(*  Title:      HOL/MicroJava/J/Conform.thy
    Author:     David von Oheimb
    Copyright   1999 Technische Universitaet Muenchen
*)

section {* Conformity Relations for Type Soundness Proof *}

theory Conform imports State WellType Exceptions begin

type_synonym 'c env' = "'c prog \<times> (vname \<rightharpoonup> ty)"  -- "same as @{text env} of @{text WellType.thy}"

definition hext :: "aheap => aheap => bool" ("_ <=| _" [51,51] 50) where
 "h<=|h' == \<forall>a C fs. h a = Some(C,fs) --> (\<exists>fs'. h' a = Some(C,fs'))"

definition conf :: "'c prog => aheap => val => ty => bool" 
                                   ("_,_ |- _ ::<= _"  [51,51,51,51] 50) where
 "G,h|-v::<=T == \<exists>T'. typeof (map_option obj_ty o h) v = Some T' \<and> G\<turnstile>T'\<preceq>T"

definition lconf :: "'c prog => aheap => ('a \<rightharpoonup> val) => ('a \<rightharpoonup> ty) => bool"
                                   ("_,_ |- _ [::<=] _" [51,51,51,51] 50) where
 "G,h|-vs[::<=]Ts == \<forall>n T. Ts n = Some T --> (\<exists>v. vs n = Some v \<and> G,h|-v::<=T)"

definition oconf :: "'c prog => aheap => obj => bool" ("_,_ |- _ [ok]" [51,51,51] 50) where
 "G,h|-obj [ok] == G,h|-snd obj[::<=]map_of (fields (G,fst obj))"

definition hconf :: "'c prog => aheap => bool" ("_ |-h _ [ok]" [51,51] 50) where
 "G|-h h [ok]    == \<forall>a obj. h a = Some obj --> G,h|-obj [ok]"
 
definition xconf :: "aheap \<Rightarrow> val option \<Rightarrow> bool" where
  "xconf hp vo  == preallocated hp \<and> (\<forall> v. (vo = Some v) \<longrightarrow> (\<exists> xc. v = (Addr (XcptRef xc))))"

definition conforms :: "xstate => java_mb env' => bool" ("_ ::<= _" [51,51] 50) where
 "s::<=E == prg E|-h heap (store s) [ok] \<and> 
            prg E,heap (store s)|-locals (store s)[::<=]localT E \<and> 
            xconf (heap (store s)) (abrupt s)"


notation (xsymbols)
  hext  ("_ \<le>| _" [51,51] 50) and
  conf  ("_,_ \<turnstile> _ ::\<preceq> _" [51,51,51,51] 50) and
  lconf  ("_,_ \<turnstile> _ [::\<preceq>] _" [51,51,51,51] 50) and
  oconf  ("_,_ \<turnstile> _ \<surd>" [51,51,51] 50) and
  hconf  ("_ \<turnstile>h _ \<surd>" [51,51] 50) and
  conforms  ("_ ::\<preceq> _" [51,51] 50)


subsection "hext"

lemma hextI: 
" \<forall>a C fs . h  a = Some (C,fs) -->   
      (\<exists>fs'. h' a = Some (C,fs')) ==> h\<le>|h'"
apply (unfold hext_def)
apply auto
done

lemma hext_objD: "[|h\<le>|h'; h a = Some (C,fs) |] ==> \<exists>fs'. h' a = Some (C,fs')"
apply (unfold hext_def)
apply (force)
done

lemma hext_refl [simp]: "h\<le>|h"
apply (rule hextI)
apply (fast)
done

lemma hext_new [simp]: "h a = None ==> h\<le>|h(a\<mapsto>x)"
apply (rule hextI)
apply auto
done

lemma hext_trans: "[|h\<le>|h'; h'\<le>|h''|] ==> h\<le>|h''"
apply (rule hextI)
apply (fast dest: hext_objD)
done

lemma hext_upd_obj: "h a = Some (C,fs) ==> h\<le>|h(a\<mapsto>(C,fs'))"
apply (rule hextI)
apply auto
done


subsection "conf"

