| // <experimental/memory_resource> -*- C++ -*- |
| |
| // Copyright (C) 2015-2020 Free Software Foundation, Inc. |
| // |
| // This file is part of the GNU ISO C++ Library. This library is free |
| // software; you can redistribute it and/or modify it under the |
| // terms of the GNU General Public License as published by the |
| // Free Software Foundation; either version 3, or (at your option) |
| // any later version. |
| |
| // This library is distributed in the hope that it will be useful, |
| // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| // GNU General Public License for more details. |
| |
| // Under Section 7 of GPL version 3, you are granted additional |
| // permissions described in the GCC Runtime Library Exception, version |
| // 3.1, as published by the Free Software Foundation. |
| |
| // You should have received a copy of the GNU General Public License and |
| // a copy of the GCC Runtime Library Exception along with this program; |
| // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
| // <http://www.gnu.org/licenses/>. |
| |
| /** @file experimental/memory_resource |
| * This is a TS C++ Library header. |
| * @ingroup libfund-ts |
| */ |
| |
| #ifndef _GLIBCXX_EXPERIMENTAL_MEMORY_RESOURCE |
| #define _GLIBCXX_EXPERIMENTAL_MEMORY_RESOURCE 1 |
| |
| #pragma GCC system_header |
| |
| #if __cplusplus >= 201402L |
| |
| #include <memory> // align, uses_allocator, __uses_alloc |
| #include <experimental/utility> // pair, experimental::erased_type |
| #include <atomic> // atomic |
| #include <new> // placement new |
| #include <cstddef> // max_align_t |
| #include <ext/new_allocator.h> |
| #include <debug/assertions.h> |
| |
| /// @cond |
| namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) |
| { |
| _GLIBCXX_BEGIN_NAMESPACE_VERSION |
| template<typename _Tp> class malloc_allocator; |
| _GLIBCXX_END_NAMESPACE_VERSION |
| } // namespace __gnu_cxx |
| /// @endcond |
| |
| namespace std { |
| _GLIBCXX_BEGIN_NAMESPACE_VERSION |
| |
| namespace experimental { |
| inline namespace fundamentals_v2 { |
| namespace pmr { |
| #define __cpp_lib_experimental_memory_resources 201402L |
| |
| // Standard memory resources |
| |
| // 8.5 Class memory_resource |
| class memory_resource; |
| |
| // 8.6 Class template polymorphic_allocator |
| template<typename _Tp> |
| class polymorphic_allocator; |
| |
| template<typename _Alloc, typename _Resource = memory_resource> |
| class __resource_adaptor_imp; |
| |
| // 8.7 Alias template resource_adaptor |
| template<typename _Alloc> |
| using resource_adaptor = __resource_adaptor_imp< |
| typename allocator_traits<_Alloc>::template rebind_alloc<char>>; |
| |
| // 8.8 Global memory resources |
| memory_resource* new_delete_resource() noexcept; |
| memory_resource* null_memory_resource() noexcept; |
| memory_resource* get_default_resource() noexcept; |
| memory_resource* set_default_resource(memory_resource* __r) noexcept; |
| |
| // TODO 8.9 Pool resource classes |
| |
| class memory_resource |
| { |
| static constexpr size_t _S_max_align = alignof(max_align_t); |
| |
| public: |
| memory_resource() = default; |
| memory_resource(const memory_resource&) = default; |
| virtual ~memory_resource() = default; |
| |
| memory_resource& operator=(const memory_resource&) = default; |
| |
| _GLIBCXX_NODISCARD void* |
| allocate(size_t __bytes, size_t __alignment = _S_max_align) |
| { return do_allocate(__bytes, __alignment); } |
| |
| void |
| deallocate(void* __p, size_t __bytes, size_t __alignment = _S_max_align) |
| { return do_deallocate(__p, __bytes, __alignment); } |
| |
| bool |
