mirror of
https://github.com/achlipala/frap.git
synced 2024-11-10 00:07:51 +00:00
CompilerCorrectness: a new simulation condition to get trace equivalence for free
This commit is contained in:
Adam Chlipala
parent
2832696faa
commit
7c705bb2fb
1 changed files with 124 additions and 75 deletions
|
|
@ -174,6 +174,74 @@ Fixpoint cfoldExprs (c : cmd) : cmd :=
|
|||
| Output e => Output (cfoldArith e)
|
||||
end.
|
||||
|
||||
Theorem skip_or_step : forall v c,
|
||||
c = Skip
|
||||
\/ exists v' l c', cstep (v, c) l (v', c').
|
||||
Proof.
|
||||
induct c; simplify; first_order; subst;
|
||||
try match goal with
|
||||
| [ H : cstep _ _ _ |- _ ] => invert H
|
||||
end;
|
||||
try match goal with
|
||||
| [ |- context[cstep (?v, If ?e _ _)] ] => cases (interp e v ==n 0)
|
||||
| [ |- context[cstep (?v, While ?e _)] ] => cases (interp e v ==n 0)
|
||||
end; eauto 10.
|
||||
Qed.
|
||||
|
||||
Lemma deterministic0 : forall vc l vc',
|
||||
step0 vc l vc'
|
||||
-> forall l' vc'', step0 vc l' vc''
|
||||
-> l = l' /\ vc'' = vc'.
|
||||
Proof.
|
||||
invert 1; invert 1; simplify; propositional.
|
||||
Qed.
|
||||
|
||||
Theorem plug_function : forall C c1 c2, plug C c1 c2
|
||||
-> forall c2', plug C c1 c2'
|
||||
-> c2 = c2'.
|
||||
Proof.
|
||||
induct 1; invert 1; eauto.
|
||||
apply IHplug in H5.
|
||||
equality.
|
||||
Qed.
|
||||
|
||||
Lemma peel_cseq : forall C1 C2 c (c1 c2 : cmd),
|
||||
C1 = C2 /\ c1 = c2
|
||||
-> CSeq C1 c = CSeq C2 c /\ c1 = c2.
|
||||
Proof.
|
||||
equality.
|
||||
Qed.
|
||||
|
||||
Hint Resolve peel_cseq.
|
||||
|
||||
Lemma plug_deterministic : forall v C c1 c2, plug C c1 c2
|
||||
-> forall l vc1, step0 (v, c1) l vc1
|
||||
-> forall C' c1', plug C' c1' c2
|
||||
-> forall l' vc1', step0 (v, c1') l' vc1'
|
||||
-> C' = C /\ c1' = c1.
|
||||
Proof.
|
||||
induct 1; invert 1; invert 1; invert 1; auto;
|
||||
try match goal with
|
||||
| [ H : plug _ _ _ |- _ ] => invert1 H
|
||||
end; eauto.
|
||||
Qed.
|
||||
|
||||
Theorem deterministic : forall vc l vc',
|
||||
cstep vc l vc'
|
||||
-> forall l' vc'', cstep vc l' vc''
|
||||
-> l = l' /\ vc' = vc''.
|
||||
Proof.
|
||||
invert 1; invert 1; simplify.
|
||||
eapply plug_deterministic in H0; eauto.
|
||||
invert H0.
|
||||
eapply deterministic0 in H1; eauto.
|
||||
propositional; subst; auto.
|
||||
invert H0.
|
||||
auto.
|
||||
eapply plug_function in H2; eauto.
|
||||
equality.
|
||||
Qed.
|
||||
|
||||
Section simulation.
|
||||
Variable R : valuation * cmd -> valuation * cmd -> Prop.
|
||||
|
||||
|
|
@ -181,7 +249,10 @@ Section simulation.
|
|||
-> forall vc1' l, cstep vc1 l vc1'
|
||||
-> exists vc2', cstep vc2 l vc2' /\ R vc1' vc2'.
