prog: add concept of "special pointers"

Currently we only generate either valid user-space pointers or NULL.
Extend NULL to a set of special pointers that we will use in programs.
All targets now contain 3 special values:
 - NULL
 - 0xfffffffffffffff (invalid kernel pointer)
 - 0x999999999999999 (non-canonical address)
Each target can add additional special pointers on top of this.

Also generate NULL/special pointers for non-opt ptr's.
This restriction was always too restrictive. We may want to generate
them with very low probability, but we do want to generate them.

Also change pointers to NULL/special during mutation
(but still not in the opposite direction).

0 files changed, 0 insertions, 0 deletions