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+(** Low-level specifications of the simulation tests by symbolic execution with hash-consing *)
+
+Require Import Coqlib Maps Floats.
+Require Import AST Integers Values Events Memory Globalenvs Smallstep.
+Require Import Op Registers.
+Require Import RTL RTLpath.
+Require Import Errors.
+Require Import RTLpathSE_theory RTLpathLivegenproof.
+Require Import Axioms.
+
+Local Open Scope error_monad_scope.
+Local Open Scope option_monad_scope.
+
+Require Export Impure.ImpHCons.
+
+Import ListNotations.
+Local Open Scope list_scope.
+
+(** * Auxilary notions on simulation tests *)
+
+Definition silocal_simu (dm: PTree.t node) (f: RTLpath.function) (sl1 sl2: sistate_local) (ctx: simu_proof_context f): Prop :=
+ forall is1, ssem_local (the_ge1 ctx) (the_sp ctx) sl1 (the_rs0 ctx) (the_m0 ctx) (irs is1) (imem is1) ->
+ exists is2, ssem_local (the_ge2 ctx) (the_sp ctx) sl2 (the_rs0 ctx) (the_m0 ctx) (irs is2) (imem is2)
+ /\ istate_simu f dm is1 is2.
+
+(* a kind of negation of sabort_local *)
+Definition sok_local (ge: RTL.genv) (sp:val) (rs0: regset) (m0: mem) (st: sistate_local): Prop :=
+ (st.(si_pre) ge sp rs0 m0)
+ /\ seval_smem ge sp st.(si_smem) rs0 m0 <> None
+ /\ forall (r: reg), seval_sval ge sp (si_sreg st r) rs0 m0 <> None.
+
+Lemma ssem_local_sok ge sp rs0 m0 st rs m:
+ ssem_local ge sp st rs0 m0 rs m -> sok_local ge sp rs0 m0 st.
+Proof.
+ unfold sok_local, ssem_local.
+ intuition congruence.
+Qed.
+
+Definition siexit_simu (dm: PTree.t node) (f: RTLpath.function) (ctx: simu_proof_context f) (se1 se2: sistate_exit) :=
+ (sok_local (the_ge1 ctx) (the_sp ctx) (the_rs0 ctx) (the_m0 ctx) (si_elocal se1) ->
+ (seval_condition (the_ge1 ctx) (the_sp ctx) (si_cond se1) (si_scondargs se1)
+ (si_smem (si_elocal se1)) (the_rs0 ctx) (the_m0 ctx)) =
+ (seval_condition (the_ge2 ctx) (the_sp ctx) (si_cond se2) (si_scondargs se2)
+ (si_smem (si_elocal se2)) (the_rs0 ctx) (the_m0 ctx)))
+ /\ forall is1,
+ icontinue is1 = false ->
+ ssem_exit (the_ge1 ctx) (the_sp ctx) se1 (the_rs0 ctx) (the_m0 ctx) (irs is1) (imem is1) (ipc is1) ->
+ exists is2,
+ ssem_exit (the_ge2 ctx) (the_sp ctx) se2 (the_rs0 ctx) (the_m0 ctx) (irs is2) (imem is2) (ipc is2)
+ /\ istate_simu f dm is1 is2.
+
+Definition siexits_simu (dm: PTree.t node) (f: RTLpath.function) (lse1 lse2: list sistate_exit) (ctx: simu_proof_context f) :=
+ list_forall2 (siexit_simu dm f ctx) lse1 lse2.
+
+
+(** * Implementation of Data-structure use in Hash-consing *)
+
+(** ** Implementation of symbolic values/symbolic memories with hash-consing data *)
+
+Inductive hsval :=
+ | HSinput (r: reg) (hid: hashcode)
+ | HSop (op: operation) (lhsv: list_hsval) (hid: hashcode) (** NB: does not depend on the memory ! *)
+ | HSload (hsm: hsmem) (trap: trapping_mode) (chunk: memory_chunk) (addr: addressing) (lhsv: list_hsval) (hid: hashcode)
+with list_hsval :=
+ | HSnil (hid: hashcode)
+ | HScons (hsv: hsval) (lhsv: list_hsval) (hid: hashcode)
+with hsmem :=
+ | HSinit (hid: hashcode)
+ | HSstore (hsm: hsmem) (chunk: memory_chunk) (addr: addressing) (lhsv: list_hsval) (srce: hsval) (hid:hashcode).
+
+Scheme hsval_mut := Induction for hsval Sort Prop
+with list_hsval_mut := Induction for list_hsval Sort Prop
+with hsmem_mut := Induction for hsmem Sort Prop.
+
+
+
+(** Symbolic final value -- from hash-consed values
+ It does not seem useful to hash-consed these final values (because they are final).
+*)
+Inductive hsfval :=
+ | HSnone
+ | HScall (sig: signature) (svos: hsval + ident) (lsv: list_hsval) (res: reg) (pc: node)
+ | HStailcall (sig: signature) (svos: hsval + ident) (lsv: list_hsval)
+ | HSbuiltin (ef: external_function) (sargs: list (builtin_arg hsval)) (res: builtin_res reg) (pc: node)
+ | HSjumptable (sv: hsval) (tbl: list node)
+ | HSreturn (res: option hsval)
+.
+
+(** * gives the semantics of hash-consed symbolic values *)
+Fixpoint hsval_proj hsv :=
+ match hsv with
+ | HSinput r _ => Sinput r
+ | HSop op hl _ => Sop op (hsval_list_proj hl) Sinit (** NB: use the initial memory of the path ! *)
+ | HSload hm t chk addr hl _ => Sload (hsmem_proj hm) t chk addr (hsval_list_proj hl)
+ end
+with hsval_list_proj hl :=
+ match hl with
+ | HSnil _ => Snil
+ | HScons hv hl _ => Scons (hsval_proj hv) (hsval_list_proj hl)
+ end
+with hsmem_proj hm :=
+ match hm with
+ | HSinit _ => Sinit
+ | HSstore hm chk addr hl hv _ => Sstore (hsmem_proj hm) chk addr (hsval_list_proj hl) (hsval_proj hv)
+ end.
+
+Declare Scope hse.
+Local Open Scope hse.
+
+
+(** We use a Notation instead a Definition, in order to get more automation "for free" *)
+Notation "'seval_hsval' ge sp hsv" := (seval_sval ge sp (hsval_proj hsv))
+ (only parsing, at level 0, ge at next level, sp at next level, hsv at next level): hse.
+Notation "'seval_list_hsval' ge sp lhv" := (seval_list_sval ge sp (hsval_list_proj lhv))
+ (only parsing, at level 0, ge at next level, sp at next level, lhv at next level): hse.
+Notation "'seval_hsmem' ge sp hsm" := (seval_smem ge sp (hsmem_proj hsm))
+ (only parsing, at level 0, ge at next level, sp at next level, hsm at next level): hse.
+
+Notation "'sval_refines' ge sp rs0 m0 hv sv" := (seval_hsval ge sp hv rs0 m0 = seval_sval ge sp sv rs0 m0)
+ (only parsing, at level 0, ge at next level, sp at next level, rs0 at next level, m0 at next level, hv at next level, sv at next level): hse.
