llvm-project/libcxx/include/new

// -*- 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++20
void* operator new(std::size_t size, std::align_val_t alignment);       // replaceable, C++17, nodiscard in C++20
void* operator new(std::size_t size, const std::nothrow_t&) noexcept;   // replaceable, nodiscard in C++20
void* operator new(std::size_t size, std::align_val_t alignment,
                   const std::nothrow_t&) noexcept;                     // replaceable, C++17, nodiscard in C++20
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++20
void* operator new[](std::size_t size,
                     std::align_val_t alignment) noexcept;              // replaceable, C++17, nodiscard in C++20
void* operator new[](std::size_t size, const std::nothrow_t&) noexcept; // replaceable, nodiscard in C++20
void* operator new[](std::size_t size, std::align_val_t alignment,
                     const std::nothrow_t&) noexcept;                   // replaceable, C++17, nodiscard in C++20
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++20
void* operator new[](std::size_t size, void* ptr) noexcept;             // nodiscard in C++20
void  operator delete  (void* ptr, void*) noexcept;
void  operator delete[](void* ptr, void*) noexcept;

*/

#include <__availability>
#include <__config>
#include <cstddef>
#include <cstdlib>
#include <exception>
#include <type_traits>
#include <version>

#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
}

#if !defined(_LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION)
// Low-level helpers to call the aligned allocation and deallocation functions
// on the target platform. This is used to implement libc++'s own memory
// allocation routines -- if you need to allocate memory inside the library,
// chances are that you want to use `__libcpp_allocate` instead.
//
// Returns the allocated memory, or `nullptr` on failure.
inline _LIBCPP_INLINE_VISIBILITY
void* __libcpp_aligned_alloc(std::size_t __alignment, std::size_t __size) {
#if defined(_LIBCPP_MSVCRT_LIKE)
  return ::_aligned_malloc(__size, __alignment);
#else
  void* __result = nullptr;
  (void)::posix_memalign(&__result, __alignment, __size);
  // If posix_memalign fails, __result is unmodified so we still return `nullptr`.
  return __result;
#endif
}

inline _LIBCPP_INLINE_VISIBILITY
void __libcpp_aligned_free(void* __ptr) {
#if defined(_LIBCPP_MSVCRT_LIKE)
  ::_aligned_free(__ptr);
#else
  ::free(__ptr);
#endif
}
#endif // !_LIBCPP_HAS_NO_ALIGNED_ALLOCATION


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