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 valid_genv_alloc_global: forall {F V} (ge: Genv.t F V) a m0 m1 (GA: Genv.alloc_global ge m0 a = Some m1), valid_genv ge m0 -> valid_genv ge m1.