| // MT-optimized allocator -*- C++ -*- |
| |
| // Copyright (C) 2003-2022 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 ext/mt_allocator.h |
| * This file is a GNU extension to the Standard C++ Library. |
| */ |
| |
| #ifndef _MT_ALLOCATOR_H |
| #define _MT_ALLOCATOR_H 1 |
| |
| #include <bits/requires_hosted.h> // getenv |
| |
| #include <new> |
| #include <cstdlib> |
| #include <bits/functexcept.h> |
| #include <ext/atomicity.h> |
| #include <bits/move.h> |
| #if __cplusplus >= 201103L |
| #include <type_traits> |
| #endif |
| |
| namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) |
| { |
| _GLIBCXX_BEGIN_NAMESPACE_VERSION |
| |
| |
| typedef void (*__destroy_handler)(void*); |
| |
| /// Base class for pool object. |
| struct __pool_base |
| { |
| // Using short int as type for the binmap implies we are never |
| // caching blocks larger than 32768 with this allocator. |
| typedef unsigned short int _Binmap_type; |
| typedef std::size_t size_t; |
| |
| // Variables used to configure the behavior of the allocator, |
| // assigned and explained in detail below. |
| struct _Tune |
| { |
| // Compile time constants for the default _Tune values. |
| enum { _S_align = 8 }; |
| enum { _S_max_bytes = 128 }; |
| enum { _S_min_bin = 8 }; |
| enum { _S_chunk_size = 4096 - 4 * sizeof(void*) }; |
| enum { _S_max_threads = 4096 }; |
| enum { _S_freelist_headroom = 10 }; |
| |
| // Alignment needed. |
| // NB: In any case must be >= sizeof(_Block_record), that |
| // is 4 on 32 bit machines and 8 on 64 bit machines. |
| size_t _M_align; |
| |
| // Allocation requests (after round-up to power of 2) below |
| // this value will be handled by the allocator. A raw new/ |
| // call will be used for requests larger than this value. |
| // NB: Must be much smaller than _M_chunk_size and in any |
| // case <= 32768. |
| size_t _M_max_bytes; |
| |
| // Size in bytes of the smallest bin. |
| // NB: Must be a power of 2 and >= _M_align (and of course |
| // much smaller than _M_max_bytes). |
| size_t _M_min_bin; |
| |
| // In order to avoid fragmenting and minimize the number of |
| // new() calls we always request new memory using this |
| // value. Based on previous discussions on the libstdc++ |
| // mailing list we have chosen the value below. |
| // See http://gcc.gnu.org/ml/libstdc++/2001-07/msg00077.html |
| // NB: At least one order of magnitude > _M_max_bytes. |
| size_t _M_chunk_size; |
| |
| // The maximum number of supported threads. For |
| // single-threaded operation, use one. Maximum values will |
| // vary depending on details of the underlying system. (For |
| // instance, Linux 2.4.18 reports 4070 in |
| // /proc/sys/kernel/threads-max, while Linux 2.6.6 reports |
| // 65534) |
| size_t _M_max_threads; |
| |
| // Each time a deallocation occurs in a threaded application |
| // we make sure that there are no more than |
| // _M_freelist_headroom % of used memory on the freelist. If |
| // the number of additional records is more than |
| // _M_freelist_headroom % of the freelist, we move these |
| // records back to the global pool. |
| size_t _M_freelist_headroom; |
| |
| // Set to true forces all allocations to use new(). |
| bool _M_force_new; |
| |
| explicit |
| _Tune() |
| : _M_align(_S_align), _M_max_bytes(_S_max_bytes), _M_min_bin(_S_min_bin), |
| _M_chunk_size(_S_chunk_size), _M_max_threads(_S_max_threads), |
| _M_freelist_headroom(_S_freelist_headroom), |
| _M_force_new(std::getenv("GLIBCXX_FORCE_NEW") ? true : false) |
| { } |
| |
| explicit |
| _Tune(size_t __align, size_t __maxb, size_t __minbin, size_t __chunk, |
| size_t __maxthreads, size_t __headroom, bool __force) |
| : _M_align(__align), _M_max_bytes(__maxb), _M_min_bin(__minbin), |
