mirror of
https://github.com/RGBCube/serenity
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69bbf0285b
Empty string is extremely common and we can avoid a lot of heap churn by simply caching one in the VM. Primitive strings are immutable anyway so there is no observable behavior change outside of fewer collections.
94 lines
2.9 KiB
C++
94 lines
2.9 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/HashMap.h>
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#include <AK/RefCounted.h>
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#include <LibJS/Heap/Heap.h>
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namespace JS {
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class VM : public RefCounted<VM> {
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public:
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static NonnullRefPtr<VM> create();
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~VM();
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Heap& heap() { return m_heap; }
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const Heap& heap() const { return m_heap; }
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Interpreter& interpreter();
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Interpreter* interpreter_if_exists();
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void push_interpreter(Interpreter&);
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void pop_interpreter(Interpreter&);
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Exception* exception()
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{
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return m_exception;
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}
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void set_exception(Badge<Interpreter>, Exception* exception) { m_exception = exception; }
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void clear_exception() { m_exception = nullptr; }
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class InterpreterExecutionScope {
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public:
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InterpreterExecutionScope(Interpreter&);
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~InterpreterExecutionScope();
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private:
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Interpreter& m_interpreter;
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};
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void gather_roots(HashTable<Cell*>&);
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#define __JS_ENUMERATE(SymbolName, snake_name) \
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Symbol* well_known_symbol_##snake_name() const { return m_well_known_symbol_##snake_name; }
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JS_ENUMERATE_WELL_KNOWN_SYMBOLS
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#undef __JS_ENUMERATE
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Symbol* get_global_symbol(const String& description);
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PrimitiveString& empty_string() { return *m_empty_string; }
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private:
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VM();
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Exception* m_exception { nullptr };
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Heap m_heap;
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Vector<Interpreter*> m_interpreters;
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HashMap<String, Symbol*> m_global_symbol_map;
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PrimitiveString* m_empty_string { nullptr };
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#define __JS_ENUMERATE(SymbolName, snake_name) \
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Symbol* m_well_known_symbol_##snake_name { nullptr };
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JS_ENUMERATE_WELL_KNOWN_SYMBOLS
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#undef __JS_ENUMERATE
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};
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}
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