3c74dc9f4d
This patch adds two macros to declare per-type allocators: - JS_DECLARE_ALLOCATOR(TypeName) - JS_DEFINE_ALLOCATOR(TypeName) When used, they add a type-specific CellAllocator that the Heap will delegate allocation requests to. The result of this is that GC objects of the same type always end up within the same HeapBlock, drastically reducing the ability to perform type confusion attacks. It also improves HeapBlock utilization, since each block now has cells sized exactly to the type used within that block. (Previously we only had a handful of block sizes available, and most GC allocations ended up with a large amount of slack in their tails.) There is a small performance hit from this, but I'm sure we can make up for it elsewhere. Note that the old size-based allocators still exist, and we fall back to them for any type that doesn't have its own CellAllocator.
50 lines
1.4 KiB
C++
50 lines
1.4 KiB
C++
/*
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* Copyright (c) 2021, Idan Horowitz <idan.horowitz@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 <LibJS/Runtime/GlobalObject.h>
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#include <LibJS/Runtime/Map.h>
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#include <LibJS/Runtime/Object.h>
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#include <LibJS/Runtime/Value.h>
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namespace JS {
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class Set : public Object {
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JS_OBJECT(Set, Object);
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JS_DECLARE_ALLOCATOR(Set);
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public:
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static NonnullGCPtr<Set> create(Realm&);
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virtual void initialize(Realm&) override;
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virtual ~Set() override = default;
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// NOTE: Unlike what the spec says, we implement Sets using an underlying map,
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// so all the functions below do not directly implement the operations as
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// defined by the specification.
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void set_clear() { m_values->map_clear(); }
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bool set_remove(Value const& value) { return m_values->map_remove(value); }
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bool set_has(Value const& key) const { return m_values->map_has(key); }
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void set_add(Value const& key) { m_values->map_set(key, js_undefined()); }
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size_t set_size() const { return m_values->map_size(); }
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auto begin() const { return const_cast<Map const&>(*m_values).begin(); }
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auto begin() { return m_values->begin(); }
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auto end() const { return m_values->end(); }
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NonnullGCPtr<Set> copy() const;
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private:
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explicit Set(Object& prototype);
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virtual void visit_edges(Visitor& visitor) override;
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GCPtr<Map> m_values;
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};
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}
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