| _M_chunk_size(__chunk), _M_max_threads(__maxthreads), |
| _M_freelist_headroom(__headroom), _M_force_new(__force) |
| { } |
| }; |
| |
| struct _Block_address |
| { |
| void* _M_initial; |
| _Block_address* _M_next; |
| }; |
| |
| const _Tune& |
| _M_get_options() const |
| { return _M_options; } |
| |
| void |
| _M_set_options(_Tune __t) |
| { |
| if (!_M_init) |
| _M_options = __t; |
| } |
| |
| bool |
| _M_check_threshold(size_t __bytes) |
| { return __bytes > _M_options._M_max_bytes || _M_options._M_force_new; } |
| |
| size_t |
| _M_get_binmap(size_t __bytes) |
| { return _M_binmap[__bytes]; } |
| |
| size_t |
| _M_get_align() |
| { return _M_options._M_align; } |
| |
| explicit |
| __pool_base() |
| : _M_options(_Tune()), _M_binmap(0), _M_init(false) { } |
| |
| explicit |
| __pool_base(const _Tune& __options) |
| : _M_options(__options), _M_binmap(0), _M_init(false) { } |
| |
| private: |
| explicit |
| __pool_base(const __pool_base&); |
| |
| __pool_base& |
| operator=(const __pool_base&); |
| |
| protected: |
| // Configuration options. |
| _Tune _M_options; |
| |
| _Binmap_type* _M_binmap; |
| |
| // Configuration of the pool object via _M_options can happen |
| // after construction but before initialization. After |
| // initialization is complete, this variable is set to true. |
| bool _M_init; |
| }; |
| |
| |
| /** |
| * @brief Data describing the underlying memory pool, parameterized on |
| * threading support. |
| */ |
| template<bool _Thread> |
| class __pool; |
| |
| /// Specialization for single thread. |
| template<> |
| class __pool<false> : public __pool_base |
| { |
| public: |
| union _Block_record |
| { |
| // Points to the block_record of the next free block. |
| _Block_record* _M_next; |
| }; |
| |
| struct _Bin_record |
| { |
| // An "array" of pointers to the first free block. |
| _Block_record** _M_first; |
| |
| // A list of the initial addresses of all allocated blocks. |
| _Block_address* _M_address; |
| }; |
| |
| void |
| _M_initialize_once() |
| { |
| if (__builtin_expect(_M_init == false, false)) |
| _M_initialize(); |
| } |
| |
| void |
| _M_destroy() throw(); |
| |
| char* |
| _M_reserve_block(size_t __bytes, const size_t __thread_id); |
| |
| void |
| _M_reclaim_block(char* __p, size_t __bytes) throw (); |
| |
| size_t |
| _M_get_thread_id() { return 0; } |
| |
| const _Bin_record& |
| _M_get_bin(size_t __which) |
| { return _M_bin[__which]; } |
| |
| void |
| _M_adjust_freelist(const _Bin_record&, _Block_record*, size_t) |
| { } |
| |
| explicit __pool() |
| : _M_bin(0), _M_bin_size(1) { } |
| |
| explicit __pool(const __pool_base::_Tune& __tune) |
| : __pool_base(__tune), _M_bin(0), _M_bin_size(1) { } |
| |
| private: |
| // An "array" of bin_records each of which represents a specific |
| // power of 2 size. Memory to this "array" is allocated in |
| // _M_initialize(). |
| _Bin_record* _M_bin; |
| |
| // Actual value calculated in _M_initialize(). |
| size_t _M_bin_size; |
| |
| void |
| _M_initialize(); |
| }; |
| |
| #ifdef __GTHREADS |
| /// Specialization for thread enabled, via gthreads.h. |
| template<> |
| class __pool<true> : public __pool_base |
| { |
| public: |
| // Each requesting thread is assigned an id ranging from 1 to |
| // _S_max_threads. Thread id 0 is used as a global memory pool. |
| // In order to get constant performance on the thread assignment |
| // routine, we keep a list of free ids. When a thread first |
| // requests memory we remove the first record in this list and |
| // stores the address in a __gthread_key. When initializing the |
| // __gthread_key we specify a destructor. When this destructor |
| // (i.e. the thread dies) is called, we return the thread id to |