lemma conf_Null [simp]: "G,h\<turnstile>Null::\<preceq>T = G\<turnstile>RefT NullT\<preceq>T"
apply (unfold conf_def)
apply (simp (no_asm))
done

lemma conf_litval [rule_format (no_asm), simp]: 
  "typeof (\<lambda>v. None) v = Some T --> G,h\<turnstile>v::\<preceq>T"
apply (unfold conf_def)
apply (rule val.induct)
apply auto
done

lemma conf_AddrI: "[|h a = Some obj; G\<turnstile>obj_ty obj\<preceq>T|] ==> G,h\<turnstile>Addr a::\<preceq>T"
apply (unfold conf_def)
apply (simp)
done

lemma conf_obj_AddrI: "[|h a = Some (C,fs); G\<turnstile>C\<preceq>C D|] ==> G,h\<turnstile>Addr a::\<preceq> Class D"
apply (unfold conf_def)
apply (simp)
done

lemma defval_conf [rule_format (no_asm)]: 
  "is_type G T --> G,h\<turnstile>default_val T::\<preceq>T"
apply (unfold conf_def)
apply (rule_tac y = "T" in ty.exhaust)
apply  (erule ssubst)
apply  (rename_tac prim_ty, rule_tac y = "prim_ty" in prim_ty.exhaust)
apply    (auto simp add: widen.null)
done

lemma conf_upd_obj: 
"h a = Some (C,fs) ==> (G,h(a\<mapsto>(C,fs'))\<turnstile>x::\<preceq>T) = (G,h\<turnstile>x::\<preceq>T)"
apply (unfold conf_def)
apply (rule val.induct)
apply auto
done

lemma conf_widen [rule_format (no_asm)]: 
  "wf_prog wf_mb G ==> G,h\<turnstile>x::\<preceq>T --> G\<turnstile>T\<preceq>T' --> G,h\<turnstile>x::\<preceq>T'"
apply (unfold conf_def)
apply (rule val.induct)
apply (auto intro: widen_trans)
done

lemma conf_hext [rule_format (no_asm)]: "h\<le>|h' ==> G,h\<turnstile>v::\<preceq>T --> G,h'\<turnstile>v::\<preceq>T"
apply (unfold conf_def)
apply (rule val.induct)
apply (auto dest: hext_objD)
done

lemma new_locD: "[|h a = None; G,h\<turnstile>Addr t::\<preceq>T|] ==> t\<noteq>a"
apply (unfold conf_def)
apply auto
done

lemma conf_RefTD [rule_format]: 
 "G,h\<turnstile>a'::\<preceq>RefT T \<Longrightarrow> a' = Null \<or>
  (\<exists>a obj T'. a' = Addr a \<and>  h a = Some obj \<and>  obj_ty obj = T' \<and>  G\<turnstile>T'\<preceq>RefT T)"
unfolding conf_def by (induct a') auto

lemma conf_NullTD: "G,h\<turnstile>a'::\<preceq>RefT NullT ==> a' = Null"
apply (drule conf_RefTD)
apply auto
done

lemma non_npD: "[|a' \<noteq> Null; G,h\<turnstile>a'::\<preceq>RefT t|] ==>  
  \<exists>a C fs. a' = Addr a \<and>  h a = Some (C,fs) \<and>  G\<turnstile>Class C\<preceq>RefT t"
apply (drule conf_RefTD)
apply auto
done

lemma non_np_objD: "!!G. [|a' \<noteq> Null; G,h\<turnstile>a'::\<preceq> Class C|] ==>  
  (\<exists>a C' fs. a' = Addr a \<and>  h a = Some (C',fs) \<and>  G\<turnstile>C'\<preceq>C C)"
apply (fast dest: non_npD)
done

lemma non_np_objD' [rule_format (no_asm)]: 
  "a' \<noteq> Null ==> wf_prog wf_mb G ==> G,h\<turnstile>a'::\<preceq>RefT t --> 
  (\<exists>a C fs. a' = Addr a \<and>  h a = Some (C,fs) \<and>  G\<turnstile>Class C\<preceq>RefT t)"
apply(rule_tac y = "t" in ref_ty.exhaust)
 apply (fast dest: conf_NullTD)
apply (fast dest: non_np_objD)
done

