RFR(XS) 8027388: JVM crashes with SIGSEGV (0xb) at pc=0x00000001077cbbf6

[Christian Thalinger]

+         // assume that the result of the LoadP is the the argument of the StoreP.
Typo: “the the”

The fix is good.

On Dec 21, 2013, at 12:53 AM, Igor Veresov <igor.veresov at oracle.com> wrote:

> Given the following graph, escape analysis currently fails to track the fact that we can load from null. 
> 
>  Allocate A <-- ...---------- StoreP
>  Allocate B <-- ... - AddP <--/
>           \
>            Phi <--- ... -- AddP <--- LoadP
>  null <-- /
> 
> The AddPs may refer to the same field of B, however, B could be null so we cannot assume that the result of the LoadP is the the argument of the StoreP.
> We don't want to add edges to null_obj for performance reasons, so we handle this case by faking the effect of storing a null to this field, which will force a potential non-escaping object (that is also stored to this field) to be marked as not scalarizable. The end result is the same -- we cannot predict that value of the field. Notice that if B is non-escaping it will be made non-scalarizable as well because the field has two bases.
> 
> Webrev: http://cr.openjdk.java.net/~iveresov/8027388/webrev.00/
> Testing: jtreg, ctw
> 
> Huge thanks to Vladimir for discussions and helping me out with this problem!
> 
> igor

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/attachments/20131223/537c31c0/attachment.html