Definition context_below (ctx1 ctx2: context): Prop :=
  Ple (Pos.add ctx1.(dreg) ctx1.(mreg)) ctx2.(dreg).Definition context_stack_call (ctx1 ctx2: context): Prop :=
  ctx1.(mstk) >= 0 /\ ctx1.(dstk) + ctx1.(mstk) <= ctx2.(dstk).Definition context_stack_tailcall (ctx1: context) (f: function) (ctx2: context) : Prop :=
  ctx2.(dstk) = align ctx1.(dstk) (min_alignment f.(fn_stacksize)).Remark min_alignment_pos:
  forall sz, min_alignment sz > 0.Ltac inv_incr :=
  match goal with
  | [ H: sincr _ _ |- _ ] => destruct H; inv_incr
  | _ => idtac
  end.(** ** Relational specification of the translation of a function *)

Inductive tr_function: program -> function -> function -> Prop :=
  | tr_function_intro: forall p fenv f f' ctx,
      fenv_compat p fenv ->
      tr_funbody fenv f'.(fn_stacksize) ctx f f'.(fn_code) ->
      ctx.(dstk) = 0 ->
      ctx.(retinfo) = None ->
      f'.(fn_sig) = f.(fn_sig) ->
      f'.(fn_params) = sregs ctx f.(fn_params) ->
      f'.(fn_entrypoint) = spc ctx f.(fn_entrypoint) ->
      0 <= fn_stacksize f' < Ptrofs.max_unsigned ->
      tr_function p f f'.(** ** Relational specification of the translation of a function *)

Inductive tr_function: program -> function -> function -> Prop :=
  | tr_function_intro: forall p fenv f f' ctx,
      fenv_compat p fenv ->
      tr_funbody fenv f'.(fn_stacksize) ctx f f'.(fn_code) ->
      ctx.(dstk) = 0 ->
      ctx.(retinfo) = None ->
      f'.(fn_sig) = f.(fn_sig) ->
      f'.(fn_params) = sregs ctx f.(fn_params) ->
      f'.(fn_entrypoint) = spc ctx f.(fn_entrypoint) ->
      0 <= fn_stacksize f' < Ptrofs.max_unsigned ->
      tr_function p f f'.

Lemma transf_function_spec: forall cunit f f', transf_function (funenv_program cunit) f = OK f' -> tr_function cunit f f'.