Theory JTypeSafe

theory JTypeSafe
imports Eval Conform
(*  Title:      HOL/MicroJava/J/JTypeSafe.thy
Author: David von Oheimb, Technische Universitaet Muenchen
*)


header {* \isaheader{Type Safety Proof} *}

theory JTypeSafe imports Eval Conform begin

declare split_beta [simp]

lemma NewC_conforms:
"[|h a = None; (x,(h, l))::\<preceq>(G, lT); wf_prog wf_mb G; is_class G C|] ==>
(x,(h(a\<mapsto>(C,(init_vars (fields (G,C))))), l))::\<preceq>(G, lT)"

apply( erule conforms_upd_obj)
apply( unfold oconf_def)
apply( auto dest!: fields_is_type simp add: wf_prog_ws_prog)
done


lemma Cast_conf:
"[| wf_prog wf_mb G; G,h\<turnstile>v::\<preceq>CC; G\<turnstile>CC \<preceq>? Class D; cast_ok G D h v|]
==> G,h\<turnstile>v::\<preceq>Class D"

apply (case_tac "CC")
apply simp
apply (case_tac "ref_ty")
apply (clarsimp simp add: conf_def)
apply simp
apply (ind_cases "G \<turnstile> Class cname \<preceq>? Class D" for cname, simp)
apply (rule conf_widen, assumption+) apply (erule widen.subcls)

apply (unfold cast_ok_def)
apply( case_tac "v = Null")
apply( simp)
apply( clarify)
apply( drule (1) non_npD)
apply( auto intro!: conf_AddrI simp add: obj_ty_def)
done


lemma FAcc_type_sound:
"[| wf_prog wf_mb G; field (G,C) fn = Some (fd, ft); (x,(h,l))::\<preceq>(G,lT);
x' = None --> G,h\<turnstile>a'::\<preceq> Class C; np a' x' = None |] ==>
G,h\<turnstile>the (snd (the (h (the_Addr a'))) (fn, fd))::\<preceq>ft"

apply( drule np_NoneD)
apply( erule conjE)
apply( erule (1) notE impE)
apply( drule non_np_objD)
apply auto
apply( drule conforms_heapD [THEN hconfD])
apply( assumption)
apply (frule wf_prog_ws_prog)
apply( drule (2) widen_cfs_fields)
apply( drule (1) oconf_objD)
apply auto
done

lemma FAss_type_sound:
"[| wf_prog wf_mb G; a = the_Addr a'; (c, fs) = the (h a);
(G, lT)\<turnstile>v::T'; G\<turnstile>T'\<preceq>ft;
(G, lT)\<turnstile>aa::Class C;
field (G,C) fn = Some (fd, ft); h''≤|h';
x' = None --> G,h'\<turnstile>a'::\<preceq> Class C; h'≤|h;
Norm (h, l)::\<preceq>(G, lT); G,h\<turnstile>x::\<preceq>T'; np a' x' = None|] ==>
h''≤|h(a\<mapsto>(c,(fs((fn,fd)\<mapsto>x)))) ∧
Norm(h(a\<mapsto>(c,(fs((fn,fd)\<mapsto>x)))), l)::\<preceq>(G, lT) ∧
G,h(a\<mapsto>(c,(fs((fn,fd)\<mapsto>x))))\<turnstile>x::\<preceq>T'"

apply( drule np_NoneD)
apply( erule conjE)
apply( simp)
apply( drule non_np_objD)
apply( assumption)
apply( clarify)
apply( simp (no_asm_use))
apply( frule (1) hext_objD)
apply( erule exE)
apply( simp)
apply( clarify)
apply( rule conjI)
apply( fast elim: hext_trans hext_upd_obj)
apply( rule conjI)
prefer 2
apply( fast elim: conf_upd_obj [THEN iffD2])

apply( rule conforms_upd_obj)
apply auto
apply( rule_tac [2] hextI)
prefer 2
apply( force)
apply( rule oconf_hext)
apply( erule_tac [2] hext_upd_obj)
apply (frule wf_prog_ws_prog)
apply( drule (2) widen_cfs_fields)
apply( rule oconf_obj [THEN iffD2])
apply( simp (no_asm))
apply( intro strip)
apply( case_tac "(aaa, b) = (fn, fd)")
apply( simp)
apply( fast intro: conf_widen)
apply( fast dest: conforms_heapD [THEN hconfD] oconf_objD)
done