+Notation "'list_sval_refines' ge sp rs0 m0 lhv lsv" := (seval_list_hsval ge sp lhv rs0 m0 = seval_list_sval ge sp lsv rs0 m0)
+ (only parsing, at level 0, ge at next level, sp at next level, rs0 at next level, m0 at next level, lhv at next level, lsv at next level): hse.
+Notation "'smem_refines' ge sp rs0 m0 hm sm" := (seval_hsmem ge sp hm rs0 m0 = seval_smem ge sp sm rs0 m0)
+ (only parsing, at level 0, ge at next level, sp at next level, rs0 at next level, m0 at next level, hm at next level, sm at next level): hse.
+
+
+(** ** Implementation of symbolic states (with hash-consing) *)
+
+(** *** Syntax and semantics of symbolic internal local states
+
+The semantics is given by the refinement relation [hsilocal_refines] wrt to (abstract) symbolic internal local states
+
+*)
+
+(* NB: "h" stands for hash-consing *)
+Record hsistate_local :=
+ {
+ (** [hsi_smem] represents the current smem symbolic evaluations.
+ (we also recover the history of smem in hsi_smem) *)
+ hsi_smem:> hsmem;
+ (** For the values in registers:
+ 1) we store a list of sval evaluations
+ 2) we encode the symbolic regset by a PTree *)
+ hsi_ok_lsval: list hsval;
+ hsi_sreg:> PTree.t hsval
+ }.
+
+Definition hsi_sreg_proj (hst: PTree.t hsval) r: sval :=
+ match PTree.get r hst with
+ | None => Sinput r
+ | Some hsv => hsval_proj hsv
+ end.
+
+Definition hsi_sreg_eval ge sp hst r := seval_sval ge sp (hsi_sreg_proj hst r).
+
+Definition hsok_local ge sp rs0 m0 (hst: hsistate_local) : Prop :=
+ (forall hsv, List.In hsv (hsi_ok_lsval hst) -> seval_hsval ge sp hsv rs0 m0 <> None)
+ /\ (seval_hsmem ge sp (hst.(hsi_smem)) rs0 m0 <> None).
+
+(* refinement link between a (st: sistate_local) and (hst: hsistate_local) *)
+Definition hsilocal_refines ge sp rs0 m0 (hst: hsistate_local) (st: sistate_local) :=
+ (sok_local ge sp rs0 m0 st <-> hsok_local ge sp rs0 m0 hst)
+ /\ (hsok_local ge sp rs0 m0 hst -> smem_refines ge sp rs0 m0 (hsi_smem hst) (st.(si_smem)))
+ /\ (hsok_local ge sp rs0 m0 hst -> forall r, hsi_sreg_eval ge sp hst r rs0 m0 = seval_sval ge sp (si_sreg st r) rs0 m0)
+ /\ (* the below invariant allows to evaluate operations in the initial memory of the path instead of the current memory *)
+ (forall m b ofs, seval_smem ge sp st.(si_smem) rs0 m0 = Some m -> Mem.valid_pointer m b ofs = Mem.valid_pointer m0 b ofs)
+ .
+
+(** *** Syntax and semantics of symbolic exit states *)
+Record hsistate_exit := mk_hsistate_exit
+ { hsi_cond: condition; hsi_scondargs: list_hsval; hsi_elocal: hsistate_local; hsi_ifso: node }.
+
+(** NB: we split the refinement relation between a "static" part -- independendent of the initial context
+ and a "dynamic" part -- that depends on it
+*)
+Definition hsiexit_refines_stat (hext: hsistate_exit) (ext: sistate_exit): Prop :=
+ hsi_ifso hext = si_ifso ext.
+
+Definition hseval_condition ge sp cond hcondargs hmem rs0 m0 :=
+ seval_condition ge sp cond (hsval_list_proj hcondargs) (hsmem_proj hmem) rs0 m0.
+
+Lemma hseval_condition_preserved ge ge' sp cond args mem rs0 m0:
+ (forall s : ident, Genv.find_symbol ge' s = Genv.find_symbol ge s) ->
+ hseval_condition ge sp cond args mem rs0 m0 = hseval_condition ge' sp cond args mem rs0 m0.
+Proof.
+ intros. unfold hseval_condition. erewrite seval_condition_preserved; [|eapply H].
+ reflexivity.
+Qed.
+
+Definition hsiexit_refines_dyn ge sp rs0 m0 (hext: hsistate_exit) (ext: sistate_exit): Prop :=
+ hsilocal_refines ge sp rs0 m0 (hsi_elocal hext) (si_elocal ext)
+ /\ (hsok_local ge sp rs0 m0 (hsi_elocal hext) ->
+ hseval_condition ge sp (hsi_cond hext) (hsi_scondargs hext) (hsi_smem (hsi_elocal hext)) rs0 m0
+ = seval_condition ge sp (si_cond ext) (si_scondargs ext) (si_smem (si_elocal ext)) rs0 m0).
+
+Definition hsiexits_refines_stat lhse lse :=
+ list_forall2 hsiexit_refines_stat lhse lse.
+
+Definition hsiexits_refines_dyn ge sp rs0 m0 lhse se :=
+ list_forall2 (hsiexit_refines_dyn ge sp rs0 m0) lhse se.
+
+
+(** *** Syntax and Semantics of symbolic internal state *)
+
+Record hsistate := { hsi_pc: node; hsi_exits: list hsistate_exit; hsi_local: hsistate_local }.
+
+(* expresses the "monotony" of sok_local along sequences *)
+Inductive nested_sok ge sp rs0 m0: sistate_local -> list sistate_exit -> Prop :=
+ nsok_nil st: nested_sok ge sp rs0 m0 st nil
+ | nsok_cons st se lse:
+ (sok_local ge sp rs0 m0 st -> sok_local ge sp rs0 m0 (si_elocal se)) ->
+ nested_sok ge sp rs0 m0 (si_elocal se) lse ->
+ nested_sok ge sp rs0 m0 st (se::lse).
+
+Lemma nested_sok_prop ge sp st sle rs0 m0:
+ nested_sok ge sp rs0 m0 st sle ->
+ sok_local ge sp rs0 m0 st ->
+ forall se, In se sle -> sok_local ge sp rs0 m0 (si_elocal se).
+Proof.
+ induction 1; simpl; intuition (subst; eauto).
+Qed.
+
+Lemma nested_sok_elocal ge sp rs0 m0 st2 exits:
+ nested_sok ge sp rs0 m0 st2 exits ->
+ forall st1, (sok_local ge sp rs0 m0 st1 -> sok_local ge sp rs0 m0 st2) ->
+ nested_sok ge sp rs0 m0 st1 exits.
+Proof.
+ induction 1; [intros; constructor|].
+ intros. constructor; auto.
+Qed.
+
+Lemma nested_sok_tail ge sp rs0 m0 st lx exits:
+ is_tail lx exits ->
+ nested_sok ge sp rs0 m0 st exits ->
+ nested_sok ge sp rs0 m0 st lx.
