RFR(S): 8193927: Optimize scanning code for oops.

[Volker Simonis]

Hi Goetz,

this seems to be a little strange flag for me because it can not be
used for really controlling the emission of immediate oops. It only
records if a platform can emit immediate oops or not.

So wouldn't it be better to either have a flag like
"EmitImmediateOops" which really controls the emission of immediate
oops. I.e. it could be used to switch the emission of immediate oops
off even on platforms which usually do that. Or if that's not
reasonable, don't introduce a new flag at all but just declare a
platform specific method instead which returns if immediate oops can
be emitted on that platform or not.

Thanks,
Volker

On Thu, Dec 21, 2017 at 9:30 AM, Lindenmaier, Goetz
<goetz.lindenmaier at sap.com> wrote:
> Hi,
>
> Some platforms don't emit immediate oops to the code. If so, scans
> of the code for oops can be skipped.
>
> Add flag ImmediateOopsEmitted to each platform specifying the behavior.
> Only search code for immediate oops if this flag is set. Make sure no
> oops are emitted to code if the flag is not set.
>
> @aarch people: should the flag set to 'false' on aarch/arm?  So far it
> is true, which defaults to the old behavior.
>
> Please review this change. I please need a sponsor.
> http://cr.openjdk.java.net/~goetz/wr17/8193927-oopsInCode/webrev.01/
>
> Best regards,
>   Goetz