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Commit df4574f2 authored by Robbert Krebbers's avatar Robbert Krebbers
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Iris Proofmode.

parent 631c8260
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_CoqProject
View file @ df4574f2
......@@ -79,7 +79,6 @@ program_logic/saved_one_shot.v
program_logic/auth.v
program_logic/sts.v
program_logic/namespaces.v
program_logic/tactics.v
heap_lang/lang.v
heap_lang/tactics.v
heap_lang/wp_tactics.v
......@@ -96,7 +95,20 @@ heap_lang/lib/barrier/specification.v
heap_lang/lib/barrier/protocol.v
heap_lang/lib/barrier/proof.v
heap_lang/lib/barrier/client.v
heap_lang/proofmode.v
tests/heap_lang.v
tests/program_logic.v
tests/one_shot.v
tests/joining_existentials.v
tests/proofmode.v
proofmode/coq_tactics.v
proofmode/pviewshifts.v
proofmode/environments.v
proofmode/intro_patterns.v
proofmode/spec_patterns.v
proofmode/tactics.v
proofmode/notation.v
proofmode/invariants.v
proofmode/weakestpre.v
proofmode/ghost_ownership.v
proofmode/sts.v
algebra/upred.v
View file @ df4574f2
......@@ -974,19 +974,6 @@ Lemma later_wand P Q : ▷ (P -★ Q) ⊢ (▷ P -★ ▷ Q).
Proof. apply wand_intro_r;rewrite -later_sep; apply later_mono,wand_elim_l. Qed.
Lemma later_iff P Q : ▷ (P ↔ Q) ⊢ (▷ P ↔ ▷ Q).
Proof. by rewrite /uPred_iff later_and !later_impl. Qed.
Lemma löb_strong P Q : (P ∧ ▷ Q) ⊢ Q → P ⊢ Q.
Proof.
intros Hlöb. apply impl_entails. rewrite -(löb (P → Q)).
apply entails_impl, impl_intro_l. rewrite -{2}Hlöb.
apply and_intro; first by eauto.
by rewrite {1}(later_intro P) later_impl impl_elim_r.
Qed.
Lemma löb_strong_sep P Q : (P ★ ▷ (P -★ Q)) ⊢ Q → P ⊢ Q.
Proof.
move/wand_intro_l=>Hlöb. apply impl_entails.
rewrite -[(_ → _)%I]always_elim. apply löb_strong.
by rewrite left_id -always_wand_impl -always_later Hlöb.
Qed.
(* Own *)
Lemma ownM_op (a1 a2 : M) :
......
algebra/upred_tactics.v
View file @ df4574f2
......@@ -248,50 +248,3 @@ Ltac strip_later :=
intros_revert ltac:(
etrans; [apply: strip_later_r|];
etrans; [|apply: strip_later_l]; apply later_mono).
(** Transforms a goal of the form ∀ ..., ?0... → ?1 ⊢ ?2
into True ⊢ ∀..., ■?0... → ?1 → ?2, applies tac, and
the moves all the assumptions back. *)
(* TODO: this name may be a big too general *)
Ltac revert_all :=
lazymatch goal with
| |- ∀ _, _ =>
let H := fresh in intro H; revert_all;
(* TODO: Really, we should distinguish based on whether this is a
dependent function type or not. Right now, we distinguish based
on the sort of the argument, which is suboptimal. *)
first [ apply (const_intro_impl _ _ _ H); clear H
| revert H; apply forall_elim']
| |- _ ⊢ _ => apply impl_entails
end.
(** This starts on a goal of the form ∀ ..., ?0... → ?1 ⊢ ?2.
