memory checking proposal

[Per Bothner <bothner at cygnus dot com>]

I mentioned on egcs-patches that I've been working on a design for
how to do compiler-assisted bounds-checking for C/C++ in Gcc.
I don't know when I'll have a change to finish the design, let
alone implement it, so I thought I'd just post what I have.
My design is in http://www.cygnus.com/~bothner/mem-check.html.

I realize there are other designs and packages out there.
I haven't really looked into them in depth.  As far as I know,
none are complete enough or convenient enough to be ready for
prime time.  For example, some designs rely on fat pointers,
which is impractical.  (For example Checker requires that the
program be "closed" - all compiled with Checker or using
special stubs.  Such a requirement makes people to use
purify instead.)  It would be really nice if Gcc
had really solid easy-to-use standard bounds-checking.
This would be a nice project for someone.  Probably one
could re-use some of the code from previous attempts.

	--Per Bothner
Cygnus Solutions     bothner@cygnus.com     http://www.cygnus.com/~bothner