FYI: Linker & Verifier fixes (really GC mark procedures)

[Andrew Haley]

Boehm, Hans writes:
 > I haven't been following the details here, but some of the suggested
 > directions scare me a bit.
 > 
 > The present issue aside, I think we're in general far better off
 > allocating collectable memory for anything that interacts with the
 > collector, and making the mark descriptors conservative, and eventually
 > correct.  (If we know that fields will contain either small integers or
 > pointers, just allocating it as potentially pointer-containing would
 > also currently work fine.)  Certainly I think we should be moving in
 > that direction.
 > 
 > The code in _Jv_MarkObj that directly traces objects referenced from
 > class objects (instead of pushing them on the mark stack) is on very
 > thin ice.  That's not how mark procedures are supposed to work.  In my
 > opinion, if we could make it go away, that would be great.

Indeed.  I have a patch in the pipeline that causes all objects of
class Class to be properly allocated rather than statically allocated
by the linker.  In turn, this has the potential to make _Jv_MarkObj
eventually go away.

Andrew.