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f6aee2b9e8
Instead of keeping bytecode as a set of disjoint basic blocks on the
malloc heap, bytecode is now a contiguous sequence of bytes(!)
The transformation happens at the end of Bytecode::Generator::generate()
and the only really hairy part is rerouting jump labels.
This required solving a few problems:
- The interpreter execution loop had to change quite a bit, since we
were storing BasicBlock pointers all over the place, and control
transfer was done by redirecting the interpreter's current block.
- Exception handlers & finalizers are now stored per-bytecode-range
in a side table in Executable.
- The interpreter now has a plain program counter instead of a stream
iterator. This actually makes error stack generation a bit nicer
since we just have to deal with a number instead of reaching into
the iterator.
This yields a 25% performance improvement on this microbenchmark:
for (let i = 0; i < 1_000_000; ++i) { }
But basically everything gets faster. :^)
39 lines
830 B
C++
39 lines
830 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/String.h>
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#include <LibJS/Bytecode/BasicBlock.h>
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#include <LibJS/Bytecode/Op.h>
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namespace JS::Bytecode {
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NonnullOwnPtr<BasicBlock> BasicBlock::create(String name)
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{
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return adopt_own(*new BasicBlock(move(name)));
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}
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BasicBlock::BasicBlock(String name)
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: m_name(move(name))
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{
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}
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BasicBlock::~BasicBlock()
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{
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Bytecode::InstructionStreamIterator it(instruction_stream());
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while (!it.at_end()) {
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auto& to_destroy = (*it);
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++it;
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Instruction::destroy(const_cast<Instruction&>(to_destroy));
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}
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}
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void BasicBlock::grow(size_t additional_size)
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{
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m_buffer.grow_capacity(m_buffer.size() + additional_size);
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m_buffer.resize(m_buffer.size() + additional_size);
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}
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}
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