(* Title: HOL/MicroJava/BV/Effect.thy
Author: Gerwin Klein
Copyright 2000 Technische Universitaet Muenchen
*)
section {* Effect of Instructions on the State Type *}
theory Effect
imports JVMType "../JVM/JVMExceptions"
begin
type_synonym succ_type = "(p_count \<times> state_type option) list"
text {* Program counter of successor instructions: *}
primrec succs :: "instr \<Rightarrow> p_count \<Rightarrow> p_count list" where
"succs (Load idx) pc = [pc+1]"
| "succs (Store idx) pc = [pc+1]"
| "succs (LitPush v) pc = [pc+1]"
| "succs (Getfield F C) pc = [pc+1]"
| "succs (Putfield F C) pc = [pc+1]"
| "succs (New C) pc = [pc+1]"
| "succs (Checkcast C) pc = [pc+1]"
| "succs Pop pc = [pc+1]"
| "succs Dup pc = [pc+1]"
| "succs Dup_x1 pc = [pc+1]"
| "succs Dup_x2 pc = [pc+1]"
| "succs Swap pc = [pc+1]"
| "succs IAdd pc = [pc+1]"
| "succs (Ifcmpeq b) pc = [pc+1, nat (int pc + b)]"
| "succs (Goto b) pc = [nat (int pc + b)]"
| "succs Return pc = [pc]"
| "succs (Invoke C mn fpTs) pc = [pc+1]"
| "succs Throw pc = [pc]"
text "Effect of instruction on the state type:"
fun eff' :: "instr \<times> jvm_prog \<times> state_type \<Rightarrow> state_type"
where
"eff' (Load idx, G, (ST, LT)) = (ok_val (LT ! idx) # ST, LT)" |
"eff' (Store idx, G, (ts#ST, LT)) = (ST, LT[idx:= OK ts])" |
"eff' (LitPush v, G, (ST, LT)) = (the (typeof (\<lambda>v. None) v) # ST, LT)" |
"eff' (Getfield F C, G, (oT#ST, LT)) = (snd (the (field (G,C) F)) # ST, LT)" |
"eff' (Putfield F C, G, (vT#oT#ST, LT)) = (ST,LT)" |
"eff' (New C, G, (ST,LT)) = (Class C # ST, LT)" |
"eff' (Checkcast C, G, (RefT rt#ST,LT)) = (Class C # ST,LT)" |
"eff' (Pop, G, (ts#ST,LT)) = (ST,LT)" |
"eff' (Dup, G, (ts#ST,LT)) = (ts#ts#ST,LT)" |
"eff' (Dup_x1, G, (ts1#ts2#ST,LT)) = (ts1#ts2#ts1#ST,LT)" |
"eff' (Dup_x2, G, (ts1#ts2#ts3#ST,LT)) = (ts1#ts2#ts3#ts1#ST,LT)" |
"eff' (Swap, G, (ts1#ts2#ST,LT)) = (ts2#ts1#ST,LT)" |
"eff' (IAdd, G, (PrimT Integer#PrimT Integer#ST,LT))
= (PrimT Integer#ST,LT)" |
"eff' (Ifcmpeq b, G, (ts1#ts2#ST,LT)) = (ST,LT)" |
"eff' (Goto b, G, s) = s" |
-- "Return has no successor instruction in the same method"
"eff' (Return, G, s) = s" |
-- "Throw always terminates abruptly"
"eff' (Throw, G, s) = s" |
"eff' (Invoke C mn fpTs, G, (ST,LT)) = (let ST' = drop (length fpTs) ST
in (fst (snd (the (method (G,C) (mn,fpTs))))#(tl ST'),LT))"
primrec match_any :: "jvm_prog \<Rightarrow> p_count \<Rightarrow> exception_table \<Rightarrow> cname list" where
"match_any G pc [] = []"
| "match_any G pc (e#es) = (let (start_pc, end_pc, handler_pc, catch_type) = e;
es' = match_any G pc es
in
if start_pc <= pc \<and> pc < end_pc then catch_type#es' else es')"
primrec match :: "jvm_prog \<Rightarrow> xcpt \<Rightarrow> p_count \<Rightarrow> exception_table \<Rightarrow> cname list" where
"match G X pc [] = []"
| "match G X pc (e#es) =
(if match_exception_entry G (Xcpt X) pc e then [Xcpt X] else match G X pc es)"
lemma match_some_entry:
"match G X pc et = (if \<exists>e \<in> set et. match_exception_entry G (Xcpt X) pc e then [Xcpt X] else [])"
