Sha256: 8dac740d6a4c499d868c29d8426d113da9cdd6ef22bf8084b8cf8c1de513b09c
Contents?: true
Size: 1.73 KB
Versions: 30
Compression:
Stored size: 1.73 KB
Contents
# Small wasm files
[View full source code][code] or [view the compiled example online][online]
[online]: https://rustwasm.github.io/wasm-bindgen/exbuild/add/
[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 710 byte wasm binary:
```
$ ls -l add_bg.wasm
-rw-rw-r-- 1 alex alex 710 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 172 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)
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
Version data entries
30 entries across 30 versions & 1 rubygems