| is_equal(const memory_resource& __other) const noexcept |
| { return do_is_equal(__other); } |
| |
| protected: |
| virtual void* |
| do_allocate(size_t __bytes, size_t __alignment) = 0; |
| |
| virtual void |
| do_deallocate(void* __p, size_t __bytes, size_t __alignment) = 0; |
| |
| virtual bool |
| do_is_equal(const memory_resource& __other) const noexcept = 0; |
| }; |
| |
| inline bool |
| operator==(const memory_resource& __a, const memory_resource& __b) noexcept |
| { return &__a == &__b || __a.is_equal(__b); } |
| |
| inline bool |
| operator!=(const memory_resource& __a, const memory_resource& __b) noexcept |
| { return !(__a == __b); } |
| |
| |
| template<typename _Tp> |
| class polymorphic_allocator |
| { |
| public: |
| using value_type = _Tp; |
| |
| polymorphic_allocator() noexcept |
| : _M_resource(get_default_resource()) |
| { } |
| |
| polymorphic_allocator(memory_resource* __r) |
| : _M_resource(__r) |
| { _GLIBCXX_DEBUG_ASSERT(__r); } |
| |
| polymorphic_allocator(const polymorphic_allocator& __other) = default; |
| |
| template <typename _Up> |
| polymorphic_allocator(const polymorphic_allocator<_Up>& |
| __other) noexcept |
| : _M_resource(__other.resource()) |
| { } |
| |
| polymorphic_allocator& |
| operator=(const polymorphic_allocator& __rhs) = default; |
| |
| _GLIBCXX_NODISCARD _Tp* allocate(size_t __n) |
| { return static_cast<_Tp*>(_M_resource->allocate(__n * sizeof(_Tp), |
| alignof(_Tp))); } |
| |
| void |
| deallocate(_Tp* __p, size_t __n) |
| { _M_resource->deallocate(__p, __n * sizeof(_Tp), alignof(_Tp)); } |
| |
| template <typename _Tp1, typename... _Args> //used here |
| void |
| construct(_Tp1* __p, _Args&&... __args) |
| { |
| std::__uses_allocator_construct(this->resource(), __p, |
| std::forward<_Args>(__args)...); |
| } |
| |
| // Specializations for pair using piecewise construction |
| template <typename _Tp1, typename _Tp2, |
| typename... _Args1, typename... _Args2> |
| void |
| construct(pair<_Tp1, _Tp2>* __p, piecewise_construct_t, |
| tuple<_Args1...> __x, tuple<_Args2...> __y) |
| { |
| memory_resource* const __resource = this->resource(); |
| auto __x_use_tag = |
| std::__use_alloc<_Tp1, memory_resource*, _Args1...>(__resource); |
| auto __y_use_tag = |
| std::__use_alloc<_Tp2, memory_resource*, _Args2...>(__resource); |
| |
| ::new(__p) std::pair<_Tp1, _Tp2>(piecewise_construct, |
| _M_construct_p(__x_use_tag, __x), |
| _M_construct_p(__y_use_tag, __y)); |
| } |
| |
| template <typename _Tp1, typename _Tp2> |
| void |
| construct(pair<_Tp1,_Tp2>* __p) |
| { this->construct(__p, piecewise_construct, tuple<>(), tuple<>()); } |
| |
| template <typename _Tp1, typename _Tp2, typename _Up, typename _Vp> |
| void |
| construct(pair<_Tp1,_Tp2>* __p, _Up&& __x, _Vp&& __y) |
| { |
| this->construct(__p, piecewise_construct, |
| forward_as_tuple(std::forward<_Up>(__x)), |
| forward_as_tuple(std::forward<_Vp>(__y))); |
| } |
| |
| template <typename _Tp1, typename _Tp2, typename _Up, typename _Vp> |
| void |
| construct(pair<_Tp1,_Tp2>* __p, const std::pair<_Up, _Vp>& __pr) |
| { |
| this->construct(__p, piecewise_construct, |
| forward_as_tuple(__pr.first), |
| forward_as_tuple(__pr.second)); |
| } |
| |
| template <typename _Tp1, typename _Tp2, typename _Up, typename _Vp> |
| void |
| construct(pair<_Tp1,_Tp2>* __p, pair<_Up, _Vp>&& __pr) |
| { |
| this->construct(__p, piecewise_construct, |
| forward_as_tuple(std::forward<_Up>(__pr.first)), |
| forward_as_tuple(std::forward<_Vp>(__pr.second))); |
| } |
| |
| template <typename _Up> |
| void |
| destroy(_Up* __p) |
| { __p->~_Up(); } |
| |
