Compiling Zig to WASI, then calling it from Go using Wazero (https://ziglang.org, https://go.dev, https://wazero.io)

.gitignore

zig-cache
bin

add.zig

const std = @import("std");

export fn add(a: i64, b: i64) i64 {
    return a + b;
}

test "add 1+2=3" {
    try std.testing.expectEqual(add(1, 2), 3);
}

test "add 4+5=9" {
    try std.testing.expectEqual(add(4, 5), 9);
}

build.zig

const std = @import("std");

pub fn build(b: *std.Build) void {
    const exe = b.addExecutable(.{
        .single_threaded = true,
        .name = "add",
        .root_source_file = .{ .path = "add.zig" },
        .target = .{ .cpu_arch = .wasm32, .os_tag = .wasi },
        .optimize = .ReleaseSmall,
    });

    exe.entry = .disabled;
    exe.export_table = true;
    exe.export_symbol_names = &[_][]const u8{"add"};

    b.installArtifact(exe);

    const unit_tests = b.addTest(.{
        .root_source_file = .{ .path = "add.zig" },
        .target = .{ .cpu_arch = .wasm32, .os_tag = .wasi },
        .optimize = .ReleaseSmall,
    });
    const run_unit_tests = b.addRunArtifact(unit_tests);

    const test_step = b.step("test", "Run unit tests");
    test_step.dependOn(&run_unit_tests.step);
}

go.mod

module experiments/gists/go-zig-wasm-add

go 1.21.4

require github.com/tetratelabs/wazero v1.5.0

go.sum

github.com/tetratelabs/wazero v1.5.0 h1:Yz3fZHivfDiZFUXnWMPUoiW7s8tC1sjdBtlJn08qYa0=
github.com/tetratelabs/wazero v1.5.0/go.mod h1:0U0G41+ochRKoPKCJlh0jMg1CHkyfK8kDqiirMmKY8A=

main.go

package main

import (
	"context"
	"flag"
	"fmt"
	"log"
	"strconv"

	_ "embed"

	"github.com/tetratelabs/wazero"
	"github.com/tetratelabs/wazero/imports/wasi_snapshot_preview1"
)

//go:generate zig build -p . --cache-dir /tmp/go-zig-wasm-add

// addWasm was generated by the following:
//
//	go generate
//
// Run the Zig tests like this:
//
//	zig build test -fwasmtime
//
//go:embed bin/add.wasm
var addWasm []byte

func main() {
	flag.Parse()

	ctx := context.Background()

	r := wazero.NewRuntime(ctx)
	defer r.Close(ctx)

	wasi_snapshot_preview1.MustInstantiate(ctx, r)

	mod, err := r.Instantiate(ctx, addWasm)
	if err != nil {
		log.Panicf("failed to instantiate module: %v", err)
	}

	x, y, err := readTwoArgs(flag.Arg(0), flag.Arg(1))
	if err != nil {
		log.Panicf("failed to read arguments: %v", err)
	}

	add := mod.ExportedFunction("add")

	results, err := add.Call(ctx, uint64(x), uint64(y))
	if err != nil {
		log.Panicf("failed to call add: %v", err)
	}

	fmt.Printf("%d + %d = %d\n", x, y, int64(results[0]))
}

func readTwoArgs(xs, ys string) (int64, int64, error) {
	if xs == "" || ys == "" {
		return 0, 0, fmt.Errorf("must specify two command line arguments")
	}

	x, err := strconv.ParseInt(xs, 10, 64)
	if err != nil {
		return 0, 0, fmt.Errorf("argument X: %v", err)
	}

	y, err := strconv.ParseInt(ys, 10, 64)
	if err != nil {
		return 0, 0, fmt.Errorf("argument Y: %v", err)
	}

	return x, y, nil
}