| // the front of this list. |
| struct _Thread_record |
| { |
| // Points to next free thread id record. NULL if last record in list. |
| _Thread_record* _M_next; |
| |
| // Thread id ranging from 1 to _S_max_threads. |
| size_t _M_id; |
| }; |
| |
| union _Block_record |
| { |
| // Points to the block_record of the next free block. |
| _Block_record* _M_next; |
| |
| // The thread id of the thread which has requested this block. |
| size_t _M_thread_id; |
| }; |
| |
| struct _Bin_record |
| { |
| // An "array" of pointers to the first free block for each |
| // thread id. Memory to this "array" is allocated in |
| // _S_initialize() for _S_max_threads + global pool 0. |
| _Block_record** _M_first; |
| |
| // A list of the initial addresses of all allocated blocks. |
| _Block_address* _M_address; |
| |
| // An "array" of counters used to keep track of the amount of |
| // blocks that are on the freelist/used for each thread id. |
| // - Note that the second part of the allocated _M_used "array" |
| // actually hosts (atomic) counters of reclaimed blocks: in |
| // _M_reserve_block and in _M_reclaim_block those numbers are |
| // subtracted from the first ones to obtain the actual size |
| // of the "working set" of the given thread. |
| // - Memory to these "arrays" is allocated in _S_initialize() |
| // for _S_max_threads + global pool 0. |
| size_t* _M_free; |
| size_t* _M_used; |
| |
| // Each bin has its own mutex which is used to ensure data |
| // integrity while changing "ownership" on a block. The mutex |
| // is initialized in _S_initialize(). |
| __gthread_mutex_t* _M_mutex; |
| }; |
| |
| // XXX GLIBCXX_ABI Deprecated |
| void |
| _M_initialize(__destroy_handler); |
| |
| void |
| _M_initialize_once() |
| { |
| if (__builtin_expect(_M_init == false, false)) |
| _M_initialize(); |
| } |
| |
| void |
| _M_destroy() throw(); |
| |
| char* |
| _M_reserve_block(size_t __bytes, const size_t __thread_id); |
| |
| void |
| _M_reclaim_block(char* __p, size_t __bytes) throw (); |
| |
| const _Bin_record& |
| _M_get_bin(size_t __which) |
| { return _M_bin[__which]; } |
| |
| void |
| _M_adjust_freelist(const _Bin_record& __bin, _Block_record* __block, |
| size_t __thread_id) |
| { |
| if (__gthread_active_p()) |
| { |
| __block->_M_thread_id = __thread_id; |
| --__bin._M_free[__thread_id]; |
| ++__bin._M_used[__thread_id]; |
| } |
| } |
| |
| // XXX GLIBCXX_ABI Deprecated |
| void |
| _M_destroy_thread_key(void*) throw (); |
| |
| size_t |
| _M_get_thread_id(); |
| |
| explicit __pool() |
| : _M_bin(0), _M_bin_size(1), _M_thread_freelist(0) |
| { } |
| |
| explicit __pool(const __pool_base::_Tune& __tune) |
| : __pool_base(__tune), _M_bin(0), _M_bin_size(1), |
| _M_thread_freelist(0) |
| { } |
| |
| private: |
| // An "array" of bin_records each of which represents a specific |
| // power of 2 size. Memory to this "array" is allocated in |
| // _M_initialize(). |
| _Bin_record* _M_bin; |
| |
| // Actual value calculated in _M_initialize(). |
| size_t _M_bin_size; |
| |
| _Thread_record* _M_thread_freelist; |
| void* _M_thread_freelist_initial; |
| |
| void |
| _M_initialize(); |
| }; |
| #endif |
| |
| template<template <bool> class _PoolTp, bool _Thread> |
| struct __common_pool |
| { |
| typedef _PoolTp<_Thread> pool_type; |
| |
| static pool_type& |
| _S_get_pool() |
| { |
| static pool_type _S_pool; |
| return _S_pool; |
| } |
| }; |
| |
| template<template <bool> class _PoolTp, bool _Thread> |
| struct __common_pool_base; |
| |
| template<template <bool> class _PoolTp> |
| struct __common_pool_base<_PoolTp, false> |
| : public __common_pool<_PoolTp, false> |
| { |
| using __common_pool<_PoolTp, false>::_S_get_pool; |
| |
| static void |
