELEMETRY_MAYBE_UNUSED int a;
/// class OPENTELEMETRY_MAYBE_UNUSED a;
/// OPENTELEMETRY_MAYBE_UNUSED int a();
///
#if defined(__cplusplus) && __cplusplus >= 201703L
# define OPENTELEMETRY_MAYBE_UNUSED [[maybe_unused]]
#elif defined(__clang__)
# define OPENTELEMETRY_MAYBE_UNUSED __attribute__((unused))
#elif defined(__GNUC__) && ((__GNUC__ >= 4) || ((__GNUC__ == 3) && (__GNUC_MINOR__ >= 1)))
# define OPENTELEMETRY_MAYBE_UNUSED __attribute__((unused))
#elif (defined(_MSC_VER) && _MSC_VER >= 1910) && (defined(_MSVC_LANG) && _MSVC_LANG >= 201703L)
# define OPENTELEMETRY_MAYBE_UNUSED [[maybe_unused]]
#else
# define OPENTELEMETRY_MAYBE_UNUSED
#endif
#ifndef OPENTELEMETRY_RTTI_ENABLED
# if defined(__clang__)
# if __has_feature(cxx_rtti)
# define OPENTELEMETRY_RTTI_ENABLED
# endif
# elif defined(__GNUG__)
# if defined(__GXX_RTTI)
# define OPENTELEMETRY_RTTI_ENABLED
# endif
# elif defined(_MSC_VER)
# if defined(_CPPRTTI)
# define OPENTELEMETRY_RTTI_ENABLED
# endif
# endif
#endif
#if defined(__cplusplus) && __cplusplus >= 201402L
# define OPENTELEMETRY_DEPRECATED [[deprecated]]
#elif defined(__clang__)
# define OPENTELEMETRY_DEPRECATED __attribute__((deprecated))
#elif defined(__GNUC__)
# define OPENTELEMETRY_DEPRECATED __attribute__((deprecated))
#elif defined(_MSC_VER)
# if _MSC_VER >= 1910 && defined(_MSVC_LANG) && _MSVC_LANG >= 201703L
# define OPENTELEMETRY_DEPRECATED [[deprecated]]
# else
# define OPENTELEMETRY_DEPRECATED __declspec(deprecated)
# endif
#else
# define OPENTELEMETRY_DEPRECATED
#endif
#if defined(__cplusplus) && __cplusplus >= 201402L
# define OPENTELEMETRY_DEPRECATED_MESSAGE(msg) [[deprecated(msg)]]
#elif defined(__clang__)
# define OPENTELEMETRY_DEPRECATED_MESSAGE(msg) __attribute__((deprecated(msg)))
#elif defined(__GNUC__)
# define OPENTELEMETRY_DEPRECATED_MESSAGE(msg) __attribute__((deprecated(msg)))
#elif defined(_MSC_VER)
# if _MSC_VER >= 1910 && defined(_MSVC_LANG) && _MSVC_LANG >= 201703L
# define OPENTELEMETRY_DEPRECATED_MESSAGE(msg) [[deprecated(msg)]]
# else
# define OPENTELEMETRY_DEPRECATED_MESSAGE(msg) __declspec(deprecated(msg))
# endif
#else
# define OPENTELEMETRY_DEPRECATED_MESSAGE(msg)
#endif
// Regex support
#if (__GNUC__ == 4 && (__GNUC_MINOR__ == 8 || __GNUC_MINOR__ == 9))
# define OPENTELEMETRY_HAVE_WORKING_REGEX 0
#else
# define OPENTELEMETRY_HAVE_WORKING_REGEX 1
#endif
/* clang-format off */
/**
@page HEADER_ONLY_SINGLETON Header only singleton.
@section ELF_SINGLETON
For clang and gcc, the desired coding pattern is as follows.
@verbatim
class Foo
{
// (a)
__attribute__((visibility("default")))
// (b)
T& get_singleton()
{
// (c)
static T singleton;
return singleton;
}
};
@endverbatim
(a) is needed when the code is build with
@code -fvisibility="hidden" @endcode
to ensure that all instances of (b) are visible to the linker.
What is duplicated in the binary is @em code, in (b).
The linker will make sure only one instance
of all the (b) methods is used.
(c) is a singleton implemented inside a method.
This is very desirable, because:
- the C++ compiler guarantees that construction
of the variable (c) is thread safe.
- constructors for (c) singletons are executed in code path order,
or not at all if the singleton is never used.
@section OTHER_SINGLETON
For other platforms, header only singletons are not supported at this
point.
