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

Thomas Schatzl thomas.schatzl at oracle.com
Wed Mar 26 11:36:16 UTC 2014

Hi Mikael,

On Wed, 2014-03-26 at 12:25 +0100, Mikael Gerdin wrote:
> Hi Thomas,
> On Wednesday 26 March 2014 12.01.02 Thomas Schatzl wrote:
> >   looks okay, two minor nits:
> > 
> > - in the test testResizeNonResource(), is it possible to set the
> > ArrayAllocatorMallocLimit in both cases? Command line flags may set that
> > to a value that makes the first test equal to the second.
> Good point, that way I can make sure that I hit both paths in ArrayAllocator.
> > 
> > - ArrayAllocator::reallocate should verify that this is indeed a
> > reallocation and not called incorrectly, i.e. _addr is non-NULL.
> I was attempting to follow the way libc realloc(ptr, sz) works, if you pass 
> ptr as null it degenerates to a malloc(sz).
> If I change it to a "pure" realloc I would need to change BitMap to keep track 
> of its previous allocations or ask ArrayAllocator if anything is already 
> allocated as well since the call from BitMap's constructor to resize is also 
> the only way in which BitMap allocates memory.

I was concerned about the use of memcpy() in that case in the
implementation of reallocate(). I looked at it again, and it should be
okay after all.

If _addr is still NULL, memcpy does not access _addr at all since the
size given is zero.

So disregard this comment :)


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