2079881 - Change NAMESPACE representation in ResolvedBinding Record

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect, P3)

Description

[Dan Minor [:dminor]]

Attachment: poc-namespace.tgz

We currently use star_namespace_star to represent ~NAMESPACE~ in the ResolvedBinding record. This works fine for JavaScript, but any utf-8 string can be used for wasm exports, meaning that *namespace* is a valid wasm export name. If someone attempted to use this name, it would be shadowed by our existing use.

I've attached some claude generated test files illustrating the problem.

Comment 1

[Jon Coppeard (:jonco)]

Yoshi, could you take a look when you get a minute?

Comment 2

[Yoshi Cheng-Hao Huang [:allstars.chh][:allstarschh][:yoshi]]

ResolvedBindingObject::bindingName() still uses atom,

For WebAssembly module, the [[BindingName]] is the exportName,
https://webassembly.github.io/esm-integration/js-api/index.html#resolve-export

whereas in ECMAScript, the [[BindingName]] is the ExportEntry.[[LocalName]]
https://tc39.es/ecma262/#sec-resolveexport

// module.mjs
var x = 1;
export { x as "*namespace*" }; 

In ECMAScript, the ResolvedBinding record's [[BindingName]] is "x"

In the ns.wat example from comment 0,

(export "*namespace*" (func $f))

The ResolvedBinding record's [[BindingName]] is "namespace"

I'll fix the [[BindingName]], maybe along with others.

Comment 3

[Yoshi Cheng-Hao Huang [:allstars.chh][:allstarschh][:yoshi]]

Attachment: Bug 2079881 - Part 1: Add ResolvedBindingObject::BindingNameType. r?jonco!

ResolveExport can return String, NAMESPACE or DEFERRED-NAMESPACE in
[[BindingName]], this patch adds a BindingNameType in ResolvedBindingObject to
indicate the type of the [[BindingName]].

Comment 4

[Yoshi Cheng-Hao Huang [:allstars.chh][:allstarschh][:yoshi]]

Attachment: Bug 2079881 - Part 2: Add resolveExport to ShellModuleObjectWrapper. r?jonco!

Add a resolveExport function to ShellModuleObjectWrapper, the function returns
a ResolvedBindingObject, which can be used to verify the type and the value of
[[BindingName]] of Resolved Binding Record returned from ResolveExport.

Comment 5

[Yoshi Cheng-Hao Huang [:allstars.chh][:allstarschh][:yoshi]]

Attachment: Bug 2079881 - Part 3: Add createSyntheticModule to the JS shell. r?jonco!

Synthetic Module Records can have arbitrary [[ExportNames]].
See https://tc39.es/ecma262/#table-synthetic-module-record-fields

Add a createSyntheticModule test function in the JS shell to simulate export
arbitrary names from a synthetic module or a wasm modules.

Comment 6

[Yoshi Cheng-Hao Huang [:allstars.chh][:allstarschh][:yoshi]]

Attachment: Bug 2079881 - Part 4: Store the namespace objects in ModuleEnvironmentObject. r?jonco!

An export named namespace or deferred-namespace shadowed the
internal slots. Name them with a lone surrogate, which no export name
can contain.

Comment 7

[Yoshi Cheng-Hao Huang [:allstars.chh][:allstarschh][:yoshi]]

Attachment: Bug 2079881 - Part 5: Remove the *namespace* pseudo-bindings from module scopes. r?jonco!

The namespace objects of a module are now stored in reserved slots of its
environment, so the namespace and deferred-namespace bindings that the
parser declared in every module scope are no longer used.

Comment 8

[Yoshi Cheng-Hao Huang [:allstars.chh][:allstarschh][:yoshi]]

Attachment: Bug 2079881 - Part 6: Throw a LinkError for namespace imports in WasmModuleExecute. r?dminor!

The spec doesn't handle the case when the [[BindingName]] is namespace,
See https://github.com/WebAssembly/esm-integration/issues/127.

Throws an exception first to prvent hitting assertion.

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/4b674cec411d
https://hg.mozilla.org/integration/autoland/rev/82b7ddac5905
Part 1: Add ResolvedBindingObject::BindingNameType. r=jonco
https://github.com/mozilla-firefox/firefox/commit/f2d7ed231b83
https://hg.mozilla.org/integration/autoland/rev/ce62ff0c1127
Part 2: Add resolveExport to ShellModuleObjectWrapper. r=jonco
https://github.com/mozilla-firefox/firefox/commit/c87eee4ab11c
https://hg.mozilla.org/integration/autoland/rev/4da0efb782eb
Part 3: Add createSyntheticModule to the JS shell. r=jonco
https://github.com/mozilla-firefox/firefox/commit/b04020040103
https://hg.mozilla.org/integration/autoland/rev/700a75da3c43
Part 4: Store the namespace objects in ModuleEnvironmentObject. r=jonco
https://github.com/mozilla-firefox/firefox/commit/e2e7d67bc6ba
https://hg.mozilla.org/integration/autoland/rev/8bf9fe6fca95
Part 5: Remove the *namespace* pseudo-bindings from module scopes. r=jonco
https://github.com/mozilla-firefox/firefox/commit/66b11b285564
https://hg.mozilla.org/integration/autoland/rev/d603d8d72586
Part 6: Throw a LinkError for namespace imports in WasmModuleExecute. r=dminor

Comment 11

[Goloman Adrian[:agoloman]]

https://hg.mozilla.org/mozilla-central/rev/82b7ddac5905
https://hg.mozilla.org/mozilla-central/rev/ce62ff0c1127
https://hg.mozilla.org/mozilla-central/rev/4da0efb782eb
https://hg.mozilla.org/mozilla-central/rev/700a75da3c43
https://hg.mozilla.org/mozilla-central/rev/8bf9fe6fca95
https://hg.mozilla.org/mozilla-central/rev/d603d8d72586