Library zoo.program_logic.ghost_state

From iris.bi Require Export
  lib.fractional.
From iris.base_logic Require Import
  lib.ghost_map
  lib.invariants.

From zoo Require Import
  prelude.
From zoo.iris.bi Require Import
  big_op.
From zoo.iris.base_logic Require Import
  lib.auth_nat_max
  lib.ghost_heap
  lib.ghost_list
  lib.mono_list.
From zoo.iris Require Import
  diaframe.
From zoo.language Require Export
  language.
From zoo.language Require Import
  notations.
From zoo Require Import
  options.

Implicit Types cnt ns nt : nat.
Implicit Type pid : prophet_id.
Implicit Types tid : thread_id.
Implicit Types l : location.
Implicit Types v : val.
Implicit Types vs : list val.
Implicit Types hdr : header.
Implicit Types hdrs : gmap location header.
Implicit Types σ : state.
Implicit Type proph : val × val.
Implicit Type prophs : list (val × val).
Implicit Type prophets : gmap prophet_id (list (val × val)).
Implicit Types κ κs : list observation.

Parameter zoo_counter : location.

Class ZooG₀ Σ :=
  { #[local] zoo_G₀_headers_G :: GhostHeapG Σ location header
  ; #[local] zoo_G₀_heap_G :: ghost_mapG Σ location val
  ; #[local] zoo_G_prophets_G :: ghost_mapG Σ prophet_id (list (val × val))
  ; #[local] zoo_G₀_steps_G :: AuthNatMaxG Σ
  ; #[local] zoo_G₀_locals_G :: GhostListG Σ val
  ; #[local] zoo_G₀_counter_G :: MonoListG Σ val
  }.

#[local] Definition zoo_Σ₀ :=
  #[ghost_heap_Σ location header
  ; ghost_mapΣ location val
  ; ghost_mapΣ prophet_id (list (val × val))
  ; auth_nat_max_Σ
  ; ghost_list_Σ val
  ; mono_list_Σ val
  ].
#[local] Instance subG_zoo_Σ₀ Σ :
  subG zoo_Σ₀ Σ
  ZooG₀ Σ.

Class ZooGpre Σ :=
  { #[global] zoo_Gpre_inv_Gpre :: invGpreS Σ
  ; #[local] zoo_Gpre_G₀ :: ZooG₀ Σ
  }.

Definition zoo_Σ :=
  #[invΣ
  ; zoo_Σ₀
  ].
#[global] Instance subG_zoo_Σ Σ :
  subG zoo_Σ Σ
  ZooGpre Σ.

Class ZooG Σ :=
  { #[global] zoo_G_inv_G :: invGS Σ
  ; #[local] zoo_G_G₀ :: ZooG₀ Σ
  ; zoo_G_headers_name : ghost_heap_name
  ; zoo_G_heap_name : gname
  ; zoo_G_prophets_name : gname
  ; zoo_G_steps_name : gname
  ; zoo_G_locals_name : gname
  ; zoo_G_counter_name : gname
  }.
#[global] Arguments Build_ZooG {_ _ _} _ _ _ _ _ _ : assert.

Section zoo_G₀.
  Context `{zoo_G₀ : !ZooG₀ Σ}.

  #[local] Definition headers_auth' γ_headers hdrs :=
    ghost_heap_auth γ_headers hdrs.
  #[local] Definition headers_at' γ_headers l hdr :=
    ghost_heap_at γ_headers l DfracDiscarded hdr.

  #[local] Definition meta_token' γ_headers l E :=
    ghost_heap_meta_token γ_headers l E.
  #[local] Definition meta' `{Countable A} γ_headers l ι (x : A) :=
    ghost_heap_meta γ_headers l ι x.

  #[local] Lemma headers_alloc hdrs :
     |==>
       γ_headers,
      headers_auth' γ_headers hdrs.
End zoo_G₀.

Section zoo_G.
  Context `{zoo_G : !ZooG Σ}.

  Definition headers_auth :=
    headers_auth' zoo_G_headers_name.
  Definition headers_at :=
    headers_at' zoo_G_headers_name.

  Definition meta_token :=
    meta_token' zoo_G_headers_name.
  Definition meta `{Countable A} :=
    meta' (A := A) zoo_G_headers_name.
End zoo_G.

Notation "l ↦ₕ hdr" := (
  headers_at l hdr
)(at level 20,
  format "l ↦ₕ hdr"
) : bi_scope.

