RFR(S) 8038412: Move object_iterate_careful down from Space to ContigousSpace and CFLSpace

[Thomas Schatzl]

Hi Mikael,

On Wed, 2014-03-26 at 17:21 +0100, Mikael Gerdin wrote:
> Hi,
> 
> I'm doing some cleanups in the "Space" classes to simplify the code for the G1 
> class unloading work[1].
> Here's a change to move code only used for CMS from virtuals on Space to only 
> be declared and defined where needed.
> 

 some comments:

 - in ContiguousSpace, after moving object_iterate_careful(), the
comment "// iterates on objects up to the safe limit" seems to be
obsolete now since the new comment seems better.

 - object_iterate_careful() seems to be only used by CFLSpace: why not
move it to compactibleFreeListSpace?

Actually everything that has to do with it
(concurrent_iteration_safe_limit(), oop_since_save_marks_iterate*, and a
lot of other code) seems to be specific to CMS.

Are you going to merge this code with similar G1 code like
HeapRegion::object_iterate_*mem_*careful() later, so you kept this code
for now in ContiguousSpace?

Otherwise seems okay.

Thanks,
  Thomas