Closed Bug 1651208 Opened 5 months ago Closed 3 months ago

Set a bit in the UsedNameTracker to determine if there are any private names


(Core :: JavaScript Engine, enhancement, P3)




82 Branch
Tracking Status
firefox82 --- fixed


(Reporter: mgaudet, Assigned: yozaam, Mentored)



(Keywords: good-first-bug, Whiteboard: [lang=c++])


(1 file)

For private fields we need to check if there are unbound private names. Right now we do this by iterating over the names, aggregating those that are private + unbound, then figuring out of they have a binding accessible.

This can be optimized by adding a bit to UsedNameTracker to track if we even have seen a private name. If we haven't, then we can bypass these checks. This will be a win avoiding work where it's not necessary.

I want to work on resolving this bug, but this is my first time on Bugzilla and I found this bug using CodeTribute. Could you please initialize me into the system so that I can learn how to contribute?

Flags: needinfo?(mgaudet)

Hi aggarwaluddhav: Apologies for not including this info when I opened the bug. The code I'm asking you to change was added as part of this patch.


Before getting started, you'll want to

Success Criteria

  • The UsedNameTracker has a new boolean which is set to false at initialization, and true if and only if a private declaration is discovered.
  • That boolean is used to return early from methods that are looking to summarize the private names (ie, one place would be UsedNameTracker::getUnboundPrivateNames
  • After this work, the engine compiles, and passes the tests (run ./mach jit-test )


If you have questions, feel free to visit us on in the Spidermonkey room on Matrix, or post questions here.

Tips and Tricks:

  • SearchFox indexes the Firefox codebase, and allows you to easily find functions, definitions, and more. It's a powerful tool! Note: at the point I'm submitting the comment, the relevant code has not yet been indexed on searchfox; however that will happen sometime today.
Flags: needinfo?(mgaudet)

I would like to work on this bug. I am a new contributor. I have cloned the repo and learning about the contribution guidelines. Please assign this bug to me. Please let me know about the basic norms about contribution.

Flags: needinfo?(mgaudet)

So, as you can see there's multiple people vyying for this work. The norm here is that we tend not to assign bugs until we have a patch developed (it avoids the case where someone isn't able to complete the work, and so it gets lost).

I would wait a little bit before tackling this, to give aggarwaluddhav a chance, but if you're partially done no worries, feel free to submit a patch.

Flags: needinfo?(mgaudet)

Thanks Matthew! Let me look into this, and will get back after some time.

Priority: -- → P3
Severity: -- → N/A
Assignee: nobody → yozaam

I have tried to add this -> UsedNameTracker class and in the getUnboundPrivateNames hasUnboundPrivateNames

I am sure I have missed a few spots where we need to add it -> I have set it to true when there is visibility private in sed NameTracker::noteUse but I need to still understand this -> where can i set it as true... ? inserting into map_ is what i thought happens there

Also when we delete from the map, i need to remove the private bool to false? so should we change this into a counter?

Counting how many private Names in the usedNameTracker / does delete not take place when going out of scope?

Attachment #9172008 - Attachment description: Bug 1651208 put boolean in constructor and get,has functions to track private names in used name tracker r?mgaudet → Bug 1651208 Set a bit in the UsedNameTracker and short circuit some private field early error checks r?mgaudet
Pushed by
Set a bit in the UsedNameTracker and short circuit some private field early error checks r=mgaudet
Closed: 3 months ago
Resolution: --- → FIXED
Target Milestone: --- → 82 Branch
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