| // Return a default-constructed allocator (no allocator propagation) |
| polymorphic_allocator |
| select_on_container_copy_construction() const |
| { return polymorphic_allocator(); } |
| |
| memory_resource* resource() const { return _M_resource; } |
| |
| private: |
| using __uses_alloc1_ = __uses_alloc1<memory_resource*>; |
| using __uses_alloc2_ = __uses_alloc2<memory_resource*>; |
| |
| template<typename _Tuple> |
| _Tuple&& |
| _M_construct_p(__uses_alloc0, _Tuple& __t) |
| { return std::move(__t); } |
| |
| template<typename... _Args> |
| decltype(auto) |
| _M_construct_p(__uses_alloc1_ __ua, tuple<_Args...>& __t) |
| { return tuple_cat(make_tuple(allocator_arg, *(__ua._M_a)), |
| std::move(__t)); } |
| |
| template<typename... _Args> |
| decltype(auto) |
| _M_construct_p(__uses_alloc2_ __ua, tuple<_Args...>& __t) |
| { return tuple_cat(std::move(__t), make_tuple(*(__ua._M_a))); } |
| |
| memory_resource* _M_resource; |
| }; |
| |
| template <class _Tp1, class _Tp2> |
| bool |
| operator==(const polymorphic_allocator<_Tp1>& __a, |
| const polymorphic_allocator<_Tp2>& __b) noexcept |
| { return *__a.resource() == *__b.resource(); } |
| |
| template <class _Tp1, class _Tp2> |
| bool |
| operator!=(const polymorphic_allocator<_Tp1>& __a, |
| const polymorphic_allocator<_Tp2>& __b) noexcept |
| { return !(__a == __b); } |
| |
| |
| /// @cond undocumented |
| class __resource_adaptor_common |
| { |
| template<typename, typename> friend class __resource_adaptor_imp; |
| |
| struct _AlignMgr |
| { |
| _AlignMgr(size_t __nbytes, size_t __align) |
| : _M_nbytes(__nbytes), _M_align(__align) |
| { } |
| |
| // Total size that needs to be allocated. |
| size_t |
| _M_alloc_size() const { return _M_buf_size() + _M_token_size(); } |
| |
| void* |
| _M_adjust(void* __ptr) const |
| { |
| const auto __orig_ptr = static_cast<char*>(__ptr); |
| size_t __space = _M_buf_size(); |
| // Align the pointer within the buffer: |
| std::align(_M_align, _M_nbytes, __ptr, __space); |
| const auto __aligned_ptr = static_cast<char*>(__ptr); |
| const auto __token_size = _M_token_size(); |
| // Store token immediately after the aligned block: |
| char* const __end = __aligned_ptr + _M_nbytes; |
| if (__token_size == 1) |
| _S_write<unsigned char>(__end, __aligned_ptr - __orig_ptr); |
| else if (__token_size == sizeof(short)) |
| _S_write<unsigned short>(__end, __aligned_ptr - __orig_ptr); |
| else if (__token_size == sizeof(int) && sizeof(int) < sizeof(char*)) |
| _S_write<unsigned int>(__end, __aligned_ptr - __orig_ptr); |
| else // (__token_size == sizeof(char*)) |
| // Just store the original pointer: |
| _S_write<char*>(__end, __orig_ptr); |
| return __aligned_ptr; |
| } |
| |
| char* |
| _M_unadjust(char* __ptr) const |
| { |
| const char* const __end = __ptr + _M_nbytes; |
| char* __orig_ptr; |
| const auto __token_size = _M_token_size(); |
| // Read the token and restore the original pointer: |
| if (__token_size == 1) |
| __orig_ptr = __ptr - _S_read<unsigned char>(__end); |
| else if (__token_size == sizeof(short)) |
| __orig_ptr = __ptr - _S_read<unsigned short>(__end); |
| else if (__token_size == sizeof(int) |
| && sizeof(int) < sizeof(char*)) |
| __orig_ptr = __ptr - _S_read<unsigned int>(__end); |
| else // (__token_size == sizeof(char*)) |
| __orig_ptr = _S_read<char*>(__end); |
| // The adjustment is always less than the requested alignment, |
| // so if that isn't true now then either the wrong size was passed |
| // to deallocate or the token was overwritten by a buffer overflow: |
| __glibcxx_assert(static_cast<size_t>(__ptr - __orig_ptr) < _M_align); |