+Proof.
+ induction 1; [auto|].
+ intros. inv H0. eapply IHis_tail. eapply nested_sok_elocal; eauto.
+Qed.
+
+Definition hsistate_refines_stat (hst: hsistate) (st:sistate): Prop :=
+ hsi_pc hst = si_pc st
+ /\ hsiexits_refines_stat (hsi_exits hst) (si_exits st).
+
+Definition hsistate_refines_dyn ge sp rs0 m0 (hst: hsistate) (st:sistate): Prop :=
+ hsiexits_refines_dyn ge sp rs0 m0 (hsi_exits hst) (si_exits st)
+ /\ hsilocal_refines ge sp rs0 m0 (hsi_local hst) (si_local st)
+ /\ nested_sok ge sp rs0 m0 (si_local st) (si_exits st) (* invariant necessary to prove "monotony" of sok_local along execution *)
+ .
+
+(** *** Syntax and Semantics of symbolic state *)
+
+Definition hfinal_proj (hfv: hsfval) : sfval :=
+ match hfv with
+ | HSnone => Snone
+ | HScall s hvi hlv r pc => Scall s (sum_left_map hsval_proj hvi) (hsval_list_proj hlv) r pc
+ | HStailcall s hvi hlv => Stailcall s (sum_left_map hsval_proj hvi) (hsval_list_proj hlv)
+ | HSbuiltin ef lbh br pc => Sbuiltin ef (List.map (builtin_arg_map hsval_proj) lbh) br pc
+ | HSjumptable hv ln => Sjumptable (hsval_proj hv) ln
+ | HSreturn oh => Sreturn (option_map hsval_proj oh)
+ end.
+
+Section HFINAL_REFINES.
+
+Variable ge: RTL.genv.
+Variable sp: val.
+Variable rs0: regset.
+Variable m0: mem.
+
+Definition option_refines (ohsv: option hsval) (osv: option sval) :=
+ match ohsv, osv with
+ | Some hsv, Some sv => sval_refines ge sp rs0 m0 hsv sv
+ | None, None => True
+ | _, _ => False
+ end.
+
+Definition sum_refines (hsi: hsval + ident) (si: sval + ident) :=
+ match hsi, si with
+ | inl hv, inl sv => sval_refines ge sp rs0 m0 hv sv
+ | inr id, inr id' => id = id'
+ | _, _ => False
+ end.
+
+Definition bargs_refines (hargs: list (builtin_arg hsval)) (args: list (builtin_arg sval)): Prop :=
+ seval_list_builtin_sval ge sp (List.map (builtin_arg_map hsval_proj) hargs) rs0 m0 = seval_list_builtin_sval ge sp args rs0 m0.
+
+Inductive hfinal_refines: hsfval -> sfval -> Prop :=
+ | hsnone_ref: hfinal_refines HSnone Snone
+ | hscall_ref: forall hros ros hargs args s r pc,
+ sum_refines hros ros ->
+ list_sval_refines ge sp rs0 m0 hargs args ->
+ hfinal_refines (HScall s hros hargs r pc) (Scall s ros args r pc)
+ | hstailcall_ref: forall hros ros hargs args s,
+ sum_refines hros ros ->
+ list_sval_refines ge sp rs0 m0 hargs args ->
+ hfinal_refines (HStailcall s hros hargs) (Stailcall s ros args)
+ | hsbuiltin_ref: forall ef lbha lba br pc,
+ bargs_refines lbha lba ->
+ hfinal_refines (HSbuiltin ef lbha br pc) (Sbuiltin ef lba br pc)
+ | hsjumptable_ref: forall hsv sv lpc,
+ sval_refines ge sp rs0 m0 hsv sv -> hfinal_refines (HSjumptable hsv lpc) (Sjumptable sv lpc)
+ | hsreturn_ref: forall ohsv osv,
+ option_refines ohsv osv -> hfinal_refines (HSreturn ohsv) (Sreturn osv).
+
+End HFINAL_REFINES.
+
+
+Record hsstate := { hinternal:> hsistate; hfinal: hsfval }.
+
+Definition hsstate_refines (hst: hsstate) (st:sstate): Prop :=
+ hsistate_refines_stat (hinternal hst) (internal st)
+ /\ (forall ge sp rs0 m0, hsistate_refines_dyn ge sp rs0 m0 (hinternal hst) (internal st))
+ /\ (forall ge sp rs0 m0, hsok_local ge sp rs0 m0 (hsi_local (hinternal hst)) -> hfinal_refines ge sp rs0 m0 (hfinal hst) (final st))
+ .
+
+(** * Intermediate specifications of the simulation tests *)
+
+(** ** Specification of the simulation test on [hsistate_local].
+ It is motivated by [hsilocal_simu_spec_correct theorem] below
+*)
+Definition hsilocal_simu_spec (oalive: option Regset.t) (hst1 hst2: hsistate_local) :=
+ List.incl (hsi_ok_lsval hst2) (hsi_ok_lsval hst1)
+ /\ (forall r, (match oalive with Some alive => Regset.In r alive | _ => True end) -> PTree.get r hst2 = PTree.get r hst1)
+ /\ hsi_smem hst1 = hsi_smem hst2.
+
+Definition seval_sval_partial ge sp rs0 m0 hsv :=
+ match seval_hsval ge sp hsv rs0 m0 with
+ | Some v => v
+ | None => Vundef
+ end.
+
+Definition select_first (ox oy: option val) :=
+ match ox with
+ | Some v => Some v
+ | None => oy
+ end.
+
+(** If the register was computed by hrs, evaluate the symbolic value from hrs.
+ Else, take the value directly from rs0 *)
+Definition seval_partial_regset ge sp rs0 m0 hrs :=
+ let hrs_eval := PTree.map1 (seval_sval_partial ge sp rs0 m0) hrs in
+ (fst rs0, PTree.combine select_first hrs_eval (snd rs0)).
+
+Lemma seval_partial_regset_get ge sp rs0 m0 hrs r:
+ (seval_partial_regset ge sp rs0 m0 hrs) # r =
+ match (hrs ! r) with Some sv => seval_sval_partial ge sp rs0 m0 sv | None => (rs0 # r) end.
+Proof.
+ unfold seval_partial_regset. unfold Regmap.get. simpl.
+ rewrite PTree.gcombine; [| simpl; reflexivity]. rewrite PTree.gmap1.
+ destruct (hrs ! r); simpl; [reflexivity|].
+ destruct ((snd rs0) ! r); reflexivity.
+Qed.
+
+Lemma ssem_local_refines_hok ge sp rs0 m0 hst st rs m:
+ ssem_local ge sp st rs0 m0 rs m -> hsilocal_refines ge sp rs0 m0 hst st -> hsok_local ge sp rs0 m0 hst.
+Proof.
+ intros H0 (H1 & _ & _). apply H1. eapply ssem_local_sok. eauto.
+Qed.
