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76 lines
2.3 KiB
76 lines
2.3 KiB
4 months ago
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# C setjmp/longjmp support
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## Build an application
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To build an application using setjmp/longjmp, you need two things:
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* Enable the necessary LLVM translation (`-mllvm -wasm-enable-sjlj`)
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* Link the setjmp library (`-lsetjmp`)
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### Example without LTO
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```shell
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clang -Os -mllvm -wasm-enable-sjlj -o your_app.wasm your_app.c -lsetjmp
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```
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### Example with LTO
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```shell
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clang -Os -flto=full -mllvm -wasm-enable-sjlj -Wl,-mllvm,-wasm-enable-sjlj -o your_app.wasm your_app.c -lsetjmp
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```
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## Run an application
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To run the application built as in the previous section,
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you need to use a runtime with [exception handling proposal] support.
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Unfortunately, there are two incompatible versions of
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[exception handling proposal], which is commonly implemented by runtimes.
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* The latest version with `exnref`
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* The [phase3] version
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### Example with the latest exception handling proposal
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Because the current version of WASI-SDK produces an old version
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of [exception handling proposal] instructions, if your runtime
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implements the latest version of the proposal, you need to convert
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your module to the latest version.
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[toywasm] is an example of such runtimes.
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You can use binaryen `wasm-opt` command for the conversion.
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```shell
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wasm-opt --translate-to-exnref -all -o your_app.exnref.wasm your_app.wasm
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```
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Then you can run it with a runtime supporting the latest version of
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[exception handling proposal].
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```shell
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toywasm --wasi your_app.exnref.wasm
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```
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(You may need to enable the support with `-D TOYWASM_ENABLE_WASM_EXCEPTION_HANDLING=ON`.)
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### Example with the phase3 exception handling proposal (a bit older version)
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If your runtime supports the [phase3] version of
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[exception handling proposal], which is the same version as what WASI-SDK
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currently produces, you can run the produced module as it is.
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For example, the classic interpreter of [wasm-micro-runtime] is
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one of such runtimes.
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```shell
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iwasm your_app.wasm
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```
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(You may need to enable the support with `-D WAMR_BUILD_EXCE_HANDLING=1 -D WAMR_BUILD_FAST_INTERP=0`.)
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[exception handling proposal]: https://github.com/WebAssembly/exception-handling/
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[phase3]: https://github.com/WebAssembly/exception-handling/tree/main/proposals/exception-handling/legacy
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[toywasm]: https://github.com/yamt/toywasm
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[wasm-micro-runtime]: https://github.com/bytecodealliance/wasm-micro-runtime
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