It applies löb where all the Coq assumptions have been turned into logical
assumptions, then moves all the Coq assumptions back out to the context,
applies [tac] on the goal (now of the form _ ⊢ _), and then reverts the
Coq assumption so that we end up with the same shape as where we started,
but with an additional assumption ★-ed to the context *)
Ltac löb tac :=
revert_all;
(* Add a box *)
etrans; last (eapply always_elim; reflexivity);
(* We now have a goal for the form True ⊢ P, with the "original" conclusion
being locked. *)
apply löb_strong; etransitivity;
first (apply equiv_entails, left_id, _; reflexivity);
apply: always_intro;
(* Now introduce again all the things that we reverted, and at the bottom,
do the work *)
let rec go :=
lazymatch goal with
| |- _ ⊢ (∀ _, _) =>
apply forall_intro; let H := fresh in intro H; go; revert H
| |- _ ⊢ (■ _ → _) =>
apply impl_intro_l, const_elim_l; let H := fresh in intro H; go; revert H
(* This is the "bottom" of the goal, where we see the impl introduced
by uPred_revert_all as well as the ▷ from löb_strong and the □ we added. *)
| |- ▷ □ ?R ⊢ (?L → _) => apply impl_intro_l;
trans (L ★ ▷ □ R)%I;
[eapply equiv_entails, always_and_sep_r, _; reflexivity | tac]
end
in go.
heap_lang/lib/barrier/client.v
View file @ df4574f2
From iris.heap_lang.lib.barrier Require Import proof.
From iris.heap_lang Require Import par.
From iris.program_logic Require Import auth sts saved_prop hoare ownership.
From iris.heap_lang Require Import proofmode.
Import uPred.
Definition worker (n : Z) : val :=
......@@ -15,63 +16,44 @@ Section client.
Context {Σ : gFunctors} `{!heapG Σ, !barrierG Σ, !spawnG Σ} (heapN N : namespace).
Local Notation iProp := (iPropG heap_lang Σ).
Definition y_inv q y : iProp :=
(∃ f : val, y ↦{q} f ★ □ ∀ n : Z, WP f #n {{ λ v, v = #(n + 42) }})%I.
Definition y_inv (q : Qp) (l : loc) : iProp :=
(∃ f : val, l ↦{q} f ★ □ ∀ n : Z, WP f #n {{ λ v, v = #(n + 42) }})%I.
Lemma y_inv_split q y :
y_inv q y ⊢ (y_inv (q/2) y ★ y_inv (q/2) y).
Lemma y_inv_split q l : y_inv q l ⊢ (y_inv (q/2) l ★ y_inv (q/2) l).
Proof.
rewrite /y_inv. apply exist_elim=>f.
rewrite -!(exist_intro f). rewrite heap_mapsto_op_split.
ecancel [y ↦{_} _; y ↦{_} _]%I. by rewrite [X in X ⊢ _]always_sep_dup.
iIntros "Hl"; iDestruct "Hl" as {f} "[[Hl1 Hl2] #Hf]".
iSplitL "Hl1"; iExists f; by iSplitL; try iAlways.
Qed.
Lemma worker_safe q (n : Z) (b y : loc) :
(heap_ctx heapN ★ recv heapN N b (y_inv q y))
⊢ WP worker n (%b) (%y) {{ λ _, True }}.
⊢ WP worker n (%b) (%y) {{ λ _, True }}.
Proof.
rewrite /worker. wp_lam. wp_let. ewp apply wait_spec.
rewrite comm. apply sep_mono_r. apply wand_intro_l.
rewrite sep_exist_r. apply exist_elim=>f. wp_seq.
(* TODO these parenthesis are rather surprising. *)
(ewp apply: (wp_load heapN _ _ q f)); eauto with I.
strip_later. (* hu, shouldn't it do that? *)
rewrite -assoc. apply sep_mono_r. apply wand_intro_l.
rewrite always_elim (forall_elim n) sep_elim_r sep_elim_l.
apply wp_mono=>?. eauto with I.
iIntros "[#Hh Hrecv]". wp_lam. wp_let.
wp_apply wait_spec; iFrame "Hrecv".
iIntros "Hy"; iDestruct "Hy" as {f} "[Hy #Hf]".
wp_seq. wp_load.
iApply wp_wand_r; iSplitR; [iApply "Hf"|by iIntros {v} "_"].
Qed.
Lemma client_safe :
heapN ⊥ N → heap_ctx heapN ⊢ WP client {{ λ _, True }}.
Lemma client_safe : heapN ⊥ N → heap_ctx heapN ⊢ WP client {{ λ _, True }}.
Proof.
intros ?. rewrite /client.
