Section permMapDefs.
Definition empty_map : access_map :=
(fun z => None, Maps.PTree.empty (Z -> option permission)).
intros. unfold empty_map, Maps.PMap.get.
rewrite Maps.PTree.gempty; reflexivity.
Qed.
Definition permission_at (m : mem) (b : block) (ofs : Z) (k : perm_kind) :=
Maps.PMap.get b (Mem.mem_access m) ofs k.
(** Coherence between permissions. This is used for the relation between data and lock permissions*)
(** Note: p1 should be data permission and p2 lock permission*)
Definition perm_coh (p1 p2 : option permission) :=
match p1 with
| Some Freeable | Some Writable | Some Readable =>
match p2 with
| None => True
| _ => False
end
| Some Nonempty | None =>
match p2 with
| Some Freeable => False
| _ => True
end
end.
destruct res; simpl; auto.
- apply perm_coh_empty_1.
- destruct k; try apply perm_coh_empty_1; simpl.
destruct (perm_of_sh (Share.glb Share.Rsh sh)) eqn: ?; auto.
destruct p0; auto.
eapply perm_of_glb_not_Freeable; eauto.
Qed.

Lemma perm_coh_joins:
forall a b, joins a b ->
perm_coh (perm_of_res a) (perm_of_res_lock b).