ladybird/Userland/Libraries/LibJS/Bytecode/Generator.cpp
Andreas Kling 4bdfe73895 LibJS: Add basic support for "continue" in the bytecode VM
Unlike the convoluted unwind-until-scope-type mechanism in the AST
interpreter, "continue" maps to a simple Bytecode::Op::Jump here. :^)

We know where to jump based on a stack of "continuable scopes" that
we now maintain on the Bytecode::Generator as we go.

Note that this only supports bare "continue", not continue-with-label.
2021-06-07 18:11:59 +02:00

65 lines
1.3 KiB
C++

/*
* Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/OwnPtr.h>
#include <LibJS/AST.h>
#include <LibJS/Bytecode/Block.h>
#include <LibJS/Bytecode/Generator.h>
#include <LibJS/Bytecode/Instruction.h>
#include <LibJS/Bytecode/Register.h>
#include <LibJS/Forward.h>
namespace JS::Bytecode {
Generator::Generator()
{
m_block = Block::create();
}
Generator::~Generator()
{
}
OwnPtr<Block> Generator::generate(ASTNode const& node)
{
Generator generator;
[[maybe_unused]] auto dummy = node.generate_bytecode(generator);
generator.m_block->set_register_count({}, generator.m_next_register);
return move(generator.m_block);
}
void Generator::append(NonnullOwnPtr<Instruction> instruction)
{
m_block->append({}, move(instruction));
}
Register Generator::allocate_register()
{
VERIFY(m_next_register != NumericLimits<u32>::max());
return Register { m_next_register++ };
}
Label Generator::make_label() const
{
return Label { m_block->instructions().size() };
}
Label Generator::nearest_continuable_scope() const
{
return m_continuable_scopes.last();
}
void Generator::begin_continuable_scope()
{
m_continuable_scopes.append(make_label());
}
void Generator::end_continuable_scope()
{
m_continuable_scopes.take_last();
}
}