RFR: JDK-8211241: Missing obj equals in TemplateTable::fast_aldc

[Daniel D. Daugherty]

On 9/27/18 4:07 PM, Roman Kennke wrote:
> TemplateTable::fast_aldc compares the just-loaded reference with
> Universe::the_null_sentinel. If it really is that null-sentinel, we may
> get a false negative (with GCs like Shenandoah that allow both
> from-space and to-space copies of an object to be around), and thus skip
> NULL-ing the ref. In other words, it would allow to get
> the-null-sentinel out into the wild as oop which can cause subtle and
> not-so-subtle bugs.
>
> Fix is easy, call cmpoop() which re-routes through GC-interface for GCs
> that need it:
>
> http://cr.openjdk.java.net/~rkennke/JDK-8211241/webrev.00/

src/hotspot/cpu/aarch64/templateTable_aarch64.cpp
     No comments.

src/hotspot/cpu/x86/templateTable_x86.cpp
     No comments.

Thumbs up (on the change)!

> Testing: hotspot/jtreg:tier1

Did you use jdk_submit or local testing? I don't expect build
problems but the templateTable_x86.cpp will affect all X86/X64
platforms right?

Dan

>
> Ok?
>
> Roman
>