lemma Call_lemma2: "[| wf_prog wf_mb G; list_all2 (conf G h) pvs pTs;
list_all2 (λT T'. G\<turnstile>T\<preceq>T') pTs pTs'; wf_mhead G (mn,pTs') rT;
length pTs' = length pns; distinct pns;
Ball (set lvars) (split (λvn. is_type G))
|] ==> G,h\<turnstile>init_vars lvars(pns[\<mapsto>]pvs)[::\<preceq>]map_of lvars(pns[\<mapsto>]pTs')"

apply (unfold wf_mhead_def)
apply( clarsimp)
apply( rule lconf_ext_list)
apply( rule Ball_set_table [THEN lconf_init_vars])
apply( force)
apply( assumption)
apply( assumption)
apply( erule (2) conf_list_gext_widen)
done

lemma Call_type_sound:
"[| wf_java_prog G; a' ≠ Null; Norm (h, l)::\<preceq>(G, lT); class G C = Some y;
max_spec G C (mn,pTsa) = {((mda,rTa),pTs')}; xc≤|xh; xh≤|h;
list_all2 (conf G h) pvs pTsa;
(md, rT, pns, lvars, blk, res) =
the (method (G,fst (the (h (the_Addr a')))) (mn, pTs'));
∀lT. (np a' None, h, init_vars lvars(pns[\<mapsto>]pvs)(This\<mapsto>a'))::\<preceq>(G, lT) -->
(G, lT)\<turnstile>blk\<surd> --> h≤|xi ∧ (xcptb, xi, xl)::\<preceq>(G, lT);
∀lT. (xcptb,xi, xl)::\<preceq>(G, lT) --> (∀T. (G, lT)\<turnstile>res::T -->
xi≤|h' ∧ (x',h', xj)::\<preceq>(G, lT) ∧ (x' = None --> G,h'\<turnstile>v::\<preceq>T));
G,xh\<turnstile>a'::\<preceq> Class C
|] ==>
xc≤|h' ∧ (x',(h', l))::\<preceq>(G, lT) ∧ (x' = None --> G,h'\<turnstile>v::\<preceq>rTa)"

apply( drule max_spec2mheads)
apply( clarify)
apply( drule (2) non_np_objD')
apply( clarsimp)
apply( frule (1) hext_objD)
apply( clarsimp)
apply( drule (3) Call_lemma)
apply( clarsimp simp add: wf_java_mdecl_def)
apply( erule_tac V = "method ?sig ?x = ?y" in thin_rl)
apply( drule spec, erule impE, erule_tac [2] notE impE, tactic "assume_tac 2")
apply( rule conformsI)
apply( erule conforms_heapD)
apply( rule lconf_ext)
apply( force elim!: Call_lemma2)
apply( erule conf_hext, erule (1) conf_obj_AddrI)
apply( erule_tac V = "?E\<turnstile>?blk\<surd>" in thin_rl)
apply (simp add: conforms_def)

apply( erule conjE)
apply( drule spec, erule (1) impE)
apply( drule spec, erule (1) impE)
apply( erule_tac V = "?E\<turnstile>res::?rT" in thin_rl)
apply( clarify)
apply( rule conjI)
apply( fast intro: hext_trans)
apply( rule conjI)
apply( rule_tac [2] impI)
apply( erule_tac [2] notE impE, tactic "assume_tac 2")
apply( frule_tac [2] conf_widen)
apply( tactic "assume_tac 4")
apply( tactic "assume_tac 2")
prefer 2
apply( fast elim!: widen_trans)
apply (rule conforms_xcpt_change)
apply( rule conforms_hext) apply assumption
apply( erule (1) hext_trans)
apply( erule conforms_heapD)
apply (simp add: conforms_def)
done



declare split_if [split del]
declare fun_upd_apply [simp del]
declare fun_upd_same [simp]
declare wf_prog_ws_prog [simp]

ML{*
val forward_hyp_tac = ALLGOALS (TRY o (EVERY' [dtac spec, mp_tac,
(mp_tac ORELSE' (dtac spec THEN' mp_tac)), REPEAT o (etac conjE)]))
*}



