mirror of
https://github.com/fluencelabs/wasm-bindgen
synced 2025-06-07 18:11:21 +00:00
69 lines
1.7 KiB
Markdown
69 lines
1.7 KiB
Markdown
|
# Small wasm files
|
||
|
|
|
||
|
|
[View full source code][code]
|
||
|
|
|
||
|
|
[code]: https://github.com/rustwasm/wasm-bindgen/tree/master/examples/add
|
||
|
|
|
||
|
|
One of `wasm-bindgen`'s core goals is a pay-only-for-what-you-use philosophy, so
|
||
|
|
if we don't use much then we shouldn't be paying much! As a result
|
||
|
|
`#[wasm_bindgen]` can generate super-small executables
|
||
|
|
|
||
|
|
Currently this code...
|
||
|
|
|
||
|
|
```rust
|
||
|
|
{{#include ../../../examples/add/src/lib.rs}}
|
||
|
|
```
|
||
|
|
|
||
|
|
generates a 723 byte wasm binary:
|
||
|
|
|
||
|
|
```
|
||
|
|
$ ls -l add_bg.wasm
|
||
|
|
-rw-rw-r-- 1 alex alex 723 Sep 19 17:32 add_bg.wasm
|
||
|
|
```
|
||
|
|
|
||
|
|
If you run [wasm-opt], a C++ tool for optimize WebAssembly, you can make it
|
||
|
|
even smaller too!
|
||
|
|
|
||
|
|
```
|
||
|
|
$ wasm-opt -Os add_bg.wasm -o add.wasm
|
||
|
|
$ ls -l add.wasm
|
||
|
|
-rw-rw-r-- 1 alex alex 182 Sep 19 17:33 add.wasm
|
||
|
|
```
|
||
|
|
|
||
|
|
And sure enough, using the [wasm2wat] tool it's quite small!
|
||
|
|
|
||
|
|
```
|
||
|
|
$ wasm2wat add.wasm
|
||
|
|
(module
|
||
|
|
(type (;0;) (func (param i32 i32) (result i32)))
|
||
|
|
(func (;0;) (type 0) (param i32 i32) (result i32)
|
||
|
|
i32.const 1048640
|
||
|
|
i32.const 0
|
||
|
|
i32.store
|
||
|
|
get_local 1
|
||
|
|
get_local 0
|
||
|
|
i32.add)
|
||
|
|
(table (;0;) 1 1 anyfunc)
|
||
|
|
(memory (;0;) 17)
|
||
|
|
(global (;0;) i32 (i32.const 1049118))
|
||
|
|
(global (;1;) i32 (i32.const 1049118))
|
||
|
|
(export "memory" (memory 0))
|
||
|
|
(export "__indirect_function_table" (table 0))
|
||
|
|
(export "__heap_base" (global 0))
|
||
|
|
(export "__data_end" (global 1))
|
||
|
|
(export "add" (func 0))
|
||
|
|
(data (i32.const 1049096) "invalid malloc request"))
|
||
|
|
```
|
||
|
|
|
||
|
|
Also don't forget to compile in release mode for the smallest binaries! For
|
||
|
|
larger applications you'll likely also want to turn on LTO to generate the
|
||
|
|
smallest binaries:
|
||
|
|
|
||
|
|
```toml
|
||
|
|
[profile.release]
|
||
|
|
lto = true
|
||
|
|
```
|
||
|
|
|
||
|
|
[wasm2wat]: https://github.com/webassembly/wabt
|
||
|
|
[wasm-opt]: https://github.com/webassembly/binaryen
|