| _S_initialize_once() |
| { |
| static bool __init; |
| if (__builtin_expect(__init == false, false)) |
| { |
| _S_get_pool()._M_initialize_once(); |
| __init = true; |
| } |
| } |
| }; |
| |
| #ifdef __GTHREADS |
| template<template <bool> class _PoolTp> |
| struct __common_pool_base<_PoolTp, true> |
| : public __common_pool<_PoolTp, true> |
| { |
| using __common_pool<_PoolTp, true>::_S_get_pool; |
| |
| static void |
| _S_initialize() |
| { _S_get_pool()._M_initialize_once(); } |
| |
| static void |
| _S_initialize_once() |
| { |
| static bool __init; |
| if (__builtin_expect(__init == false, false)) |
| { |
| if (__gthread_active_p()) |
| { |
| // On some platforms, __gthread_once_t is an aggregate. |
| static __gthread_once_t __once = __GTHREAD_ONCE_INIT; |
| __gthread_once(&__once, _S_initialize); |
| } |
| |
| // Double check initialization. May be necessary on some |
| // systems for proper construction when not compiling with |
| // thread flags. |
| _S_get_pool()._M_initialize_once(); |
| __init = true; |
| } |
| } |
| }; |
| #endif |
| |
| /// Policy for shared __pool objects. |
| template<template <bool> class _PoolTp, bool _Thread> |
| struct __common_pool_policy : public __common_pool_base<_PoolTp, _Thread> |
| { |
| template<typename _Tp1, template <bool> class _PoolTp1 = _PoolTp, |
| bool _Thread1 = _Thread> |
| struct _M_rebind |
| { typedef __common_pool_policy<_PoolTp1, _Thread1> other; }; |
| |
| using __common_pool_base<_PoolTp, _Thread>::_S_get_pool; |
| using __common_pool_base<_PoolTp, _Thread>::_S_initialize_once; |
| }; |
| |
| |
| template<typename _Tp, template <bool> class _PoolTp, bool _Thread> |
| struct __per_type_pool |
| { |
| typedef _Tp value_type; |
| typedef _PoolTp<_Thread> pool_type; |
| |
| static pool_type& |
| _S_get_pool() |
| { |
| using std::size_t; |
| // Sane defaults for the _PoolTp. |
| typedef typename pool_type::_Block_record _Block_record; |
| const static size_t __a = (__alignof__(_Tp) >= sizeof(_Block_record) |
| ? __alignof__(_Tp) : sizeof(_Block_record)); |
| |
| typedef typename __pool_base::_Tune _Tune; |
| static _Tune _S_tune(__a, sizeof(_Tp) * 64, |
| sizeof(_Tp) * 2 >= __a ? sizeof(_Tp) * 2 : __a, |
| sizeof(_Tp) * size_t(_Tune::_S_chunk_size), |
| _Tune::_S_max_threads, |
| _Tune::_S_freelist_headroom, |
| std::getenv("GLIBCXX_FORCE_NEW") ? true : false); |
| static pool_type _S_pool(_S_tune); |
| return _S_pool; |
| } |
| }; |
| |
| template<typename _Tp, template <bool> class _PoolTp, bool _Thread> |
| struct __per_type_pool_base; |
| |
| template<typename _Tp, template <bool> class _PoolTp> |
| struct __per_type_pool_base<_Tp, _PoolTp, false> |
| : public __per_type_pool<_Tp, _PoolTp, false> |
| { |
| using __per_type_pool<_Tp, _PoolTp, false>::_S_get_pool; |
| |
| static void |
| _S_initialize_once() |
| { |
| static bool __init; |
| if (__builtin_expect(__init == false, false)) |
| { |
| _S_get_pool()._M_initialize_once(); |
| __init = true; |
| } |
| } |
| }; |
| |
| #ifdef __GTHREADS |
| template<typename _Tp, template <bool> class _PoolTp> |
| struct __per_type_pool_base<_Tp, _PoolTp, true> |
| : public __per_type_pool<_Tp, _PoolTp, true> |
| { |
| using __per_type_pool<_Tp, _PoolTp, true>::_S_get_pool; |
| |
| static void |
| _S_initialize() |
| { _S_get_pool()._M_initialize_once(); } |
| |
| static void |
| _S_initialize_once() |
| { |
| static bool __init; |
| if (__builtin_expect(__init == false, false)) |
| { |
| if (__gthread_active_p()) |
| { |
| // On some platforms, __gthread_once_t is an aggregate. |
| static __gthread_once_t __once = __GTHREAD_ONCE_INIT; |
| __gthread_once(&__once, _S_initialize); |
| } |
| |
| // Double check initialization. May be necessary on some |
