Hi Daryl, That looks like a compiler bug. There have been significant changes as well as follow-up fixes recently. If it's still happening with 12.8, we'd be super interested in a repro (that's sufficiently complete that we can run it locally to see the bug happening). 12.2 is too old to be worth anyone's time, yours or ours.
Sorry for the trouble. Cheers, Jakob On Fri, Jul 26, 2024 at 10:07 PM Daryl Haresign <[email protected]> wrote: > I have evidence of what I would call an impossibility, but it's supported > by explicit logs that came out of running code, so I'm going to believe the > logs. This is from v8 12.2, so I'm interested to know whether a) anyone > has seen anything like this, b) whether there have been any recent fixes in > this space, c) if not whether anyone knows what might be up. > > Thanks, > Daryl. > > Code (not the exact code, but functionally equivalent): > function f(blob) { > let logs = []; > let bits = 0; > > function e() { > bits -= 6; > logs.push(`e(), bits = ${bits}`); > } > > blob.bytes() // native function that returns an array of integers > .forEach(function (byte) { > logs.push(`bytes forEach #0, bits = ${bits}`); > bits += 8; > logs.push(`bytes forEach #1, bits = ${bits}`); > e(); > logs.push(`bytes forEach #2, bits = ${bits}`); > if (6 <= bits) { > logs.push(`bytes forEach #3, bits = ${bits}`); > e(); > logs.push(`bytes forEach #4, bits = ${bits}`); > } > }); > > console.log(logs); > } > > and the logs look like: > <many occurrences where everything is fine> > bytes forEach #0, bits = 4 > bytes forEach #1, bits = 12 > e(), bits = 6 > bytes forEach #2, bits = 6 > bytes forEach #3, bits = 6 > e(), bits = 0 > bytes forEach #4, bits = 0 > bytes forEach #0, bits = 0 > bytes forEach #1, bits = 8 > e(), bits = 2 > bytes forEach #2, bits = 8 // <- STALE READ!! > bytes forEach #3, bits = 8 // <- STALE READ!! > e(), bits = -4 // <- CORRECT READ > bytes forEach #4, bits = -4 // <- CORRECT READ > bytes forEach #0, bits = -4 // <- CORRECT READ > bytes forEach #1, bits = 4 // <- CORRECT READ > e(), bits = -2 // <- CORRECT READ > bytes forEach #2, bits = 4 // <- STALE READ!! > bytes forEach #0, bits = -2 // <- CORRECT READ > bytes forEach #1, bits = 6 // <- CORRECT READ > e(), bits = 0 // <- CORRECT READ > bytes forEach #2, bits = 6 // <- STALE READ!! > bytes forEach #3, bits = 6 // <- STALE READ!! > e(), bits = -6 // <- CORRECT READ > bytes forEach #4, bits = -6 // <- CORRECT READ > <from this point, logs #2 and #3 are stale every iteration> > > -- > -- > v8-dev mailing list > [email protected] > http://groups.google.com/group/v8-dev > --- > You received this message because you are subscribed to the Google Groups > "v8-dev" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/v8-dev/681a3f93-83be-48c9-ae07-55db28509b9fn%40googlegroups.com > <https://groups.google.com/d/msgid/v8-dev/681a3f93-83be-48c9-ae07-55db28509b9fn%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- -- v8-dev mailing list [email protected] http://groups.google.com/group/v8-dev --- You received this message because you are subscribed to the Google Groups "v8-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/v8-dev/CAKSzg3SVr3EM7eLDUE855YkGNNZGN1PU3fg1WXOk7SH9B7EP-A%40mail.gmail.com.