Notation "l ↪[ ι ] x" := (
  meta l ι x
)(at level 20,
  format "l ↪[ ι ] x"
) : bi_scope.
Notation "l ↪ x" := (
  meta l nroot x
)(at level 20,
  format "l ↪ x"
) : bi_scope.

Section zoo_G.
  Context `{zoo_G : !ZooG Σ}.

  #[global] Instance headers_at_timeless l hdr :
    Timeless (l ↦ₕ hdr).

  #[global] Instance headers_at_persistent l hdr :
    Persistent (l ↦ₕ hdr).

  Lemma headers_at_agree l hdr1 hdr2 :
    l ↦ₕ hdr1 -∗
    l ↦ₕ hdr2 -∗
    hdr1 = hdr2.
End zoo_G.

Section zoo_G.
  Context `{zoo_G : !ZooG Σ}.

  #[global] Instance meta_token_timeless l N :
    Timeless (meta_token l N).
  #[global] Instance meta_timeless `{Countable A} l ι (x : A) :
    Timeless (l ↪[ι] x).

  #[global] Instance meta_persistent `{Countable A} l ι (x : A) :
    Persistent (l ↪[ι] x).

  Lemma meta_token_difference {l} E1 E2 :
    E1 E2
    meta_token l E2 ⊣⊢
      meta_token l E1
      meta_token l (E2 E1).

  Lemma meta_set `{Countable A} {l E} (x : A) ι :
     ι E
    meta_token l E |==>
    l ↪[ι] x.
  Lemma meta_agree `{Countable A} l ι (x1 x2 : A) :
    l ↪[ι] x1 -∗
    l ↪[ι] x2 -∗
    x1 = x2.

  Lemma headers_lookup hdrs l hdr :
    headers_auth hdrs -∗
    l ↦ₕ hdr -∗
    hdrs !! l = Some hdr.

  Lemma headers_insert {hdrs} l hdr :
    hdrs !! l = None
    headers_auth hdrs |==>
      headers_auth (<[l := hdr]> hdrs)
      l ↦ₕ hdr
      meta_token l .
End zoo_G.

#[global] Opaque headers_auth'.
#[global] Opaque headers_at'.
#[global] Opaque meta_token'.
#[global] Opaque meta'.

Section zoo_G₀.
  Context `{zoo_G₀ : !ZooG₀ Σ}.

  #[local] Definition heap_auth' γ_heap h :=
    ghost_map_auth (V := val) γ_heap 1 h.
  #[local] Definition pointsto' γ_heap l dq v :=
    ghost_map_elem (V := val) γ_heap l dq v.

  #[local] Lemma heap_alloc h :
     |==>
       γ_heap,
      heap_auth' γ_heap h
      [∗ map] l v h, pointsto' γ_heap l (DfracOwn 1) v.
End zoo_G₀.

Section cheriot_G.
  Context `{zoo_G : !ZooG Σ}.

  Definition heap_auth :=
    heap_auth' zoo_G_heap_name.
  Definition pointsto :=
    pointsto' zoo_G_heap_name.
End cheriot_G.

Notation "l ↦ dq v" := (
  pointsto l dq v%V
)(at level 20,
  dq custom dfrac at level 1,
  format "l ↦ dq v"
) : bi_scope.
Notation "l ↦-" := (
  ( v, l v)%I
)(at level 20,
  format "l ↦-"
) : bi_scope.

Notation "l ↦∗ dq vs" :=
  ([∗ list] i v vs, (l +ₗ i) {dq} v)%I
( at level 20,
  dq custom dfrac at level 1,
  format "l ↦∗ dq vs"
) : bi_scope.
Notation "l ↦∗-" :=
  ( vs, l ↦∗ vs)%I
( at level 20,
  format "l ↦∗-"
) : bi_scope.

Notation "l ↦ᵣ dq v" := (
  pointsto (location_add l (Z.of_nat (in_type "@ref" 0))) dq v%V
)(at level 20,
  dq custom dfrac at level 1,
  format "l ↦ᵣ dq v"
) : bi_scope.
Notation "l ↦ᵣ-" := (
  ( v, l ↦ᵣ v)%I
)(at level 20,
  format "l ↦ᵣ-"
) : bi_scope.

Section zoo_G.
  Context `{zoo_G : !ZooG Σ}.

  #[global] Instance pointsto_timeless l dq v :
    Timeless (l {dq} v).

