(** * Semantic invariant *)
Inductive match_stackframes: stackframe -> stackframe -> Prop :=
| match_stackframes_intro:
forall res f sp pc e tf te cu an
(LINK: linkorder cu prog)
(FUN: transf_function (romem_for cu) f = OK tf)
(ANL: analyze (vanalyze cu f) f = Some an)
(RES: forall v tv,
Val.lessdef v tv ->
eagree (e#res <- v) (te#res<- tv)
(fst (transfer f (vanalyze cu f) pc an!!pc))),
match_stackframes (Stackframe res f (Vptr sp Ptrofs.zero) pc e)
(Stackframe res tf (Vptr sp Ptrofs.zero) pc te).
Inductive match_states: state -> state -> Prop :=
| match_regular_states:
forall s f sp pc e m ts tf te tm cu an
(STACKS: list_forall2 match_stackframes s ts)
(LINK: linkorder cu prog)
(FUN: transf_function (romem_for cu) f = OK tf)
(ANL: analyze (vanalyze cu f) f = Some an)
(ENV: eagree e te (fst (transfer f (vanalyze cu f) pc an!!pc)))
(MEM: magree m tm (nlive ge sp (snd (transfer f (vanalyze cu f) pc an!!pc)))),
match_states (State s f (Vptr sp Ptrofs.zero) pc e m)
(State ts tf (Vptr sp Ptrofs.zero) pc te tm)
| match_call_states:
forall s f args m ts tf targs tm cu
(STACKS: list_forall2 match_stackframes s ts)
(LINK: linkorder cu prog)
(FUN: transf_fundef (romem_for cu) f = OK tf)
(ARGS: Val.lessdef_list args targs)
(MEM: Mem.extends m tm),
match_states (Callstate s f args m)
(Callstate ts tf targs tm)
| match_return_states:
forall s v m ts tv tm
(STACKS: list_forall2 match_stackframes s ts)
(RES: Val.lessdef v tv)
(MEM: Mem.extends m tm),
match_states (Returnstate s v m)
(Returnstate ts tv tm).
(** [match_states] and CFG successors *)

Lemma analyze_successors:
forall cu f an pc instr pc',
analyze (vanalyze cu f) f = Some an ->
f.(fn_code)!pc = Some instr ->
In pc' (successors_instr instr) ->
NA.ge an!!pc (transfer f (vanalyze cu f) pc' an!!pc').