6089d6566b
This patch makes all HeapBlock allocations aligned to their block size, enabling us to find the HeapBlock* for a given Cell* by simply masking bits off of the cell address. Use this to make a simple Heap& getter for Cell, which lets us avoid plumbing the Heap& everywhere.
128 lines
3.3 KiB
C++
128 lines
3.3 KiB
C++
/*
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* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <AK/Badge.h>
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#include <AK/HashTable.h>
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#include <LibJS/Heap.h>
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#include <LibJS/HeapBlock.h>
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#include <LibJS/Interpreter.h>
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#include <LibJS/Object.h>
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#define HEAP_DEBUG
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namespace JS {
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Heap::Heap(Interpreter& interpreter)
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: m_interpreter(interpreter)
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{
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}
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Heap::~Heap()
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{
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}
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Cell* Heap::allocate_cell(size_t size)
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{
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for (auto& block : m_blocks) {
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if (size > block->cell_size())
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continue;
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if (auto* cell = block->allocate())
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return cell;
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}
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auto block = HeapBlock::create_with_cell_size(*this, size);
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auto* cell = block->allocate();
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m_blocks.append(move(block));
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return cell;
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}
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void Heap::collect_garbage()
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{
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HashTable<Cell*> roots;
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collect_roots(roots);
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mark_live_cells(roots);
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sweep_dead_cells();
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}
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void Heap::collect_roots(HashTable<Cell*>& roots)
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{
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m_interpreter.collect_roots({}, roots);
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#ifdef HEAP_DEBUG
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dbg() << "collect_roots:";
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for (auto* root : roots) {
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dbg() << " + " << root;
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}
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#endif
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}
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class MarkingVisitor final : public Cell::Visitor {
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public:
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MarkingVisitor() {}
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virtual void visit(Cell* cell)
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{
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if (cell->is_marked())
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return;
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#ifdef HEAP_DEBUG
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dbg() << " ! " << cell;
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#endif
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cell->set_marked(true);
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cell->visit_children(*this);
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}
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};
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void Heap::mark_live_cells(const HashTable<Cell*>& roots)
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{
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#ifdef HEAP_DEBUG
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dbg() << "mark_live_cells:";
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#endif
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MarkingVisitor visitor;
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for (auto* root : roots)
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visitor.visit(root);
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}
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void Heap::sweep_dead_cells()
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{
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#ifdef HEAP_DEBUG
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dbg() << "sweep_dead_cells:";
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#endif
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for (auto& block : m_blocks) {
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block->for_each_cell([&](Cell* cell) {
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if (cell->is_live()) {
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if (!cell->is_marked()) {
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#ifdef HEAP_DEBUG
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dbg() << " ~ " << cell;
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#endif
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block->deallocate(cell);
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} else {
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cell->set_marked(false);
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}
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}
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});
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}
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}
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}
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