lemma conf_list_gext_widen [rule_format (no_asm)]: 
  "wf_prog wf_mb G ==> \<forall>Ts Ts'. list_all2 (conf G h) vs Ts --> 
  list_all2 (\<lambda>T T'. G\<turnstile>T\<preceq>T') Ts Ts' -->  list_all2 (conf G h) vs Ts'"
apply(induct_tac "vs")
 apply(clarsimp)
apply(clarsimp)
apply(frule list_all2_lengthD [THEN sym])
apply(simp (no_asm_use) add: length_Suc_conv)
apply(safe)
apply(frule list_all2_lengthD [THEN sym])
apply(simp (no_asm_use) add: length_Suc_conv)
apply(clarify)
apply(fast elim: conf_widen)
done


subsection "lconf"

lemma lconfD: "[| G,h\<turnstile>vs[::\<preceq>]Ts; Ts n = Some T |] ==> G,h\<turnstile>(the (vs n))::\<preceq>T"
apply (unfold lconf_def)
apply (force)
done

lemma lconf_hext [elim]: "[| G,h\<turnstile>l[::\<preceq>]L; h\<le>|h' |] ==> G,h'\<turnstile>l[::\<preceq>]L"
apply (unfold lconf_def)
apply  (fast elim: conf_hext)
done

lemma lconf_upd: "!!X. [| G,h\<turnstile>l[::\<preceq>]lT;  
  G,h\<turnstile>v::\<preceq>T; lT va = Some T |] ==> G,h\<turnstile>l(va\<mapsto>v)[::\<preceq>]lT"
apply (unfold lconf_def)
apply auto
done

lemma lconf_init_vars_lemma [rule_format (no_asm)]: 
  "\<forall>x. P x --> R (dv x) x ==> (\<forall>x. map_of fs f = Some x --> P x) -->  
  (\<forall>T. map_of fs f = Some T -->  
  (\<exists>v. map_of (map (\<lambda>(f,ft). (f, dv ft)) fs) f = Some v \<and>  R v T))"
apply( induct_tac "fs")
apply auto
done

lemma lconf_init_vars [intro!]: 
"\<forall>n. \<forall>T. map_of fs n = Some T --> is_type G T ==> G,h\<turnstile>init_vars fs[::\<preceq>]map_of fs"
apply (unfold lconf_def init_vars_def)
apply auto
apply( rule lconf_init_vars_lemma)
apply(   erule_tac [3] asm_rl)
apply(  intro strip)
apply(  erule defval_conf)
apply auto
done

lemma lconf_ext: "[|G,s\<turnstile>l[::\<preceq>]L; G,s\<turnstile>v::\<preceq>T|] ==> G,s\<turnstile>l(vn\<mapsto>v)[::\<preceq>]L(vn\<mapsto>T)"
apply (unfold lconf_def)
apply auto
done

lemma lconf_ext_list [rule_format (no_asm)]: 
  "G,h\<turnstile>l[::\<preceq>]L ==> \<forall>vs Ts. distinct vns --> length Ts = length vns --> 
  list_all2 (\<lambda>v T. G,h\<turnstile>v::\<preceq>T) vs Ts --> G,h\<turnstile>l(vns[\<mapsto>]vs)[::\<preceq>]L(vns[\<mapsto>]Ts)"
apply (unfold lconf_def)
apply( induct_tac "vns")
apply(  clarsimp)
apply( clarsimp)
apply( frule list_all2_lengthD)
apply( auto simp add: length_Suc_conv)
done

lemma lconf_restr: "\<lbrakk>lT vn = None; G, h \<turnstile> l [::\<preceq>] lT(vn\<mapsto>T)\<rbrakk> \<Longrightarrow> G, h \<turnstile> l [::\<preceq>] lT"
apply (unfold lconf_def)
apply (intro strip)
apply (case_tac "n = vn")
apply auto
done

subsection "oconf"

lemma oconf_hext: "G,h\<turnstile>obj\<surd> ==> h\<le>|h' ==> G,h'\<turnstile>obj\<surd>"
apply (unfold oconf_def)
apply (fast)
done

