https://github.com/xigh/wasm-dec-rs
wasm binary decoder written in rust
https://github.com/xigh/wasm-dec-rs
rust wasm webassembly
Last synced: 4 months ago
JSON representation
wasm binary decoder written in rust
- Host: GitHub
- URL: https://github.com/xigh/wasm-dec-rs
- Owner: xigh
- License: mit
- Created: 2021-10-28T16:59:06.000Z (over 3 years ago)
- Default Branch: master
- Last Pushed: 2021-11-18T19:33:55.000Z (over 3 years ago)
- Last Synced: 2025-01-08T06:20:04.872Z (5 months ago)
- Topics: rust, wasm, webassembly
- Language: Rust
- Homepage:
- Size: 30.3 KB
- Stars: 1
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# Introduction
This program *wasm-dec-rs* is a simple [wasm](https://webassembly.org/) binary decoder. My first official [rust](https://www.rust-lang.org/) program in fact.
I had to write this in order to learn how it works and how we can "tweak" / "optimize" rust wasm32-unknown-unknown generated binaries.
I'll describe how as soon as possible in another github repository.
# Usage
## example 1: (module) only
cat examples/ok0.wat
```wat
;; wat2wasm -o examples/ok0.wasm examples/ok0.wat
(module)
```
cargo run examples/ok0.wasm
```text
Wasm magic 6d736100
version 1
```
## example 2: module with exported function (TODO: fill the blanks)
cat examples/ok1.wat
```wat
;; wat2wasm -o examples/ok1.wasm examples/ok1.wat
(module
(func (export "f") (result i32)
i32.const 42
)
)
```
cargo run examples/ok2.wasm
```text
Wasm magic 6d736100
version 1
section "type"
0: fn() -> i32
1: fn(i32) -> i32
2: fn(i32, i32) -> i32
section "function"
range=[28-32]
04 00 01 02 02
found 4 functions
section "memory"
range=[35-38]
01 03 01 01
section "export"
0: hello type=Function index=0
1: world type=Function index=1
2: foobar type=Function index=2
3: another_test type=Function index=3
section "code"
0: 0 local
41 2a i32.const 42
0b end
1: 0 local
20 00 local.get 0
0b end
2: 0 local
20 00 local.get 0
20 01 local.get 1
6a i32.add
0b end
3: 0 local
20 00 local.get 0
20 01 local.get 1
6b i32.sub
0b end
```
# Resources
Here are a list of websites I read to learn about WebAssembly :
- [https://webassembly.org](https://webassembly.org)
- [https://webassembly.github.io/spec/core/binary/index.html](https://webassembly.github.io/spec/core/binary/index.html)
- [https://github.com/sunfishcode/wasm-reference-manual/blob/master/WebAssembly.md](https://github.com/sunfishcode/wasm-reference-manual/blob/master/WebAssembly.md)
- [https://en.wikipedia.org/wiki/LEB128](https://en.wikipedia.org/wiki/LEB128)