  #[global] Instance pointsto_persistent l v :
    Persistent (l v).

  #[global] Instance pointsto_fractional l v :
    Fractional (λ q, l {#q} v)%I.
  #[global] Instance pointsto_as_fractional l q v :
    AsFractional (l {#q} v) (λ q, l {#q} v)%I q.

  Lemma pointsto_valid l dq v :
    l {dq} v
     dq.
  Lemma pointsto_combine l dq1 v1 dq2 v2 :
    l {dq1} v1 -∗
    l {dq2} v2 -∗
      v1 = v2
      l {dq1 dq2} v1.
  Lemma pointsto_valid_2 l dq1 v1 dq2 v2 :
    l {dq1} v1 -∗
    l {dq2} v2 -∗
       (dq1 dq2)
      v1 = v2.
  Lemma pointsto_agree l dq2 v1 dq1 v2 :
    l {dq1} v1 -∗
    l {dq2} v2 -∗
    v1 = v2.
  Lemma pointsto_dfrac_ne l1 dq1 v1 l2 dq2 v2 :
    ¬ (dq1 dq2)
    l1 {dq1} v1 -∗
    l2 {dq2} v2 -∗
    l1 l2.
  Lemma pointsto_ne l1 v1 l2 dq2 v2 :
    l1 v1 -∗
    l2 {dq2} v2 -∗
    l1 l2.
  Lemma pointsto_exclusive l v1 dq2 v2 :
    l v1 -∗
    l {dq2} v2 -∗
    False.
  Lemma pointsto_persist l dq v :
    l {dq} v |==>
    l v.

  #[global] Instance pointsto_combine_sep_gives l dq1 v1 dq2 v2 :
    CombineSepGives (l {dq1} v1) (l {dq2} v2) (dq1 dq2) v1 = v2
  | 30.
  #[global] Instance pointsto_combine_as l dq1 dq2 v1 v2 :
    CombineSepAs (l {dq1} v1) (l {dq2} v2) (l {dq1 dq2} v1)
  | 60.
  #[global] Instance frame_pointsto p l v q1 q2 q :
    FrameFractionalQp q1 q2 q
    Frame p (l {#q1} v) (l {#q2} v) (l {#q} v)
  | 5.

  Lemma heap_lookup h a dq c :
    heap_auth h -∗
    a {dq} c -∗
    h !! a = Some c.
  Lemma heap_insert {h1} h2 :
    h2 ##ₘ h1
    heap_auth h1 |==>
      heap_auth (h2 h1)
      [∗ map] l v h2, l v.
  Lemma heap_update {h a c1} c2 :
    heap_auth h -∗
    a c1 ==∗
      heap_auth (<[a := c2]> h)
      a c2.
End zoo_G.

#[global] Opaque heap_auth'.
#[global] Opaque pointsto'.

Section zoo_G.
  Context `{zoo_G : !ZooG Σ}.

  Lemma big_sepL2_pointsto_agree ls dq1 vs1 dq2 vs2 :
    ([∗ list] l; v ls; vs1, l {dq1} v) -∗
    ([∗ list] l; v ls; vs2, l {dq2} v) -∗
    vs1 = vs2.
  Lemma big_sepL2_ref_pointsto_agree ls dq1 vs1 dq2 vs2 :
    ([∗ list] l; v ls; vs1, l ↦ᵣ{dq1} v) -∗
    ([∗ list] l; v ls; vs2, l ↦ᵣ{dq2} v) -∗
    vs1 = vs2.

  Lemma big_sepL2_pointsto_prefix ls1 dq1 vs1 ls2 dq2 vs2 :
    ls1 `prefix_of` ls2
    ([∗ list] l; v ls1; vs1, l {dq1} v) -∗
    ([∗ list] l; v ls2; vs2, l {dq2} v) -∗
    vs1 `prefix_of` vs2.
  Lemma big_sepL2_ref_pointsto_prefix ls1 dq1 vs1 ls2 dq2 vs2 :
    ls1 `prefix_of` ls2
    ([∗ list] l; v ls1; vs1, l ↦ᵣ{dq1} v) -∗
    ([∗ list] l; v ls2; vs2, l ↦ᵣ{dq2} v) -∗
    vs1 `prefix_of` vs2.

