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+Require Import AST Linking Values Maps Globalenvs Smallstep Registers.
+Require Import Coqlib Maps Events Errors Op.
+Require Import RTL RTLpath RTLpathLivegen RTLpathLivegenproof RTLpathSE_theory.
+Require Import MyRTLpathScheduler.
+
+Definition match_prog (p tp: program) :=
+ match_program (fun _ f tf => transf_fundef f = OK tf) eq p tp.
+
+Lemma transf_program_match:
+ forall prog tprog, transf_program prog = OK tprog -> match_prog prog tprog.
+Proof.
+ intros. eapply match_transform_partial_program_contextual; eauto.
+Qed.
+
+Section PRESERVATION.
+
+Variable prog: program.
+Variable tprog: program.
+
+Hypothesis TRANSL: match_prog prog tprog.
+
+Let pge := Genv.globalenv prog.
+Let tpge := Genv.globalenv tprog.
+
+Hypothesis all_fundef_liveness_ok: forall b fd, Genv.find_funct_ptr pge b = Some fd -> liveness_ok_fundef fd.
+
+Lemma symbols_preserved s: Genv.find_symbol tpge s = Genv.find_symbol pge s.
+Proof.
+ rewrite <- (Genv.find_symbol_match TRANSL). reflexivity.
+Qed.
+
+Lemma senv_preserved:
+ Senv.equiv pge tpge.
+Proof.
+ eapply (Genv.senv_match TRANSL).
+Qed.
+
+Lemma functions_preserved:
+ forall (v: val) (f: fundef),
+ Genv.find_funct pge v = Some f ->
+ exists tf cunit, transf_fundef f = OK tf /\ Genv.find_funct tpge v = Some tf /\ linkorder cunit prog.
+Proof.
+ intros. exploit (Genv.find_funct_match TRANSL); eauto.
+ intros (cu & tf & A & B & C).
+ repeat eexists; intuition eauto.
+ + unfold incl; auto.
+ + eapply linkorder_refl.
+Qed.
+
+Lemma function_ptr_preserved:
+ forall v f,
+ Genv.find_funct_ptr pge v = Some f ->
+ exists tf,
+ Genv.find_funct_ptr tpge v = Some tf /\ transf_fundef f = OK tf.
+Proof.
+ intros.
+ exploit (Genv.find_funct_ptr_transf_partial TRANSL); eauto.
+Qed.
+
+Lemma function_sig_preserved:
+ forall f tf, transf_fundef f = OK tf -> funsig tf = funsig f.
+Proof.
+ intros. destruct f.
+ - simpl in H. monadInv H.
+ destruct (transf_function f) as [res H]; simpl in * |- *; auto.
+ destruct (H _ EQ).
+ intuition subst; auto.
+ symmetry.
+ eapply match_function_preserves.
+ eassumption.
+ - simpl in H. monadInv H. reflexivity.
+Qed.
+
+Theorem transf_initial_states:
+ forall s1, initial_state prog s1 ->
+ exists s2, initial_state tprog s2 /\ match_states s1 s2.
+Proof.
+ intros. inv H.
+ exploit function_ptr_preserved; eauto. intros (tf & FIND & TRANSF).
+ exists (Callstate nil tf nil m0).
+ split.
+ - econstructor; eauto.
+ + intros; apply (Genv.init_mem_match TRANSL); assumption.
+ + replace (prog_main tprog) with (prog_main prog). rewrite symbols_preserved. eauto.
+ symmetry. eapply match_program_main. eauto.
+ + destruct f.
+ * monadInv TRANSF. rewrite <- H3.
+ destruct (transf_function f) as [res H]; simpl in * |- *; auto.
+ destruct (H _ EQ).
+ intuition subst; auto.
+ symmetry; eapply match_function_preserves. eassumption.
+ * monadInv TRANSF. assumption.
+ - constructor; eauto.
+ + constructor.
+ + apply transf_fundef_correct; auto.
+(* + eapply all_fundef_liveness_ok; eauto. *)
+Qed.
+
+Theorem transf_final_states s1 s2 r:
+ final_state s1 r -> match_states s1 s2 -> final_state s2 r.
+Proof.
+ unfold final_state.
+ intros H; inv H.
+ intros H; inv H; simpl in * |- *; try congruence.
+ inv H1.
+ destruct st; simpl in * |- *; try congruence.
+ inv STACKS. constructor.
+Qed.
+
+
+Let ge := Genv.globalenv (RTLpath.transf_program prog).