by (induct et) auto
fun
xcpt_names :: "instr \<times> jvm_prog \<times> p_count \<times> exception_table \<Rightarrow> cname list"
where
"xcpt_names (Getfield F C, G, pc, et) = match G NullPointer pc et"
| "xcpt_names (Putfield F C, G, pc, et) = match G NullPointer pc et"
| "xcpt_names (New C, G, pc, et) = match G OutOfMemory pc et"
| "xcpt_names (Checkcast C, G, pc, et) = match G ClassCast pc et"
| "xcpt_names (Throw, G, pc, et) = match_any G pc et"
| "xcpt_names (Invoke C m p, G, pc, et) = match_any G pc et"
| "xcpt_names (i, G, pc, et) = []"
definition xcpt_eff :: "instr \<Rightarrow> jvm_prog \<Rightarrow> p_count \<Rightarrow> state_type option \<Rightarrow> exception_table \<Rightarrow> succ_type" where
"xcpt_eff i G pc s et ==
map (\<lambda>C. (the (match_exception_table G C pc et), case s of None \<Rightarrow> None | Some s' \<Rightarrow> Some ([Class C], snd s')))
(xcpt_names (i,G,pc,et))"
definition norm_eff :: "instr \<Rightarrow> jvm_prog \<Rightarrow> state_type option \<Rightarrow> state_type option" where
"norm_eff i G == map_option (\<lambda>s. eff' (i,G,s))"
definition eff :: "instr \<Rightarrow> jvm_prog \<Rightarrow> p_count \<Rightarrow> exception_table \<Rightarrow> state_type option \<Rightarrow> succ_type" where
"eff i G pc et s == (map (\<lambda>pc'. (pc',norm_eff i G s)) (succs i pc)) @ (xcpt_eff i G pc s et)"
definition isPrimT :: "ty \<Rightarrow> bool" where
"isPrimT T == case T of PrimT T' \<Rightarrow> True | RefT T' \<Rightarrow> False"
definition isRefT :: "ty \<Rightarrow> bool" where
"isRefT T == case T of PrimT T' \<Rightarrow> False | RefT T' \<Rightarrow> True"
lemma isPrimT [simp]:
"isPrimT T = (\<exists>T'. T = PrimT T')" by (simp add: isPrimT_def split: ty.splits)
lemma isRefT [simp]:
"isRefT T = (\<exists>T'. T = RefT T')" by (simp add: isRefT_def split: ty.splits)
lemma "list_all2 P a b \<Longrightarrow> \<forall>(x,y) \<in> set (zip a b). P x y"
by (simp add: list_all2_iff)
text "Conditions under which eff is applicable:"
fun
app' :: "instr \<times> jvm_prog \<times> p_count \<times> nat \<times> ty \<times> state_type \<Rightarrow> bool"
where
"app' (Load idx, G, pc, maxs, rT, s) =
(idx < length (snd s) \<and> (snd s) ! idx \<noteq> Err \<and> length (fst s) < maxs)" |
"app' (Store idx, G, pc, maxs, rT, (ts#ST, LT)) =
(idx < length LT)" |
"app' (LitPush v, G, pc, maxs, rT, s) =
(length (fst s) < maxs \<and> typeof (\<lambda>t. None) v \<noteq> None)" |
"app' (Getfield F C, G, pc, maxs, rT, (oT#ST, LT)) =
(is_class G C \<and> field (G,C) F \<noteq> None \<and> fst (the (field (G,C) F)) = C \<and>
G \<turnstile> oT \<preceq> (Class C))" |
"app' (Putfield F C, G, pc, maxs, rT, (vT#oT#ST, LT)) =
(is_class G C \<and> field (G,C) F \<noteq> None \<and> fst (the (field (G,C) F)) = C \<and>
G \<turnstile> oT \<preceq> (Class C) \<and> G \<turnstile> vT \<preceq> (snd (the (field (G,C) F))))" |
"app' (New C, G, pc, maxs, rT, s) =
(is_class G C \<and> length (fst s) < maxs)" |
"app' (Checkcast C, G, pc, maxs, rT, (RefT rt#ST,LT)) =