| // systems for proper construction when not compiling with |
| // thread flags. |
| _S_get_pool()._M_initialize_once(); |
| __init = true; |
| } |
| } |
| }; |
| #endif |
| |
| /// Policy for individual __pool objects. |
| template<typename _Tp, template <bool> class _PoolTp, bool _Thread> |
| struct __per_type_pool_policy |
| : public __per_type_pool_base<_Tp, _PoolTp, _Thread> |
| { |
| template<typename _Tp1, template <bool> class _PoolTp1 = _PoolTp, |
| bool _Thread1 = _Thread> |
| struct _M_rebind |
| { typedef __per_type_pool_policy<_Tp1, _PoolTp1, _Thread1> other; }; |
| |
| using __per_type_pool_base<_Tp, _PoolTp, _Thread>::_S_get_pool; |
| using __per_type_pool_base<_Tp, _PoolTp, _Thread>::_S_initialize_once; |
| }; |
| |
| |
| /// Base class for _Tp dependent member functions. |
| template<typename _Tp> |
| class __mt_alloc_base |
| { |
| public: |
| typedef std::size_t size_type; |
| typedef std::ptrdiff_t difference_type; |
| typedef _Tp* pointer; |
| typedef const _Tp* const_pointer; |
| typedef _Tp& reference; |
| typedef const _Tp& const_reference; |
| typedef _Tp value_type; |
| |
| #if __cplusplus >= 201103L |
| // _GLIBCXX_RESOLVE_LIB_DEFECTS |
| // 2103. propagate_on_container_move_assignment |
| typedef std::true_type propagate_on_container_move_assignment; |
| #endif |
| |
| pointer |
| address(reference __x) const _GLIBCXX_NOEXCEPT |
| { return std::__addressof(__x); } |
| |
| const_pointer |
| address(const_reference __x) const _GLIBCXX_NOEXCEPT |
| { return std::__addressof(__x); } |
| |
| size_type |
| max_size() const _GLIBCXX_USE_NOEXCEPT |
| { return size_type(-1) / sizeof(_Tp); } |
| |
| #if __cplusplus >= 201103L |
| template<typename _Up, typename... _Args> |
| void |
| construct(_Up* __p, _Args&&... __args) |
| { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); } |
| |
| template<typename _Up> |
| void |
| destroy(_Up* __p) { __p->~_Up(); } |
| #else |
| // _GLIBCXX_RESOLVE_LIB_DEFECTS |
| // 402. wrong new expression in [some_] allocator::construct |
| void |
| construct(pointer __p, const _Tp& __val) |
| { ::new((void *)__p) _Tp(__val); } |
| |
| void |
| destroy(pointer __p) { __p->~_Tp(); } |
| #endif |
| }; |
| |
| #ifdef __GTHREADS |
| #define __thread_default true |
| #else |
| #define __thread_default false |
| #endif |
| |
| /** |
| * @brief This is a fixed size (power of 2) allocator which - when |
| * compiled with thread support - will maintain one freelist per |
| * size per thread plus a @a global one. Steps are taken to limit |
| * the per thread freelist sizes (by returning excess back to |
| * the @a global list). |
| * @ingroup allocators |
| * |
| * Further details: |
| * https://gcc.gnu.org/onlinedocs/libstdc++/manual/mt_allocator.html |
| */ |
| template<typename _Tp, |
| typename _Poolp = __common_pool_policy<__pool, __thread_default> > |
| class __mt_alloc : public __mt_alloc_base<_Tp> |
| { |
| public: |
| typedef std::size_t size_type; |
| typedef std::ptrdiff_t difference_type; |
| typedef _Tp* pointer; |
| typedef const _Tp* const_pointer; |
| typedef _Tp& reference; |
| typedef const _Tp& const_reference; |
| typedef _Tp value_type; |
| typedef _Poolp __policy_type; |
| typedef typename _Poolp::pool_type __pool_type; |
| |
| template<typename _Tp1, typename _Poolp1 = _Poolp> |
| struct rebind |
| { |
| typedef typename _Poolp1::template _M_rebind<_Tp1>::other pol_type; |
| typedef __mt_alloc<_Tp1, pol_type> other; |
| }; |
| |
| __mt_alloc() _GLIBCXX_USE_NOEXCEPT { } |
| |
| __mt_alloc(const __mt_alloc&) _GLIBCXX_USE_NOEXCEPT { } |
| |
| template<typename _Tp1, typename _Poolp1> |
| __mt_alloc(const __mt_alloc<_Tp1, _Poolp1>&) _GLIBCXX_USE_NOEXCEPT { } |
| |