| return __orig_ptr; |
| } |
| |
| private: |
| size_t _M_nbytes; |
| size_t _M_align; |
| |
| // Number of bytes needed to fit block of given size and alignment. |
| size_t |
| _M_buf_size() const { return _M_nbytes + _M_align - 1; } |
| |
| // Number of additional bytes needed to write the token. |
| int |
| _M_token_size() const |
| { |
| if (_M_align <= (1ul << __CHAR_BIT__)) |
| return 1; |
| if (_M_align <= (1ul << (sizeof(short) * __CHAR_BIT__))) |
| return sizeof(short); |
| if (_M_align <= (1ull << (sizeof(int) * __CHAR_BIT__))) |
| return sizeof(int); |
| return sizeof(char*); |
| } |
| |
| template<typename _Tp> |
| static void |
| _S_write(void* __to, _Tp __val) |
| { __builtin_memcpy(__to, &__val, sizeof(_Tp)); } |
| |
| template<typename _Tp> |
| static _Tp |
| _S_read(const void* __from) |
| { |
| _Tp __val; |
| __builtin_memcpy(&__val, __from, sizeof(_Tp)); |
| return __val; |
| } |
| }; |
| }; |
| /// @endcond |
| |
| // 8.7.1 __resource_adaptor_imp |
| template<typename _Alloc, typename _Resource> |
| class __resource_adaptor_imp |
| : public _Resource, private __resource_adaptor_common |
| { |
| using memory_resource = _Resource; |
| |
| static_assert(is_same<char, |
| typename allocator_traits<_Alloc>::value_type>::value, |
| "Allocator's value_type is char"); |
| static_assert(is_same<char*, |
| typename allocator_traits<_Alloc>::pointer>::value, |
| "Allocator's pointer type is value_type*"); |
| static_assert(is_same<const char*, |
| typename allocator_traits<_Alloc>::const_pointer>::value, |
| "Allocator's const_pointer type is value_type const*"); |
| static_assert(is_same<void*, |
| typename allocator_traits<_Alloc>::void_pointer>::value, |
| "Allocator's void_pointer type is void*"); |
| static_assert(is_same<const void*, |
| typename allocator_traits<_Alloc>::const_void_pointer>::value, |
| "Allocator's const_void_pointer type is void const*"); |
| |
| public: |
| using allocator_type = _Alloc; |
| |
| __resource_adaptor_imp() = default; |
| __resource_adaptor_imp(const __resource_adaptor_imp&) = default; |
| __resource_adaptor_imp(__resource_adaptor_imp&&) = default; |
| |
| explicit __resource_adaptor_imp(const _Alloc& __a2) |
| : _M_alloc(__a2) |
| { } |
| |
| explicit __resource_adaptor_imp(_Alloc&& __a2) |
| : _M_alloc(std::move(__a2)) |
| { } |
| |
| __resource_adaptor_imp& |
| operator=(const __resource_adaptor_imp&) = default; |
| |
| allocator_type get_allocator() const noexcept { return _M_alloc; } |
| |
| protected: |
| virtual void* |
| do_allocate(size_t __bytes, size_t __alignment) override |
| { |
| // Cannot use max_align_t on 32-bit Solaris x86, see PR libstdc++/77691 |
| #if ! ((defined __sun__ || defined __VXWORKS__) && defined __i386__) |
| if (__alignment == alignof(max_align_t)) |
| return _M_allocate<alignof(max_align_t)>(__bytes); |
| #endif |
| switch (__alignment) |
| { |
| case 1: |
| return _M_alloc.allocate(__bytes); |
| case 2: |
| return _M_allocate<2>(__bytes); |
| case 4: |
| return _M_allocate<4>(__bytes); |
| case 8: |
| return _M_allocate<8>(__bytes); |
| } |
| const _AlignMgr __mgr(__bytes, __alignment); |
| // Assume _M_alloc returns 1-byte aligned memory, so allocate enough |
| // space to fit a block of the right size and alignment, plus some |
| // extra bytes to store a token for retrieving the original pointer. |
| return __mgr._M_adjust(_M_alloc.allocate(__mgr._M_alloc_size())); |
| } |
| |
| virtual void |
| do_deallocate(void* __ptr, size_t __bytes, size_t __alignment) noexcept |
| override |
| { |
| #if ! ((defined __sun__ || defined __VXWORKS__) && defined __i386__) |