  Lemma big_sepL2_pointsto_suffix ls1 dq1 vs1 ls2 dq2 vs2 :
    ls1 `suffix_of` ls2
    ([∗ list] l; v ls1; vs1, l {dq1} v) -∗
    ([∗ list] l; v ls2; vs2, l {dq2} v) -∗
    vs1 `suffix_of` vs2.
  Lemma big_sepL2_ref_pointsto_suffix ls1 dq1 vs1 ls2 dq2 vs2 :
    ls1 `suffix_of` ls2
    ([∗ list] l; v ls1; vs1, l ↦ᵣ{dq1} v) -∗
    ([∗ list] l; v ls2; vs2, l ↦ᵣ{dq2} v) -∗
    vs1 `suffix_of` vs2.
End zoo_G.

Section resolve_prophecies.
  #[local] Fixpoint resolve_prophecies κs pid :=
    match κs with
    | []
        []
    | κ :: κs
        if decide (pid = κ.1) then
          κ.2 :: resolve_prophecies κs pid
        else
          resolve_prophecies κs pid
    end.

  #[local] Definition resolve_prophets prophets κs :=
    map_Forall (λ pid prophs, prophs = resolve_prophecies κs pid) prophets.

  #[local] Lemma resolve_prophets_insert κs pid prophets :
    resolve_prophets prophets κs
    pid dom prophets
    resolve_prophets (<[pid := resolve_prophecies κs pid]> prophets) κs.
End resolve_prophecies.

Section zoo_G₀.
  Context `{zoo_G₀ : !ZooG₀ Σ}.

  #[local] Definition prophets_auth' γ_prophets κs pids : iProp Σ :=
     prophets,
    resolve_prophets prophets κs
    dom prophets pids
    ghost_map_auth γ_prophets 1 prophets.
  #[local] Definition prophet_model' γ_prophets pid prophs :=
    ghost_map_elem γ_prophets pid (DfracOwn 1) prophs.

  #[local] Lemma prophets_alloc κs pids :
     |==>
       γ_prophets,
      prophets_auth' γ_prophets κs pids.
End zoo_G₀.

Section zoo_G.
  Context `{zoo_G : !ZooG Σ}.

  Definition prophets_auth :=
    prophets_auth' zoo_G_prophets_name.
  Definition prophet_model :=
    prophet_model' zoo_G_prophets_name.

  #[global] Instance prophet_model_timeless pid prophs :
    Timeless (prophet_model pid prophs).

  Lemma prophet_model_exclusive pid prophs1 prophs2 :
    prophet_model pid prophs1 -∗
    prophet_model pid prophs2 -∗
    False.

  Lemma prophets_new {κs pids} pid :
    pid pids
    prophets_auth κs pids |==>
       prophs,
      prophets_auth κs ({[pid]} pids)
      prophet_model pid prophs.

  Lemma prophets_resolve pid proph κs pids prophs :
    prophets_auth ((pid, proph) :: κs) pids -∗
    prophet_model pid prophs ==∗
       prophs',
      prophs = proph :: prophs'
      prophets_auth κs pids
      prophet_model pid prophs'.
End zoo_G.

#[global] Opaque prophets_auth'.
#[global] Opaque prophet_model'.

Section zoo_G₀.
  Context `{zoo_G₀ : !ZooG₀ Σ}.

  #[local] Definition steps_auth' γ_steps :=
    auth_nat_max_auth γ_steps (DfracOwn 1).
  #[local] Definition steps_lb' :=
    auth_nat_max_lb.

  #[local] Lemma steps_alloc :
     |==>
       γ_steps,
      steps_auth' γ_steps 0.
End zoo_G₀.

Section zoo_G.
  Context `{zoo_G : !ZooG Σ}.

  Definition steps_auth :=
    steps_auth' zoo_G_steps_name.
  Definition steps_lb :=
    auth_nat_max_lb zoo_G_steps_name.
End zoo_G.

Notation "⧖ n" := (
  steps_lb n
)(at level 1,
  format "⧖ n"
) : bi_scope.

Section zoo_G.
  Context `{zoo_G : !ZooG Σ}.

  #[global] Instance steps_auth_timeless ns :
    Timeless (steps_auth ns).
  #[global] Instance steps_lb_timeless ns :
    Timeless ( ns).

  #[global] Instance steps_lb_persistent ns :
    Persistent ( ns).

  Lemma steps_lb_0 :
     |==>
       0.
  Lemma steps_lb_le ns1 ns2 :
    ns2 ns1
     ns1
     ns2.
  Lemma steps_lb_max ns1 ns2 :
     ns1 -∗
     ns2 -∗
     (ns1 `max` ns2).

