1499649 - Stop using (fake) ICEntries for VM calls

Status: RESOLVED FIXED

(Core :: JavaScript Engine: JIT, enhancement)

Description

[Jan de Mooij [:jandem]]

Baseline uses a fake ICEntry (with nullptr stub) for callVM and some other non-IC things. This has always been a bit of a hack - for bug 1499644 we need to split ICEntry in ICEntry and a new kind of entry that's used for the pc/return address mapping (ICs would use one of each).

(This is also nice for cache locality because it will shrink ICEntry a bit.)

Comment 1

[Jan de Mooij [:jandem]]

Attachment: Bug 1499649 - Split ICEntry in ICEntry and RetAddrEntry, get rid of fake ICEntries. r?tcampbell

The return address/offset is no longer stored in ICEntry but in VMCallEntry.
ICEntry now only stores IC-related fields.

As a follow-up I think we should get rid of ICEntry::isForOp_ but this patch is
big enough as it is.

Comment 2

[Ted Campbell [:tcampbell]]

Comment on attachment 9017805 [details]
Bug 1499649 - Split ICEntry in ICEntry and RetAddrEntry, get rid of fake ICEntries. r?tcampbell

Iain, since you've been spelunking around in the DebugOSR code around fake ICEntries, do you have any comments on this approach? Does it make sense with the Generator issues you are looking at?

Comment 3

[Iain Ireland [:iain]]

While making essentially the same change to generalize callVMEntryFromPCOffset, I noticed that it would not do the right thing for kinds that can have more than one entry per pc. This patch has the same problem. I left a comment in the review.

Other than that, this looks good and would have saved me a lot of work yesterday.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/daf8a3b98eee
Split ICEntry in ICEntry and RetAddrEntry, get rid of fake ICEntries. r=tcampbell

Comment 5

[Stefan Hindli [:stefan_hindli]]

https://hg.mozilla.org/mozilla-central/rev/daf8a3b98eee