+
+Lemma hsilocal_simu_spec_nofail ge1 ge2 of sp rs0 m0 hst1 hst2:
+ hsilocal_simu_spec of hst1 hst2 ->
+ (forall s, Genv.find_symbol ge1 s = Genv.find_symbol ge2 s) ->
+ hsok_local ge1 sp rs0 m0 hst1 ->
+ hsok_local ge2 sp rs0 m0 hst2.
+Proof.
+ intros (RSOK & _ & MEMOK) GFS (OKV & OKM). constructor.
+ - intros sv INS. apply RSOK in INS. apply OKV in INS. erewrite seval_preserved; eauto.
+ - erewrite MEMOK in OKM. erewrite smem_eval_preserved; eauto.
+Qed.
+
+Theorem hsilocal_simu_spec_correct hst1 hst2 of ge1 ge2 sp rs0 m0 rs m st1 st2:
+ hsilocal_simu_spec of hst1 hst2 ->
+ hsilocal_refines ge1 sp rs0 m0 hst1 st1 ->
+ hsilocal_refines ge2 sp rs0 m0 hst2 st2 ->
+ (forall s, Genv.find_symbol ge1 s = Genv.find_symbol ge2 s) ->
+ ssem_local ge1 sp st1 rs0 m0 rs m ->
+ match of with
+ | None => ssem_local ge2 sp st2 rs0 m0 rs m
+ | Some alive =>
+ let rs' := seval_partial_regset ge2 sp rs0 m0 (hsi_sreg hst2)
+ in ssem_local ge2 sp st2 rs0 m0 rs' m /\ eqlive_reg (fun r => Regset.In r alive) rs rs'
+ end.
+Proof.
+ intros CORE HREF1 HREF2 GFS SEML.
+ refine (modusponens _ _ (ssem_local_refines_hok _ _ _ _ _ _ _ _ _ _) _); eauto.
+ intro HOK1.
+ refine (modusponens _ _ (hsilocal_simu_spec_nofail _ _ _ _ _ _ _ _ _ _ _) _); eauto.
+ intro HOK2.
+ destruct SEML as (PRE & MEMEQ & RSEQ).
+ assert (SIPRE: si_pre st2 ge2 sp rs0 m0). { destruct HREF2 as (OKEQ & _ & _). rewrite <- OKEQ in HOK2. apply HOK2. }
+ assert (SMEMEVAL: seval_smem ge2 sp (si_smem st2) rs0 m0 = Some m). {
+ destruct HREF2 as (_ & MEMEQ2 & _). destruct HREF1 as (_ & MEMEQ1 & _).
+ destruct CORE as (_ & _ & MEMEQ3).
+ rewrite <- MEMEQ2; auto. rewrite <- MEMEQ3.
+ erewrite smem_eval_preserved; [| eapply GFS].
+ rewrite MEMEQ1; auto. }
+ destruct of as [alive |].
+ - constructor.
+ + constructor; [assumption | constructor; [assumption|]].
+ destruct HREF2 as (B & _ & A & _).
+ (** B is used for the auto below. *)
+ assert (forall r : positive, hsi_sreg_eval ge2 sp hst2 r rs0 m0 = seval_sval ge2 sp (si_sreg st2 r) rs0 m0) by auto.
+ intro r. rewrite <- H. clear H.
+ generalize (A HOK2 r). unfold hsi_sreg_eval.
+ rewrite seval_partial_regset_get.
+ unfold hsi_sreg_proj.
+ destruct (hst2 ! r) eqn:HST2; [| simpl; reflexivity].
+ unfold seval_sval_partial. generalize HOK2; rewrite <- B; intros (_ & _ & C) D.
+ assert (seval_sval ge2 sp (hsval_proj h) rs0 m0 <> None) by congruence.
+ destruct (seval_sval ge2 sp _ rs0 m0); [reflexivity | contradiction].
+ + intros r ALIVE. destruct HREF2 as (_ & _ & A & _). destruct HREF1 as (_ & _ & B & _).
+ destruct CORE as (_ & C & _). rewrite seval_partial_regset_get.
+ assert (OPT: forall (x y: val), Some x = Some y -> x = y) by congruence.
+ destruct (hst2 ! r) eqn:HST2; apply OPT; clear OPT.
+ ++ unfold seval_sval_partial.
+ assert (seval_sval ge2 sp (hsval_proj h) rs0 m0 = hsi_sreg_eval ge2 sp hst2 r rs0 m0). {
+ unfold hsi_sreg_eval, hsi_sreg_proj. rewrite HST2. reflexivity. }
+ rewrite H. clear H. unfold hsi_sreg_eval, hsi_sreg_proj. rewrite C; [|assumption].
+ erewrite seval_preserved; [| eapply GFS].
+ unfold hsi_sreg_eval, hsi_sreg_proj in B; rewrite B; [|assumption]. rewrite RSEQ. reflexivity.
+ ++ rewrite <- RSEQ. rewrite <- B; [|assumption]. unfold hsi_sreg_eval, hsi_sreg_proj.
+ rewrite <- C; [|assumption]. rewrite HST2. reflexivity.
+ - constructor; [|constructor].
+ + destruct HREF2 as (OKEQ & _ & _). rewrite <- OKEQ in HOK2. apply HOK2.
+ + destruct HREF2 as (_ & MEMEQ2 & _). destruct HREF1 as (_ & MEMEQ1 & _).
+ destruct CORE as (_ & _ & MEMEQ3).
+ rewrite <- MEMEQ2; auto. rewrite <- MEMEQ3.
+ erewrite smem_eval_preserved; [| eapply GFS].
+ rewrite MEMEQ1; auto.
+ + intro r. destruct HREF2 as (_ & _ & A & _). destruct HREF1 as (_ & _ & B & _).
+ destruct CORE as (_ & C & _). rewrite <- A; auto. unfold hsi_sreg_eval, hsi_sreg_proj.
+ rewrite C; [|auto]. erewrite seval_preserved; [| eapply GFS].
+ unfold hsi_sreg_eval, hsi_sreg_proj in B; rewrite B; auto.
+Qed.
+
+(** ** Specification of the simulation test on [hsistate_exit].
+ It is motivated by [hsiexit_simu_spec_correct theorem] below
+*)
+Definition hsiexit_simu_spec dm f (hse1 hse2: hsistate_exit) :=
+ (exists path, (fn_path f) ! (hsi_ifso hse1) = Some path
+ /\ hsilocal_simu_spec (Some path.(input_regs)) (hsi_elocal hse1) (hsi_elocal hse2))
+ /\ dm ! (hsi_ifso hse2) = Some (hsi_ifso hse1)
+ /\ hsi_cond hse1 = hsi_cond hse2
+ /\ hsi_scondargs hse1 = hsi_scondargs hse2.
+
+Definition hsiexit_simu dm f (ctx: simu_proof_context f) hse1 hse2: Prop := forall se1 se2,
+ hsiexit_refines_stat hse1 se1 ->
+ hsiexit_refines_stat hse2 se2 ->
+ hsiexit_refines_dyn (the_ge1 ctx) (the_sp ctx) (the_rs0 ctx) (the_m0 ctx) hse1 se1 ->
+ hsiexit_refines_dyn (the_ge2 ctx) (the_sp ctx) (the_rs0 ctx) (the_m0 ctx) hse2 se2 ->
+ siexit_simu dm f ctx se1 se2.
