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132d6d73ea024beab3df99df2ecf4d345995fdfd
clang-p2996/libcxx/include/new
Louis Dionne 2eadbc8614 [libc++] Rework the whole availability markup implementation 
Currently, vendor-specific availability markup is enabled by default.
This means that even when building against trunk libc++, the headers
will by default prevent you from using some features that were not
released in the dylib on your target platform. This is a source of
frustration since people building libc++ from sources are usually not
trying to use some vendor's released dylib.

For that reason, I've been thinking for a long time that availability
annotations should be off by default, which is the primary change that
this commit enables.

In addition, it reworks the implementation to make it easier for new
vendors to add availability annotations for their platform, and it
refreshes the documentation to reflect the current state of the codebase.

Finally, a CMake configuration option is added to control whether
availability annotations should be turned on for the flavor of libc++
being created. The intent is for vendors like Apple to turn it on, and
for the upstream libc++ to leave it off (the default).

Differential Revision: https://reviews.llvm.org/D90843
2020-11-05 12:28:52 -05:00

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// -*- C++ -*-
//===----------------------------- new ------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP_NEW
#define _LIBCPP_NEW
/*
new synopsis
namespace std
{
class bad_alloc
: public exception
{
public:
bad_alloc() noexcept;
bad_alloc(const bad_alloc&) noexcept;
bad_alloc& operator=(const bad_alloc&) noexcept;
virtual const char* what() const noexcept;
};
class bad_array_new_length : public bad_alloc // C++14
{
public:
bad_array_new_length() noexcept;
};
enum class align_val_t : size_t {}; // C++17
struct destroying_delete_t { // C++20
explicit destroying_delete_t() = default;
};
inline constexpr destroying_delete_t destroying_delete{}; // C++20
struct nothrow_t { explicit nothrow_t() = default; };
extern const nothrow_t nothrow;
typedef void (*new_handler)();
new_handler set_new_handler(new_handler new_p) noexcept;
new_handler get_new_handler() noexcept;
// 21.6.4, pointer optimization barrier
template <class T> constexpr T* launder(T* p) noexcept; // C++17
} // std
void* operator new(std::size_t size); // replaceable, nodiscard in C++2a
void* operator new(std::size_t size, std::align_val_t alignment); // replaceable, C++17, nodiscard in C++2a
void* operator new(std::size_t size, const std::nothrow_t&) noexcept; // replaceable, nodiscard in C++2a
void* operator new(std::size_t size, std::align_val_t alignment,
const std::nothrow_t&) noexcept; // replaceable, C++17, nodiscard in C++2a
void operator delete(void* ptr) noexcept; // replaceable
void operator delete(void* ptr, std::size_t size) noexcept; // replaceable, C++14
void operator delete(void* ptr, std::align_val_t alignment) noexcept; // replaceable, C++17
void operator delete(void* ptr, std::size_t size,
std::align_val_t alignment) noexcept; // replaceable, C++17
void operator delete(void* ptr, const std::nothrow_t&) noexcept; // replaceable
void operator delete(void* ptr, std:align_val_t alignment,
const std::nothrow_t&) noexcept; // replaceable, C++17
