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From: jimad@microsoft.UUCP (Jim ADCOCK)
Newsgroups: comp.std.c++
Subject: Re: Randomly ordered fields !?!? (Was: "packed" objects)
Message-ID: <56942@microsoft.UUCP>
Date: 27 Aug 90 17:28:16 GMT
References: <56638@microsoft.UUCP> <1229@lupine.NCD.COM> <56744@microsoft.UUCP> <1313@lupine.NCD.COM> <DL.90Aug25124455@g.g.oswego.edu>
Reply-To: jimad@microsoft.UUCP (Jim ADCOCK)
Organization: Microsoft Corp., Redmond WA
Lines: 15

In article <DL.90Aug25124455@g.g.oswego.edu> dl@g.oswego.edu writes:
|
|Perhaps among the best arguments for allowing compilers to at least
|sometimes reorder fields is to simply make conceivable someday the use
|of C++ adaptations of the clever MI layout algorithms described in
|Pugh & Weddell's SIGPLAN '90 conference paper.

Also, at the other end of the performance spectrum, imagine creating
an interactive C++ "interpreter" or actually p-coded compiler.  The goal is to
have minimal recompilation and relinking, in order to minimize the
response time to changes.  One simple scheme to accomplish this would
be to not embed objects, inherit via pointer, and always tack new fields
to the end of an "object's" structure.  This would violate today's field
ordering constraints [unless the user always added new fields to the end
of a labeled section.]