Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Add Module.customSections #877

Merged
merged 7 commits into from
Nov 29, 2016
Merged

Add Module.customSections #877

Changes from 4 commits
Commits
Show all changes
7 commits
Select commit Hold shift + click to select a range
bd1f38b
Add Module.sections
Nov 22, 2016
c10e7b4
Don't say 'instance' to avoid confusion
Nov 23, 2016
94f3942
s/sections/userSections/
Nov 23, 2016
fea04e4
Put ToString() back, for JS API regularity
Nov 23, 2016
8dde47e
Fix spelling of moduleObject
Nov 23, 2016
1ae783e
Clarify returning a copy
Nov 23, 2016
a441a8c
s/user|unknown/custom/ and in BinaryEncoding.md too
Nov 28, 2016
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
25 changes: 22 additions & 3 deletions JS.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -174,7 +174,7 @@ The `exports` function has the signature:
Array exports(moduleObject)
```

If `moduleObject` is not a `WebAssembly.Module` instance, a [`TypeError`](https://tc39.github.io/ecma262/#sec-native-error-types-used-in-this-standard-typeerror)
If `moduleObject` is not a `WebAssembly.Module`, a [`TypeError`](https://tc39.github.io/ecma262/#sec-native-error-types-used-in-this-standard-typeerror)
is thrown.

This function returns an `Array` produced by mapping each
Expand All @@ -193,7 +193,7 @@ The `imports` function has the signature:
Array imports(moduleObject)
```

If `moduleObject` is not a `WebAssembly.Module` instance, a [`TypeError`](https://tc39.github.io/ecma262/#sec-native-error-types-used-in-this-standard-typeerror)
If `moduleObject` is not a `WebAssembly.Module`, a [`TypeError`](https://tc39.github.io/ecma262/#sec-native-error-types-used-in-this-standard-typeerror)
is thrown.

This function returns an `Array` produced by mapping each
Expand All @@ -205,6 +205,25 @@ to the Object `{ module: String(i.module_name), name: String(i.item_name), kind:

Note: other fields like `signature` may be added in the future.

### `WebAssembly.Module.userSections`
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

We call them "unknown" sections in the binary format. I'd rather be consistent (either name is fine).

Copy link
Member Author

@lukewagner lukewagner Nov 23, 2016 •
edited
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Ugh, I hadn't noticed; it seems we call them both "user-defined" and "unknown" sections. Seems like we should just go with one. I actually like "unknown" better than "user defined"; it contrasts better with "known". @rossberg-chromium ?

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

TBH I don't like the term "user". Seems condescending.
But "unknown" is weird.
So yeah, I don't care for either name ;-)

How about "named sections" everywhere?

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Yeah, I have the same vague feeling re "user". I like "named".

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

We moved to calling these "user" sections in wabt, and in my proposed llvm binutils patch.

I think "user" is fine, and has more meaning than either "named" or "unkown" which don't seem to convey much to me. We're all used to "user_data" pointers in callbacks.


The `userSections` function has the signature:

```
Array userSections(modueObject, sectionName)
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Typo "modueObject".

```

If `moduleObject` is not a `WebAssembly.Module`, a [`TypeError`](https://tc39.github.io/ecma262/#sec-native-error-types-used-in-this-standard-typeerror)
is thrown.

Let `sectionNameString` be the result of [`ToString`](https://tc39.github.io/ecma262/#sec-tostring)(`sectionName`).

This function returns an `Array` produced by mapping each
[user-defined section](BinaryEncoding.md#high-level-structure) (i.e., section with
`id` 0) whose `name` field ([decoded as UTF-8](Web.md#names)) is equal to
`sectionNameString` to an `ArrayBuffer` containing the section's `payload_data`.
(Note: `payload_data` does not include `name` or `name_len`.)
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This Array is a copy of the original content, correct?

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Well, technically ArrayBuffer, but yes. I'll add "copy of" to clarify.

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I was wondering about this. Why make a copy? Don't we have the original buffer copied already (to prevent user from modifying it while compiling)? Maybe not a big deal, but it seems wasteful when we could just provide a view over the existing copy.

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

If we had the ability to return a read-only view, I'd do that, but otherwise we're in trouble if the user tries to write to the view.

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Hm, too bad. Though I suppose users who are concerned about this cost for very large modules can parse the module themselves.


### Structured Clone of a `WebAssembly.Module`

A `WebAssembly.Module` is a
Expand Down Expand Up @@ -248,7 +267,7 @@ If the NewTarget is `undefined`, a [`TypeError`](https://tc39.github.io/ecma262/
exception is thrown (i.e., this
constructor cannot be called as a function without `new`).

If `moduleObject` is not a `WebAssembly.Module` instance, a [`TypeError`](https://tc39.github.io/ecma262/#sec-native-error-types-used-in-this-standard-typeerror)
If `moduleObject` is not a `WebAssembly.Module`, a [`TypeError`](https://tc39.github.io/ecma262/#sec-native-error-types-used-in-this-standard-typeerror)
is thrown.

Let `module` be the [`Ast.module`](https://github.com/WebAssembly/spec/blob/master/interpreter/spec/ast.ml#L176)
Expand Down