(ewp eapply wp_alloc); eauto with I. strip_later. apply forall_intro=>y.
apply wand_intro_l. wp_let.
ewp eapply (newbarrier_spec heapN N (y_inv 1 y)); last done.
rewrite comm. rewrite {1}[heap_ctx _]always_sep_dup -!assoc.
apply sep_mono_r. apply forall_intro=>b. apply wand_intro_l.
wp_let. (ewp eapply (wp_par heapN N (λ _, True%I) (λ _, True%I))); eauto.
rewrite 2!{1}[heap_ctx _]always_sep_dup !assoc [(_ ★ heap_ctx _)%I]comm.
ecancel [heap_ctx _]. sep_split right: []; last first.
{ do 2 apply forall_intro=>_. apply wand_intro_l.
eauto using later_intro with I. }
sep_split left: [send heapN _ _ _; heap_ctx _; y ↦ _]%I.
iIntros {?} "#Hh"; rewrite /client. wp_alloc y as "Hy". wp_let.
wp_apply (newbarrier_spec heapN N (y_inv 1 y)); first done.
iFrame "Hh". iIntros {l} "[Hr Hs]". wp_let.
iApply (wp_par heapN N (λ _, True%I) (λ _, True%I)); first done.
iFrame "Hh". iSplitL "Hy Hs".
- (* The original thread, the sender. *)
(ewp eapply wp_store); eauto with I. strip_later.
ecancel [y ↦ _]%I. apply wand_intro_l.
wp_seq. rewrite -signal_spec right_id assoc sep_elim_l comm.
apply sep_mono_r. rewrite /y_inv -(exist_intro (λ: "z", '"z" + #42)%V).
apply sep_intro_True_r; first done. apply: always_intro.
apply forall_intro=>n. wp_let. wp_op. by apply const_intro.
wp_store. wp_seq. iApply signal_spec; iFrame "Hs"; iSplit; [|done].
iExists _; iSplitL; [done|]. iAlways; iIntros {n}. wp_let. by wp_op.
- (* The two spawned threads, the waiters. *)
rewrite recv_mono; last exact: y_inv_split.
rewrite (recv_split _ _ ⊤) // pvs_frame_r. apply wp_strip_pvs.
(ewp eapply (wp_par heapN N (λ _, True%I) (λ _, True%I))); eauto.
do 2 rewrite {1}[heap_ctx _]always_sep_dup.
ecancel [heap_ctx _]. rewrite !assoc. sep_split right: []; last first.
{ do 2 apply forall_intro=>_. apply wand_intro_l.
eauto using later_intro with I. }
sep_split left: [recv heapN _ _ _; heap_ctx _]%I; by rewrite -worker_safe comm.
iSplitL; [|iIntros {_ _} "_"; by iNext].
iDestruct recv_weaken "[] Hr" as "Hr".
{ iIntros "?". by iApply y_inv_split "-". }
iPvs recv_split "Hr" as "[H1 H2]"; first done.
iApply (wp_par heapN N (λ _, True%I) (λ _, True%I)); eauto.
iFrame "Hh"; iSplitL "H1"; [|iSplitL "H2"; [|iIntros {_ _} "_"; by iNext]];
iApply worker_safe; by iSplit.
Qed.
End client.
......@@ -81,11 +63,9 @@ Section ClosedProofs.
Lemma client_safe_closed σ : {{ ownP σ : iProp }} client {{ λ v, True }}.
Proof.
apply ht_alt. rewrite (heap_alloc (nroot .@ "Barrier")); last done.
apply wp_strip_pvs, exist_elim=> ?. rewrite and_elim_l.
rewrite -(client_safe (nroot .@ "Barrier") (nroot .@ "Heap")) //.
(* This, too, should be automated. *)
by apply ndot_ne_disjoint.
iIntros "! Hσ".
iPvs (heap_alloc (nroot .@ "Barrier")) "Hσ" as {h} "[#Hh _]"; first done.
iApply (client_safe (nroot .@ "Barrier") (nroot .@ "Heap")); auto with ndisj.
Qed.
Print Assumptions client_safe_closed.
......
heap_lang/lib/barrier/proof.v
View file @ df4574f2
From iris.prelude Require Import functions.
From iris.algebra Require Import upred_big_op.
From iris.program_logic Require Import sts saved_prop tactics.
From iris.heap_lang Require Export heap wp_tactics.
From iris.program_logic Require Import saved_prop.
