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Don't emit mutable globals #2391

Merged
merged 1 commit into from
Dec 6, 2020
Merged

Don't emit mutable globals #2391

merged 1 commit into from
Dec 6, 2020

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arilotter
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@arilotter arilotter commented Dec 4, 2020

A proposed fix for #2386, based on @alexcrichton's comment here: #2386 (comment)

We emit a shim function that sets the stack pointer, so we can avoid emitting mutable globals.
Mutable globals aren't supported everywhere Wasm is.

This PR seems to pass tests, but I believe it doesn't actually avoid exporting the stack pointer yet.
I'm not sure where to look for that, and I imagine we should add a test to ensure we actually don't export mutable globals.

This is my first foray into the wasm-bindgen codebase, so I expect there to be some mistakes in this code.

I think I might still need to modify export_shadow_stack_pointer to not export it to the wasm module...

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Looks great to me, thanks for tackling this!

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We emit a shim function that sets the stack pointer,
so we can avoid emitting mutable globals.
Mutable globals aren't supported everywhere Wasm is.
@arilotter arilotter marked this pull request as ready for review December 5, 2020 19:50
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arilotter commented Dec 5, 2020

@alexcrichton I've resolved all the comments from your previous review :)

@alexcrichton alexcrichton merged commit b584407 into rustwasm:master Dec 6, 2020
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Thanks!

@arilotter arilotter deleted the stack-pointer-shim-mutable-globals branch December 7, 2020 07:14
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Which version will include the improvement? I need it as well. @alexcrichton

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I've done a version bump at #2435

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3 participants