195736 - Small change to xptcinvoke_gcc_x86_unix.cpp

Status: VERIFIED FIXED

(Core :: XPConnect, defect, P3)

Description

[tenthumbs]

I was going over some old notes for bug 140412 and bug 168508 and i found that I
had forgotten a change to make xptcinvoke use the regparm calling convention
just as xptcstubs does.

As I looked at it, I noticed that mozilla can theoretically pass 64-bit
quantities, like doubles, which work better if they're properly aligned. While
the rest of mozilla doesn't know about such things, it's easy to align the data
block created in XPTC_InvokeByIndex.

I'll attach a patch. Since it saves a few instructions there is some minuscule
performance improvement. :-)

Comment 1

[tenthumbs]

Attachment: xptcall patch

Switches from stdcall to regparm calling convention internally and marks wher
alignment may be useful.

Comment 2

[David Bradley]

Comment on attachment 116091 [details] [diff] [review]
xptcall patch

r=dbradley

I don't have any way to verify this patch. I assume you ran TestXPTCInvoke and
it didn't report any additional errors.

Comment 3

[tenthumbs]

Yes, I tested it. I have to update the patch. Stand by for a new 
version.

Comment 4

[Mike Shaver (:shaver emeritus)]

dbradley's review is enough for me, on the new patch.

Comment 5

[tenthumbs]

Attachment: revised patch

This should do it. It works on my tree form a few days ago. I'm updating and
rebuilding but there shouldn't be any problem.

There are some comments about alignment. It would be interesting to see if they
make any perceptible difference.

Also note that gcc 3.2.2 tries hard to maintain stack alignment but xptcinvoke
messes it up and there's no way at the moment to fix that. It may be a prblem
down the road.

Comment 6

[David Bradley]

Comment on attachment 120581 [details] [diff] [review]
revised patch

r=dbradley

Comment 7

[David Bradley]

Patch checked in

Comment 8

[Phil Schwartau]

Checkin verified -