| ~__mt_alloc() _GLIBCXX_USE_NOEXCEPT { } |
| |
| _GLIBCXX_NODISCARD pointer |
| allocate(size_type __n, const void* = 0); |
| |
| void |
| deallocate(pointer __p, size_type __n); |
| |
| const __pool_base::_Tune |
| _M_get_options() |
| { |
| // Return a copy, not a reference, for external consumption. |
| return __policy_type::_S_get_pool()._M_get_options(); |
| } |
| |
| void |
| _M_set_options(__pool_base::_Tune __t) |
| { __policy_type::_S_get_pool()._M_set_options(__t); } |
| }; |
| |
| template<typename _Tp, typename _Poolp> |
| _GLIBCXX_NODISCARD typename __mt_alloc<_Tp, _Poolp>::pointer |
| __mt_alloc<_Tp, _Poolp>:: |
| allocate(size_type __n, const void*) |
| { |
| if (__n > this->max_size()) |
| std::__throw_bad_alloc(); |
| |
| #if __cpp_aligned_new |
| // Types with extended alignment are handled by operator new/delete. |
| if (alignof(_Tp) > __STDCPP_DEFAULT_NEW_ALIGNMENT__) |
| { |
| std::align_val_t __al = std::align_val_t(alignof(_Tp)); |
| return static_cast<_Tp*>(::operator new(__n * sizeof(_Tp), __al)); |
| } |
| #endif |
| |
| __policy_type::_S_initialize_once(); |
| |
| // Requests larger than _M_max_bytes are handled by operator |
| // new/delete directly. |
| __pool_type& __pool = __policy_type::_S_get_pool(); |
| const size_type __bytes = __n * sizeof(_Tp); |
| if (__pool._M_check_threshold(__bytes)) |
| { |
| void* __ret = ::operator new(__bytes); |
| return static_cast<_Tp*>(__ret); |
| } |
| |
| // Round up to power of 2 and figure out which bin to use. |
| const size_type __which = __pool._M_get_binmap(__bytes); |
| const size_type __thread_id = __pool._M_get_thread_id(); |
| |
| // Find out if we have blocks on our freelist. If so, go ahead |
| // and use them directly without having to lock anything. |
| char* __c; |
| typedef typename __pool_type::_Bin_record _Bin_record; |
| const _Bin_record& __bin = __pool._M_get_bin(__which); |
| if (__bin._M_first[__thread_id]) |
| { |
| // Already reserved. |
| typedef typename __pool_type::_Block_record _Block_record; |
| _Block_record* __block = __bin._M_first[__thread_id]; |
| __bin._M_first[__thread_id] = __block->_M_next; |
| |
| __pool._M_adjust_freelist(__bin, __block, __thread_id); |
| __c = reinterpret_cast<char*>(__block) + __pool._M_get_align(); |
| } |
| else |
| { |
| // Null, reserve. |
| __c = __pool._M_reserve_block(__bytes, __thread_id); |
| } |
| return static_cast<_Tp*>(static_cast<void*>(__c)); |
| } |
| |
| template<typename _Tp, typename _Poolp> |
| void |
| __mt_alloc<_Tp, _Poolp>:: |
| deallocate(pointer __p, size_type __n) |
| { |
| if (__builtin_expect(__p != 0, true)) |
| { |
| #if __cpp_aligned_new |
| // Types with extended alignment are handled by operator new/delete. |
| if (alignof(_Tp) > __STDCPP_DEFAULT_NEW_ALIGNMENT__) |
| { |
| ::operator delete(__p, std::align_val_t(alignof(_Tp))); |
| return; |
| } |
| #endif |
| |
| // Requests larger than _M_max_bytes are handled by |
| // operators new/delete directly. |
| __pool_type& __pool = __policy_type::_S_get_pool(); |
| const size_type __bytes = __n * sizeof(_Tp); |
| if (__pool._M_check_threshold(__bytes)) |
| ::operator delete(__p); |
| else |
| __pool._M_reclaim_block(reinterpret_cast<char*>(__p), __bytes); |
| } |
| } |
| |
| template<typename _Tp, typename _Poolp> |
| inline bool |
| operator==(const __mt_alloc<_Tp, _Poolp>&, const __mt_alloc<_Tp, _Poolp>&) |
| { return true; } |
| |
| #if __cpp_impl_three_way_comparison < 201907L |
| template<typename _Tp, typename _Poolp> |
| inline bool |
| operator!=(const __mt_alloc<_Tp, _Poolp>&, const __mt_alloc<_Tp, _Poolp>&) |
| { return false; } |
| #endif |
| |
| #undef __thread_default |
| |
| _GLIBCXX_END_NAMESPACE_VERSION |
| } // namespace |
| |
| #endif |