| if (__alignment == alignof(max_align_t)) |
| return (void) _M_deallocate<alignof(max_align_t)>(__ptr, __bytes); |
| #endif |
| switch (__alignment) |
| { |
| case 1: |
| return (void) _M_alloc.deallocate((char*)__ptr, __bytes); |
| case 2: |
| return (void) _M_deallocate<2>(__ptr, __bytes); |
| case 4: |
| return (void) _M_deallocate<4>(__ptr, __bytes); |
| case 8: |
| return (void) _M_deallocate<8>(__ptr, __bytes); |
| } |
| const _AlignMgr __mgr(__bytes, __alignment); |
| // Use the stored token to retrieve the original pointer. |
| _M_alloc.deallocate(__mgr._M_unadjust((char*)__ptr), |
| __mgr._M_alloc_size()); |
| } |
| |
| virtual bool |
| do_is_equal(const memory_resource& __other) const noexcept override |
| { |
| if (auto __p = dynamic_cast<const __resource_adaptor_imp*>(&__other)) |
| return _M_alloc == __p->_M_alloc; |
| return false; |
| } |
| |
| private: |
| template<size_t _Num> |
| struct _Aligned_type { alignas(_Num) char __c[_Num]; }; |
| |
| // Rebind the allocator to the specified type and use it to allocate. |
| template<size_t _Num, typename _Tp = _Aligned_type<_Num>> |
| void* |
| _M_allocate(size_t __bytes) |
| { |
| typename allocator_traits<_Alloc>::template |
| rebind_alloc<_Tp> __a2(_M_alloc); |
| const size_t __n = (__bytes + _Num - 1) / _Num; |
| return __a2.allocate(__n); |
| } |
| |
| // Rebind the allocator to the specified type and use it to deallocate. |
| template<size_t _Num, typename _Tp = _Aligned_type<_Num>> |
| void |
| _M_deallocate(void* __ptr, size_t __bytes) noexcept |
| { |
| typename allocator_traits<_Alloc>::template |
| rebind_alloc<_Tp> __a2(_M_alloc); |
| const size_t __n = (__bytes + _Num - 1) / _Num; |
| __a2.deallocate((_Tp*)__ptr, __n); |
| } |
| |
| _Alloc _M_alloc{}; |
| }; |
| |
| // Global memory resources |
| |
| inline memory_resource* |
| new_delete_resource() noexcept |
| { |
| using type = resource_adaptor<__gnu_cxx::new_allocator<char>>; |
| alignas(type) static unsigned char __buf[sizeof(type)]; |
| static type* __r = new(__buf) type; |
| return __r; |
| } |
| |
| inline memory_resource* |
| null_memory_resource() noexcept |
| { |
| class type final : public memory_resource |
| { |
| void* |
| do_allocate(size_t, size_t) override |
| { std::__throw_bad_alloc(); } |
| |
| void |
| do_deallocate(void*, size_t, size_t) noexcept override |
| { } |
| |
| bool |
| do_is_equal(const memory_resource& __other) const noexcept override |
| { return this == &__other; } |
| }; |
| |
| alignas(type) static unsigned char __buf[sizeof(type)]; |
| static type* __r = new(__buf) type; |
| return __r; |
| } |
| |
| // The default memory resource |
| |
| /// @cond undocumented |
| inline std::atomic<memory_resource*>& |
| __get_default_resource() |
| { |
| using type = atomic<memory_resource*>; |
| alignas(type) static unsigned char __buf[sizeof(type)]; |
| static type* __r = new(__buf) type(new_delete_resource()); |
| return *__r; |
| } |
| /// @endcond |
| |
| /// Get the current default resource. |
| inline memory_resource* |
| get_default_resource() noexcept |
| { return __get_default_resource().load(); } |
| |
| /// Change the default resource and return the previous one. |
| inline memory_resource* |
| set_default_resource(memory_resource* __r) noexcept |
| { |
| if (__r == nullptr) |
| __r = new_delete_resource(); |
| return __get_default_resource().exchange(__r); |
| } |
| |
| } // namespace pmr |
| } // namespace fundamentals_v2 |
| } // namespace experimental |
| |
| _GLIBCXX_END_NAMESPACE_VERSION |
| } // namespace std |
| #endif // C++14 |
| #endif // _GLIBCXX_EXPERIMENTAL_MEMORY_RESOURCE |