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8ae3c09dc0
The 'arena' allocator does not take memory alignment into account, which can result in crashes at -O3 with gcc 7.5 (presumably because of SSE instructions). This accounts for alignment issues, fixing the issue. Also do various cleanup in lib/allocators. Reported by: Bellaz89, Freagarach Comments by: vladislavbelov Differential Revision: https://code.wildfiregames.com/D3181 This was SVN commit r24517.
116 lines
3 KiB
C++
116 lines
3 KiB
C++
/* Copyright (C) 2021 Wildfire Games.
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be included
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* in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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#ifndef INCLUDED_ALLOCATORS_DYNAMIC_ARENA
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#define INCLUDED_ALLOCATORS_DYNAMIC_ARENA
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#include "lib/bits.h"
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#include <new> // bad_alloc
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#include <memory> // unique_ptr
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#include <vector>
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namespace Allocators {
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/**
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* 'Blind' memory allocator. Characteristics:
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* - grows dynamically, and linearily, by BLOCK_SIZE
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* - no reallocations, pointers remain valid
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* - can allocate objects up to BLOCK_SIZE in size
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* - can handle any aligment (up to BLOCK_SIZE)
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* - Doesn't de-allocate unless cleared or destroyed.
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*/
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template<size_t BLOCK_SIZE>
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class DynamicArena
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{
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protected:
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struct Block
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{
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bool Available(size_t n, size_t alignment) const
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{
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return n + ROUND_UP(size, alignment) <= BLOCK_SIZE;
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}
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uint8_t* Allocate(size_t n, size_t alignment)
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{
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size = ROUND_UP(size, alignment);
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uint8_t* ptr = &block[size];
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size += n;
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return ptr;
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}
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alignas(8) uint8_t block[BLOCK_SIZE];
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size_t size = 0;
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};
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NONCOPYABLE(DynamicArena);
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public:
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DynamicArena()
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{
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m_Blocks.reserve(16);
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AllocateNewBlock();
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};
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void AllocateNewBlock()
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{
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m_Blocks.emplace_back(std::make_unique<Block>());
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m_NewestBlock = m_Blocks.back().get();
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}
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void* allocate(size_t n, const void*, size_t alignment)
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{
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// Safely handle zero-sized allocations (happens with GCC STL - see ticket #909).
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if (n == 0)
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n = 1;
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if (n > BLOCK_SIZE)
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{
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debug_warn("DynamicArena cannot allocate more than chunk size");
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throw std::bad_alloc();
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}
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if (!m_NewestBlock->Available(n, alignment))
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AllocateNewBlock();
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return reinterpret_cast<void*>(m_NewestBlock->Allocate(n, alignment));
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}
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void deallocate(void* UNUSED(p), size_t UNUSED(n))
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{
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// ignored
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}
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void clear()
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{
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m_NewestBlock = nullptr;
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m_Blocks.clear();
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AllocateNewBlock();
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}
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protected:
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std::vector<std::unique_ptr<Block>> m_Blocks;
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Block* m_NewestBlock = nullptr;
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};
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} // namespace Allocators
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#endif // INCLUDED_ALLOCATORS_DYNAMIC_ARENA
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