+Let tge := Genv.globalenv (RTLpath.transf_program tprog).
+
+Lemma senv_sym x y: Senv.equiv x y -> Senv.equiv y x.
+Proof.
+ unfold Senv.equiv. intuition congruence.
+Qed.
+
+Lemma senv_transitivity x y z: Senv.equiv x y -> Senv.equiv y z -> Senv.equiv x z.
+Proof.
+ unfold Senv.equiv. intuition congruence.
+Qed.
+
+Lemma senv_preserved_RTL:
+ Senv.equiv ge tge.
+Proof.
+ eapply senv_transitivity. { eapply senv_sym; eapply RTLpath.senv_preserved. }
+ eapply senv_transitivity. { eapply senv_preserved. }
+ eapply RTLpath.senv_preserved.
+Qed.
+
+Lemma symbols_preserved_RTL s: Genv.find_symbol tge s = Genv.find_symbol ge s.
+Proof.
+ unfold tge, ge. erewrite RTLpath.symbols_preserved; eauto.
+ rewrite symbols_preserved.
+ erewrite RTLpath.symbols_preserved; eauto.
+Qed.
+
+Program Definition mkctx sp rs0 m0 {f1: RTLpath.function} (hyp: liveness_ok_function f1)
+ : simu_proof_context f1
+ := {| the_ge1:= ge; the_ge2 := tge; the_sp:=sp; the_rs0:=rs0; the_m0:=m0 |}.
+Obligation 2.
+ erewrite symbols_preserved_RTL. eauto.
+Qed.
+
+Lemma s_find_function_fundef f sp svos rs0 m0 fd
+ (LIVE: liveness_ok_function f):
+ sfind_function pge ge sp svos rs0 m0 = Some fd ->
+ liveness_ok_fundef fd.
+Proof.
+ unfold sfind_function. destruct svos; simpl.
+ + destruct (seval_sval _ _ _ _); try congruence.
+ eapply find_funct_liveness_ok; eauto.
+ + destruct (Genv.find_symbol _ _); try congruence.
+ intros. eapply all_fundef_liveness_ok; eauto.
+Qed.
+Local Hint Resolve s_find_function_fundef: core.
+
+Lemma s_find_function_preserved f sp svos1 svos2 rs0 m0 fd
+ (LIVE: liveness_ok_function f):
+ (svident_simu f (mkctx sp rs0 m0 LIVE) svos1 svos2) ->
+ sfind_function pge ge sp svos1 rs0 m0 = Some fd ->
+ exists fd', sfind_function tpge tge sp svos2 rs0 m0 = Some fd'
+ /\ transf_fundef fd = OK fd'.
+Proof.
+ Local Hint Resolve symbols_preserved_RTL: core.
+ unfold sfind_function. intros [sv1 sv2 SIMU|]; simpl in *.
+ + rewrite !(seval_preserved ge tge) in *; eauto.
+ destruct (seval_sval _ _ _ _); try congruence.
+ erewrite <- SIMU; try congruence. clear SIMU.
+ intros; exploit functions_preserved; eauto.
+ intros (fd' & cunit & (X1 & X2 & X3)). eexists.
+ repeat split; eauto.
+ + subst. rewrite symbols_preserved. destruct (Genv.find_symbol _ _); try congruence.
+ intros; exploit function_ptr_preserved; eauto.
+Qed.
+
+Lemma sistate_simu f dupmap outframe sp st st' rs m is
+ (LIVE: liveness_ok_function f):
+ ssem_internal ge sp st rs m is ->
+ sistate_simu dupmap f outframe st st' (mkctx sp rs m LIVE)->
+ exists is',
+ ssem_internal tge sp st' rs m is' /\ istate_simu f dupmap outframe is is'.
+Proof.
+ intros SEM X; eapply X; eauto.
+Qed.
+
+Lemma seval_builtin_sval_preserved sp rs m:
+ forall bs, seval_builtin_sval ge sp bs rs m = seval_builtin_sval tge sp bs rs m.
+Proof.
+ induction bs.
+ all: try (simpl; try reflexivity; erewrite seval_preserved by eapply symbols_preserved_RTL; reflexivity).
+ all: simpl; rewrite IHbs1; rewrite IHbs2; reflexivity.
+Qed.
+
+Lemma seval_list_builtin_sval_preserved sp rs m:
+ forall lbs,
+ seval_list_builtin_sval ge sp lbs rs m = seval_list_builtin_sval tge sp lbs rs m.
