Re: USE_LSB_TAG and MS-DOS

[Stefan Monnier <monnier@iro.umontreal.ca>]

>> From the ChangeLog text it seems that cmpiling with USE_LISP_UNION_TYPE
>> would have caught that eons ago.

> Probably.  Alas, I have no resources to do such experiments with the
> DOS port, unless I have a specific bug and a good reason to believe
> that some non-standard switch will help me find it.

USE_LISP_UNION_TYPE is only useful when compiling, so doing such a compile
every once in a while can be handy.  It's definitely more useful in
connection with USE_LSB_TAG since int/Lisp_Object mixups are not as
harmless as they were before.

> (I did compile with ENABLE_CHECKING, as you suggested, but that didn't
> help to hunt this specific bug, as Emacs crashed in precisely the same
> place as before.

That's right.  ENABLE_CHECKING won't catch Lisp_Object/int mixups as well.
I was thinking the problem had to do with alignment in which case
ENABLE_CHECKING is often helpful.

> Hmm... the last garbage-collect that is run at the end of `loadup'
> says:

>   ((48784 . 10021) (10244 . 0) (543 . 60) 69410 144160 (48 . 16) (17 . 12) (4927 . 1814))

> 4900 strings is far too few to explain 40KB growth of pure storage, so
> where else is the extra storage coming from?

Hmm... that's indeed not right.
But wait, GC will only report about non-pure objects.


        Stefan