+
+Lemma hsiexit_simu_spec_nofail dm f hse1 hse2 ge1 ge2 sp rs m:
+ hsiexit_simu_spec dm f hse1 hse2 ->
+ (forall s, Genv.find_symbol ge1 s = Genv.find_symbol ge2 s) ->
+ hsok_local ge1 sp rs m (hsi_elocal hse1) ->
+ hsok_local ge2 sp rs m (hsi_elocal hse2).
+Proof.
+ intros CORE GFS HOK1.
+ destruct CORE as ((p & _ & CORE') & _ & _ & _).
+ eapply hsilocal_simu_spec_nofail; eauto.
+Qed.
+
+Theorem hsiexit_simu_spec_correct dm f hse1 hse2 ctx:
+ hsiexit_simu_spec dm f hse1 hse2 ->
+ hsiexit_simu dm f ctx hse1 hse2.
+Proof.
+ intros SIMUC st1 st2 HREF1 HREF2 HDYN1 HDYN2.
+ assert (SEVALC:
+ sok_local (the_ge1 ctx) (the_sp ctx) (the_rs0 ctx) (the_m0 ctx) (si_elocal st1) ->
+ (seval_condition (the_ge1 ctx) (the_sp ctx) (si_cond st1) (si_scondargs st1) (si_smem (si_elocal st1))
+ (the_rs0 ctx) (the_m0 ctx)) =
+ (seval_condition (the_ge2 ctx) (the_sp ctx) (si_cond st2) (si_scondargs st2) (si_smem (si_elocal st2))
+ (the_rs0 ctx) (the_m0 ctx))).
+ { destruct HDYN1 as ((OKEQ1 & _) & SCOND1).
+ rewrite OKEQ1; intro OK1. rewrite <- SCOND1 by assumption. clear SCOND1.
+ generalize (genv_match ctx).
+ intro GFS; exploit hsiexit_simu_spec_nofail; eauto.
+ destruct HDYN2 as (_ & SCOND2). intro OK2. rewrite <- SCOND2 by assumption. clear OK1 OK2 SCOND2.
+ destruct SIMUC as ((path & _ & LSIMU) & _ & CONDEQ & ARGSEQ). destruct LSIMU as (_ & _ & MEMEQ).
+ rewrite CONDEQ. rewrite ARGSEQ. rewrite MEMEQ. erewrite <- hseval_condition_preserved; eauto.
+ }
+ constructor; [assumption|]. intros is1 ICONT SSEME.
+ assert (OK1: sok_local (the_ge1 ctx) (the_sp ctx) (the_rs0 ctx) (the_m0 ctx) (si_elocal st1)). {
+ destruct SSEME as (_ & SSEML & _). eapply ssem_local_sok; eauto. }
+ assert (HOK1: hsok_local (the_ge1 ctx) (the_sp ctx) (the_rs0 ctx) (the_m0 ctx) (hsi_elocal hse1)). {
+ destruct HDYN1 as (LREF & _). destruct LREF as (OKEQ & _ & _). rewrite <- OKEQ. assumption. }
+ exploit hsiexit_simu_spec_nofail. 2: eapply ctx. all: eauto. intro HOK2.
+ destruct SSEME as (SCOND & SLOC & PCEQ). destruct SIMUC as ((path & PATH & LSIMU) & REVEQ & _ & _); eauto.
+ destruct HDYN1 as (LREF1 & _). destruct HDYN2 as (LREF2 & _).
+ exploit hsilocal_simu_spec_correct; eauto; [apply ctx|]. simpl.
+ intros (SSEML & EQREG).
+ eexists (mk_istate (icontinue is1) (si_ifso st2) _ (imem is1)). simpl. constructor.
+ - constructor; intuition congruence || eauto.
+ - unfold istate_simu. rewrite ICONT.
+ simpl. assert (PCEQ': hsi_ifso hse1 = ipc is1) by congruence.
+ exists path. constructor; [|constructor]; [congruence| |congruence].
+ constructor; [|constructor]; simpl; auto.
+Qed.
+
+Remark hsiexit_simu_siexit dm f ctx hse1 hse2 se1 se2:
+ hsiexit_simu dm f ctx hse1 hse2 ->
+ hsiexit_refines_stat hse1 se1 ->
+ hsiexit_refines_stat hse2 se2 ->
+ hsiexit_refines_dyn (the_ge1 ctx) (the_sp ctx) (the_rs0 ctx) (the_m0 ctx) hse1 se1 ->
+ hsiexit_refines_dyn (the_ge2 ctx) (the_sp ctx) (the_rs0 ctx) (the_m0 ctx) hse2 se2 ->
+ siexit_simu dm f ctx se1 se2.
+Proof.
+ auto.
+Qed.
+
+(** ** Specification of the simulation test on [list hsistate_exit].
+ It is motivated by [hsiexit_simu_spec_correct theorem] below
+*)
+
+Definition hsiexits_simu dm f (ctx: simu_proof_context f) (lhse1 lhse2: list hsistate_exit): Prop :=
+ list_forall2 (hsiexit_simu dm f ctx) lhse1 lhse2.
+
+Definition hsiexits_simu_spec dm f lhse1 lhse2: Prop :=
+ list_forall2 (hsiexit_simu_spec dm f) lhse1 lhse2.
+
+Theorem hsiexits_simu_spec_correct dm f lhse1 lhse2 ctx:
+ hsiexits_simu_spec dm f lhse1 lhse2 ->
+ hsiexits_simu dm f ctx lhse1 lhse2.
+Proof.
+ induction 1; [constructor|].
+ constructor; [|apply IHlist_forall2; assumption].
+ apply hsiexit_simu_spec_correct; assumption.
+Qed.
+
+
+Lemma siexits_simu_all_fallthrough dm f ctx: forall lse1 lse2,
+ siexits_simu dm f lse1 lse2 ctx ->
+ all_fallthrough (the_ge1 ctx) (the_sp ctx) lse1 (the_rs0 ctx) (the_m0 ctx) ->
+ (forall se1, In se1 lse1 -> sok_local (the_ge1 ctx) (the_sp ctx) (the_rs0 ctx) (the_m0 ctx) (si_elocal se1)) ->
+ all_fallthrough (the_ge2 ctx) (the_sp ctx) lse2 (the_rs0 ctx) (the_m0 ctx).
+Proof.
+ induction 1; [unfold all_fallthrough; contradiction|]; simpl.
+ intros X OK ext INEXT. eapply all_fallthrough_revcons in X. destruct X as (SEVAL & ALLFU).
+ apply IHlist_forall2 in ALLFU.
+ - destruct H as (CONDSIMU & _).
+ inv INEXT; [|eauto].
+ erewrite <- CONDSIMU; eauto.
+ - intros; intuition.
+Qed.
