Theory Conform

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theory Conform = State
files [Conform.ML]:
(*  Title:      isabelle/Bali/Conform.thy
    ID:         $Id: Conform.thy,v 1.5 2000/10/19 21:21:51 oheimb Exp $
    Author:     David von Oheimb
    Copyright   1997 Technische Universitaet Muenchen

Conformance notions for the type soundness proof for Java

design issues:
* lconf allows for (arbitrary) inaccessible values
* "conforms" does not directly imply that the dynamic types of all objects on
  the heap are indeed existing classes. Yet this can be inferred for all
  referenced objs.
*)

Conform = State +

types   env_ = "prog × (lname, ty) table" (* same as env of WellType.thy *)

constdefs

  gext    :: "st \<Rightarrow> st \<Rightarrow> bool"                ("_\<le>|_"       [71,71]   70)
   "s\<le>|s' \<equiv> \<forall>r. \<forall>(oi, fs)\<in>globs s r: \<exists>(oi',fs')\<in>globs s' r: oi' = oi"

  conf  :: "prog \<Rightarrow> st \<Rightarrow> val \<Rightarrow> ty \<Rightarrow> bool"    ("_,_\<turnstile>_\<Colon>\<preceq>_"   [71,71,71,71] 70)
           "G,s\<turnstile>v\<Colon>\<preceq>T \<equiv> \<exists>T'\<in>typeof (\<lambda>a. option_map obj_ty (heap s a)) v:G\<turnstile>T'\<preceq>T"

  lconf :: "prog \<Rightarrow> st \<Rightarrow> ('a, val) table \<Rightarrow> ('a, ty) table \<Rightarrow> bool"
                                                ("_,_\<turnstile>_[\<Colon>\<preceq>]_" [71,71,71,71] 70)
           "G,s\<turnstile>vs[\<Colon>\<preceq>]Ts \<equiv> \<forall>n. \<forall>T\<in>Ts n: \<exists>v\<in>vs n: G,s\<turnstile>v\<Colon>\<preceq>T"

  oconf :: "prog \<Rightarrow> st \<Rightarrow> obj \<Rightarrow> oref \<Rightarrow> bool"  ("_,_\<turnstile>_\<Colon>\<preceq>\<surd>_"  [71,71,71,71] 70)
           "G,s\<turnstile>obj\<Colon>\<preceq>\<surd>r \<equiv> G,s\<turnstile>snd obj[\<Colon>\<preceq>]var_tys G (fst obj) r \<and> (case r of 
                              Heap a \<Rightarrow> is_type G (obj_ty obj) | Stat C \<Rightarrow> True)"

  conforms :: "state \<Rightarrow> env_ \<Rightarrow> bool"           (     "_\<Colon>\<preceq>_"   [71,71]      70)
              "xs\<Colon>\<preceq>E \<equiv> let (G, L) = E; s = snd xs; l = locals s in
          (\<forall>r. \<forall>obj\<in>globs s r:           G,s\<turnstile>obj   \<Colon>\<preceq>\<surd>r) \<and>
                                          G,s\<turnstile>l    [\<Colon>\<preceq>]L   \<and>
          (\<forall>a. fst xs=Some(XcptLoc a) \<longrightarrow> G,s\<turnstile>Addr a\<Colon>\<preceq>Class (SXcpt Throwable))"

end

gext

theorem gext_objD:

  [| s\<le>|s'; globs s r = Some (oi, fs) |]
  ==> EX fs'. globs s' r = Some (oi, fs')

theorem rev_gext_objD:

  [| globs s r = Some (oi, fs); s\<le>|s' |]
  ==> EX fs'. globs s' r = Some (oi, fs')

theorem init_class_obj_inited:

  (init_class_obj G C) s1\<le>|s2 ==> inited C (globs s2)

theorem gext_refl:

  s\<le>|s

theorem gext_gupd:

  globs s r = None ==> s\<le>|gupd(r\<mapsto>x) s

theorem gext_new:

  globs s r = None ==> s\<le>|init_obj G oi r s

theorem gext_trans:

  [| s\<le>|s'; s'\<le>|s'' |] ==> s\<le>|s''

theorem gext_upd_gobj:

  s\<le>|upd_gobj r n v s

theorem gext_cong1:

  set_locals l s1\<le>|s2 = s1\<le>|s2

theorem gext_cong2:

  s1\<le>|set_locals l s2 = s1\<le>|s2

theorem gext_lupd1:

  lupd(vn\<mapsto>v) s1\<le>|s2 = s1\<le>|s2

theorem gext_lupd2:

  s1\<le>|lupd(vn\<mapsto>v) s2 = s1\<le>|s2

theorem inited_gext:

  [| inited C (globs s); s\<le>|s' |] ==> inited C (globs s')

value conformance

theorem conf_cong:

  G,set_locals l s\<turnstile>v\<Colon>\<preceq>T =
  G,s\<turnstile>v\<Colon>\<preceq>T

theorem conf_lupd:

  G,lupd(vn\<mapsto>va) s\<turnstile>v\<Colon>\<preceq>T =
  G,s\<turnstile>v\<Colon>\<preceq>T

theorem conf_PrimT:

  ALL dt. typeof dt v = Some (PrimT t)
  ==> G,s\<turnstile>v\<Colon>\<preceq>PrimT t

theorem conf_litval:

  typeof (%a. None) v = Some T ==> G,s\<turnstile>v\<Colon>\<preceq>T

theorem conf_Null:

  G,s\<turnstile>Null\<Colon>\<preceq>T = G|-NT<=:T

theorem conf_Addr:

  G,s\<turnstile>Addr a\<Colon>\<preceq>T =
  (EX obj. heap s a = Some obj & G|-obj_ty obj<=:T)

theorem defval_conf:

  is_type G T ==> G,s\<turnstile>default_val T\<Colon>\<preceq>T

theorem conf_widen:

  [| G|-T<=:T'; G,s\<turnstile>x\<Colon>\<preceq>T; ws_prog G |]
  ==> G,s\<turnstile>x\<Colon>\<preceq>T'

theorem conf_gext:

  [| G,s\<turnstile>v\<Colon>\<preceq>T; s\<le>|s' |]
  ==> G,s'\<turnstile>v\<Colon>\<preceq>T

theorem conf_list_widen:

  [| ws_prog G; list_all2 (conf G s) vs Ts; G\<turnstile>Ts[\<preceq>]Ts' |]
  ==> list_all2 (conf G s) vs Ts'

theorem conf_RefTD:

  G,s\<turnstile>a'\<Colon>\<preceq>RefT T
  ==> a' = Null |
      (EX a oi vs T'.
          a' = Addr a &
          heap s a = Some (oi, vs) & obj_ty (oi, vs) = T' & G|-T'<=:RefT T)

lconf

theorem lconfD:

  [| G,s\<turnstile>vs[\<Colon>\<preceq>]Ts; Ts n = Some T |]
  ==> G,s\<turnstile>the (vs n)\<Colon>\<preceq>T

theorem lconf_cong:

  G,set_locals x s\<turnstile>l[\<Colon>\<preceq>]L =
  G,s\<turnstile>l[\<Colon>\<preceq>]L

theorem lconf_lupd:

  G,lupd(vn\<mapsto>v) s\<turnstile>l[\<Colon>\<preceq>]L =
  G,s\<turnstile>l[\<Colon>\<preceq>]L

theorem lconf_new:

  [| L vn = None; G,s\<turnstile>l[\<Colon>\<preceq>]L |]
  ==> G,s\<turnstile>l(vn|->v)[\<Colon>\<preceq>]L

theorem lconf_upd:

  [| G,s\<turnstile>l[\<Colon>\<preceq>]L; G,s\<turnstile>v\<Colon>\<preceq>T;
     L vn = Some T |]
  ==> G,s\<turnstile>l(vn|->v)[\<Colon>\<preceq>]L

theorem lconf_ext:

  [| G,s\<turnstile>l[\<Colon>\<preceq>]L; G,s\<turnstile>v\<Colon>\<preceq>T |]
  ==> G,s\<turnstile>l(vn|->v)[\<Colon>\<preceq>]L(vn|->T)

theorem lconf_map_sum:

  G,s\<turnstile>l1 (+) l2[\<Colon>\<preceq>]L1 (+) L2 =
  (G,s\<turnstile>l1[\<Colon>\<preceq>]L1 &
   G,s\<turnstile>l2[\<Colon>\<preceq>]L2)

theorem lconf_ext_list:

  [| G,s\<turnstile>l[\<Colon>\<preceq>]L; nodups vns; length Ts = length vns;
     list_all2 (conf G s) vs Ts |]
  ==> G,s\<turnstile>l(vns[|->]vs)[\<Colon>\<preceq>]L(vns[|->]Ts)

theorem lconf_deallocL:

  [| G,s\<turnstile>l[\<Colon>\<preceq>]L(vn|->T); L vn = None |]
  ==> G,s\<turnstile>l[\<Colon>\<preceq>]L

theorem lconf_gext:

  [| G,s\<turnstile>l[\<Colon>\<preceq>]L; s\<le>|s' |]
  ==> G,s'\<turnstile>l[\<Colon>\<preceq>]L

theorem lconf_empty:

  G,s\<turnstile>vs[\<Colon>\<preceq>]empty

theorem lconf_init_vals:

  ALL n. Ball (o2s (fs n)) (is_type G)
  ==> G,s\<turnstile>init_vals fs[\<Colon>\<preceq>]fs

object conformance

theorem oconf_def2:

  G,s\<turnstile>(oi, fs)\<Colon>\<preceq>\<surd>r =
  (G,s\<turnstile>fs[\<Colon>\<preceq>]var_tys G oi r &
   (case r of Inl a => is_type G (obj_ty (oi, fs)) | Inr C => True))

theorem oconf_is_type:

  G,s\<turnstile>obj\<Colon>\<preceq>\<surd>Inl a ==> is_type G (obj_ty obj)

theorem oconf_cong:

  G,set_locals l s\<turnstile>obj\<Colon>\<preceq>\<surd>r =
  G,s\<turnstile>obj\<Colon>\<preceq>\<surd>r

theorem oconf_init_obj_lemma:

  [| !!C c. class G C = Some c ==> unique (fields G C);
     !!C c f m T.
        [| class G C = Some c; table_of (fields G C) f = Some (m, T) |]
        ==> is_type G T;
     case r of Inl a => is_type G (obj_ty (oi, fs)) | Inr C => is_class G C |]
  ==> G,s\<turnstile>(oi, init_vals (var_tys G oi r))\<Colon>\<preceq>\<surd>r

conforms

theorem conforms_globsD:

  [| (x, s)\<Colon>\<preceq>(G, L); globs s r = Some (oi, fs) |]
  ==> G,s\<turnstile>(oi, fs)\<Colon>\<preceq>\<surd>r

theorem conforms_localD:

  (x, s)\<Colon>\<preceq>(G, L) ==> G,s\<turnstile>locals s[\<Colon>\<preceq>]L

theorem conforms_XcptLocD:

  [| (x, s)\<Colon>\<preceq>(G, L); x = Some (XcptLoc a) |]
  ==> G,s\<turnstile>Addr a\<Colon>\<preceq>Class (SXcpt Throwable)

theorem conforms_RefTD:

  [| G,s2\<turnstile>a'\<Colon>\<preceq>RefT t; a' ~= Null;
     (x2, s2)\<Colon>\<preceq>(G, L) |]
  ==> EX a oi vs.
         a' = Addr a &
         globs s2 (Inl a) = Some (oi, vs) &
         G|-obj_ty (oi, vs)<=:RefT t & is_type G (obj_ty (oi, vs))

theorem conforms_StdXcpt:

