RFR(XS) 8037959: BitMap::resize frees old map before copying memory if !in_resource_area

[Mikael Gerdin]

Hi Bengt,

On Friday 21 March 2014 11.59.43 Bengt Rutisson wrote:
> Hi Mikael,
> 
> The fix looks good. Since this code path is unused it might be an idea to
> add a test to exercise it a bit. Is it worth the effort to do that?

I wrote some tests for resize and they crash with my fix since I now free the 
_map_allocator right after using it :)

I'll have to withdraw this review request and think about how to refactor the 
resize function without making it even more complex.

/Mikael

> 
> Thanks,
> Bengt
> 
> > 21 mar 2014 kl. 10:39 skrev Mikael Gerdin <mikael.gerdin at oracle.com>:
> > 
> > Hi all,
> > 
> > While reading through the code for BitMap I stumbled across a bug in the
> > resize functionality for bitmaps not allocated in the resource area.
> > 
> > The problem is that if a previous backing for the bitmap exists we free
> > the
> > backing memory before attempting to copy its contents to the new backing
> > memory.
> > 
> > I've followed the code paths leading to resize so I'm pretty sure this bug
> > is currently benign since we never actually encounter this case but it
> > seems like a good idea to fix this nevertheless.
> > 
> > Bug: https://bugs.openjdk.java.net/browse/JDK-8037959
> > Webrev: http://cr.openjdk.java.net/~mgerdin/8037959/webrev.0
> > 
> > /Mikael