From iris.heap_lang Require Import proofmode.
From iris.proofmode Require Import sts.
From iris.heap_lang.lib.barrier Require Export barrier.
From iris.heap_lang.lib.barrier Require Import protocol.
Import uPred.
......@@ -22,6 +23,7 @@ Proof. destruct H as (?&?&?). split; apply _. Qed.
Section proof.
Context {Σ : gFunctors} `{!heapG Σ, !barrierG Σ}.
Context (heapN N : namespace).
Implicit Types I : gset gname.
Local Notation iProp := (iPropG heap_lang Σ).
Definition ress (P : iProp) (I : gset gname) : iProp :=
......@@ -30,11 +32,11 @@ Definition ress (P : iProp) (I : gset gname) : iProp :=
Coercion state_to_val (s : state) : val :=
match s with State Low _ => #0 | State High _ => #1 end.
Arguments state_to_val !_ /.
Arguments state_to_val !_ / : simpl nomatch.
Definition state_to_prop (s : state) (P : iProp) : iProp :=
match s with State Low _ => P | State High _ => True%I end.
Arguments state_to_val !_ /.
Arguments state_to_prop !_ _ / : simpl nomatch.
Definition barrier_inv (l : loc) (P : iProp) (s : state) : iProp :=
(l ↦ s ★ ress (state_to_prop s P) (state_I s))%I.
......@@ -54,12 +56,8 @@ Global Instance barrier_ctx_persistent (γ : gname) (l : loc) (P : iProp) :
PersistentP (barrier_ctx γ l P).
Proof. apply _. Qed.
(* TODO: Figure out if this has a "Global" or "Local" effect.
We want it to be Global. *)
Typeclasses Opaque barrier_ctx send recv.
Implicit Types I : gset gname.
(** Setoids *)
Global Instance ress_ne n : Proper (dist n ==> (=) ==> dist n) ress.
Proof. solve_proper. Qed.
......@@ -79,33 +77,19 @@ Proof. solve_proper. Qed.
(** Helper lemmas *)
Lemma ress_split i i1 i2 Q R1 R2 P I :
i ∈ I → i1 ∉ I → i2 ∉ I → i1 ≠ i2 →
(saved_prop_own i2 R2 ★
saved_prop_own i1 R1 ★ saved_prop_own i Q ★
(saved_prop_own i Q ★ saved_prop_own i1 R1 ★ saved_prop_own i2 R2 ★
(Q -★ R1 ★ R2) ★ ress P I)
⊢ ress P ({[i1]} ∪ ({[i2]} ∪ (I ∖ {[i]}))).
Proof.
intros. rewrite /ress !sep_exist_l. apply exist_elim=>Ψ.
rewrite -(exist_intro (<[i1:=R1]> (<[i2:=R2]> Ψ))).
rewrite [(Π★{set _} (λ _, saved_prop_own _ _))%I](big_sepS_delete _ I i) //.
do 4 (rewrite big_sepS_insert; last set_solver).
rewrite !fn_lookup_insert fn_lookup_insert_ne // !fn_lookup_insert.
set savedQ := _ i Q. set savedΨ := _ i (Ψ _).
sep_split left: [savedQ; savedΨ; Q -★ _; ▷ (_ -★ Π★{set I} _)]%I.
- rewrite !assoc saved_prop_agree /=. strip_later.
apply wand_intro_l. to_front [P; P -★ _]%I. rewrite wand_elim_r.
rewrite (big_sepS_delete _ I i) //.
sep_split right: [Π★{set _} _]%I.
+ rewrite !assoc.
eapply wand_apply_r'; first done.
apply: (eq_rewrite (Ψ i) Q (λ x, x)%I); last by eauto with I.
rewrite eq_sym. eauto with I.
+ apply big_sepS_mono; [done|] => j.
rewrite elem_of_difference not_elem_of_singleton=> -[??].
by do 2 (rewrite fn_lookup_insert_ne; last naive_solver).