theorem eval_evals_exec_type_sound:
"wf_java_prog G ==>
(G\<turnstile>(x,(h,l)) -e \<succ>v -> (x', (h',l')) -->
(∀lT. (x,(h ,l ))::\<preceq>(G,lT) --> (∀T . (G,lT)\<turnstile>e :: T -->
h≤|h' ∧ (x',(h',l'))::\<preceq>(G,lT) ∧ (x'=None --> G,h'\<turnstile>v ::\<preceq> T )))) ∧
(G\<turnstile>(x,(h,l)) -es[\<succ>]vs-> (x', (h',l')) -->
(∀lT. (x,(h ,l ))::\<preceq>(G,lT) --> (∀Ts. (G,lT)\<turnstile>es[::]Ts -->
h≤|h' ∧ (x',(h',l'))::\<preceq>(G,lT) ∧ (x'=None --> list_all2 (λv T. G,h'\<turnstile>v::\<preceq>T) vs Ts)))) ∧
(G\<turnstile>(x,(h,l)) -c -> (x', (h',l')) -->
(∀lT. (x,(h ,l ))::\<preceq>(G,lT) --> (G,lT)\<turnstile>c \<surd> -->
h≤|h' ∧ (x',(h',l'))::\<preceq>(G,lT)))"

apply( rule eval_evals_exec_induct)
apply( unfold c_hupd_def)

-- "several simplifications, XcptE, XcptEs, XcptS, Skip, Nil??"
apply( simp_all)
apply( tactic "ALLGOALS (REPEAT o resolve_tac [impI, allI])")
apply( tactic {* ALLGOALS (eresolve_tac [@{thm ty_expr.cases}, @{thm ty_exprs.cases}, @{thm wt_stmt.cases}]
THEN_ALL_NEW (full_simp_tac (put_simpset (simpset_of @{theory_context Conform}) @{context}))) *}
)
apply(tactic "ALLGOALS (EVERY' [REPEAT o (etac conjE), REPEAT o hyp_subst_tac @{context}])")

-- "Level 7"
-- "15 NewC"
apply (drule sym)
apply( drule new_AddrD)
apply( erule disjE)
prefer 2
apply( simp (no_asm_simp))
apply (rule conforms_xcpt_change, assumption)
apply (simp (no_asm_simp) add: xconf_def)
apply( clarsimp)
apply( rule conjI)
apply( force elim!: NewC_conforms)
apply( rule conf_obj_AddrI)
apply( rule_tac [2] rtrancl.rtrancl_refl)
apply( simp (no_asm))

-- "for Cast"
defer 1

-- "14 Lit"
apply( erule conf_litval)

-- "13 BinOp"
apply (tactic "forward_hyp_tac")
apply (tactic "forward_hyp_tac")
apply( rule conjI, erule (1) hext_trans)
apply( erule conjI)
apply( clarsimp)
apply( drule eval_no_xcpt)
apply( simp split add: binop.split)

-- "12 LAcc"
apply simp
apply( fast elim: conforms_localD [THEN lconfD])

-- "for FAss"
apply( tactic {* EVERY'[eresolve_tac [@{thm ty_expr.cases}, @{thm ty_exprs.cases}, @{thm wt_stmt.cases}]
THEN_ALL_NEW (full_simp_tac @{context}), REPEAT o (etac conjE), hyp_subst_tac @{context}] 3*}
)

-- "for if"
apply( tactic {* (Induct_Tacs.case_tac @{context} "the_Bool v" THEN_ALL_NEW
(asm_full_simp_tac @{context})) 7*}
)

apply (tactic "forward_hyp_tac")

-- "11+1 if"
prefer 7
apply( fast intro: hext_trans)
prefer 7
apply( fast intro: hext_trans)

-- "10 Expr"
prefer 6
apply( fast)

-- "9 ???"
apply( simp_all)

-- "8 Cast"
prefer 8
apply (rule conjI)
apply (fast intro: conforms_xcpt_change xconf_raise_if)

apply clarify
apply (drule raise_if_NoneD)
apply (clarsimp)
apply (rule Cast_conf)
apply assumption+


-- "7 LAss"
apply (fold fun_upd_def)
apply( tactic {* (eresolve_tac [@{thm ty_expr.cases}, @{thm ty_exprs.cases}, @{thm wt_stmt.cases}]
THEN_ALL_NEW (full_simp_tac @{context})) 1 *}
)
apply (intro strip)
apply (case_tac E)
apply (simp)
apply( blast intro: conforms_upd_local conf_widen)

-- "6 FAcc"
apply (rule conjI)
apply (simp add: np_def)
apply (fast intro: conforms_xcpt_change xconf_raise_if)
apply( fast elim!: FAcc_type_sound)

-- "5 While"
prefer 5
apply(erule_tac V = "?a --> ?b" in thin_rl)
apply(drule (1) ty_expr_ty_exprs_wt_stmt.Loop)
apply(force elim: hext_trans)

apply (tactic "forward_hyp_tac")