lemma oconf_obj: "G,h\<turnstile>(C,fs)\<surd> =  
  (\<forall>T f. map_of(fields (G,C)) f = Some T --> (\<exists>v. fs f = Some v \<and>  G,h\<turnstile>v::\<preceq>T))"
apply (unfold oconf_def lconf_def)
apply auto
done

lemmas oconf_objD = oconf_obj [THEN iffD1, THEN spec, THEN spec, THEN mp]


subsection "hconf"

lemma hconfD: "[|G\<turnstile>h h\<surd>; h a = Some obj|] ==> G,h\<turnstile>obj\<surd>"
apply (unfold hconf_def)
apply (fast)
done

lemma hconfI: "\<forall>a obj. h a=Some obj --> G,h\<turnstile>obj\<surd> ==> G\<turnstile>h h\<surd>"
apply (unfold hconf_def)
apply (fast)
done


subsection "xconf"

lemma xconf_raise_if: "xconf h x \<Longrightarrow> xconf h (raise_if b xcn x)"
by (simp add: xconf_def raise_if_def)



subsection "conforms"

lemma conforms_heapD: "(x, (h, l))::\<preceq>(G, lT) ==> G\<turnstile>h h\<surd>"
apply (unfold conforms_def)
apply (simp)
done

lemma conforms_localD: "(x, (h, l))::\<preceq>(G, lT) ==> G,h\<turnstile>l[::\<preceq>]lT"
apply (unfold conforms_def)
apply (simp)
done

lemma conforms_xcptD: "(x, (h, l))::\<preceq>(G, lT) ==> xconf h x"
apply (unfold conforms_def)
apply (simp)
done

lemma conformsI: "[|G\<turnstile>h h\<surd>; G,h\<turnstile>l[::\<preceq>]lT; xconf h x|] ==> (x, (h, l))::\<preceq>(G, lT)"
apply (unfold conforms_def)
apply auto
done

lemma conforms_restr: "\<lbrakk>lT vn = None; s ::\<preceq> (G, lT(vn\<mapsto>T)) \<rbrakk> \<Longrightarrow> s ::\<preceq> (G, lT)"
by (simp add: conforms_def, fast intro: lconf_restr)

lemma conforms_xcpt_change: "\<lbrakk> (x, (h,l))::\<preceq> (G, lT); xconf h x \<longrightarrow> xconf h x' \<rbrakk> \<Longrightarrow> (x', (h,l))::\<preceq> (G, lT)"
by (simp add: conforms_def)


lemma preallocated_hext: "\<lbrakk> preallocated h; h\<le>|h'\<rbrakk> \<Longrightarrow> preallocated h'"
by (simp add: preallocated_def hext_def)

lemma xconf_hext: "\<lbrakk> xconf h vo; h\<le>|h'\<rbrakk> \<Longrightarrow> xconf h' vo"
by (simp add: xconf_def preallocated_def hext_def)

lemma conforms_hext: "[|(x,(h,l))::\<preceq>(G,lT); h\<le>|h'; G\<turnstile>h h'\<surd> |] 
  ==> (x,(h',l))::\<preceq>(G,lT)"
by (fast dest: conforms_localD conforms_xcptD elim!: conformsI xconf_hext)


lemma conforms_upd_obj: 
  "[|(x,(h,l))::\<preceq>(G, lT); G,h(a\<mapsto>obj)\<turnstile>obj\<surd>; h\<le>|h(a\<mapsto>obj)|] 
  ==> (x,(h(a\<mapsto>obj),l))::\<preceq>(G, lT)"
apply(rule conforms_hext)
apply  auto
apply(rule hconfI)
apply(drule conforms_heapD)
apply(auto elim: oconf_hext dest: hconfD)
done

lemma conforms_upd_local: 
"[|(x,(h, l))::\<preceq>(G, lT); G,h\<turnstile>v::\<preceq>T; lT va = Some T|] 
  ==> (x,(h, l(va\<mapsto>v)))::\<preceq>(G, lT)"
apply (unfold conforms_def)
apply( auto elim: lconf_upd)
done

end
