1586030 - BytecodeIterator post-increment operator is wrong

Status: RESOLVED FIXED

(Core :: JavaScript Engine, task, P3)

Description

[Matthew Gaudet (he/him) [:mgaudet]]

Looking at the implementation of pre- and post-increment in BytecodeIterator, they have the same implementation... which means one of them is wrong.

I am pretty sure it's the post-increment.

To finish this bug we'll need to

1. Fix the implementation
2. Normally we'd have to audit the uses, but I don't see any currently.

I am going to set this as blocking Bug 1572504, because we'll need to make sure it doesn't use post increment unless we have fixed it.

Comment 1

[Adam Holm]

Attachment: Bug 1586030 - Fixed BytecodeIterator post-increment operator. r=mgaudet

Post-increment overload operator for BytecodeIterator class matches the
operator for pre-increment in BytecodeIterator, meaning the implementation of
post-increment is incorrect.

Comment 2

[Adam Holm]

(In reply to Matthew Gaudet (he/him) [:mgaudet] from comment #0)

Any suggestions on methods for testing the change? I guess I could use the increment operators in bug 1572504, but I would worry it would be difficult to untangle problems with the post-increment fix from problems with the patch for bug 1572504.

Comment 3

[Adam Holm]

try build: https://treeherder.mozilla.org/#/jobs?repo=try&revision=342cf576342099a010993bb8e2fac57fff952754

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/1613ca5b96c8
Fixed BytecodeIterator post-increment operator. r=mgaudet

Comment 5

[Natalia Csoregi [:nataliaCs]]

https://hg.mozilla.org/mozilla-central/rev/1613ca5b96c8