-- "4 Cond"
prefer 4
apply (case_tac "the_Bool v")
apply simp
apply( fast dest: evals_no_xcpt intro: conf_hext hext_trans)
apply simp
apply( fast dest: evals_no_xcpt intro: conf_hext hext_trans)

-- "3 ;;"
prefer 3
apply( fast dest: evals_no_xcpt intro: conf_hext hext_trans)


-- "2 FAss"
apply (subgoal_tac "(np a' x1, aa, ba) ::\<preceq> (G, lT)")
prefer 2
apply (simp add: np_def)
apply (fast intro: conforms_xcpt_change xconf_raise_if)
apply( case_tac "x2")
-- "x2 = None"
apply (simp)
apply (tactic forward_hyp_tac, clarify)
apply( drule eval_no_xcpt)
apply( erule FAss_type_sound, rule HOL.refl, assumption+)
-- "x2 = Some a"
apply ( simp (no_asm_simp))
apply( fast intro: hext_trans)


apply( tactic prune_params_tac)
-- "Level 52"

-- "1 Call"
apply( case_tac "x")
prefer 2
apply( clarsimp)
apply( drule exec_xcpt)
apply( simp)
apply( drule_tac eval_xcpt)
apply( simp)
apply( fast elim: hext_trans)
apply( clarify)
apply( drule evals_no_xcpt)
apply( simp)
apply( case_tac "a' = Null")
apply( simp)
apply( drule exec_xcpt)
apply( simp)
apply( drule eval_xcpt)
apply( simp)
apply (rule conjI)
apply( fast elim: hext_trans)
apply (rule conforms_xcpt_change, assumption)
apply (simp (no_asm_simp) add: xconf_def)
apply(clarsimp)

apply( drule ty_expr_is_type, simp)
apply(clarsimp)
apply(unfold is_class_def)
apply(clarsimp)

apply(rule Call_type_sound);
prefer 11
apply blast
apply (simp (no_asm_simp))+

done


lemma eval_type_sound: "!!E s s'.
[| wf_java_prog G; G\<turnstile>(x,s) -e\<succ>v -> (x',s'); (x,s)::\<preceq>E; E\<turnstile>e::T; G=prg E |]
==> (x',s')::\<preceq>E ∧ (x'=None --> G,heap s'\<turnstile>v::\<preceq>T) ∧ heap s ≤| heap s'"

apply (simp (no_asm_simp) only: split_tupled_all)
apply (drule eval_evals_exec_type_sound [THEN conjunct1, THEN mp, THEN spec, THEN mp])
apply auto
done


lemma evals_type_sound: "!!E s s'.
[| wf_java_prog G; G\<turnstile>(x,s) -es[\<succ>]vs -> (x',s'); (x,s)::\<preceq>E; E\<turnstile>es[::]Ts; G=prg E |]
==> (x',s')::\<preceq>E ∧ (x'=None --> (list_all2 (λv T. G,heap s'\<turnstile>v::\<preceq>T) vs Ts)) ∧ heap s ≤| heap s'"

apply (simp (no_asm_simp) only: split_tupled_all)
apply (drule eval_evals_exec_type_sound [THEN conjunct2, THEN conjunct1, THEN mp, THEN spec, THEN mp])
apply auto
done

lemma exec_type_sound: "!!E s s'.
[| wf_java_prog G; G\<turnstile>(x,s) -s0-> (x',s'); (x,s)::\<preceq>E; E\<turnstile>s0\<surd>; G=prg E |]
==> (x',s')::\<preceq>E ∧ heap s ≤| heap s'"

apply( simp (no_asm_simp) only: split_tupled_all)
apply (drule eval_evals_exec_type_sound
[THEN conjunct2, THEN conjunct2, THEN mp, THEN spec, THEN mp])
apply auto
done

theorem all_methods_understood:
"[|G=prg E; wf_java_prog G; G\<turnstile>(x,s) -e\<succ>a'-> Norm s'; a' ≠ Null;
(x,s)::\<preceq>E; E\<turnstile>e::Class C; method (G,C) sig ≠ None|] ==>
method (G,fst (the (heap s' (the_Addr a')))) sig ≠ None"

apply (frule eval_type_sound, assumption+)
apply(clarsimp)
apply( frule widen_methd)
apply assumption
prefer 2
apply( fast)
apply( drule non_npD)
apply auto
done

declare split_beta [simp del]
declare fun_upd_apply [simp]
declare wf_prog_ws_prog [simp del]

end