void* operator new[](std::size_t size); // replaceable, nodiscard in C++2a
void* operator new[](std::size_t size,
std::align_val_t alignment) noexcept; // replaceable, C++17, nodiscard in C++2a
void* operator new[](std::size_t size, const std::nothrow_t&) noexcept; // replaceable, nodiscard in C++2a
void* operator new[](std::size_t size, std::align_val_t alignment,
const std::nothrow_t&) noexcept; // replaceable, C++17, nodiscard in C++2a
void operator delete[](void* ptr) noexcept; // replaceable
void operator delete[](void* ptr, std::size_t size) noexcept; // replaceable, C++14
void operator delete[](void* ptr,
std::align_val_t alignment) noexcept; // replaceable, C++17
void operator delete[](void* ptr, std::size_t size,
std::align_val_t alignment) noexcept; // replaceable, C++17
void operator delete[](void* ptr, const std::nothrow_t&) noexcept; // replaceable
void operator delete[](void* ptr, std::align_val_t alignment,
const std::nothrow_t&) noexcept; // replaceable, C++17
void* operator new (std::size_t size, void* ptr) noexcept; // nodiscard in C++2a
void* operator new[](std::size_t size, void* ptr) noexcept; // nodiscard in C++2a
void operator delete (void* ptr, void*) noexcept;
void operator delete[](void* ptr, void*) noexcept;
*/
#include <__config>
#include <__availability>
#include <exception>
#include <type_traits>
#include <cstddef>
#include <version>
#ifdef _LIBCPP_NO_EXCEPTIONS
#include <cstdlib>
#endif
#if defined(_LIBCPP_ABI_VCRUNTIME)
#include <new.h>
#endif
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header
#endif
#if !defined(__cpp_sized_deallocation) || __cpp_sized_deallocation < 201309L
#define _LIBCPP_HAS_NO_LANGUAGE_SIZED_DEALLOCATION
#endif
#if !defined(_LIBCPP_BUILDING_LIBRARY) && _LIBCPP_STD_VER < 14 && \
defined(_LIBCPP_HAS_NO_LANGUAGE_SIZED_DEALLOCATION)
# define _LIBCPP_HAS_NO_LIBRARY_SIZED_DEALLOCATION
#endif
#if defined(_LIBCPP_HAS_NO_LIBRARY_SIZED_DEALLOCATION) || \
defined(_LIBCPP_HAS_NO_LANGUAGE_SIZED_DEALLOCATION)
# define _LIBCPP_HAS_NO_SIZED_DEALLOCATION
#endif
namespace std // purposefully not using versioning namespace
{
#if !defined(_LIBCPP_ABI_VCRUNTIME)
struct _LIBCPP_TYPE_VIS nothrow_t { explicit nothrow_t() = default; };
extern _LIBCPP_FUNC_VIS const nothrow_t nothrow;
class _LIBCPP_EXCEPTION_ABI bad_alloc
: public exception
{
public:
bad_alloc() _NOEXCEPT;
virtual ~bad_alloc() _NOEXCEPT;
virtual const char* what() const _NOEXCEPT;
};
class _LIBCPP_EXCEPTION_ABI bad_array_new_length
: public bad_alloc
{
public:
bad_array_new_length() _NOEXCEPT;
virtual ~bad_array_new_length() _NOEXCEPT;
virtual const char* what() const _NOEXCEPT;
};
typedef void (*new_handler)();
_LIBCPP_FUNC_VIS new_handler set_new_handler(new_handler) _NOEXCEPT;
_LIBCPP_FUNC_VIS new_handler get_new_handler() _NOEXCEPT;
#endif // !_LIBCPP_ABI_VCRUNTIME
_LIBCPP_NORETURN _LIBCPP_FUNC_VIS void __throw_bad_alloc(); // not in C++ spec
#if !defined(_LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION) && \
!defined(_LIBCPP_ABI_VCRUNTIME)
#ifndef _LIBCPP_CXX03_LANG
enum class _LIBCPP_ENUM_VIS align_val_t : size_t { };
#else
enum align_val_t { __zero = 0, __max = (size_t)-1 };
#endif
#endif
#if _LIBCPP_STD_VER > 17
// Enable the declaration even if the compiler doesn't support the language
// feature.
