wax - An WebAssembly host environment and tools

How to use

Before starting using wax or other tools, you need to build them.

./scripts/build.sh

The build script builds wax, wadisasm, wadump or other tools, as well as examples in examples directory.

wax command - executes .wasm files

You can invoke a function in a .wasm file and get its result:

./cmd/wax/wax -f "add" -a "i32:1" -a "i32:2" examples/go/add/main.wasm

Options:

• -f: name of a function to invoke. need to be an exported function.
• -a: argument. specify as type:value. you can specify -a multiple times.

The result will be shown in the following format:

0:i32:3

The first part (number 0) is index of the returned value. (Due to the current version of WebAssembly spec, functions can have up to 1 returned value. So this is for the future extension.) The second part (i32) is the type of the returned value. The third part (number 3) is the returned value of the function invocation.

wadump command - dump .wasm module

wadump command reads a .wasm file and dump its parsed structure in JSON format:

./cmd/wadump/wadump examples/go/add/main.wasm

The result will be JSON string like the following:

{"Preamble":{"MagicNumber":1836278016,"Version":1},"Sections":[{"ID":1,"Size":30,"Content":"BmAAAX9gA39/fwF/YAAAYAF/AGACf38AYAJ/
...(snip)...

More readable jqed version:

{
  "Preamble": {
    "MagicNumber": 1836278016,
    "Version": 1
  },
  "Sections": [
    {
      "ID": 1,
      "Size": 30,
      "Content": "BmAAAX9gA39/fwF/YAAAYAF/AGACf38AYAJ/fwF/",
      "FuncTypes": [
        {
          "ParamTypes": "",
          "ReturnTypes": "fw=="
        },
        {
          "ParamTypes": "f39/",
          "ReturnTypes": "fw=="
        },

        :
      (snip)
        :
  ]
}

wadisasm command - disassemble .wasm module

wadisasm command reads a .wasm file and output disassembled list for a specified function or all functions in the module:

./cmd/wadisasm/wadisasm -n add examples/go/add/main.wasm

The output is like the following:

func:12
20 01 local.get 00000001
20 00 local.get 00000000
6a    i32.add
0b    end