Make wasm_global_set a safe API.
#133
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Make `wasm_global_set` a safe API by allowing it to return a trap in error cases. Traps in the wasm spec are used to report runtime errors, and the errors `wasm_global_set` reports are things that wasm would catch at validation time. Nevertheless, using a trap here is consistent with the official JS API raising exceptions on the same conditions. And, it provides a message explaining the reason for the error. To support users for whom mutablility and type checks are believed to be unacceptable overhead, add a `wasm_global_set_unsafe` function which skips those checks, at the penalty of undefined behavior.
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Note that this PR does not yet update the wasm-c.cc implementation or the C++ API, so it's not ready to be merged as-is. This just illustrates a change to the C API so that we can discuss it in detail. |
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Let's perhaps reach a conclusion on issue #132 first? Personally, I still think this is not a natural or principled way to go about incorrect API usage in a language like C. Adding arbitrary one-off "unsafe" functions -- when everything is unsafe anyway -- kind of reenforces that point. I don't think comparison to the JS API is particularly helpful, since that is (1) for a safe language and (2) not designed for efficiently building safer, more high-level API abstractions on top. |
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Superseded by #134. |
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Make
wasm_global_seta safe API by allowing it to return a trapin error cases.
Traps in the wasm spec are used to report runtime errors, and the
errors
wasm_global_setreports are things that wasm would catchat validation time.
Nevertheless, using a trap here is consistent with the official
JS API raising exceptions on the same conditions. And, it provides
a message explaining the reason for the error.
To support users for whom mutablility and type checks are believed
to be unacceptable overhead, add a
wasm_global_set_unsafefunctionwhich skips those checks, at the penalty of undefined behavior.