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62 lines
1.4 KiB
Markdown
62 lines
1.4 KiB
Markdown
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# Adding Numbers
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[View this example online](https://webassembly.studio/?f=612vwsrmwft)
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This directory is an example of using the `#[wasm_bindgen]` macro to simply add
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two numbers. The neat part about this is that it's an example of how to generate
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the smallest wasm-bindgen binary.
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You can build the example with:
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```
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$ ./build.sh
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```
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(or running the commands on Windows manually)
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Currently this generates a 651 byte wasm binary:
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```
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$ ls -alh add_bg.wasm
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-rw-rw-r-- 1 alex alex 651 Apr 20 22:16 add_bg.wasm
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```
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If you run [wasm-opt], a C++ tool for optimize WebAssembly, you can make it even
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smaller too!
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```
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$ wasm-opt -Os add_bg.wasm -o add.wasm
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$ ls -alh add.wasm
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-rw-rw-r-- 1 alex alex 100 Apr 20 22:19 add.wasm
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```
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And sure enough, using the [wasm2wat] tool it's quite small!
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```
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$ wasm2wat add.wasm
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(module
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(type (;0;) (func (param i32 i32) (result i32)))
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(func (;0;) (type 0) (param i32 i32) (result i32)
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get_local 1
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get_local 0
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i32.add)
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(memory (;0;) 2)
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(export "memory" (memory 0))
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(export "add" (func 0))
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(data (i32.const 1545) "invalid malloc request"))
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```
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Note that it's important to point out that the size reductions here are because
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the wasm is compiled in release mode by the build script and this crate's
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workspace has the following configuration
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```toml
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[profile.release]
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lto = true
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opt-level = 's'
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panic = 'abort'
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```
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[wasm2wat]: https://github.com/webassembly/wabt
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[wasm-opt]: https://github.com/webassembly/binaryen
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