@section CODING_PATTERN
The coding pattern to use in the source code is as follows
@verbatim
class Foo
{
OPENTELEMETRY_API_SINGLETON
T& get_singleton()
{
static T singleton;
return singleton;
}
};
@endverbatim
*/
/* clang-format on */
#if defined(__clang__)
# define OPENTELEMETRY_API_SINGLETON __attribute__((visibility("default")))
# define OPENTELEMETRY_LOCAL_SYMBOL __attribute__((visibility("hidden")))
#elif defined(__GNUC__)
# define OPENTELEMETRY_API_SINGLETON __attribute__((visibility("default")))
# define OPENTELEMETRY_LOCAL_SYMBOL __attribute__((visibility("hidden")))
#else
/* Add support for other compilers here. */
# define OPENTELEMETRY_API_SINGLETON
# define OPENTELEMETRY_LOCAL_SYMBOL
#endif
//
// Atomic wrappers based on compiler intrinsics for memory read/write.
// The tailing number is read/write length in bits.
//
// N.B. Compiler instrinsic is used because the usage of C++ standard library is restricted in the
// OpenTelemetry C++ API.
//
#if defined(__GNUC__)
# define OPENTELEMETRY_ATOMIC_READ_8(ptr) __atomic_load_n(ptr, __ATOMIC_SEQ_CST)
# define OPENTELEMETRY_ATOMIC_WRITE_8(ptr, value) __atomic_store_n(ptr, value, __ATOMIC_SEQ_CST)
#elif defined(_MSC_VER)
# include <intrin.h>
# define OPENTELEMETRY_ATOMIC_READ_8(ptr) \
static_cast<uint8_t>(_InterlockedCompareExchange8(reinterpret_cast<char *>(ptr), 0, 0))
# define OPENTELEMETRY_ATOMIC_WRITE_8(ptr, value) \
_InterlockedExchange8(reinterpret_cast<char *>(ptr), static_cast<char>(value))
#else
# error port atomics read/write for the current platform
#endif
/* clang-format on */
//
// The if/elif order matters here. If both OPENTELEMETRY_BUILD_IMPORT_DLL and
// OPENTELEMETRY_BUILD_EXPORT_DLL are defined, the former takes precedence.
//
// TODO: consider define OPENTELEMETRY_EXPORT for cygwin/gcc, see below link.
//
#if defined(_MSC_VER) && defined(OPENTELEMETRY_BUILD_IMPORT_DLL)
# define OPENTELEMETRY_EXPORT __declspec(dllimport)
#elif defined(_MSC_VER) && defined(OPENTELEMETRY_BUILD_EXPORT_DLL)
# define OPENTELEMETRY_EXPORT __declspec(dllexport)
#else
//
// build OpenTelemetry as static library or not on Windows.
//
# define OPENTELEMETRY_EXPORT
#endif
// OPENTELEMETRY_HAVE_EXCEPTIONS
//
// Checks whether the compiler both supports and enables exceptions. Many
// compilers support a "no exceptions" mode that disables exceptions.
//
// Generally, when OPENTELEMETRY_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.
#ifndef OPENTELEMETRY_HAVE_EXCEPTIONS
# if defined(__clang__) && ((__clang_major__ * 100) + __clang_minor__) < 306
// Clang < 3.6
# if defined(__EXCEPTIONS) && OPENTELEMETRY_HAVE_FEATURE(cxx_exceptions)
# define OPENTELEMETRY_HAVE_EXCEPTIONS 1
# endif // defined(__EXCEPTIONS) && OPENTELEMETRY_HAVE_FEATURE(cxx_exceptions)
# elif OPENTELEMETRY_HAVE_FEATURE(cxx_exceptions)
# define OPENTELEMETRY_HAVE_EXCEPTIONS 1
// Handle remaining special cases and default to exceptions being supported.
# elif !(defined(__GNUC__) && !defined(__EXCEPTIONS) && !defined(__cpp_exceptions)) && \
!(defined(_MSC_VER) && !defined(_CPPUNWIND))
# define OPENTELEMETRY_HAVE_EXCEPTIONS 1
# endif
#endif
#ifndef OPENTELEMETRY_HAVE_EXCEPTIONS
# define OPENTELEMETRY_HAVE_EXCEPTIONS 0
#endif
/*
OPENTELEMETRY_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:
*/
#ifndef OPENTELEMETRY_ATTRIBUTE_LIFETIME_BOUND
# if OPENTELEMETRY_HAVE_CPP_ATTRIBUTE(clang::lifetimebound)
# define OPENTELEMETRY_ATTRIBUTE_LIFETIME_BOUND [[clang::lifetimebound]]
# elif OPENTELEMETRY_HAVE_ATTRIBUTE(lifetimebound)
# define OPENTELEMETRY_ATTRIBUTE_LIFETIME_BOUND __attribute__((lifetimebound))
# else
# define OPENTELEMETRY_ATTRIBUTE_LIFETIME_BOUND
# endif
#endif
// OPENTELEMETRY_HAVE_MEMORY_SANITIZER
//
// MemorySanitizer (MSan) is a detector of uninitialized reads. It consists of
// a compiler instrumentation module and a run-time library.
