Definition globalfunction_ptr_inject (j:meminj):=
forall b f, Genv.find_funct_ptr ge b = Some f ->
j b = Some(b,0) /\ isGlobalBlock ge b = true.

Lemma restrict_preserves_globalfun_ptr: forall j X
(PG : globalfunction_ptr_inject j)
(Glob : forall b, isGlobalBlock ge b = true -> X b = true),
globalfunction_ptr_inject (restrict j X).