+Proof.
+ induction lbs; [simpl; reflexivity|].
+ simpl. rewrite seval_builtin_sval_preserved. rewrite IHlbs.
+ reflexivity.
+Qed.
+
+Lemma ssem_final_simu dm f f' stk stk' sp st st' rs0 m0 sv sv' rs m t s
+ (LIVE: liveness_ok_function f):
+ match_function dm f f' ->
+ list_forall2 match_stackframes stk stk' ->
+ sfval_simu dm f st.(si_pc) st'.(si_pc) (mkctx sp rs0 m0 LIVE) sv sv' ->
+ ssem_final pge ge sp st.(si_pc) stk f rs0 m0 sv rs m t s ->
+ exists s', ssem_final tpge tge sp st'.(si_pc) stk' f' rs0 m0 sv' rs m t s' /\ match_states s s'.
+Proof.
+ Local Hint Resolve transf_fundef_correct: core.
+ intros FUN STK SFV. destruct SFV; intros SEM; inv SEM; simpl in *.
+ - (* Snone *)
+ exploit initialize_path. { eapply dupmap_path_entry1; eauto. }
+ intros (path & PATH).
+ eexists; split; econstructor; eauto.
+ eapply eqlive_reg_refl.
+ - (* Scall *)
+ exploit s_find_function_preserved; eauto.
+ intros (fd' & FIND & TRANSF).
+ erewrite <- function_sig_preserved; eauto.
+ exploit initialize_path. { eapply dupmap_path_entry1; eauto. }
+ intros (path & PATH).
+ eexists; split; econstructor; eauto.
+ + eapply eq_trans; try eassumption; auto.
+ + simpl. repeat (econstructor; eauto).
+ - (* Stailcall *)
+ exploit s_find_function_preserved; eauto.
+ intros (fd' & FIND & TRANSF).
+ erewrite <- function_sig_preserved; eauto.
+ eexists; split; econstructor; eauto.
+ + erewrite <- preserv_fnstacksize; eauto.
+ + eapply eq_trans; try eassumption; auto.
+ - (* Sbuiltin *)
+ pose senv_preserved_RTL as SRTL.
+ exploit initialize_path. { eapply dupmap_path_entry1; eauto. }
+ intros (path & PATH).
+ eexists; split; econstructor; eauto.
+ + eapply seval_builtin_args_preserved; eauto.
+ eapply seval_list_builtin_sval_correct; eauto.
+ rewrite H0.
+ erewrite seval_list_builtin_sval_preserved; eauto.
+ + eapply external_call_symbols_preserved; eauto.
+ + eapply eqlive_reg_refl.
+ - (* Sjumptable *)
+ exploit ptree_get_list_nth_rev; eauto. intros (p2 & LNZ & DM).
+ exploit initialize_path. { eapply dupmap_path_entry1; eauto. }
+ intros (path & PATH).
+ eexists; split; econstructor; eauto.
+ + eapply eq_trans; try eassumption; auto.
+ + eapply eqlive_reg_refl.
+ - (* Sreturn *)
+ eexists; split; econstructor; eauto.
+ erewrite <- preserv_fnstacksize; eauto.
+ - (* Sreturn bis *)
+ eexists; split; econstructor; eauto.
+ + erewrite <- preserv_fnstacksize; eauto.
+ + rewrite <- H. erewrite <- seval_preserved; eauto.
+Qed.
+
+Lemma siexec_snone_por_correct rs' is t s alive path0 i sp s0 st0 stk stk' f rs0 m0: forall
+ (SSEM2 : ssem_final pge ge sp (si_pc s0) stk f rs0 m0 Snone
+ (irs is) (imem is) t s)
+ (SIEXEC : siexec_inst i st0 = Some s0)
+ (ICHK : inst_checker (fn_path f) alive (pre_output_regs path0) i = Some tt),
+ (liveness_ok_function f) ->
+ list_forall2 match_stackframes stk stk' ->
+ eqlive_reg (fun r : Regset.elt => Regset.In r (pre_output_regs path0)) (irs is) rs' ->
+ exists s' : state,
+ ssem_final pge ge sp (si_pc s0) stk f rs0 m0 Snone rs' (imem is) t s' /\
+ eqlive_states s s'.
+Proof.
+ Local Hint Resolve eqlive_stacks_refl: core.
+ intros ? ? ? LIVE STK EQLIVE.
+ inversion SSEM2; subst; clear SSEM2.
