What are offsets relative to?

[eqrion]

The overview states:

Each branch hint structure consists of

    the |U32| byte offset of the hinted instruction from the beginning of the function body,

What is the beginning of the function body? Is that before the vector of locals or after the vector of locals?

[yuri91]

just after the size field, corresponding with the beginning of the vector of locals.

[eqrion]

Would you be able to update the overview or spec for this? We accidentally implemented this the wrong way in SM.

[yuri91]

Yes. Sorry for the confusion, it is indeed not very clear. It also used to be the other way around earlier in the design.

[yuri91]

Looking into how to improve the wording, I realized that the spec already has a concept of the function "body":

the actual function code, which in turn consists of

• the declaration of locals,

• the function body as an expression

which is at odds with the usage in this proposal.

I will change the overview like this:

• the |U32| byte offset of the hinted instruction from the beginning of the function body

->

• the |U32| byte offset of the hinted instruction, relative to the beginning of the function locals declaration

and similarly the spec text.

Thanks for bringing this up!

[rossberg]

Why not just replace "body" with "code" to match the terminology defined in the spec?

[yuri91]

@rossberg for the overview, i think that the term code would not be clear enough on its own, without the surrounding context (especially because code is both the name of the production rule and the name of the field). But I can expand the description if this is not enough.

For the spec, I opted to use the |Bfunc| term, because it becomes a link to the actual definition in the main spec. The "code" field is defined as |Bfunc|, so it should be more or less in line with your suggestion, i think?

[rossberg]

Makes sense, thanks.