RFR(XS): 8232921: assert(is_object_aligned(result)) failed: address not aligned

coleen.phillimore at oracle.com coleen.phillimore at oracle.com
Wed Oct 30 18:36:08 UTC 2019


Hi Goetz, I like Tom's suggestion in the bug, which is to preallocate a 
boolean(true) object, somewhere like universe.cpp.  Or put the 
bool_mirror() in that spot. I don't think there's any downside to 
putting the methods array there, but it's really mind blowing.

Sorry I didn't notice this in the review.  I should have looked more 
closely when I saw the PauseNoSafepointVerifier.

   // GC unsafe class for assigning backtrace elements.  Allocation is 
only allowed
   // in expand().
   NoSafepointVerifier _nsv;

You could add a comment like this.

Coleen

On 10/29/19 10:32 AM, Lindenmaier, Goetz wrote:
> Hi,
>
> Originally, I wanted to model indicating that frames
> have been dropped nicely in Java using
> a meaningful java object. Exceptions in hidden frames
> should be rare, so allocating only in that case should have
> been cheap. Unfortunately, I can not allocate here.
> Also, Boolean::TRUE is not necessarily initialized properly.
>
> Actually, putting the modeling aside, I only need any legal
> oop for this field. It is only tested for null later on.
> So the most simple (and cheap) fix is just reusing
> one of the oops in the array at hand.
>
> So please review this fix.
> http://cr.openjdk.java.net/~goetz/wr19/8232921-fix_hidden_frames/01/
>
> I'll run it through our testing tonight.
>
> Best regards,
>    Goetz.



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