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feat(interface-types) New numbers and strings instructions #1329

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Hywan
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@Hywan Hywan commented Mar 24, 2020

This PR does 3 things:

  • Transforms the x-to-y number lowerings and liftings instructions to the new set of instructions y.from_x. It's just the opposite. It's more logical, but the diff is dense due to that. The lowering_lifting module is renamed numbers.
  • Renames memory-to-string to string.lift_memory, and string-to-memory to string.lower_memory. It's also more logical, but the diff is dense due to that too. The memory_to_string and string_to_module modules are merged into the strings module.
  • Introduce the new string.size instruction (in the strings module).

I think commits are clean and atomic enough, so it might be better to review it like that.

For binary encoding/decoding, the binary representation is absolutely entirely arbitrary (since the working notes define nothing, obviously).

Cf https://github.com/WebAssembly/interface-types/blob/master/proposals/interface-types/working-notes/Instructions.md

Basically the `x-to-y` instructions have been renamed `y.from_x`. This
patch updates the instruction. The binary representation isn't
specified yet, so it's just arbitrary values.
@Hywan Hywan changed the title feat(interface-types) New types and instructions feat(interface-types) New numbers and strings instructions Mar 24, 2020
@Hywan Hywan marked this pull request as ready for review March 24, 2020 14:42
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Looks good to me!

)
})?;

let pointer = to_native::<i32>(&inputs[0], instruction)? as usize;
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Does the fact this is an i32 cause a problem? It seems that we can't access the upper 2gb of memory by casting from i32 to usize because -1i32 as usize is 18446744073709551615; -1i32 as u32 as usize is 4294967295 which seems closer to what we'd want here.

If this is a mistake, perhaps we should add some tests using the upper 2gb of memory to make sure everything is working as expected as this issue will likely be in a lot of places!

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Hmm. The pointer is of kind i32 in the spec. It is regular a Wasm core type i32. Our API needs a usize, hence the casting.

You're right we need to check it is positive. I'm opening an issue to focus on that.

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Hywan commented Mar 26, 2020

bors r+

bors bot added a commit that referenced this pull request Mar 26, 2020
1329: feat(interface-types) New numbers and strings instructions r=Hywan a=Hywan

This PR does 3 things:

* Transforms the `x-to-y` number lowerings and liftings instructions to the new set of instructions `y.from_x`. It's just the opposite. It's more logical, but the diff is dense due to that. The `lowering_lifting` module is renamed `numbers`.
* Renames `memory-to-string` to `string.lift_memory`, and `string-to-memory` to `string.lower_memory`. It's also more logical, but the diff is dense due to that too. The `memory_to_string` and `string_to_module` modules are merged into the `strings` module.
* Introduce the new `string.size` instruction (in the `strings` module).

I think commits are clean and atomic enough, so it might be better to review it like that.

For binary encoding/decoding, the binary representation is absolutely entirely arbitrary (since the working notes define nothing, obviously).

Cf https://github.com/WebAssembly/interface-types/blob/master/proposals/interface-types/working-notes/Instructions.md

Co-authored-by: Ivan Enderlin <ivan.enderlin@hoa-project.net>
Co-authored-by: Ivan Enderlin <ivan.enderlin@wanadoo.fr>
@syrusakbary syrusakbary merged commit 531ec45 into wasmerio:master Mar 26, 2020
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bors bot commented Mar 26, 2020

Timed out

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3 participants