Re: Removal of VAX/VMS support

[Ian Lance Taylor <ian at airs dot com>]

Andrew Cagney <ac131313@redhat.com> writes:

> Instead of the total rewrite from scratch, more incremental aproaches
> can be taken.   GDB, for instance, is trying to overhaul and replace
> sections.  New objects and structures get added as needed.  I'm told
> the buzword is refactor :-)

In theory, sure.  My experience is that it doesn't work in practice.
Or, rather, of course it works eventually; but it takes longer than a
rewrite based on the existing code, and the result is worse.

Not that I expect to convince anybody of that point.  People always
look at the existing code and ask how we can throw that away.

> Things run into problem though when a core change involves
> modifications to those vectors - adding something  better, simpler,
> cleaner, faster methods.

BFD never does that.

> GDB partially addressed the problem by following a process of:
> introducing a new interface; deprecating the old interface; provide a
> legacy implementation that reverts back to the old / deprecated
> mechanisms; eventually deleting the deprecated code.  It has made it
> possible to implement core changes without also rewrite all
> targets. Target maintainers can then, later, upgrade their target - cf
> frame rewrites currently occuring in GDB.

BFD follows a much simpler procedure.  New interfaces are introduced,
and old interfaces remain.  No deprecation, legacy implementation, or
deletion is required.

Ian