Exploring Time-Space trade-offs for "synchronized" in Lilliput

[John Rose]

On Nov 8, 2021, at 2:44 PM, Roman Kennke <rkennke at redhat.com<mailto:rkennke at redhat.com>> wrote:

Indeed! This is a good suggestion! But doesn't this make size-based heap-parsing a bit more complicated? Given an object O in heap, how to find the next object after O?

A bit more, and a bit less as Gil said (since you don’t compute the object size).
I tend to think putting the extension before is better than after, but there are
pros and cons.

(a) the extension field is probably on an off-aligned word just before the header,
so if you check alignment bits you won’t be fooled.  Also (b) you might consider
using a tag bit or two, as with header tag bits today, to make the extension word
look different from a bonafide header.