[gclist] conservative gc

[Bob Kerns]

	-----Original Message-----
	From:	Eliot Moss [SMTP:moss@rhea.cs.umass.edu]
	Sent:	Friday, January 16, 1998 10:56 AM
	To:	gclist@iecc.com
	Subject:	%%:  [gclist] conservative gc
	In connection with this, I observe that conservative techniques
will NEVER
	ignore dead variables. We also found that one cannot always get
rid of the
	problem by setting a variable to nil after its last use, at
least for Java. If
	the last use is as an argument to a call, there is no way to
"slip in" the
	assignment of nil between passing the variable as an argument
and making the
	call.

	In lisp, you can write (call-some-function (prog1 some-var (setq
some-var nil))) to slip in the assignment to nil.

	Unfortunately, as ugly as that is, it would be even uglier in
Java.