+ eexists; split.
+ * econstructor.
+ * generalize ICHK.
+ unfold inst_checker. destruct i; simpl in *;
+ unfold exit_checker; try discriminate.
+ all:
+ try destruct Pos.eq_dec; simpl;
+ try destruct (list_mem _ _); simpl;
+ try (destruct (Regset.subset _ _) eqn:SUB_ALIVE; try congruence; fail).
+ 4,5:
+ destruct (Regset.mem _ _); destruct (Regset.subset _ _) eqn:SUB_ALIVE; try congruence.
+ 1,2,3,4: assert (NPC: n=(si_pc s0)).
+ all: try (inv SIEXEC; simpl; auto; fail).
+ 1,2,3,4:
+ try (destruct (Regset.subset _ _) eqn:SUB_ALIVE; try congruence);
+ simpl; inversion_SOME p;
+ destruct (Regset.subset (input_regs p) (pre_output_regs path0)) eqn:SUB_PATH; try congruence;
+ intros NPATH _; econstructor; eauto;
+ try (instantiate (1:=p); rewrite <- NPC; auto; fail).
+ 1,2,3,4:
+ eapply eqlive_reg_monotonic; eauto; simpl;
+ intros; apply Regset.subset_2 in SUB_PATH;
+ unfold Regset.Subset in SUB_PATH;
+ apply SUB_PATH in H; auto.
+ assert (NPC: n0=(si_pc s0)). { inv SIEXEC; simpl; auto. }
+ inversion_SOME p.
+ 2: { destruct (Regset.subset _ _) eqn:?; try congruence. }
+ destruct (Regset.subset _ _) eqn:SUB_ALIVE; try congruence.
+ 2: {
+ destruct (Regset.subset (pre_output_regs path0) alive) eqn:?; try congruence;
+ destruct ((fn_path f) ! n); intros; try discriminate.
+ all: inversion SIEXEC; simpl; auto.
+ all: destruct Regset.subset in ICHK0; try discriminate;
+ destruct Regset.subset in ICHK0; try discriminate;
+ simpl in ICHK0.
+ all: destruct PTree.get eqn:GET in ICHK0; try discriminate.
+ all: destruct Regset.subset eqn:SUBS_PATH0 in ICHK0; try discriminate.
+ all: econstructor; eauto.
+ all: eapply eqlive_reg_monotonic; eauto.
+ all: destruct (Regset.subset (input_regs p0) (pre_output_regs path0)) eqn:SUB_PATH; try congruence.
+ all: intros; apply Regset.subset_2 in SUB_PATH.
+ all: unfold Regset.Subset in SUB_PATH; apply SUB_PATH in H; auto. }
+ intros; simpl.
+ destruct (Regset.subset (pre_output_regs path0) alive) eqn:SUB_ALIVE'; try congruence.
+ destruct (Regset.subset (input_regs p) (pre_output_regs path0)) eqn:SUB_PATH; try congruence.
+ apply Regset.subset_2 in SUB_PATH.
+ unfold Regset.Subset in SUB_PATH.
+ econstructor; eauto. { rewrite <- NPC; eauto. }
+ eapply eqlive_reg_monotonic; eauto.
+Qed.
+
+Lemma pre_output_regs_correct f pc0 path0 stk stk' sp (st:sstate) rs0 m0 t s is rs':
+ (liveness_ok_function f) ->
+ (fn_path f) ! pc0 = Some path0 ->
+ sexec f pc0 = Some st ->
+ list_forall2 match_stackframes stk stk' ->
+ ssem_final pge ge sp (si_pc st) stk f rs0 m0 (final st) (irs is) (imem is) t s ->
+ eqlive_reg (fun r : Regset.elt => Regset.In r (pre_output_regs path0)) (irs is) rs' ->
+ exists s', ssem_final pge ge sp (si_pc st) stk f rs0 m0 (final st) rs' (imem is) t s' /\ eqlive_states s s'.
+Proof.
+ Local Hint Resolve eqlive_stacks_refl: core.
+ intros LIVE PATH0 SEXEC STK SSEM2 EQLIVE.
+ (* start decomposing path_checker *)
+ generalize (LIVE pc0 path0 PATH0).
+ unfold path_checker.
+ inversion_SOME res; intros IPCHK.
+ inversion_SOME i; intros INST ICHK.
+ exploit ipath_checker_default_succ; eauto. intros DEFSUCC.
+ (* start decomposing SEXEC *)
+ generalize SEXEC; clear SEXEC.