struct destroying_delete_t {
explicit destroying_delete_t() = default;
};
_LIBCPP_INLINE_VAR constexpr destroying_delete_t destroying_delete{};
#endif // _LIBCPP_STD_VER > 17
} // std
#if defined(_LIBCPP_CXX03_LANG)
#define _THROW_BAD_ALLOC throw(std::bad_alloc)
#else
#define _THROW_BAD_ALLOC
#endif
#if !defined(_LIBCPP_ABI_VCRUNTIME)
_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new(std::size_t __sz) _THROW_BAD_ALLOC;
_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new(std::size_t __sz, const std::nothrow_t&) _NOEXCEPT _LIBCPP_NOALIAS;
_LIBCPP_OVERRIDABLE_FUNC_VIS void operator delete(void* __p) _NOEXCEPT;
_LIBCPP_OVERRIDABLE_FUNC_VIS void operator delete(void* __p, const std::nothrow_t&) _NOEXCEPT;
#ifndef _LIBCPP_HAS_NO_LIBRARY_SIZED_DEALLOCATION
_LIBCPP_OVERRIDABLE_FUNC_VIS _LIBCPP_AVAILABILITY_SIZED_NEW_DELETE void operator delete(void* __p, std::size_t __sz) _NOEXCEPT;
#endif
_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new[](std::size_t __sz) _THROW_BAD_ALLOC;
_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new[](std::size_t __sz, const std::nothrow_t&) _NOEXCEPT _LIBCPP_NOALIAS;
_LIBCPP_OVERRIDABLE_FUNC_VIS void operator delete[](void* __p) _NOEXCEPT;
_LIBCPP_OVERRIDABLE_FUNC_VIS void operator delete[](void* __p, const std::nothrow_t&) _NOEXCEPT;
#ifndef _LIBCPP_HAS_NO_LIBRARY_SIZED_DEALLOCATION
_LIBCPP_OVERRIDABLE_FUNC_VIS _LIBCPP_AVAILABILITY_SIZED_NEW_DELETE void operator delete[](void* __p, std::size_t __sz) _NOEXCEPT;
#endif
#ifndef _LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION
_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new(std::size_t __sz, std::align_val_t) _THROW_BAD_ALLOC;
_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new(std::size_t __sz, std::align_val_t, const std::nothrow_t&) _NOEXCEPT _LIBCPP_NOALIAS;
_LIBCPP_OVERRIDABLE_FUNC_VIS void operator delete(void* __p, std::align_val_t) _NOEXCEPT;
_LIBCPP_OVERRIDABLE_FUNC_VIS void operator delete(void* __p, std::align_val_t, const std::nothrow_t&) _NOEXCEPT;
#ifndef _LIBCPP_HAS_NO_LIBRARY_SIZED_DEALLOCATION
_LIBCPP_OVERRIDABLE_FUNC_VIS _LIBCPP_AVAILABILITY_SIZED_NEW_DELETE void operator delete(void* __p, std::size_t __sz, std::align_val_t) _NOEXCEPT;
#endif
_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new[](std::size_t __sz, std::align_val_t) _THROW_BAD_ALLOC;
_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new[](std::size_t __sz, std::align_val_t, const std::nothrow_t&) _NOEXCEPT _LIBCPP_NOALIAS;
_LIBCPP_OVERRIDABLE_FUNC_VIS void operator delete[](void* __p, std::align_val_t) _NOEXCEPT;
_LIBCPP_OVERRIDABLE_FUNC_VIS void operator delete[](void* __p, std::align_val_t, const std::nothrow_t&) _NOEXCEPT;
#ifndef _LIBCPP_HAS_NO_LIBRARY_SIZED_DEALLOCATION
_LIBCPP_OVERRIDABLE_FUNC_VIS _LIBCPP_AVAILABILITY_SIZED_NEW_DELETE void operator delete[](void* __p, std::size_t __sz, std::align_val_t) _NOEXCEPT;
#endif
#endif
_LIBCPP_NODISCARD_AFTER_CXX17 inline _LIBCPP_INLINE_VISIBILITY void* operator new (std::size_t, void* __p) _NOEXCEPT {return __p;}
_LIBCPP_NODISCARD_AFTER_CXX17 inline _LIBCPP_INLINE_VISIBILITY void* operator new[](std::size_t, void* __p) _NOEXCEPT {return __p;}
inline _LIBCPP_INLINE_VISIBILITY void operator delete (void*, void*) _NOEXCEPT {}
