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Re: SIMPLE and fat pointers
- From: kenner at vlsi1 dot ultra dot nyu dot edu (Richard Kenner)
- To: s dot bosscher at student dot tudelft dot nl
- Cc: gcc at gcc dot gnu dot org
- Date: Sat, 13 Jul 02 09:42:56 EDT
- Subject: Re: SIMPLE and fat pointers
I had actually expected some GNAT people to join this discussion.
After all, they will have a problem when they implement a pass to
build functions as SIMPLE trees. I looked at the change logs, and
_ALL_(*) changelog entries that involve these PLACEHOLDER_EXPR and
WITH_RECORD_EXPR nodes are from Richard Kenner, so I guess the only
reason why these nodes are in the back end now is to support Ada...
So I hope to hear from Richard Kenner ;-)
I don't understand the issue, but have not been following the SIMPLE
stuff much at all.
Certainly PLACEHOLDER_EXPR is required for Ada and not just for
unconstrained arrays: the more common use is in discriminated records.
The bounds of an array and position of a field will often be quite
complex expressions involving PLACEHOLDER_EXPR. They cannot be simplified
until RTL generation since they represent different values for each
occurrence of the type.