- rewrite !assoc [(saved_prop_own i2 _ ★ _)%I]comm; apply sep_mono_r.
apply big_sepS_mono; [done|]=> j.
rewrite elem_of_difference not_elem_of_singleton=> -[??].
by do 2 (rewrite fn_lookup_insert_ne; last naive_solver).
iIntros {????} "(#HQ&#H1&#H2&HQR&H)"; iDestruct "H" as {Ψ} "[HPΨ HΨ]".
iDestruct (big_sepS_delete _ _ i) "HΨ" as "[#HΨi HΨ]"; first done.
iExists (<[i1:=R1]> (<[i2:=R2]> Ψ)). iSplitL "HQR HPΨ".
- iPoseProof (saved_prop_agree i Q (Ψ i)) "#" as "Heq"; first by iSplit.
iNext. iRewrite "Heq" in "HQR". iIntros "HP". iSpecialize "HPΨ" "HP".
iDestruct (big_sepS_delete _ _ i) "HPΨ" as "[HΨ HPΨ]"; first done.
iDestruct "HQR" "HΨ" as "[HR1 HR2]".
rewrite !big_sepS_insert''; [|set_solver ..]. by iFrame "HR1 HR2".
- rewrite !big_sepS_insert'; [|set_solver ..]. by repeat iSplit.
Qed.
(** Actual proofs *)
......@@ -114,176 +98,110 @@ Lemma newbarrier_spec (P : iProp) (Φ : val → iProp) :
(heap_ctx heapN ★ ∀ l, recv l P ★ send l P -★ Φ (%l))
⊢ WP newbarrier #() {{ Φ }}.
Proof.
intros HN. rewrite /newbarrier. wp_seq.
rewrite -wp_pvs. wp eapply wp_alloc; eauto with I ndisj.
apply forall_intro=>l. rewrite (forall_elim l). apply wand_intro_l.
rewrite !assoc. rewrite- pvs_wand_r; apply sep_mono_l.
(* The core of this proof: Allocating the STS and the saved prop. *)
eapply sep_elim_True_r; first by eapply (saved_prop_alloc (F:=idCF) _ P).
rewrite pvs_frame_l. apply pvs_strip_pvs. rewrite sep_exist_l.
apply exist_elim=>i.
trans (pvs ⊤ ⊤ (heap_ctx heapN ★
▷ (barrier_inv l P (State Low {[ i ]})) ★ saved_prop_own i P)).
- rewrite -pvs_intro. cancel [heap_ctx heapN].
rewrite {1}[saved_prop_own _ _]always_sep_dup. cancel [saved_prop_own i P].
rewrite /barrier_inv /ress -later_intro. cancel [l ↦ #0]%I.
rewrite -(exist_intro (const P)) /=. rewrite -[saved_prop_own _ _](left_id True%I (★)%I).
by rewrite !big_sepS_singleton /= wand_diag -later_intro.
- rewrite (sts_alloc (barrier_inv l P) ⊤ N); last by eauto.
rewrite !pvs_frame_r !pvs_frame_l.
rewrite pvs_trans'. apply pvs_strip_pvs. rewrite sep_exist_r sep_exist_l.
apply exist_elim=>γ.
rewrite /recv /send. rewrite -(exist_intro γ) -(exist_intro P).
rewrite -(exist_intro P) -(exist_intro i) -(exist_intro γ).
rewrite always_and_sep_l wand_diag later_True right_id.
rewrite [heap_ctx _]always_sep_dup [sts_ctx _ _ _]always_sep_dup.
rewrite /barrier_ctx const_equiv // left_id.
ecancel_pvs [saved_prop_own i _; heap_ctx _; heap_ctx _;
sts_ctx _ _ _; sts_ctx _ _ _].
rewrite (sts_own_weaken ⊤ _ _ (i_states i ∩ low_states) _
({[ Change i ]} ∪ {[ Send ]})).
+ apply pvs_mono.
rewrite -sts_ownS_op; eauto using i_states_closed, low_states_closed.
set_solver.
+ intros []; set_solver.
iIntros {HN} "[#? HΦ]".
rewrite /newbarrier. wp_seq. iApply wp_pvs. wp_alloc l as "Hl".
iApply "HΦ".
iPvs (saved_prop_alloc (F:=idCF) _ P) as {γ} "#?".
iPvs (sts_alloc (barrier_inv l P) _ N (State Low {[ γ ]}))
"-" as {γ'} "[#? Hγ']"; eauto.