+
+
+Lemma siexits_simu_all_fallthrough_upto dm f ctx lse1 lse2:
+ siexits_simu dm f lse1 lse2 ctx ->
+ forall ext1 lx1,
+ (forall se1, In se1 lx1 -> sok_local (the_ge1 ctx) (the_sp ctx) (the_rs0 ctx) (the_m0 ctx) (si_elocal se1)) ->
+ all_fallthrough_upto_exit (the_ge1 ctx) (the_sp ctx) ext1 lx1 lse1 (the_rs0 ctx) (the_m0 ctx) ->
+ exists ext2 lx2,
+ all_fallthrough_upto_exit (the_ge2 ctx) (the_sp ctx) ext2 lx2 lse2 (the_rs0 ctx) (the_m0 ctx)
+ /\ length lx1 = length lx2.
+Proof.
+ induction 1.
+ - intros ext lx1. intros OK H. destruct H as (ITAIL & ALLFU). eapply is_tail_false in ITAIL. contradiction.
+ - simpl; intros ext lx1 OK ALLFUE.
+ destruct ALLFUE as (ITAIL & ALLFU). inv ITAIL.
+ + eexists; eexists.
+ constructor; [| eapply list_forall2_length; eauto].
+ constructor; [econstructor | eapply siexits_simu_all_fallthrough; eauto].
+ + exploit IHlist_forall2.
+ * intuition. apply OK. eassumption.
+ * constructor; eauto.
+ * intros (ext2 & lx2 & ALLFUE2 & LENEQ).
+ eexists; eexists. constructor; eauto.
+ eapply all_fallthrough_upto_exit_cons; eauto.
+Qed.
+
+
+Lemma hsiexits_simu_siexits dm f ctx lhse1 lhse2:
+ hsiexits_simu dm f ctx lhse1 lhse2 ->
+ forall lse1 lse2,
+ hsiexits_refines_stat lhse1 lse1 ->
+ hsiexits_refines_stat lhse2 lse2 ->
+ hsiexits_refines_dyn (the_ge1 ctx) (the_sp ctx) (the_rs0 ctx) (the_m0 ctx) lhse1 lse1 ->
+ hsiexits_refines_dyn (the_ge2 ctx) (the_sp ctx) (the_rs0 ctx) (the_m0 ctx) lhse2 lse2 ->
+ siexits_simu dm f lse1 lse2 ctx.
+Proof.
+ induction 1.
+ - intros. inv H. inv H0. constructor.
+ - intros lse1 lse2 SREF1 SREF2 DREF1 DREF2. inv SREF1. inv SREF2. inv DREF1. inv DREF2.
+ constructor; [| eapply IHlist_forall2; eauto].
+ eapply hsiexit_simu_siexit; eauto.
+Qed.
+
+
+(** ** Specification of the simulation test on [hsistate].
+ It is motivated by [hsistate_simu_spec_correct theorem] below
+*)
+
+Definition hsistate_simu_spec dm f (hse1 hse2: hsistate) :=
+ list_forall2 (hsiexit_simu_spec dm f) (hsi_exits hse1) (hsi_exits hse2)
+ /\ hsilocal_simu_spec None (hsi_local hse1) (hsi_local hse2).
+
+Definition hsistate_simu dm f (hst1 hst2: hsistate) (ctx: simu_proof_context f): Prop := forall st1 st2,
+ hsistate_refines_stat hst1 st1 ->
+ hsistate_refines_stat hst2 st2 ->
+ hsistate_refines_dyn (the_ge1 ctx) (the_sp ctx) (the_rs0 ctx) (the_m0 ctx) hst1 st1 ->
+ hsistate_refines_dyn (the_ge2 ctx) (the_sp ctx) (the_rs0 ctx) (the_m0 ctx) hst2 st2 ->
+ sistate_simu dm f st1 st2 ctx.
+
+Lemma list_forall2_nth_error {A} (l1 l2: list A) P:
+ list_forall2 P l1 l2 ->
+ forall x1 x2 n,
+ nth_error l1 n = Some x1 ->
+ nth_error l2 n = Some x2 ->
+ P x1 x2.
+Proof.
+ induction 1.
+ - intros. rewrite nth_error_nil in H. discriminate.
+ - intros x1 x2 n. destruct n as [|n]; simpl.
+ + intros. inv H1. inv H2. assumption.
+ + apply IHlist_forall2.
+Qed.
+
+Lemma is_tail_length {A} (l1 l2: list A):
+ is_tail l1 l2 ->
+ (length l1 <= length l2)%nat.
+Proof.
+ induction l2.
+ - intro. destruct l1; auto. apply is_tail_false in H. contradiction.
+ - intros ITAIL. inv ITAIL; auto.
+ apply IHl2 in H1. clear IHl2. simpl. omega.
+Qed.
+
+Lemma is_tail_nth_error {A} (l1 l2: list A) x:
+ is_tail (x::l1) l2 ->
+ nth_error l2 ((length l2) - length l1 - 1) = Some x.
+Proof.
+ induction l2.
+ - intro ITAIL. apply is_tail_false in ITAIL. contradiction.
+ - intros ITAIL. assert (length (a::l2) = S (length l2)) by auto. rewrite H. clear H.
+ assert (forall n n', ((S n) - n' - 1)%nat = (n - n')%nat) by (intros; omega). rewrite H. clear H.
+ inv ITAIL.
+ + assert (forall n, (n - n)%nat = 0%nat) by (intro; omega). rewrite H.
+ simpl. reflexivity.
+ + exploit IHl2; eauto. intros. clear IHl2.
+ assert (forall n n', (n > n')%nat -> (n - n')%nat = S (n - n' - 1)%nat) by (intros; omega).
+ exploit (is_tail_length (x::l1)); eauto. intro. simpl in H2.
+ assert ((length l2 > length l1)%nat) by omega. clear H2.
+ rewrite H0; auto.
+Qed.
+
+Theorem hsistate_simu_spec_correct dm f hst1 hst2 ctx:
+ hsistate_simu_spec dm f hst1 hst2 ->
+ hsistate_simu dm f hst1 hst2 ctx.
+Proof.
+ intros (ESIMU & LSIMU) st1 st2 (PCREF1 & EREF1) (PCREF2 & EREF2) DREF1 DREF2 is1 SEMI.
+ destruct DREF1 as (DEREF1 & LREF1 & NESTED). destruct DREF2 as (DEREF2 & LREF2 & _).
+ exploit hsiexits_simu_spec_correct; eauto. intro HESIMU.
+ unfold ssem_internal in SEMI. destruct (icontinue _) eqn:ICONT.
+ - destruct SEMI as (SSEML & PCEQ & ALLFU).
+ exploit hsilocal_simu_spec_correct; eauto; [apply ctx|]. simpl. intro SSEML2.
+ exists (mk_istate (icontinue is1) (si_pc st2) (irs is1) (imem is1)). constructor.
+ + unfold ssem_internal. simpl. rewrite ICONT. constructor; [assumption | constructor; [reflexivity |]].
+ eapply siexits_simu_all_fallthrough; eauto.
