Definition getBlocks (V:list val) (b: block): bool :=
   in_dec eq_block b
    (fold_right (fun v L => match v with Vptr b' z => b'::L | _ => L end) nil V).

Lemma getBlocks_inject: forall j vals1 vals2 (ValInjMu : Forall2 (val_inject j) vals1 vals2) b (B: getBlocks vals1 b = true), exists jb d, j b = Some (jb, d) /\ getBlocks vals2 jb = true.