9bed2e4f4a
This commit introduces the concept of an accumulator register to LibJS's bytecode interpreter. The accumulator register is always register 0, and most simple instructions use it for reading and writing. Not only does this slim down the AST, but it also simplifies a lot of the code. For example, the generate_bytecode methods no longer need to return an Optional<Register>, as any opcode which has a "return" value will always put it into the accumulator. This also renames the old Op::Load to Op::LoadImmediate, and uses Op::Load to load from a register into the accumulator. There is also an Op::Store to put the value in the accumulator into another register.
71 lines
1.4 KiB
C++
71 lines
1.4 KiB
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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node.generate_bytecode(generator);
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generator.m_block->set_register_count({}, generator.m_next_register);
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generator.m_block->seal();
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return move(generator.m_block);
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}
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void Generator::grow(size_t additional_size)
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{
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m_block->grow(additional_size);
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}
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void* Generator::next_slot()
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{
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return m_block->next_slot();
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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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Label Generator::make_label() const
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{
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return Label { m_block->instruction_stream().size() };
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}
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Label Generator::nearest_continuable_scope() const
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{
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return m_continuable_scopes.last();
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}
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void Generator::begin_continuable_scope()
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{
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m_continuable_scopes.append(make_label());
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}
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void Generator::end_continuable_scope()
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{
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m_continuable_scopes.take_last();
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}
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}
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