Runtime bug? and other questions

[Daniel Wang]

"Stephen Weeks" <sweeks@intertrust.com> writes:

> > Hmm looks like the bug is still there.... but only manifests itself when I
> > *don't* compile with -DGC_EVERY_CHECK
> 
> Found the bug.  I've appended the fixed gc.c to the end of this
> message.  The problem was due to the stack resizing code in forward.
> When the stack was grown, the entire new stack size bytes were copied
> from fromSpace instead of just copying the part of the stack that was
> used.  The new code only copies the used part of the stack and bumps
> the back of the queue in toSpace by a "skip" amount (which is only
> nonzero for stacks).  Your example now works.  Lemme know if there are 
> more problems.  Doubtless this are, since this runtime is so
> untested.

Seems to work now for a few slightly harder tests. BTW what does the GC do
when it finds a pointer to an object outside of the fromspace? The SML/NJ
runtime would just leave these objects alone. (i.e. not trace or forward
them). Can MLton be made to behave the same way?