ladybird/Userland/Libraries/LibJS/Bytecode/Op.h
Andreas Kling 6ae9346cd3 LibJS: Add basic support for while loops in the bytecode engine
This introduces two new instructions: Jump and JumpIfFalse.
Jumps are made to a Bytecode::Label, which is a simple object that
represents a location in the bytecode stream.

Note that you may not always know the target of a jump when adding the
jump instruction itself, but we can just update the instruction later
on during codegen once we know where the jump target is.

The Bytecode::Interpreter now implements jumping via a jump slot that
gets checked after each instruction to see if a jump is pending.
If not, we just increment the PC as usual.
2021-06-07 18:11:59 +02:00

177 lines
3.8 KiB
C++

/*
* Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/FlyString.h>
#include <LibJS/Bytecode/Instruction.h>
#include <LibJS/Bytecode/Label.h>
#include <LibJS/Bytecode/Register.h>
#include <LibJS/Heap/Cell.h>
#include <LibJS/Runtime/Value.h>
namespace JS::Bytecode::Op {
class Load final : public Instruction {
public:
Load(Register dst, Value value)
: m_dst(dst)
, m_value(value)
{
}
virtual ~Load() override { }
virtual void execute(Bytecode::Interpreter&) const override;
virtual String to_string() const override;
private:
Register m_dst;
Value m_value;
};
class Add final : public Instruction {
public:
Add(Register dst, Register src1, Register src2)
: m_dst(dst)
, m_src1(src1)
, m_src2(src2)
{
}
virtual ~Add() override { }
virtual void execute(Bytecode::Interpreter&) const override;
virtual String to_string() const override;
private:
Register m_dst;
Register m_src1;
Register m_src2;
};
class Sub final : public Instruction {
public:
Sub(Register dst, Register src1, Register src2)
: m_dst(dst)
, m_src1(src1)
, m_src2(src2)
{
}
virtual ~Sub() override { }
virtual void execute(Bytecode::Interpreter&) const override;
virtual String to_string() const override;
private:
Register m_dst;
Register m_src1;
Register m_src2;
};
class LessThan final : public Instruction {
public:
LessThan(Register dst, Register src1, Register src2)
: m_dst(dst)
, m_src1(src1)
, m_src2(src2)
{
}
virtual ~LessThan() override { }
virtual void execute(Bytecode::Interpreter&) const override;
virtual String to_string() const override;
private:
Register m_dst;
Register m_src1;
Register m_src2;
};
class NewString final : public Instruction {
public:
NewString(Register dst, String string)
: m_dst(dst)
, m_string(move(string))
{
}
virtual ~NewString() override { }
virtual void execute(Bytecode::Interpreter&) const override;
virtual String to_string() const override;
private:
Register m_dst;
String m_string;
};
class SetVariable final : public Instruction {
public:
SetVariable(FlyString identifier, Register src)
: m_identifier(move(identifier))
, m_src(src)
{
}
virtual ~SetVariable() override { }
virtual void execute(Bytecode::Interpreter&) const override;
virtual String to_string() const override;
private:
FlyString m_identifier;
Register m_src;
};
class GetVariable final : public Instruction {
public:
GetVariable(Register dst, FlyString identifier)
: m_dst(dst)
, m_identifier(move(identifier))
{
}
virtual ~GetVariable() override { }
virtual void execute(Bytecode::Interpreter&) const override;
virtual String to_string() const override;
private:
Register m_dst;
FlyString m_identifier;
};
class Jump final : public Instruction {
public:
explicit Jump(Label target)
: m_target(target)
{
}
virtual ~Jump() override { }
virtual void execute(Bytecode::Interpreter&) const override;
virtual String to_string() const override;
private:
Label m_target;
};
class JumpIfFalse final : public Instruction {
public:
explicit JumpIfFalse(Register result, Optional<Label> target = {})
: m_result(result)
, m_target(move(target))
{
}
void set_target(Optional<Label> target) { m_target = move(target); }
virtual ~JumpIfFalse() override { }
virtual void execute(Bytecode::Interpreter&) const override;
virtual String to_string() const override;
private:
Register m_result;
Optional<Label> m_target;
};
}