+ unfold sexec; rewrite PATH0.
+ inversion_SOME st0; intros SEXEC_PATH.
+ exploit siexec_path_default_succ; eauto.
+ simpl. rewrite DEFSUCC.
+ clear DEFSUCC. destruct res as [alive pc1]. simpl in *.
+ try_simplify_someHyps.
+ destruct (siexec_inst i st0) eqn: SIEXEC; try_simplify_someHyps; intros.
+ (* Snone *)
+ eapply siexec_snone_por_correct; eauto.
+ destruct i; try_simplify_someHyps; try congruence;
+ inversion SSEM2; subst; clear SSEM2; simpl in *.
+ + (* Scall *)
+ eexists; split.
+ * econstructor; eauto.
+ * econstructor; eauto.
+ econstructor; eauto.
+ (* wf *)
+ generalize ICHK.
+ unfold inst_checker; simpl in *.
+ destruct (Regset.subset _ _) eqn:SUB_ALIVE; try congruence.
+ destruct (list_mem _ _); try congruence.
+ destruct (reg_sum_mem _ _); try congruence.
+ intros EXIT.
+ exploit exit_checker_eqlive_ext1; eauto.
+ intros. destruct H as [p [PATH EQLIVE']].
+ econstructor; eauto.
+ + (* Stailcall *)
+ eexists; split.
+ * econstructor; eauto.
+ * econstructor; eauto.
+ + (* Sbuiltin *)
+ eexists; split.
+ * econstructor; eauto.
+ * (* wf *)
+ generalize ICHK.
+ unfold inst_checker; simpl in *.
+ destruct (Regset.subset _ _) eqn:SUB_ALIVE; try congruence.
+ destruct (list_mem _ _); try congruence.
+ intros EXIT.
+ exploit exit_checker_eqlive_builtin_res; eauto.
+ intros. destruct H as [p [PATH EQLIVE']].
+ econstructor; eauto.
+ + (* Icond *)
+ eexists; split.
+ * econstructor.
+ * generalize ICHK.
+ unfold inst_checker; simpl in *.
+ destruct Pos.eq_dec; destruct (Regset.subset _ _) eqn:SUB_ALIVE; try congruence.
+ + (* Sjumptable *)
+ eexists; split.
+ * econstructor; eauto.
+ * (* wf *)
+ generalize ICHK.
+ unfold inst_checker; simpl in *.
+ destruct (Regset.subset _ _) eqn:SUB_ALIVE; try congruence.
+ destruct (Regset.mem _ _); try congruence.
+ destruct (exit_list_checker _ _ _) eqn:EQL; try congruence.
+ exploit exit_list_checker_eqlive; eauto.
+ intros. destruct H as [p [PATH EQLIVE']].
+ econstructor; eauto.
+ + (* Sreturn *)
+ eexists; split.
+ * econstructor; eauto.
+ * econstructor; eauto.
+Qed.
+
+(* The main theorem on simulation of symbolic states ! *)
+Theorem ssem_sstate_simu dm f f' pc0 path0 stk stk' sp st st' rs m t s:
+ (fn_path f) ! pc0 = Some path0 ->
+ sexec f pc0 = Some st ->
+ match_function dm f f' ->
+ liveness_ok_function f ->
+ list_forall2 match_stackframes stk stk' ->
+ ssem pge ge sp st stk f rs m t s ->
+ (forall ctx: simu_proof_context f, sstate_simu dm f (pre_output_regs path0) st st' ctx) ->
+ exists s', ssem tpge tge sp st' stk' f' rs m t s' /\ match_states s s'.
+Proof.
+ intros PATH0 SEXEC MFUNC LIVE STACKS SEM SIMU.
+ destruct (SIMU (mkctx sp rs m LIVE)) as (SIMU1 & SIMU2); clear SIMU.
+ destruct SEM as [is CONT SEM|is t s' CONT SEM1 SEM2]; simpl in *.
+ - (* sem_early *)
+ exploit sistate_simu; eauto.
+ unfold istate_simu; rewrite CONT.
+ intros (is' & SEM' & (path & PATH & (CONT' & RS' & M') & PC')).
+ exists (State stk' f' sp (ipc is') (irs is') (imem is')).
+ split.
+ + eapply ssem_early; auto. congruence.
+ + rewrite M'. econstructor; eauto.
+ - (* sem_normal *)
+ exploit sistate_simu; eauto.
