Bytebox

Bytebox is a Webassembly VM.

Getting started

Requirements

Bytebox currently builds with Zig 0.10.0. Other versions have not been tested - use at your discretion.

Run

git clone --recurse-submodules https://github.com/rdunnington/bytebox.git
cd bytebox
zig build test  # run the official WebAssembly spec testsuite
zig build bench # run the benchmarks (not robust)

Usage

You can use the standalone runner to load and execute WebAssembly programs:

zig build run -- <wasmfile>

Or embed Bytebox in your own programs:

// build.zig
const std = @import("std");

pub fn build(b: *std.build.Builder) void {
    const exe = b.addExecutable("my_program", "src/main.zig");
    exe.addPackage(std.build.Pkg{
        .name = "bytebox",
        .source = .{ .path = "bytebox/src/core.zig" }, // submodule in the root dir
    });
    exe.setTarget(b.standardTargetOptions(.{}));
    exe.setBuildMode(b.standardReleaseOptions());
    exe.install();
    const run = exe.run();
    const step = b.step("run", "runs my_program");
    step.dependOn(&run.step);
}

// main.zig
const std = @import("std");
const bytebox = @import("bytebox");

pub fn main() !void {
    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    var allocator: std.mem.Allocator = gpa.allocator();

    var wasm_data: []u8 = try std.fs.cwd().readFileAlloc(allocator, "example.wasm", 1024 * 128);
    defer allocator.free(wasm_data);

    var module_definition = bytebox.ModuleDefinition.init(allocator);
    try module_definition.decode(wasm_data);
    defer module_definition.deinit();

    var module_instance = bytebox.ModuleInstance.init(&module_definition, allocator);
    try module_instance.instantiate(.{});
    defer module_instance.deinit();
}

Status

This project is unstable and still in development.

WebAssembly support:

Status	Feature
✔	WebAssembly 1.0
✔	Sign extension instructions
✔	Non-trapping float-to-int conversion
✔	Multiple values
✔	Reference types
✔	Table instructions
✔	Multiple tables
✔	Bulk memory and table instructions
❌	Vector instructions

Roadmap

These tasks must be completed to enter alpha:

Documentation
Vector instructions
API ergonomics pass
Crash hardening
General TODO/code cleanup

To enter beta:

No major breaking API changes after this point
Performance within 10% of other well-known interpreters (e.g. micro-wasm-runtime, wasm3)
WASI support

To have a 1.0 release:

Tested with a wide variety of wasm programs
Successfully used in other beta-quality projects

Deecellar/bytebox