ladybird/Userland/Libraries/LibWasm/AbstractMachine/BytecodeInterpreter.h

/*
 * Copyright (c) 2021, Ali Mohammad Pur <mpfard@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#pragma once

#include <AK/StackInfo.h>
#include <LibWasm/AbstractMachine/Configuration.h>
#include <LibWasm/AbstractMachine/Interpreter.h>

namespace Wasm {

struct BytecodeInterpreter : public Interpreter {
    virtual void interpret(Configuration&) override;
    virtual ~BytecodeInterpreter() override = default;
    virtual bool did_trap() const override { return !m_trap.has<Empty>(); }
    virtual DeprecatedString trap_reason() const override
    {
        return m_trap.visit(
            [](Empty) -> DeprecatedString { VERIFY_NOT_REACHED(); },
            [](Trap const& trap) { return trap.reason; },
            [](JS::Completion const& completion) { return completion.value()->to_string_without_side_effects().release_value().to_deprecated_string(); });
    }
    virtual void clear_trap() override { m_trap = Empty {}; }

    struct CallFrameHandle {
        explicit CallFrameHandle(BytecodeInterpreter& interpreter, Configuration& configuration)
            : m_configuration_handle(configuration)
            , m_interpreter(interpreter)
        {
        }

        ~CallFrameHandle() = default;

        Configuration::CallFrameHandle m_configuration_handle;
        BytecodeInterpreter& m_interpreter;
    };

protected:
    virtual void interpret(Configuration&, InstructionPointer&, Instruction const&);
    void branch_to_label(Configuration&, LabelIndex);
    template<typename ReadT, typename PushT>
    void load_and_push(Configuration&, Instruction const&);
    template<typename PopT, typename StoreT>
    void pop_and_store(Configuration&, Instruction const&);
    void store_to_memory(Configuration&, Instruction const&, ReadonlyBytes data, i32 base);
    void call_address(Configuration&, FunctionAddress);

    template<typename PopType, typename PushType, typename Operator>
    void binary_numeric_operation(Configuration&);

    template<typename PopType, typename PushType, typename Operator>
    void unary_operation(Configuration&);

    template<typename V, typename T>
    MakeUnsigned<T> checked_unsigned_truncate(V);

    template<typename V, typename T>
    MakeSigned<T> checked_signed_truncate(V);

    template<typename T>
    T read_value(ReadonlyBytes data);

    Vector<Value> pop_values(Configuration& configuration, size_t count);
    ALWAYS_INLINE bool trap_if_not(bool value, StringView reason)
    {
        if (!value)
            m_trap = Trap { reason };
        return !m_trap.has<Empty>();
    }

    Variant<Trap, JS::Completion, Empty> m_trap;
    StackInfo m_stack_info;
};

struct DebuggerBytecodeInterpreter : public BytecodeInterpreter {
    virtual ~DebuggerBytecodeInterpreter() override = default;

    Function<bool(Configuration&, InstructionPointer&, Instruction const&)> pre_interpret_hook;
    Function<bool(Configuration&, InstructionPointer&, Instruction const&, Interpreter const&)> post_interpret_hook;

private:
    virtual void interpret(Configuration&, InstructionPointer&, Instruction const&) override;
};

}