c364520c24
This patch adds a `-z` option to js and test-js. When run in this mode, garbage cells are never actually destroyed. We instead keep them around in a special zombie state. This allows us to validate that zombies don't get marked in future GC scans (since there were not supposed to be any more references!) :^) Cells get notified when they become a zombie (via did_become_zombie()) and this is used by WeakContainer cells to deregister themselves from the heap.
79 lines
1.6 KiB
C++
79 lines
1.6 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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#pragma once
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#include <AK/Format.h>
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#include <AK/Forward.h>
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#include <AK/Noncopyable.h>
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#include <LibJS/Forward.h>
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namespace JS {
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class Cell {
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AK_MAKE_NONCOPYABLE(Cell);
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AK_MAKE_NONMOVABLE(Cell);
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public:
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virtual void initialize(GlobalObject&) { }
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virtual ~Cell() { }
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bool is_marked() const { return m_mark; }
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void set_marked(bool b) { m_mark = b; }
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virtual void did_become_zombie() { }
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enum class State {
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Live,
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Dead,
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Zombie,
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};
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State state() const { return m_state; }
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void set_state(State state) { m_state = state; }
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virtual const char* class_name() const = 0;
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class Visitor {
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public:
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void visit(Cell* cell)
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{
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if (cell)
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visit_impl(*cell);
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}
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void visit(Value);
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protected:
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virtual void visit_impl(Cell&) = 0;
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virtual ~Visitor() = default;
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};
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virtual bool is_environment() const { return false; }
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virtual void visit_edges(Visitor&) { }
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Heap& heap() const;
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VM& vm() const;
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protected:
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Cell() { }
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private:
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bool m_mark : 1 { false };
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State m_state : 7 { State::Live };
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};
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}
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template<>
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struct AK::Formatter<JS::Cell> : AK::Formatter<FormatString> {
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void format(FormatBuilder& builder, const JS::Cell* cell)
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{
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if (!cell)
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Formatter<FormatString>::format(builder, "Cell{nullptr}");
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else
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Formatter<FormatString>::format(builder, "{}({})", cell->class_name(), cell);
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}
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};
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