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.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'.