{ iNext. iFrame "Hl". iExists (const P). rewrite !big_sepS_singleton /=.
iSplit; [|done]. by iNext; iIntros "?". }
iAssert (barrier_ctx γ' l P)%I as "#?".
{ rewrite /barrier_ctx. by repeat iSplit. }
iPvsAssert (sts_ownS γ' (i_states γ) {[Change γ]}
★ sts_ownS γ' low_states {[Send]})%I as "[Hr Hs]" with "-".
{ iApply sts_ownS_op; eauto using i_states_closed, low_states_closed.
+ set_solver.
+ auto using sts.closed_op, i_states_closed, low_states_closed.
+ iApply sts_own_weaken "Hγ'";
auto using sts.closed_op, i_states_closed, low_states_closed;
set_solver. }
iPvsIntro. rewrite /recv /send. iSplitL "Hr".
- iExists γ', P, P, γ. iFrame "Hr". repeat iSplit; auto. iNext; by iIntros "?".
- iExists γ'. by iSplit.
Qed.
Lemma signal_spec l P (Φ : val → iProp) :
(send l P ★ P ★ Φ #()) ⊢ WP signal (%l) {{ Φ }}.
Proof.
rewrite /signal /send /barrier_ctx. rewrite sep_exist_r.
apply exist_elim=>γ. rewrite -!assoc. apply const_elim_sep_l=>?. wp_let.
(* I think some evars here are better than repeating *everything* *)
eapply (sts_fsaS _ (wp_fsa _)) with (N0:=N) (γ0:=γ); simpl;
eauto with I ndisj.
ecancel [sts_ownS γ _ _].
apply forall_intro=>-[p I]. apply wand_intro_l. rewrite -!assoc.
apply const_elim_sep_l=>Hs. destruct p; last done.
rewrite {1}/barrier_inv =>/={Hs}. rewrite later_sep.
eapply wp_store with (v' := #0); eauto with I ndisj.
strip_later. cancel [l ↦ #0]%I.
apply wand_intro_l. rewrite -(exist_intro (State High I)).
rewrite -(exist_intro ∅). rewrite const_equiv /=; last by eauto using signal_step.
rewrite left_id -later_intro {2}/barrier_inv -!assoc. apply sep_mono_r.
sep_split right: [Φ _]; last first.
{ apply wand_intro_l. eauto with I. }
(* Now we come to the core of the proof: Updating from waiting to ress. *)
rewrite /ress sep_exist_r. apply exist_mono=>{Φ} Φ.
ecancel [Π★{set I} (λ _, saved_prop_own _ _)]%I. strip_later.
rewrite wand_True. eapply wand_apply_l'; eauto with I.
rewrite /signal /send /barrier_ctx.
iIntros "(Hs&HP&HΦ)"; iDestruct "Hs" as {γ} "[#(%&Hh&Hsts) Hγ]". wp_let.
iSts γ as [p I]; iDestruct "Hγ" as "[Hl Hr]".
wp_store. destruct p; [|done].
iExists (State High I), (∅ : set token).
iSplit; [iPureIntro; by eauto using signal_step|].
iSplitR "HΦ"; [iNext|by iIntros "?"].
rewrite {2}/barrier_inv /ress /=; iFrame "Hl".
iDestruct "Hr" as {Ψ} "[? Hsp]"; iExists Ψ; iFrame "Hsp".
iNext; iIntros "_"; by iApply "Hr".
Qed.
Lemma wait_spec l P (Φ : val → iProp) :
(recv l P ★ (P -★ Φ #())) ⊢ WP wait (%l) {{ Φ }}.
Proof.
rename P into R. wp_rec.
rewrite {1}/recv /barrier_ctx. rewrite !sep_exist_r.
apply exist_elim=>γ. rewrite !sep_exist_r. apply exist_elim=>P.
rewrite !sep_exist_r. apply exist_elim=>Q. rewrite !sep_exist_r.
apply exist_elim=>i. rewrite -!(assoc (★)%I). apply const_elim_sep_l=>?.
wp_focus (! _)%E.