#ifndef OPENTELEMETRY_HAVE_MEMORY_SANITIZER
# if !defined(__native_client__) && OPENTELEMETRY_HAVE_FEATURE(memory_sanitizer)
# define OPENTELEMETRY_HAVE_MEMORY_SANITIZER 1
# else
# define OPENTELEMETRY_HAVE_MEMORY_SANITIZER 0
# endif
#endif
#if OPENTELEMETRY_HAVE_MEMORY_SANITIZER && OPENTELEMETRY_HAVE_ATTRIBUTE(no_sanitize_memory)
# define OPENTELEMETRY_SANITIZER_NO_MEMORY \
__attribute__((no_sanitize_memory)) // __attribute__((no_sanitize("memory")))
#else
# define OPENTELEMETRY_SANITIZER_NO_MEMORY
#endif
// OPENTELEMETRY_HAVE_THREAD_SANITIZER
//
// ThreadSanitizer (TSan) is a fast data race detector.
#ifndef OPENTELEMETRY_HAVE_THREAD_SANITIZER
# if defined(__SANITIZE_THREAD__)
# define OPENTELEMETRY_HAVE_THREAD_SANITIZER 1
# elif OPENTELEMETRY_HAVE_FEATURE(thread_sanitizer)
# define OPENTELEMETRY_HAVE_THREAD_SANITIZER 1
# else
# define OPENTELEMETRY_HAVE_THREAD_SANITIZER 0
# endif
#endif
#if OPENTELEMETRY_HAVE_THREAD_SANITIZER && OPENTELEMETRY_HAVE_ATTRIBUTE(no_sanitize_thread)
# define OPENTELEMETRY_SANITIZER_NO_THREAD \
__attribute__((no_sanitize_thread)) // __attribute__((no_sanitize("thread")))
#else
# define OPENTELEMETRY_SANITIZER_NO_THREAD
#endif
// OPENTELEMETRY_HAVE_ADDRESS_SANITIZER
//
// AddressSanitizer (ASan) is a fast memory error detector.
#ifndef OPENTELEMETRY_HAVE_ADDRESS_SANITIZER
# if defined(__SANITIZE_ADDRESS__)
# define OPENTELEMETRY_HAVE_ADDRESS_SANITIZER 1
# elif OPENTELEMETRY_HAVE_FEATURE(address_sanitizer)
# define OPENTELEMETRY_HAVE_ADDRESS_SANITIZER 1
# else
# define OPENTELEMETRY_HAVE_ADDRESS_SANITIZER 0
# endif
#endif
// OPENTELEMETRY_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.
#ifndef OPENTELEMETRY_HAVE_HWADDRESS_SANITIZER
# if defined(__SANITIZE_HWADDRESS__)
# define OPENTELEMETRY_HAVE_HWADDRESS_SANITIZER 1
# elif OPENTELEMETRY_HAVE_FEATURE(hwaddress_sanitizer)
# define OPENTELEMETRY_HAVE_HWADDRESS_SANITIZER 1
# else
# define OPENTELEMETRY_HAVE_HWADDRESS_SANITIZER 0
# endif
#endif
#if OPENTELEMETRY_HAVE_ADDRESS_SANITIZER && OPENTELEMETRY_HAVE_ATTRIBUTE(no_sanitize_address)
# define OPENTELEMETRY_SANITIZER_NO_ADDRESS \
__attribute__((no_sanitize_address)) // __attribute__((no_sanitize("address")))
#elif OPENTELEMETRY_HAVE_ADDRESS_SANITIZER && defined(_MSC_VER) && _MSC_VER >= 1928
# define OPENTELEMETRY_SANITIZER_NO_ADDRESS __declspec(no_sanitize_address)
#elif OPENTELEMETRY_HAVE_HWADDRESS_SANITIZER && OPENTELEMETRY_HAVE_ATTRIBUTE(no_sanitize)
# define OPENTELEMETRY_SANITIZER_NO_ADDRESS __attribute__((no_sanitize("hwaddress")))
#else
# define OPENTELEMETRY_SANITIZER_NO_ADDRESS
#endif