
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.
41 lines
1,013 B
C++
41 lines
1,013 B
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 <AK/HashTable.h>
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#include <LibJS/Runtime/Object.h>
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#include <LibJS/Runtime/Set.h>
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namespace JS {
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class SetIterator final : public Object {
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JS_OBJECT(SetIterator, Object);
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JS_DECLARE_ALLOCATOR(SetIterator);
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public:
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static NonnullGCPtr<SetIterator> create(Realm&, Set& set, Object::PropertyKind iteration_kind);
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virtual ~SetIterator() override = default;
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Set& set() const { return m_set; }
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bool done() const { return m_done; }
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Object::PropertyKind iteration_kind() const { return m_iteration_kind; }
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private:
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friend class SetIteratorPrototype;
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explicit SetIterator(Set& set, Object::PropertyKind iteration_kind, Object& prototype);
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virtual void visit_edges(Cell::Visitor&) override;
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NonnullGCPtr<Set> m_set;
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bool m_done { false };
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Object::PropertyKind m_iteration_kind;
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Map::ConstIterator m_iterator;
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};
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}
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