(* I think some evars here are better than repeating *everything* *)
eapply (sts_fsaS _ (wp_fsa _)) with (N0:=N) (γ0:=γ); simpl;
eauto with I ndisj.
ecancel [sts_ownS γ _ _].
apply forall_intro=>-[p I]. apply wand_intro_l. rewrite -!assoc.
apply const_elim_sep_l=>Hs.
rewrite {1}/barrier_inv =>/=. rewrite later_sep.
eapply wp_load; eauto with I ndisj.
ecancel [▷ l ↦{_} _]%I. strip_later.
apply wand_intro_l. destruct p.
{ (* a Low state. The comparison fails, and we recurse. *)
rewrite -(exist_intro (State Low I)) -(exist_intro {[ Change i ]}).
rewrite [(■ sts.steps _ _ )%I]const_equiv /=; last by apply rtc_refl.
rewrite left_id -[(▷ barrier_inv _ _ _)%I]later_intro {3}/barrier_inv.
rewrite -!assoc. apply sep_mono_r, sep_mono_r, wand_intro_l.
wp_op; first done. intros _. wp_if. rewrite !assoc.
rewrite -always_wand_impl always_elim.
rewrite -{2}pvs_wp. rewrite -pvs_wand_r; apply sep_mono_l.
rewrite -(exist_intro γ) -(exist_intro P) -(exist_intro Q) -(exist_intro i).
rewrite const_equiv // left_id -later_intro.
ecancel_pvs [heap_ctx _; saved_prop_own _ _; Q -★ _; R -★ _; sts_ctx _ _ _]%I.
apply sts_own_weaken; eauto using i_states_closed. }
(* a High state: the comparison succeeds, and we perform a transition and
return to the client *)
rewrite [(_ ★ □ (_ → _ ))%I]sep_elim_l.
rewrite -(exist_intro (State High (I ∖ {[ i ]}))) -(exist_intro ∅).
change (i ∈ I) in Hs.
rewrite const_equiv /=; last by eauto using wait_step.
rewrite left_id -[(▷ barrier_inv _ _ _)%I]later_intro {2}/barrier_inv.
rewrite -!assoc. apply sep_mono_r. rewrite /ress.
rewrite !sep_exist_r. apply exist_mono=>Ψ.
rewrite !(big_sepS_delete _ I i) //= !wand_True later_sep.
ecancel [▷ Π★{set _} Ψ; Π★{set _} (λ _, saved_prop_own _ _)]%I.
apply wand_intro_l. set savedΨ := _ i (Ψ _). set savedQ := _ i Q.
to_front [savedΨ; savedQ]. rewrite saved_prop_agree /=.
wp_op; [|done]=> _. wp_if. rewrite -pvs_intro. rewrite !assoc. eapply wand_apply_r'; first done.
eapply wand_apply_r'; first done.
apply: (eq_rewrite (Ψ i) Q (λ x, x)%I); by eauto with I.
rename P into R; rewrite /recv /barrier_ctx.
iIntros "[Hr HΦ]"; iDestruct "Hr" as {γ P Q i} "(#(%&Hh&Hsts)&Hγ&#HQ&HQR)".
iLöb "Hγ HQR HΦ" as "IH". wp_rec. wp_focus (! _)%E.
iSts γ as [p I]; iDestruct "Hγ" as "[Hl Hr]".
wp_load. destruct p.
- (* a Low state. The comparison fails, and we recurse. *)
iExists (State Low I), {[ Change i ]}; iSplit; [done|iSplitL "Hl Hr"].
{ iNext. rewrite {2}/barrier_inv /=. by iFrame "Hl". }
iIntros "Hγ".
iPvsAssert (sts_ownS γ (i_states i) {[Change i]})%I as "Hγ" with "[Hγ]".
{ iApply sts_own_weaken "Hγ"; eauto using i_states_closed. }
wp_op=> ?; simplify_eq; wp_if. iApply "IH" "Hγ [HQR] HΦ". by iNext.
- (* a High state: the comparison succeeds, and we perform a transition and
return to the client *)
iExists (State High (I ∖ {[ i ]})), (∅ : set token).
iSplit; [iPureIntro; by eauto using wait_step|].
iDestruct "Hr" as {Ψ} "[HΨ Hsp]".
iDestruct (big_sepS_delete _ _ i) "Hsp" as "[#HΨi Hsp]"; first done.
iAssert (▷ Ψ i ★ ▷ Π★{set (I ∖ {[i]})} Ψ)%I as "[HΨ HΨ']" with "[HΨ]".