  Lemma steps_lb_get ns :
    steps_auth ns
     ns.
  Lemma steps_lb_valid ns1 ns2 :
    steps_auth ns1 -∗
     ns2 -∗
    ns2 ns1.

  Lemma steps_update ns :
    steps_auth ns |==>
    steps_auth (S ns).

  #[global] Instance hint_steps_lb_le ns1 ns2 :
    SolveSepSideCondition (ns1 ns2)
    HINT
       ns2
     [- ;
      emp
    ] [id];
       ns1
     [
      emp
    ]
    | 60.
  #[global] Instance merge_steps_lbs ns1 ns2 :
    MergableConsume ( ns1) true (λ p Pin Pout,
      TCAnd (
        TCEq Pin ( ns2)%I
      ) (
        TCEq Pout ( (ns1 `max` ns2))%I
      )
    ).
End zoo_G.

#[global] Opaque steps_auth'.
#[global] Opaque steps_lb'.

Section zoo_G₀.
  Context `{zoo_G₀ : !ZooG₀ Σ}.

  #[local] Definition locals_auth' γ_locals vs :=
    ghost_list_auth γ_locals vs.
  #[local] Definition local_pointsto' γ_locals tid dq v :=
    ghost_list_at γ_locals tid dq v.

  #[local] Lemma locals_alloc vs :
     |==>
       γ_locals,
      locals_auth' γ_locals vs
      [∗ list] tid v vs, local_pointsto' γ_locals tid (DfracOwn 1) v.
End zoo_G₀.

Section zoo_G.
  Context `{zoo_G : !ZooG Σ}.

  Definition locals_auth :=
    locals_auth' zoo_G_locals_name.
  Definition local_pointsto :=
    local_pointsto' zoo_G_locals_name.
End zoo_G.

Notation "tid ↦ₗ dq v" := (
  local_pointsto tid dq v%V
)(at level 20,
  dq custom dfrac at level 1,
  format "tid ↦ₗ dq v"
) : bi_scope.
Notation "tid ↦ₗ-" := (
  ( v, tid ↦ₗ v)%I
)(at level 20,
  format "tid ↦ₗ-"
) : bi_scope.

Section zoo_G.
  Context `{zoo_G : !ZooG Σ}.

  #[global] Instance local_pointsto_timeless tid dq v :
    Timeless (tid ↦ₗ{dq} v).

  #[global] Instance local_pointsto_persistent tid v :
    Persistent (tid ↦ₗ v).

  #[global] Instance local_pointsto_fractional tid v :
    Fractional (λ q, tid ↦ₗ{#q} v)%I.
  #[global] Instance local_pointsto_as_fractional tid q v :
    AsFractional (tid ↦ₗ{#q} v) (λ q, tid ↦ₗ{#q} v)%I q.

  Lemma local_pointsto_valid tid dq v :
    tid ↦ₗ{dq} v
     dq.
  Lemma local_pointsto_combine tid dq1 v1 dq2 v2 :
    tid ↦ₗ{dq1} v1 -∗
    tid ↦ₗ{dq2} v2 -∗
      v1 = v2
      tid ↦ₗ{dq1 dq2} v1.
  Lemma local_pointsto_valid_2 tid dq1 v1 dq2 v2 :
    tid ↦ₗ{dq1} v1 -∗
    tid ↦ₗ{dq2} v2 -∗
       (dq1 dq2)
      v1 = v2.
  Lemma local_pointsto_agree tid dq2 v1 dq1 v2 :
    tid ↦ₗ{dq1} v1 -∗
    tid ↦ₗ{dq2} v2 -∗
    v1 = v2.
  Lemma local_pointsto_dfrac_ne tid1 dq1 v1 tid2 dq2 v2 :
    ¬ (dq1 dq2)
    tid1 ↦ₗ{dq1} v1 -∗
    tid2 ↦ₗ{dq2} v2 -∗
    tid1 tid2.
  Lemma local_pointsto_ne tid1 v1 tid2 dq2 v2 :
    tid1 ↦ₗ v1 -∗
    tid2 ↦ₗ{dq2} v2 -∗
    tid1 tid2.
  Lemma local_pointsto_exclusive tid v1 dq2 v2 :
    tid ↦ₗ v1 -∗
    tid ↦ₗ{dq2} v2 -∗
    False.
  Lemma local_pointsto_persist tid dq v :
    tid ↦ₗ{dq} v |==>
    tid ↦ₗ v.