inline _LIBCPP_INLINE_VISIBILITY void operator delete[](void*, void*) _NOEXCEPT {}
#endif // !_LIBCPP_ABI_VCRUNTIME
_LIBCPP_BEGIN_NAMESPACE_STD
_LIBCPP_CONSTEXPR inline _LIBCPP_INLINE_VISIBILITY bool __is_overaligned_for_new(size_t __align) _NOEXCEPT {
#ifdef __STDCPP_DEFAULT_NEW_ALIGNMENT__
return __align > __STDCPP_DEFAULT_NEW_ALIGNMENT__;
#else
return __align > alignment_of<max_align_t>::value;
#endif
}
template <class ..._Args>
_LIBCPP_INLINE_VISIBILITY
void* __libcpp_operator_new(_Args ...__args) {
#if __has_builtin(__builtin_operator_new) && __has_builtin(__builtin_operator_delete)
return __builtin_operator_new(__args...);
#else
return ::operator new(__args...);
#endif
}
template <class ..._Args>
_LIBCPP_INLINE_VISIBILITY
void __libcpp_operator_delete(_Args ...__args) {
#if __has_builtin(__builtin_operator_new) && __has_builtin(__builtin_operator_delete)
__builtin_operator_delete(__args...);
#else
::operator delete(__args...);
#endif
}
inline _LIBCPP_INLINE_VISIBILITY
void *__libcpp_allocate(size_t __size, size_t __align) {
#ifndef _LIBCPP_HAS_NO_ALIGNED_ALLOCATION
if (__is_overaligned_for_new(__align)) {
const align_val_t __align_val = static_cast<align_val_t>(__align);
return __libcpp_operator_new(__size, __align_val);
}
#endif
(void)__align;
return __libcpp_operator_new(__size);
}
template <class ..._Args>
_LIBCPP_INLINE_VISIBILITY
void __do_deallocate_handle_size(void *__ptr, size_t __size, _Args ...__args) {
#ifdef _LIBCPP_HAS_NO_SIZED_DEALLOCATION
(void)__size;
return __libcpp_operator_delete(__ptr, __args...);
#else
return __libcpp_operator_delete(__ptr, __size, __args...);
#endif
}
inline _LIBCPP_INLINE_VISIBILITY
void __libcpp_deallocate(void* __ptr, size_t __size, size_t __align) {
#if defined(_LIBCPP_HAS_NO_ALIGNED_ALLOCATION)
(void)__align;
return __do_deallocate_handle_size(__ptr, __size);
#else
if (__is_overaligned_for_new(__align)) {
const align_val_t __align_val = static_cast<align_val_t>(__align);
return __do_deallocate_handle_size(__ptr, __size, __align_val);
} else {
return __do_deallocate_handle_size(__ptr, __size);
}
#endif
}
inline _LIBCPP_INLINE_VISIBILITY void __libcpp_deallocate_unsized(void* __ptr, size_t __align) {
#if defined(_LIBCPP_HAS_NO_ALIGNED_ALLOCATION)
(void)__align;
return __libcpp_operator_delete(__ptr);
#else
if (__is_overaligned_for_new(__align)) {
const align_val_t __align_val = static_cast<align_val_t>(__align);
return __libcpp_operator_delete(__ptr, __align_val);
} else {
return __libcpp_operator_delete(__ptr);
}
#endif
}
template <class _Tp>
_LIBCPP_NODISCARD_AFTER_CXX17 inline
_LIBCPP_CONSTEXPR _Tp* __launder(_Tp* __p) _NOEXCEPT
{
static_assert (!(is_function<_Tp>::value), "can't launder functions" );
static_assert (!(is_same<void, typename remove_cv<_Tp>::type>::value), "can't launder cv-void" );
#ifdef _LIBCPP_COMPILER_HAS_BUILTIN_LAUNDER
return __builtin_launder(__p);
#else
return __p;
#endif
}
#if _LIBCPP_STD_VER > 14
template <class _Tp>
_LIBCPP_NODISCARD_AFTER_CXX17 inline _LIBCPP_INLINE_VISIBILITY
constexpr _Tp* launder(_Tp* __p) noexcept
{
return _VSTD::__launder(__p);
}
#endif
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP_NEW
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