392b5c3b19
Cell::heap() and Cell::vm() needed to access member functions from HeapBlock, and wanted to be inline, so they were moved to VM.h. That approach will no longer work with VM.h not being included in every file (starting from the next commit), so this commit fixes that circular import issue by introducing secondary base classes to host the references to Heap and VM, respectively.
66 lines
2.2 KiB
C++
66 lines
2.2 KiB
C++
/*
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* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/Assertions.h>
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#include <AK/NonnullOwnPtr.h>
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#include <AK/Platform.h>
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#include <LibJS/Heap/Heap.h>
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#include <LibJS/Heap/HeapBlock.h>
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#include <stdio.h>
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#include <sys/mman.h>
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#ifdef HAS_ADDRESS_SANITIZER
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# include <sanitizer/asan_interface.h>
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#endif
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namespace JS {
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NonnullOwnPtr<HeapBlock> HeapBlock::create_with_cell_size(Heap& heap, size_t cell_size)
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{
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#ifdef AK_OS_SERENITY
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char name[64];
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snprintf(name, sizeof(name), "LibJS: HeapBlock(%zu)", cell_size);
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#else
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char const* name = nullptr;
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#endif
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auto* block = static_cast<HeapBlock*>(heap.block_allocator().allocate_block(name));
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new (block) HeapBlock(heap, cell_size);
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return NonnullOwnPtr<HeapBlock>(NonnullOwnPtr<HeapBlock>::Adopt, *block);
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}
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HeapBlock::HeapBlock(Heap& heap, size_t cell_size)
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: HeapBlockBase(heap)
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, m_cell_size(cell_size)
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{
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VERIFY(cell_size >= sizeof(FreelistEntry));
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ASAN_POISON_MEMORY_REGION(m_storage, block_size - sizeof(HeapBlock));
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}
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void HeapBlock::deallocate(Cell* cell)
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{
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VERIFY(is_valid_cell_pointer(cell));
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VERIFY(!m_freelist || is_valid_cell_pointer(m_freelist));
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VERIFY(cell->state() == Cell::State::Live);
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VERIFY(!cell->is_marked());
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cell->~Cell();
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auto* freelist_entry = new (cell) FreelistEntry();
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freelist_entry->set_state(Cell::State::Dead);
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freelist_entry->next = m_freelist;
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m_freelist = freelist_entry;
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#ifdef HAS_ADDRESS_SANITIZER
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auto dword_after_freelist = round_up_to_power_of_two(reinterpret_cast<uintptr_t>(freelist_entry) + sizeof(FreelistEntry), 8);
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VERIFY((dword_after_freelist - reinterpret_cast<uintptr_t>(freelist_entry)) <= m_cell_size);
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VERIFY(m_cell_size >= sizeof(FreelistEntry));
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// We can't poision the cell tracking data, nor the FreeListEntry's vtable or next pointer
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// This means there's sizeof(FreelistEntry) data at the front of each cell that is always read/write
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// On x86_64, this ends up being 24 bytes due to the size of the FreeListEntry's vtable, while on x86, it's only 12 bytes.
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ASAN_POISON_MEMORY_REGION(reinterpret_cast<void*>(dword_after_freelist), m_cell_size - sizeof(FreelistEntry));
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#endif
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}
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}
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