  Lemma locals_lookup vs tid dq v :
    locals_auth vs -∗
    tid ↦ₗ{dq} v -∗
    vs !! tid = Some v.

  Lemma locals_update_push {vs} v :
    locals_auth vs |==>
      locals_auth (vs ++ [v])
      length vs ↦ₗ v.
  Lemma locals_update_pointsto {vs tid v} v' :
    locals_auth vs -∗
    tid ↦ₗ v ==∗
      locals_auth (<[tid := v']> vs)
      tid ↦ₗ v'.
End zoo_G.

#[global] Opaque locals_auth'.
#[global] Opaque local_pointsto'.

Section zoo_G₀.
  Context `{zoo_G₀ : !ZooG₀ Σ}.

  #[local] Definition zoo_counter_auth' γ_counter vs :=
    mono_list_auth γ_counter (DfracOwn 1) vs.
  #[local] Definition zoo_counter_at' γ_counter id v :=
    mono_list_at γ_counter id v.

  #[local] Lemma zoo_counter_alloc :
     |==>
       γ_counter,
      zoo_counter_auth' γ_counter (replicate 0 inhabitant).
End zoo_G₀.

Section zoo_G.
  Context `{zoo_G : !ZooG Σ}.

  Definition zoo_counter_auth :=
    zoo_counter_auth' zoo_G_counter_name.
  Definition zoo_counter_at :=
    zoo_counter_at' zoo_G_counter_name.

  #[global] Instance zoo_counter_auth_timeless vs :
    Timeless (zoo_counter_auth vs).
  #[global] Instance zoo_counter_at_timeless id v :
    Timeless (zoo_counter_at id v).

  #[global] Instance zoo_counter_at_persistent id v :
    Persistent (zoo_counter_at id v).

  Lemma zoo_counter_at_get {vs} id v :
    vs !! id = Some v
    zoo_counter_auth vs
    zoo_counter_at id v.
  Lemma zoo_counter_at_valid vs id v :
    zoo_counter_auth vs -∗
    zoo_counter_at id v -∗
    vs !! id = Some v.
  Lemma zoo_counter_at_agree id v1 v2 :
    zoo_counter_at id v1 -∗
    zoo_counter_at id v2 -∗
    v1 = v2.

  Lemma zoo_counter_update {vs} v :
    zoo_counter_auth vs |==>
    zoo_counter_auth (vs ++ [v]).
End zoo_G.

#[global] Opaque zoo_counter_auth'.
#[global] Opaque zoo_counter_at'.

Section zoo_G.
  Context `{zoo_G : !ZooG Σ}.

  Definition zoo_counter_name :=
    zoo_G_counter_name.
  Definition zoo_counter_inv_inner : iProp Σ :=
     cnt vs,
    zoo_counter ↦ᵣ #cnt
    zoo_counter_auth vs
    length vs = cnt.
  Definition zoo_counter_inv :=
    inv nroot zoo_counter_inv_inner.
End zoo_G.

Lemma zoo_init `{zoo_Gpre : !ZooGpre Σ} `{inv_G : !invGS Σ} hdrs h pids vs κs :
  h !! zoo_counter = Some 0%V
   |={}=>
     zoo_G : ZooG Σ,
    zoo_G.(zoo_G_inv_G) = inv_G
    headers_auth hdrs
    heap_auth h
    prophets_auth κs pids
    steps_auth 0
    locals_auth vs
    zoo_counter_inv
    ([∗ map] l v delete zoo_counter h, l v)
    ([∗ list] tid v vs, tid ↦ₗ v).

#[global] Opaque headers_auth.
#[global] Opaque headers_at.
#[global] Opaque meta_token.
#[global] Opaque meta.
#[global] Opaque heap_auth.
#[global] Opaque pointsto.
#[global] Opaque prophets_auth.
#[global] Opaque prophet_model.
#[global] Opaque steps_auth.
#[global] Opaque steps_lb.
#[global] Opaque locals_auth.
#[global] Opaque local_pointsto.
#[global] Opaque zoo_counter_auth.
#[global] Opaque zoo_counter_at.

Variant ownership :=
  | Own
  | Discard.

Coercion ownership_to_dfrac own :=
  match own with
  | Own
      DfracOwn 1
  | Discard
      DfracDiscarded
  end.