(** ** Sufficient and necessary conditions for the initial memory to exist. *)

(** Alignment properties *)

Definition init_data_alignment (i: init_data) : Z :=
  match i with
  | Init_int8 n => 1
  | Init_int16 n => 2
  | Init_int32 n => 4
  | Init_int64 n => 8
  | Init_float32 n => 4
  | Init_float64 n => 4
  | Init_addrof symb ofs => if Archi.ptr64 then 8 else 4
  | Init_space n => 1
  end.

Theorem init_mem_exists: forall p, (forall id v, In (id, Gvar v) (prog_defs p) -> init_data_list_aligned 0 v.(gvar_init) /\ forall i o, In (Init_addrof i o) v.(gvar_init) -> exists b, find_symbol (globalenv p) i = Some b) -> exists m, init_mem p = Some m.