1499335 - Make it easier to fuzz dynamic module import in the shell

Status: RESOLVED FIXED

(Core :: JavaScript Engine, enhancement, P3)

Description

[Jon Coppeard (:jonco)]

Dynamic import is difficult to fuzz because it requires access to external files.  Decoder requested a function that would take source code as an argument and then import that as a module.

Comment 1

[Jon Coppeard (:jonco)]

Attachment: bug1499335-inline-module-import

Would something like this work (see use of import in the test code)?

This adds the ability to import from 'inline:' URLs that embed JS source in the URL.  (It's like data: URLs but without the MIME type).

Comment 2

[Christian Holler (:decoder)]

Comment on attachment 9018237 [details] [diff] [review]
bug1499335-inline-module-import

Yes, that looks like it might be possible to integrate into the fuzzing driver.

Comment 3

[Jon Coppeard (:jonco)]

Attachment: bug1499335-inline-module-import v2

Comment 4

[Tom S. (please needinfo tschuster)]

Comment on attachment 9018337 [details] [diff] [review]
bug1499335-inline-module-import v2

Review of attachment 9018337 [details] [diff] [review]:
-----------------------------------------------------------------

::: js/src/jit-test/tests/modules/inline-data.js
@@ +1,1 @@
> +// |jit-test| module

Could change the name of the test, but inline-data still kind of fits anyway.

::: js/src/shell/ModuleLoader.js
@@ +8,5 @@
>  /* global setModuleDynamicImportHook finishDynamicModuleImport abortDynamicModuleImport */
>  
>  // A basic synchronous module loader for testing the shell.
> +//
> +// Supports loading files and 'inline:' URLs that embed JS source text.

javascript:

@@ +30,5 @@
>          this.registry = new Map();
>          this.loadPath = getModuleLoadPath();
>      }
>  
> +    isInlineURL(name) {

isJavascriptURL

@@ +163,5 @@
>  
>      fetch(path) {
> +        if (this.isInlineURL(path)) {
> +            let i = ReflectApply(StringPrototypeIndexOf, path, [":"]);
> +            return ReflectApply(StringPrototypeSubstring, path, [i + 1]);

return ReflectApply(StringPrototypeSubstring, path, ["javascript:".length]);

Maybe add a top-level constant like const JS_SCHEME = "javascript:".

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/80235331ce5f
Support module specifiers containing inline data in the shell r=evilpie

Comment 6

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

https://hg.mozilla.org/mozilla-central/rev/80235331ce5f