+ * eapply hsiexits_simu_siexits; eauto.
+ * eapply nested_sok_prop; eauto.
+ eapply ssem_local_sok; eauto.
+ + unfold istate_simu. rewrite ICONT. constructor; [simpl; assumption | constructor; [| reflexivity]].
+ constructor.
+ - destruct SEMI as (ext & lx & SSEME & ALLFU).
+ assert (SESIMU: siexits_simu dm f (si_exits st1) (si_exits st2) ctx) by (eapply hsiexits_simu_siexits; eauto).
+ exploit siexits_simu_all_fallthrough_upto; eauto.
+ * destruct ALLFU as (ITAIL & ALLF).
+ exploit nested_sok_tail; eauto. intros NESTED2.
+ inv NESTED2. destruct SSEME as (_ & SSEML & _). eapply ssem_local_sok in SSEML.
+ eapply nested_sok_prop; eauto.
+ * intros (ext2 & lx2 & ALLFU2 & LENEQ).
+ assert (EXTSIMU: siexit_simu dm f ctx ext ext2). {
+ eapply list_forall2_nth_error; eauto.
+ - destruct ALLFU as (ITAIL & _). eapply is_tail_nth_error; eauto.
+ - destruct ALLFU2 as (ITAIL & _). eapply is_tail_nth_error in ITAIL.
+ assert (LENEQ': length (si_exits st1) = length (si_exits st2)) by (eapply list_forall2_length; eauto).
+ congruence. }
+ destruct EXTSIMU as (CONDEVAL & EXTSIMU).
+ apply EXTSIMU in SSEME; [|assumption]. clear EXTSIMU. destruct SSEME as (is2 & SSEME2 & ISIMU).
+ exists (mk_istate (icontinue is1) (ipc is2) (irs is2) (imem is2)). constructor.
+ + unfold ssem_internal. simpl. rewrite ICONT. exists ext2, lx2. constructor; assumption.
+ + unfold istate_simu in *. rewrite ICONT in *. destruct ISIMU as (path & PATHEQ & ISIMULIVE & DMEQ).
+ destruct ISIMULIVE as (CONTEQ & REGEQ & MEMEQ).
+ exists path. repeat (constructor; auto).
+Qed.
+
+
+(** ** Specification of the simulation test on [sfval].
+ It is motivated by [hfinal_simu_spec_correct theorem] below
+*)
+
+
+Definition final_simu_spec (dm: PTree.t node) (f: RTLpath.function) (pc1 pc2: node) (f1 f2: sfval): Prop :=
+ match f1 with
+ | Scall sig1 svos1 lsv1 res1 pc1 =>
+ match f2 with
+ | Scall sig2 svos2 lsv2 res2 pc2 =>
+ dm ! pc2 = Some pc1 /\ sig1 = sig2 /\ svos1 = svos2 /\ lsv1 = lsv2 /\ res1 = res2
+ | _ => False
+ end
+ | Sbuiltin ef1 lbs1 br1 pc1 =>
+ match f2 with
+ | Sbuiltin ef2 lbs2 br2 pc2 =>
+ dm ! pc2 = Some pc1 /\ ef1 = ef2 /\ lbs1 = lbs2 /\ br1 = br2
+ | _ => False
+ end
+ | Sjumptable sv1 lpc1 =>
+ match f2 with
+ | Sjumptable sv2 lpc2 =>
+ ptree_get_list dm lpc2 = Some lpc1 /\ sv1 = sv2
+ | _ => False
+ end
+ | Snone =>
+ match f2 with
+ | Snone => dm ! pc2 = Some pc1
+ | _ => False
+ end
+ (* Stailcall, Sreturn *)
+ | _ => f1 = f2
+ end.
+
+Definition hfinal_simu_spec (dm: PTree.t node) (f: RTLpath.function) (pc1 pc2: node) (hf1 hf2: hsfval): Prop :=
+ final_simu_spec dm f pc1 pc2 (hfinal_proj hf1) (hfinal_proj hf2).
+
+Lemma svident_simu_refl f ctx s:
+ svident_simu f ctx s s.
+Proof.
+ destruct s; constructor; [| reflexivity].
+ erewrite <- seval_preserved; [| eapply ctx]. constructor.
+Qed.
+
+Lemma list_proj_refines_eq ge ge' sp rs0 m0 lsv lhsv:
+ (forall s, Genv.find_symbol ge s = Genv.find_symbol ge' s) ->
+ list_sval_refines ge sp rs0 m0 lhsv lsv ->
+ forall lhsv' lsv',
+ list_sval_refines ge' sp rs0 m0 lhsv' lsv' ->
+ hsval_list_proj lhsv = hsval_list_proj lhsv' ->
+ seval_list_sval ge sp lsv rs0 m0 = seval_list_sval ge' sp lsv' rs0 m0.
+Proof.
+ intros GFS H lhsv' lsv' H' H0.
+ erewrite <- H, H0.
+ erewrite list_sval_eval_preserved; eauto.
+Qed.
+
+Lemma seval_builtin_sval_preserved ge ge' sp sv rs0 m0:
+ (forall s : ident, Genv.find_symbol ge' s = Genv.find_symbol ge s) ->
+ seval_builtin_sval ge sp sv rs0 m0 =
+ seval_builtin_sval ge' sp sv rs0 m0.
+Proof.
+ induction sv; intro FIND; cbn.
+ all: try (erewrite seval_preserved by eauto); trivial.
+ all: erewrite IHsv1 by eauto; erewrite IHsv2 by eauto; reflexivity.
+Qed.
+
+Lemma seval_list_builtin_sval_preserved ge ge' sp lsv rs0 m0:
+ (forall s : ident, Genv.find_symbol ge' s = Genv.find_symbol ge s) ->
+ seval_list_builtin_sval ge sp lsv rs0 m0 =
+ seval_list_builtin_sval ge' sp lsv rs0 m0.
+Proof.
+ induction lsv; intro FIND; cbn. { trivial. }
+ erewrite seval_builtin_sval_preserved by eauto.
+ erewrite IHlsv by eauto.
+ reflexivity.
+Qed.
+
+Lemma barg_proj_refines_eq ge ge' sp rs0 m0:
+ (forall s, Genv.find_symbol ge s = Genv.find_symbol ge' s) ->
+ forall lhsv lsv, bargs_refines ge sp rs0 m0 lhsv lsv ->
+ forall lhsv' lsv', bargs_refines ge' sp rs0 m0 lhsv' lsv' ->
+ List.map (builtin_arg_map hsval_proj) lhsv = List.map (builtin_arg_map hsval_proj) lhsv' ->
+ seval_list_builtin_sval ge sp lsv rs0 m0 = seval_list_builtin_sval ge' sp lsv' rs0 m0.
+Proof.
+ unfold bargs_refines; intros GFS lhsv lsv H lhsv' lsv' H' H0.
+ erewrite <- H, H0.
+ erewrite seval_list_builtin_sval_preserved; eauto.
+Qed.
