mirror of
https://github.com/RGBCube/serenity
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421845b0cd
Since non-strict direct eval() can insert new bindings into a surrounding var scope, we cannot safely cache some assumptions about environment chain layout after eval() has taken place. Since eval() is rare, let's do what other engines do and simply deoptimize in its presence. This patch adds a new "permanently screwed" flag to JS::Environment that will be set on the entire variable environment chain upon non-strict direct eval().
75 lines
2.9 KiB
C++
75 lines
2.9 KiB
C++
/*
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* Copyright (c) 2020-2021, 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 <LibJS/Runtime/Object.h>
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namespace JS {
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struct Variable {
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Value value;
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DeclarationKind declaration_kind;
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};
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#define JS_ENVIRONMENT(class_, base_class) \
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public: \
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using Base = base_class; \
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virtual char const* class_name() const override { return #class_; }
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class Environment : public Cell {
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public:
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GlobalObject& global_object() { return *m_global_object; }
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GlobalObject const& global_object() const { return *m_global_object; }
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virtual void initialize(GlobalObject&) override;
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virtual bool has_this_binding() const { return false; }
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virtual Value get_this_binding(GlobalObject&) const { return {}; }
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virtual Object* with_base_object() const { return nullptr; }
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virtual bool has_binding([[maybe_unused]] FlyString const& name, [[maybe_unused]] Optional<size_t>* out_index = nullptr) const { return false; }
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virtual void create_mutable_binding(GlobalObject&, [[maybe_unused]] FlyString const& name, [[maybe_unused]] bool can_be_deleted) { }
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virtual void create_immutable_binding(GlobalObject&, [[maybe_unused]] FlyString const& name, [[maybe_unused]] bool strict) { }
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virtual void initialize_binding(GlobalObject&, [[maybe_unused]] FlyString const& name, Value) { }
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virtual void set_mutable_binding(GlobalObject&, [[maybe_unused]] FlyString const& name, Value, [[maybe_unused]] bool strict) { }
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virtual Value get_binding_value(GlobalObject&, [[maybe_unused]] FlyString const& name, [[maybe_unused]] bool strict) { return {}; }
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virtual bool delete_binding(GlobalObject&, [[maybe_unused]] FlyString const& name) { return false; }
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// [[OuterEnv]]
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Environment* outer_environment() { return m_outer_environment; }
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Environment const* outer_environment() const { return m_outer_environment; }
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virtual bool is_global_environment() const { return false; }
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virtual bool is_declarative_environment() const { return false; }
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virtual bool is_function_environment() const { return false; }
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template<typename T>
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bool fast_is() const = delete;
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virtual char const* class_name() const override { return "Environment"; }
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// This flag is set on the entire variable environment chain when direct eval() is performed.
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// It is used to disable non-local variable access caching.
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bool is_permanently_screwed_by_eval() const { return m_permanently_screwed_by_eval; }
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void set_permanently_screwed_by_eval();
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protected:
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explicit Environment(Environment* parent);
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virtual void visit_edges(Visitor&) override;
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private:
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virtual bool is_environment() const final { return true; }
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GlobalObject* m_global_object { nullptr };
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Environment* m_outer_environment { nullptr };
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bool m_permanently_screwed_by_eval { false };
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};
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}
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