Inductive valid_genv {F V:Type} (ge:Genv.t F V) (m:mem) : Type :=
mk_valid_genv :
(forall b, isGlobalBlock ge b=true -> val_valid (Vptr b Ptrofs.zero) m) ->
(forall b f, Genv.find_funct_ptr ge b = Some f -> val_valid (Vptr b Ptrofs.zero) m) ->
valid_genv ge m.

Lemma freelist_mem_wd: forall l m m'
(M: Mem.free_list m l = Some m')
(WD: mem_wd m), mem_wd m'.