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69dddd4ef5
This patch begins the work of implementing JavaScript execution in a bytecode VM instead of an AST tree-walk interpreter. It's probably quite naive, but we have to start somewhere. The basic idea is that you call Bytecode::Generator::generate() on an AST node and it hands you back a Bytecode::Block filled with instructions that can then be interpreted by a Bytecode::Interpreter. This first version only implements two instructions: Load and Add. :^) Each bytecode block has infinity registers, and the interpreter resizes its register file to fit the block being executed. Two new `js` options are added in this patch as well: `-d` will dump the generated bytecode `-b` will execute the generated bytecode Note that unless `-d` and/or `-b` are specified, none of the bytecode related stuff in LibJS runs at all. This is implemented in parallel with the existing AST interpreter. :^)
46 lines
973 B
C++
46 lines
973 B
C++
/*
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* Copyright (c) 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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#include <AK/OwnPtr.h>
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#include <LibJS/AST.h>
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#include <LibJS/Bytecode/Block.h>
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#include <LibJS/Bytecode/Generator.h>
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#include <LibJS/Bytecode/Instruction.h>
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#include <LibJS/Bytecode/Register.h>
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#include <LibJS/Forward.h>
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namespace JS::Bytecode {
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Generator::Generator()
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{
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m_block = Block::create();
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}
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Generator::~Generator()
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{
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}
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OwnPtr<Block> Generator::generate(ASTNode const& node)
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{
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Generator generator;
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[[maybe_unused]] auto dummy = node.generate_bytecode(generator);
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generator.m_block->set_register_count({}, generator.m_next_register);
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return move(generator.m_block);
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}
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void Generator::append(NonnullOwnPtr<Instruction> instruction)
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{
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m_block->append({}, move(instruction));
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}
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Register Generator::allocate_register()
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{
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VERIFY(m_next_register != NumericLimits<u32>::max());
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return Register { m_next_register++ };
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}
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}
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