+
+Lemma sval_refines_proj ge ge' sp rs m hsv sv hsv' sv':
+ (forall s, Genv.find_symbol ge s = Genv.find_symbol ge' s) ->
+ sval_refines ge sp rs m hsv sv ->
+ sval_refines ge' sp rs m hsv' sv' ->
+ hsval_proj hsv = hsval_proj hsv' ->
+ seval_sval ge sp sv rs m = seval_sval ge' sp sv' rs m.
+Proof.
+ intros GFS REF REF' PROJ.
+ rewrite <- REF, PROJ.
+ erewrite <- seval_preserved; eauto.
+Qed.
+
+Theorem hfinal_simu_spec_correct dm f ctx opc1 opc2 hf1 hf2 f1 f2:
+ hfinal_simu_spec dm f opc1 opc2 hf1 hf2 ->
+ hfinal_refines (the_ge1 ctx) (the_sp ctx) (the_rs0 ctx) (the_m0 ctx) hf1 f1 ->
+ hfinal_refines (the_ge2 ctx) (the_sp ctx) (the_rs0 ctx) (the_m0 ctx) hf2 f2 ->
+ sfval_simu dm f opc1 opc2 ctx f1 f2.
+Proof.
+ assert (GFS: forall s : ident, Genv.find_symbol (the_ge1 ctx) s = Genv.find_symbol (the_ge2 ctx) s) by apply ctx.
+ intros CORE FREF1 FREF2.
+ destruct hf1; inv FREF1.
+ (* Snone *)
+ - destruct hf2; try contradiction. inv FREF2.
+ inv CORE. constructor. assumption.
+ (* Scall *)
+ - rename H5 into SREF1. rename H6 into LREF1.
+ destruct hf2; try contradiction. inv FREF2.
+ rename H5 into SREF2. rename H6 into LREF2.
+ destruct CORE as (PCEQ & ? & ? & ? & ?). subst.
+ rename H0 into SVOSEQ. rename H1 into LSVEQ.
+ constructor; [assumption | |].
+ + destruct svos.
+ * destruct svos0; try discriminate. destruct ros; try contradiction.
+ destruct ros0; try contradiction. constructor.
+ simpl in SVOSEQ. inv SVOSEQ.
+ simpl in SREF1. simpl in SREF2.
+ rewrite <- SREF1. rewrite <- SREF2.
+ erewrite <- seval_preserved; [| eapply GFS]. congruence.
+ * destruct svos0; try discriminate. destruct ros; try contradiction.
+ destruct ros0; try contradiction. constructor.
+ simpl in SVOSEQ. inv SVOSEQ. congruence.
+ + erewrite list_proj_refines_eq; eauto.
+ (* Stailcall *)
+ - rename H3 into SREF1. rename H4 into LREF1.
+ destruct hf2; try (inv CORE; fail). inv FREF2.
+ rename H4 into LREF2. rename H3 into SREF2.
+ inv CORE. rename H1 into SVOSEQ. rename H2 into LSVEQ.
+ constructor.
+ + destruct svos. (** Copy-paste from Scall *)
+ * destruct svos0; try discriminate. destruct ros; try contradiction.
+ destruct ros0; try contradiction. constructor.
+ simpl in SVOSEQ. inv SVOSEQ.
+ simpl in SREF1. simpl in SREF2.
+ rewrite <- SREF1. rewrite <- SREF2.
+ erewrite <- seval_preserved; [| eapply GFS]. congruence.
+ * destruct svos0; try discriminate. destruct ros; try contradiction.
+ destruct ros0; try contradiction. constructor.
+ simpl in SVOSEQ. inv SVOSEQ. congruence.
+ + erewrite list_proj_refines_eq; eauto.
+ (* Sbuiltin *)
+ - rename H4 into BREF1. destruct hf2; try (inv CORE; fail). inv FREF2.
+ rename H4 into BREF2. inv CORE. destruct H0 as (? & ? & ?). subst.
+ rename H into PCEQ. rename H1 into ARGSEQ. constructor; [assumption|].
+ erewrite barg_proj_refines_eq; eauto. constructor.
+ (* Sjumptable *)
+ - rename H2 into SREF1. destruct hf2; try contradiction. inv FREF2.
+ rename H2 into SREF2. destruct CORE as (A & B). constructor; [assumption|].
+ erewrite sval_refines_proj; eauto.
+ (* Sreturn *)
+ - rename H0 into SREF1.
+ destruct hf2; try discriminate. inv CORE.
+ inv FREF2. destruct osv; destruct res; inv SREF1.
+ + destruct res0; try discriminate. destruct osv0; inv H1.
+ constructor. simpl in H0. inv H0. erewrite sval_refines_proj; eauto.
+ + destruct res0; try discriminate. destruct osv0; inv H1. constructor.
+Qed.
+
+
+(** ** Specification of the simulation test on [hsstate].
+ It is motivated by [hsstate_simu_spec_correct theorem] below
+*)
+
+Definition hsstate_simu_spec (dm: PTree.t node) (f: RTLpath.function) (hst1 hst2: hsstate) :=
+ hsistate_simu_spec dm f (hinternal hst1) (hinternal hst2)
+ /\ hfinal_simu_spec dm f (hsi_pc (hinternal hst1)) (hsi_pc (hinternal hst2)) (hfinal hst1) (hfinal hst2).
+
+Definition hsstate_simu dm f (hst1 hst2: hsstate) ctx: Prop :=
+ forall st1 st2,
+ hsstate_refines hst1 st1 ->
+ hsstate_refines hst2 st2 -> sstate_simu dm f st1 st2 ctx.
+
+Theorem hsstate_simu_spec_correct dm f ctx hst1 hst2:
+ hsstate_simu_spec dm f hst1 hst2 ->
+ hsstate_simu dm f hst1 hst2 ctx.
+Proof.
+ intros (SCORE & FSIMU) st1 st2 (SREF1 & DREF1 & FREF1) (SREF2 & DREF2 & FREF2).
+ generalize SCORE. intro SIMU; eapply hsistate_simu_spec_correct in SIMU; eauto.
+ constructor; auto.
+ intros is1 SEM1 CONT1.
+ unfold hsistate_simu in SIMU. exploit SIMU; clear SIMU; eauto.
+ unfold istate_simu, ssem_internal in *; intros (is2 & SEM2 & SIMU).
+ rewrite! CONT1 in *. destruct SIMU as (CONT2 & _).
+ rewrite! CONT1, <- CONT2 in *.
+ destruct SEM1 as (SEM1 & _ & _).
+ destruct SEM2 as (SEM2 & _ & _).
+ eapply hfinal_simu_spec_correct in FSIMU; eauto.
+ - destruct SREF1 as (PC1 & _). destruct SREF2 as (PC2 & _). rewrite <- PC1. rewrite <- PC2.
+ eapply FSIMU.
+ - eapply FREF1. exploit DREF1. intros (_ & (OK & _) & _). rewrite <- OK. eapply ssem_local_sok; eauto.
+ - eapply FREF2. exploit DREF2. intros (_ & (OK & _) & _). rewrite <- OK. eapply ssem_local_sok; eauto.
+Qed.