Bug 168857 – WebAssembly: exporting a property with a name that's a number doesn't work

• Component: JavaScriptCore
• Status: RESOLVED FIXED

[JF Bastien]

The following test in test_Instance.js fails but shouldn't:

(function ExportedNumber() {
    for (let i = 0; i <= 129; ++i) {
        const name = i.toString();
        const builder = (new Builder())
             .Type().End()
             .Function().End()
             .Export()
                 .Function(name)
             .End()
             .Code()
                 .Function(name, { params: [], ret: "i32" })
                 .I32Const(i)
                 .Return()
             .End()
             .End();
        const bin = builder.WebAssembly().get();
        const module = new WebAssembly.Module(bin);
        const instance = new WebAssembly.Instance(module);
        const result = instance.exports[name]();
        assert.isA(result, "number");
        assert.eq(result, i);
    }
})();

If you prefix `name` with another string, everything works. I think the issue has to do with using AbstractModuleRecord, somewhere after:

        symbolTablePutTouchWatchpointSet(moduleEnvironment, state, exp.field, exportedValue, shouldThrowReadOnlyError, ignoreReadOnlyErrors, putResult);

exp.field is being put in properly, but then the ModuleRecord mapping is sad at string such as "0".

I'm adding this test, commented out, and leaving a FIXME. The spec tests have a similar failure.

[Yusuke Suzuki]

Is that the thing? https://bugs.webkit.org/show_bug.cgi?id=168870

[JF Bastien]

(In reply to comment #1)
> Is that the thing? https://bugs.webkit.org/show_bug.cgi?id=168870

Yeah WebAssembly doesn't limit the names. Right now they're just length + bytes. For JS we further limit to valid UTF-8, details still in flux. I expect numbers and weird Unicode will remain valid though.

Maybe the AbstractModuleThing needs a virtual function for this?

[Yusuke Suzuki]

I think r213453 already fixes this issue.
I'll enable the test in wasm js-api/test_Instance.js.

[Yusuke Suzuki]

Created attachment 308079 [details]
Patch

[JF Bastien]

Comment on attachment 308079 [details]
Patch

r=me

[WebKit Commit Bot]

Comment on attachment 308079 [details]
Patch

Clearing flags on attachment: 308079

Committed r215733: <http://trac.webkit.org/changeset/215733>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.