Add a generate_interface program

[malcolmstill]

Description

To help write host functions for known wasm binaries, adds a generate_interface binary that given a .wasm binary will generate host function stubs and a initHostFunctions function.

E.g. if I take the .wasm from https://silentspacemarine.com/ the binary generates:

const std = @import("std");
const zware = @import("zware");

pub fn initHostFunctions(module: []const u8, store: *zware.Store) !void {
	try store.addHostFunction(module, "exit", exit, [_]ValType{.I32, }, [_]ValType{});
	try store.addHostFunction(module, "emscripten_cancel_main_loop", emscripten_cancel_main_loop, [_]ValType{}, [_]ValType{});
	try store.addHostFunction(module, "emscripten_force_exit", emscripten_force_exit, [_]ValType{.I32, }, [_]ValType{});
	try store.addHostFunction(module, "time", time, [_]ValType{.I32, }, [_]ValType{.I32, });
	try store.addHostFunction(module, "__assert_fail", __assert_fail, [_]ValType{.I32, .I32, .I32, .I32, }, [_]ValType{});
	try store.addHostFunction(module, "emscripten_sleep", emscripten_sleep, [_]ValType{.I32, }, [_]ValType{});

        [deletia...]
}

pub fn exit(vm: *VirtualMachine) WasmError!void {
	const param0 = vm.popOperand(i32);
	std.debug.print("Unimplemented: exit({}, )", .{param0, });
	@panic("Unimplemented: exit");
}

pub fn emscripten_cancel_main_loop(vm: *VirtualMachine) WasmError!void {
	std.debug.print("Unimplemented: emscripten_cancel_main_loop()", .{});
	@panic("Unimplemented: emscripten_cancel_main_loop");
}

pub fn emscripten_force_exit(vm: *VirtualMachine) WasmError!void {
	const param0 = vm.popOperand(i32);
	std.debug.print("Unimplemented: emscripten_force_exit({}, )", .{param0, });
	@panic("Unimplemented: emscripten_force_exit");
}

pub fn time(vm: *VirtualMachine) WasmError!void {
	const param0 = vm.popOperand(i32);
	std.debug.print("Unimplemented: time({}, )", .{param0, });
	@panic("Unimplemented: time");
}

pub fn __assert_fail(vm: *VirtualMachine) WasmError!void {
	const param0 = vm.popOperand(i32);
	const param1 = vm.popOperand(i32);
	const param2 = vm.popOperand(i32);
	const param3 = vm.popOperand(i32);
	std.debug.print("Unimplemented: __assert_fail({}, {}, {}, {}, )", .{param0, param1, param2, param3, });
	@panic("Unimplemented: __assert_fail");
}

pub fn emscripten_sleep(vm: *VirtualMachine) WasmError!void {
	const param0 = vm.popOperand(i32);
	std.debug.print("Unimplemented: emscripten_sleep({}, )", .{param0, });
	@panic("Unimplemented: emscripten_sleep");
}

[deletia...]

The invocation for the above is just running from a command line generate_interface doom.wasm

Follow up

• TODO: just merge with interface