--- /dev/null
+// MT-optimized allocator -*- C++ -*-
+
+// Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009
+// 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 <new>
+#include <cstdlib>
+#include <bits/functexcept.h>
+#include <ext/atomicity.h>
+#include <bits/move.h>
+
+_GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
+
+ using std::size_t;
+ using std::ptrdiff_t;
+
+ 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;
+
+ // 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(NULL), _M_init(false) { }
+
+ explicit
+ __pool_base(const _Tune& __options)
+ : _M_options(__options), _M_binmap(NULL), _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);
+
+ 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(NULL), _M_bin_size(1) { }
+
+ explicit __pool(const __pool_base::_Tune& __tune)
+ : __pool_base(__tune), _M_bin(NULL), _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);
+
+ 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*);
+
+ size_t
+ _M_get_thread_id();
+
+ explicit __pool()
+ : _M_bin(NULL), _M_bin_size(1), _M_thread_freelist(NULL)
+ { }
+
+ explicit __pool(const __pool_base::_Tune& __tune)
+ : __pool_base(__tune), _M_bin(NULL), _M_bin_size(1),
+ _M_thread_freelist(NULL)
+ { }
+
+ 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()
+ {
+ // 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 size_t size_type;
+ typedef ptrdiff_t difference_type;
+ typedef _Tp* pointer;
+ typedef const _Tp* const_pointer;
+ typedef _Tp& reference;
+ typedef const _Tp& const_reference;
+ typedef _Tp value_type;
+
+ pointer
+ address(reference __x) const
+ { return &__x; }
+
+ const_pointer
+ address(const_reference __x) const
+ { return &__x; }
+
+ size_type
+ max_size() const throw()
+ { return size_t(-1) / sizeof(_Tp); }
+
+ // _GLIBCXX_RESOLVE_LIB_DEFECTS
+ // 402. wrong new expression in [some_] allocator::construct
+ void
+ construct(pointer __p, const _Tp& __val)
+ { ::new((void *)__p) _Tp(__val); }
+
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+ template<typename... _Args>
+ void
+ construct(pointer __p, _Args&&... __args)
+ { ::new((void *)__p) _Tp(std::forward<_Args>(__args)...); }
+#endif
+
+ void
+ destroy(pointer __p) { __p->~_Tp(); }
+ };
+
+#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 "global" one. Steps are taken to limit
+ * the per thread freelist sizes (by returning excess back to
+ * the "global" list).
+ * @ingroup allocators
+ *
+ * Further details:
+ * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt12ch32.html
+ */
+ template<typename _Tp,
+ typename _Poolp = __common_pool_policy<__pool, __thread_default> >
+ class __mt_alloc : public __mt_alloc_base<_Tp>
+ {
+ public:
+ typedef size_t size_type;
+ typedef 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() throw() { }
+
+ __mt_alloc(const __mt_alloc&) throw() { }
+
+ template<typename _Tp1, typename _Poolp1>
+ __mt_alloc(const __mt_alloc<_Tp1, _Poolp1>&) throw() { }
+
+ ~__mt_alloc() throw() { }
+
+ 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>
+ typename __mt_alloc<_Tp, _Poolp>::pointer
+ __mt_alloc<_Tp, _Poolp>::
+ allocate(size_type __n, const void*)
+ {
+ if (__builtin_expect(__n > this->max_size(), false))
+ std::__throw_bad_alloc();
+
+ __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_t __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_t __which = __pool._M_get_binmap(__bytes);
+ const size_t __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))
+ {
+ // Requests larger than _M_max_bytes are handled by
+ // operators new/delete directly.
+ __pool_type& __pool = __policy_type::_S_get_pool();
+ const size_t __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; }
+
+ template<typename _Tp, typename _Poolp>
+ inline bool
+ operator!=(const __mt_alloc<_Tp, _Poolp>&, const __mt_alloc<_Tp, _Poolp>&)
+ { return false; }
+
+#undef __thread_default
+
+_GLIBCXX_END_NAMESPACE
+
+#endif
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