Section AMap2PMap.
(*Need to build a permission map from a finite map*)
(*The pmap is used in the compcert memory. *)
Context {lock_info: Type}.
Variable am: AMap.t lock_info.
Definition A2PMap (*: Map.PMap*) :=
fold_left
(fun (pmap:access_map) (a:address * lock_info)=>
match a with
| ((b, ofs), _) => setPermBlock (Some Memtype.Writable) b ofs pmap LKSIZE_nat
end)
(AMap.elements am)
(PMap.init (fun _ => None)).
End AMap2PMap.

Lemma AMap_find_map_inv {A B} m (f : A -> B) k (y : B) :
AMap.find k (AMap.map f m) = Some y ->
exists x,
AMap.find k m = Some x /\
y = f x.