  (Some (StdXcpt xn), s)\<Colon>\<preceq>(G, L) = Norm s\<Colon>\<preceq>(G, L)

theorem conforms_raise_if:

  ((raise_if c xn) x, s)\<Colon>\<preceq>(G, L) = (x, s)\<Colon>\<preceq>(G, L)

theorem conforms_NormI:

  (x, s)\<Colon>\<preceq>(G, L) ==> Norm s\<Colon>\<preceq>(G, L)

theorem conformsI:

  [| ALL r. ! (oi, fs):globs s r:
               G,s\<turnstile>(oi, fs)\<Colon>\<preceq>\<surd>r;
     G,s\<turnstile>locals s[\<Colon>\<preceq>]L;
     ALL a. x = Some (XcptLoc a) -->
            G,s\<turnstile>Addr a\<Colon>\<preceq>Class (SXcpt Throwable) |]
  ==> (x, s)\<Colon>\<preceq>(G, L)

theorem conforms_xconf:

  [| (x, s)\<Colon>\<preceq>(G, L);
     ALL a. x' = Some (XcptLoc a) -->
            G,s\<turnstile>Addr a\<Colon>\<preceq>Class (SXcpt Throwable) |]
  ==> (x', s)\<Colon>\<preceq>(G, L)

theorem conforms_lupd:

  [| (x, s)\<Colon>\<preceq>(G, L); L vn = Some T;
     G,s\<turnstile>v\<Colon>\<preceq>T |]
  ==> (x, lupd(vn\<mapsto>v) s)\<Colon>\<preceq>(G, L)

theorem conforms_allocL:

  [| (x, s)\<Colon>\<preceq>(G, L); G,s\<turnstile>v\<Colon>\<preceq>T |]
  ==> (x, lupd(vn\<mapsto>v) s)\<Colon>\<preceq>(G, L(vn|->T))

theorem conforms_deallocL:

  [| s\<Colon>\<preceq>(G, L(vn|->T)); L vn = None |] ==> s\<Colon>\<preceq>(G, L)

theorem conforms_gext:

  [| (x, s)\<Colon>\<preceq>(G, L); s\<le>|s';
     ALL r. ! (oi, fs):globs s' r:
               G,s'\<turnstile>(oi, fs)\<Colon>\<preceq>\<surd>r;
     locals s' = locals s |]
  ==> (x, s')\<Colon>\<preceq>(G, L)

theorem conforms_xgext:

  [| (x, s)\<Colon>\<preceq>(G, L); (x', s')\<Colon>\<preceq>(G, L); s'\<le>|s |]
  ==> (x', s)\<Colon>\<preceq>(G, L)

theorem conforms_gupd:

  [| (x, s)\<Colon>\<preceq>(G, L); G,s\<turnstile>obj\<Colon>\<preceq>\<surd>r;
     s\<le>|gupd(r\<mapsto>obj) s |]
  ==> (x, gupd(r\<mapsto>obj) s)\<Colon>\<preceq>(G, L)

theorem conforms_upd_gobj:

  [| (x, s)\<Colon>\<preceq>(G, L); globs s r = Some (oi, vs);
     var_tys G oi r n = Some T; G,s\<turnstile>v\<Colon>\<preceq>T |]
  ==> (x, upd_gobj r n v s)\<Colon>\<preceq>(G, L)

theorem conforms_set_locals:

  [| (x, s)\<Colon>\<preceq>(G, L'); G,s\<turnstile>l[\<Colon>\<preceq>]L |]
  ==> (x, set_locals l s)\<Colon>\<preceq>(G, L)

theorem conforms_return:

  [| (x, s)\<Colon>\<preceq>(G, L); (x', s')\<Colon>\<preceq>(G, L'); s\<le>|s' |]
  ==> (x', set_locals (locals s) s')\<Colon>\<preceq>(G, L)