|
||||
|
||||
Lemma simulation' : forall vc1 ns, generate vc1 ns
|
||||
Hypothesis agree_on_termination : forall v1 v2 c2, R (v1, Skip) (v2, c2)
|
||||
-> c2 = Skip.
|
||||
|
||||
Lemma simulation_fwd' : forall vc1 ns, generate vc1 ns
|
||||
-> forall vc2, R vc1 vc2
|
||||
-> generate vc2 ns.
|
||||
Proof.
|
||||
|
|
@ -196,14 +267,59 @@ Section simulation.
|
|||
eauto.
|
||||
Qed.
|
||||
|
||||
Theorem simulation : forall vc1 vc2, R vc1 vc2
|
||||
Theorem simulation_fwd : forall vc1 vc2, R vc1 vc2
|
||||
-> vc1 <| vc2.
|
||||
Proof.
|
||||
unfold traceInclusion; eauto using simulation'.
|
||||
unfold traceInclusion; eauto using simulation_fwd'.
|
||||
Qed.
|
||||
|
||||
Lemma simulation_bwd' : forall vc2 ns, generate vc2 ns
|
||||
-> forall vc1, R vc1 vc2
|
||||
-> generate vc1 ns.
|
||||
Proof.
|
||||
induct 1; simplify; eauto.
|
||||
|
||||
cases vc1; cases vc.
|
||||
assert (c = Skip \/ exists v' l c', cstep (v, c) l (v', c')) by apply skip_or_step.
|
||||
first_order; subst.
|
||||
apply agree_on_termination in H1; subst.
|
||||
invert H.
|
||||
invert H3.
|
||||
invert H4.
|
||||
specialize (one_step H1 H2).
|
||||
first_order.
|
||||
eapply deterministic in H; eauto.
|
||||
propositional; subst.
|
||||
eauto.
|
||||
|
||||
cases vc1; cases vc.
|
||||
assert (c = Skip \/ exists v' l c', cstep (v, c) l (v', c')) by apply skip_or_step.
|
||||
first_order; subst.
|
||||
apply agree_on_termination in H1; subst.
|
||||
invert H.
|
||||
invert H3.
|
||||
invert H4.
|
||||
specialize (one_step H1 H2).
|
||||
first_order.
|
||||
eapply deterministic in H; eauto.
|
||||
propositional; subst.
|
||||
eauto.
|
||||
Qed.
|
||||
|
||||
Theorem simulation_bwd : forall vc1 vc2, R vc1 vc2
|
||||
-> vc2 <| vc1.
|
||||
Proof.
|
||||
unfold traceInclusion; eauto using simulation_bwd'.
|
||||
Qed.
|
||||
|
||||
Theorem simulation : forall vc1 vc2, R vc1 vc2
|
||||
-> vc1 =| vc2.
|
||||
Proof.
|
||||
simplify; split; auto using simulation_fwd, simulation_bwd.
|
||||
Qed.
|
||||
End simulation.
|
||||
|
||||
Lemma cfoldExprs_ok1' : forall v1 c1 l v2 c2,
|
||||
Lemma cfoldExprs_ok' : forall v1 c1 l v2 c2,
|
||||
step0 (v1, c1) l (v2, c2)
|
||||
-> step0 (v1, cfoldExprs c1) l (v2, cfoldExprs c2).
|
||||
Proof.
|
||||
|
|
@ -214,7 +330,7 @@ Proof.
|
|||
end; eauto.
|
||||
Qed.
|
||||
|
||||
Hint Resolve cfoldExprs_ok1'.
|
||||
Hint Resolve cfoldExprs_ok'.
|
||||
|
||||
Fixpoint cfoldExprsContext (C : context) : context :=
|
||||
match C with
|
||||
|
|
@ -230,8 +346,8 @@ Qed.
|
|||
|
||||
Hint Resolve plug_cfoldExprs1.