+ unfold istate_simu; rewrite CONT.
+ intros (is' & SEM' & (CONT' & RS' & M')).
+ exploit pre_output_regs_correct; eauto.
+ clear SEM2; intros (s0 & SEM2 & EQLIVE).
+ exploit ssem_final_simu; eauto.
+ clear SEM2; intros (s1 & SEM2 & MATCH0).
+ exploit ssem_final_equiv; eauto.
+ clear SEM2; rewrite M'; rewrite CONT' in CONT; intros (s2 & EQ & SEM2).
+ exists s2; split.
+ + eapply ssem_normal; eauto.
+ + eapply eqlive_match_states; eauto.
+ eapply match_states_equiv; eauto.
+Qed.
+
+Lemma exec_path_simulation dupmap path stk stk' f f' sp rs m pc pc' t s:
+ (fn_path f)!pc = Some path ->
+ path_step ge pge path.(psize) stk f sp rs m pc t s ->
+ list_forall2 match_stackframes stk stk' ->
+ dupmap ! pc' = Some pc ->
+ match_function dupmap f f' ->
+ liveness_ok_function f ->
+ exists path' s', (fn_path f')!pc' = Some path' /\ path_step tge tpge path'.(psize) stk' f' sp rs m pc' t s' /\ match_states s s'.
+Proof.
+ intros PATH STEP STACKS DUPPC MATCHF LIVE.
+ exploit initialize_path. { eapply dupmap_path_entry2; eauto. }
+ intros (path' & PATH').
+ exists path'.
+ exploit (sexec_correct f pc pge ge sp path stk rs m t s); eauto.
+ intros (st & SYMB & SEM).
+ exploit dupmap_correct; eauto.
+ intros (path0 & st' & PATH0 & SYMB' & SIMU).
+ rewrite PATH0 in PATH; inversion PATH; subst.
+ exploit ssem_sstate_simu; eauto.
+ intros (s0 & SEM0 & MATCH).
+ exploit (sexec_exact f'); eauto.
+ intros (s' & STEP' & EQ).
+ exists s'; intuition.
+ eapply match_states_equiv; eauto.
+Qed.
+
+Lemma step_simulation s1 t s1' s2:
+ step ge pge s1 t s1' ->
+ match_states s1 s2 ->
+ exists s2',
+ step tge tpge s2 t s2'
+ /\ match_states s1' s2'.
+Proof.
+ Local Hint Resolve eqlive_stacks_refl transf_fundef_correct: core.
+ destruct 1 as [path stack f sp rs m pc t s PATH STEP | | | ]; intros MS; inv MS.
+(* exec_path *)
+ - try_simplify_someHyps. intros.
+ exploit path_step_eqlive; eauto. (* { intros. eapply all_fundef_liveness_ok; eauto. } *)
+ clear STEP EQUIV rs; intros (s2 & STEP & EQLIVE).
+ exploit exec_path_simulation; eauto.
+ clear STEP; intros (path' & s' & PATH' & STEP' & MATCH').
+ exists s'; split.
+ + eapply exec_path; eauto.
+ + eapply eqlive_match_states; eauto.
+(* exec_function_internal *)
+ - inv LIVE.
+ exploit initialize_path. { eapply (fn_entry_point_wf f). }
+ destruct 1 as (path & PATH).
+ inversion TRANSF as [f0 xf tf MATCHF|]; subst. eexists. split.
+ + eapply exec_function_internal. erewrite <- preserv_fnstacksize; eauto.
+ + erewrite preserv_fnparams; eauto.
+ econstructor; eauto.
+ { apply preserv_entrypoint; auto. }
+ { apply eqlive_reg_refl. }
+(* exec_function_external *)
+ - inversion TRANSF as [|]; subst. eexists. split.
+ + econstructor. eapply external_call_symbols_preserved; eauto. apply senv_preserved_RTL.
+ + constructor. assumption.
+(* exec_return *)
+ - inv STACKS. destruct b1 as [res' f' sp' pc' rs']. eexists. split.
+ + constructor.
+ + inv H1. econstructor; eauto.
+Qed.
+
+Theorem transf_program_correct:
+ forward_simulation (semantics prog) (semantics tprog).
+Proof.
+ eapply forward_simulation_step with match_states.
+ - eapply senv_preserved.
+ - eapply transf_initial_states.
+ - intros; eapply transf_final_states; eauto.
+ - intros; eapply step_simulation; eauto.
+Qed.
+
+End PRESERVATION.