{ iNext. iApply (big_sepS_delete _ _ i); first done. by iApply "HΨ". }
iSplitL "HΨ' Hl Hsp"; [iNext|].
+ rewrite {2}/barrier_inv /=; iFrame "Hl".
iExists Ψ; iFrame "Hsp". iNext; by iIntros "_".
+ iPoseProof (saved_prop_agree i Q (Ψ i)) "#" as "Heq"; first by iSplit.
iIntros "_". wp_op=> ?; simplify_eq/=; wp_if.
iPvsIntro. iApply "HΦ". iApply "HQR". by iRewrite "Heq".
Qed.
Lemma recv_split E l P1 P2 :
nclose N ⊆ E →
recv l (P1 ★ P2) ⊢ |={E}=> recv l P1 ★ recv l P2.
nclose N ⊆ E → recv l (P1 ★ P2) ⊢ |={E}=> recv l P1 ★ recv l P2.
Proof.
rename P1 into R1. rename P2 into R2. intros HN.
rewrite {1}/recv /barrier_ctx.
apply exist_elim=>γ. rewrite sep_exist_r. apply exist_elim=>P.
apply exist_elim=>Q. apply exist_elim=>i. rewrite -!(assoc (★)%I).
apply const_elim_sep_l=>?. rewrite -pvs_trans'.
(* I think some evars here are better than repeating *everything* *)
eapply pvs_mk_fsa, (sts_fsaS _ pvs_fsa) with (N0:=N) (γ0:=γ); simpl;
eauto with I ndisj.
ecancel [sts_ownS γ _ _].
apply forall_intro=>-[p I]. apply wand_intro_l. rewrite -!assoc.
apply const_elim_sep_l=>Hs. rewrite /pvs_fsa.
eapply sep_elim_True_l.
{ eapply saved_prop_alloc_strong with (x := R1) (G := I). }
rewrite pvs_frame_r. apply pvs_strip_pvs. rewrite sep_exist_r.
apply exist_elim=>i1. rewrite always_and_sep_l. rewrite -assoc.
apply const_elim_sep_l=>Hi1. eapply sep_elim_True_l.
{ eapply saved_prop_alloc_strong with (x := R2) (G := I ∪ {[ i1 ]}). }
rewrite pvs_frame_r. apply pvs_mono. rewrite sep_exist_r.
apply exist_elim=>i2. rewrite always_and_sep_l. rewrite -assoc.
apply const_elim_sep_l=>Hi2.
rewrite ->not_elem_of_union, elem_of_singleton in Hi2.
destruct Hi2 as [Hi2 Hi12]. change (i ∈ I) in Hs.
(* Update to new state. *)
rewrite -(exist_intro (State p ({[i1]} ∪ ({[i2]} ∪ (I ∖ {[i]}))))).
rewrite -(exist_intro ({[Change i1 ]} ∪ {[ Change i2 ]})).
rewrite [(■ sts.steps _ _)%I]const_equiv; last by eauto using split_step.
rewrite left_id {1 3}/barrier_inv.
(* FIXME ssreflect rewrite fails if there are evars around. Also, this is very slow because we don't have a proof mode. *)
rewrite -(ress_split _ _ _ Q R1 R2); [|done..].
rewrite {1}[saved_prop_own i1 _]always_sep_dup.
rewrite {1}[saved_prop_own i2 _]always_sep_dup !later_sep.
rewrite -![(▷ saved_prop_own _ _)%I]later_intro.
ecancel [▷ l ↦ _; saved_prop_own i1 _; saved_prop_own i2 _ ;
▷ ress _ _ ; ▷ (Q -★ _) ; saved_prop_own i _]%I.
apply wand_intro_l. rewrite !assoc. rewrite /recv.
rewrite -(exist_intro γ) -(exist_intro P) -(exist_intro R1) -(exist_intro i1).
rewrite -(exist_intro γ) -(exist_intro P) -(exist_intro R2) -(exist_intro i2).
rewrite [heap_ctx _]always_sep_dup [sts_ctx _ _ _]always_sep_dup.
rewrite /barrier_ctx const_equiv // left_id.