|
||||
|
||||
Lemma cfoldExprs_ok1 : forall v c,
|
||||
(v, c) <| (v, cfoldExprs c).
|
||||
Lemma cfoldExprs_ok : forall v c,
|
||||
(v, c) =| (v, cfoldExprs c).
|
||||
Proof.
|
||||
simplify.
|
||||
apply simulation with (R := fun vc1 vc2 => fst vc1 = fst vc2
|
||||
|
|
@ -239,74 +355,7 @@ Proof.
|
|||
simplify; propositional.
|
||||
|
||||
invert H0; simplify; subst.
|
||||
apply cfoldExprs_ok1' in H3.
|
||||
apply cfoldExprs_ok' in H3.
|
||||
cases vc2; simplify; subst.
|
||||
eauto 7.
|
||||
Qed.
|
||||
|
||||
Lemma cfoldExprs_ok2' : forall v1 c1 l v2 c2,
|
||||
step0 (v1, cfoldExprs c1) l (v2, c2)
|
||||
-> exists c2', step0 (v1, c1) l (v2, c2') /\ c2 = cfoldExprs c2'.
|
||||
Proof.
|
||||
invert 1;
|
||||
repeat match goal with
|
||||
| [ H : _ = cfoldExprs ?c |- _ ] => cases c; invert H
|
||||
end; repeat rewrite cfoldArith_ok in *; eauto.
|
||||
Qed.
|
||||
|
||||
Hint Resolve cfoldExprs_ok2'.
|
||||
|
||||
Lemma plug_cfoldExprs2 : forall C c1 c2, plug C c1 (cfoldExprs c2)
|
||||
-> exists C' c1', plug C' c1' c2
|
||||
/\ C = cfoldExprsContext C'
|
||||
/\ c1 = cfoldExprs c1'.
|
||||
Proof.
|
||||
induct 1; simplify; eauto.
|
||||
cases c2; simplify; invert x.
|
||||
specialize (IHplug _ eq_refl).
|
||||
first_order; subst.
|
||||
eauto 7.
|
||||
Qed.
|
||||
|
||||
Lemma plug_cfoldExprs2' : forall C c1 c2, plug (cfoldExprsContext C) (cfoldExprs c1) c2
|
||||
-> exists c2', plug C c1 c2'
|
||||
/\ c2 = cfoldExprs c2'.
|
||||
Proof.
|
||||
induct 1; simplify; eauto.
|
||||
|
||||
cases C; invert x.
|
||||
eauto.
|
||||
|
||||
cases C; invert x.
|
||||
specialize (IHplug _ _ eq_refl eq_refl).
|
||||
first_order; subst.
|
||||
eauto.
|
||||
Qed.
|
||||
|
||||
Lemma cfoldExprs_ok2 : forall v c,
|
||||
(v, cfoldExprs c) <| (v, c).
|
||||
Proof.
|
||||
simplify.
|
||||
apply simulation with (R := fun vc1 vc2 => fst vc1 = fst vc2
|
||||
/\ snd vc1 = cfoldExprs (snd vc2));
|
||||
simplify; propositional.
|
||||
|
||||
invert H0; simplify; subst.
|
||||
eapply plug_cfoldExprs2 in H.
|
||||
first_order; subst.
|
||||
apply cfoldExprs_ok2' in H3.
|
||||
first_order; subst.
|
||||
cases vc2; simplify; subst.
|
||||
apply plug_cfoldExprs2' in H4.
|
||||
first_order; subst.
|
||||
eauto.
|
||||
Qed.
|
||||
|
||||
Theorem cfoldExprs_ok : forall v c,
|
||||
(v, cfoldExprs c) =| (v, c).
|
||||
Proof.
|
||||
simplify.
|
||||
split.
|
||||
apply cfoldExprs_ok2.
|
||||
apply cfoldExprs_ok1.
|
||||
Qed.
|
||||
|
|
|
|||
Loading…
Reference in a new issue