6861c619c6
This patch moves the exception state, call stack and scope stack from Interpreter to VM. I'm doing this to help myself discover what the split between Interpreter and VM should be, by shuffling things around and seeing what falls where. With these changes, we no longer have a persistent lexical environment for the current global object on the Interpreter's call stack. Instead, we push/pop that environment on Interpreter::run() enter/exit. Since it should only be used to find the global "this", and not for variable storage (that goes directly into the global object instead!), I had to insert some short-circuiting when walking the environment parent chain during variable lookup. Note that this is a "stepping stone" commit, not a final design.
107 lines
3.8 KiB
C++
107 lines
3.8 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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#pragma once
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#include <AK/FlyString.h>
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#include <AK/HashMap.h>
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#include <LibJS/Runtime/Cell.h>
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#include <LibJS/Runtime/Value.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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class LexicalEnvironment final : public Cell {
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public:
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enum class ThisBindingStatus {
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Lexical,
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Initialized,
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Uninitialized,
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};
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enum class EnvironmentRecordType {
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Declarative,
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Function,
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Global,
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Object,
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Module,
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};
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LexicalEnvironment();
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LexicalEnvironment(EnvironmentRecordType);
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LexicalEnvironment(HashMap<FlyString, Variable> variables, LexicalEnvironment* parent);
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LexicalEnvironment(HashMap<FlyString, Variable> variables, LexicalEnvironment* parent, EnvironmentRecordType);
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virtual ~LexicalEnvironment() override;
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LexicalEnvironment* parent() const { return m_parent; }
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Optional<Variable> get(const FlyString&) const;
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void set(const FlyString&, Variable);
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void clear();
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const HashMap<FlyString, Variable>& variables() const { return m_variables; }
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void set_home_object(Value object) { m_home_object = object; }
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bool has_super_binding() const;
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Value get_super_base();
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bool has_this_binding() const;
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ThisBindingStatus this_binding_status() const { return m_this_binding_status; }
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Value get_this_binding() const;
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void bind_this_value(Value this_value);
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// Not a standard operation.
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void replace_this_binding(Value this_value) { m_this_value = this_value; }
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Value new_target() const { return m_new_target; };
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void set_new_target(Value new_target) { m_new_target = new_target; }
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Function* current_function() const { return m_current_function; }
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void set_current_function(Function& function) { m_current_function = &function; }
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EnvironmentRecordType type() const { return m_environment_record_type; }
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private:
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virtual const char* class_name() const override { return "LexicalEnvironment"; }
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virtual void visit_children(Visitor&) override;
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LexicalEnvironment* m_parent { nullptr };
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HashMap<FlyString, Variable> m_variables;
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EnvironmentRecordType m_environment_record_type = EnvironmentRecordType::Declarative;
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ThisBindingStatus m_this_binding_status = ThisBindingStatus::Uninitialized;
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Value m_home_object;
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Value m_this_value;
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Value m_new_target;
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// Corresponds to [[FunctionObject]]
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Function* m_current_function { nullptr };
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};
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}
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