(is_class G C)" |
"app' (Pop, G, pc, maxs, rT, (ts#ST,LT)) =
True" |
"app' (Dup, G, pc, maxs, rT, (ts#ST,LT)) =
(1+length ST < maxs)" |
"app' (Dup_x1, G, pc, maxs, rT, (ts1#ts2#ST,LT)) =
(2+length ST < maxs)" |
"app' (Dup_x2, G, pc, maxs, rT, (ts1#ts2#ts3#ST,LT)) =
(3+length ST < maxs)" |
"app' (Swap, G, pc, maxs, rT, (ts1#ts2#ST,LT)) =
True" |
"app' (IAdd, G, pc, maxs, rT, (PrimT Integer#PrimT Integer#ST,LT)) =
True" |
"app' (Ifcmpeq b, G, pc, maxs, rT, (ts#ts'#ST,LT)) =
(0 \<le> int pc + b \<and> (isPrimT ts \<and> ts' = ts \<or> isRefT ts \<and> isRefT ts'))" |
"app' (Goto b, G, pc, maxs, rT, s) =
(0 \<le> int pc + b)" |
"app' (Return, G, pc, maxs, rT, (T#ST,LT)) =
(G \<turnstile> T \<preceq> rT)" |
"app' (Throw, G, pc, maxs, rT, (T#ST,LT)) =
isRefT T" |
"app' (Invoke C mn fpTs, G, pc, maxs, rT, s) =
(length fpTs < length (fst s) \<and>
(let apTs = rev (take (length fpTs) (fst s));
X = hd (drop (length fpTs) (fst s))
in
G \<turnstile> X \<preceq> Class C \<and> is_class G C \<and> method (G,C) (mn,fpTs) \<noteq> None \<and>
list_all2 (\<lambda>x y. G \<turnstile> x \<preceq> y) apTs fpTs))" |
"app' (i,G, pc,maxs,rT,s) = False"
definition xcpt_app :: "instr \<Rightarrow> jvm_prog \<Rightarrow> nat \<Rightarrow> exception_table \<Rightarrow> bool" where
"xcpt_app i G pc et \<equiv> \<forall>C\<in>set(xcpt_names (i,G,pc,et)). is_class G C"
definition app :: "instr \<Rightarrow> jvm_prog \<Rightarrow> nat \<Rightarrow> ty \<Rightarrow> nat \<Rightarrow> exception_table \<Rightarrow> state_type option \<Rightarrow> bool" where
"app i G maxs rT pc et s == case s of None \<Rightarrow> True | Some t \<Rightarrow> app' (i,G,pc,maxs,rT,t) \<and> xcpt_app i G pc et"
lemma match_any_match_table:
"C \<in> set (match_any G pc et) \<Longrightarrow> match_exception_table G C pc et \<noteq> None"
apply (induct et)
apply simp
apply simp
apply clarify
apply (simp split: split_if_asm)
apply (auto simp add: match_exception_entry_def)
done
lemma match_X_match_table:
"C \<in> set (match G X pc et) \<Longrightarrow> match_exception_table G C pc et \<noteq> None"
apply (induct et)
apply simp
apply (simp split: split_if_asm)
done
lemma xcpt_names_in_et:
"C \<in> set (xcpt_names (i,G,pc,et)) \<Longrightarrow>
\<exists>e \<in> set et. the (match_exception_table G C pc et) = fst (snd (snd e))"
apply (cases i)
apply (auto dest!: match_any_match_table match_X_match_table
dest: match_exception_table_in_et)
done
lemma 1: "2 < length a \<Longrightarrow> (\<exists>l l' l'' ls. a = l#l'#l''#ls)"
proof (cases a)
fix x xs assume "a = x#xs" "2 < length a"
thus ?thesis by - (cases xs, simp, cases "tl xs", auto)
qed auto
lemma 2: "\<not>(2 < length a) \<Longrightarrow> a = [] \<or> (\<exists> l. a = [l]) \<or> (\<exists> l l'. a = [l,l'])"
proof -
assume "\<not>(2 < length a)"
hence "length a < (Suc (Suc (Suc 0)))" by simp
hence * : "length a = 0 \<or> length a = Suc 0 \<or> length a = Suc (Suc 0)"
by (auto simp add: less_Suc_eq)
{
fix x
assume "length x = Suc 0"
hence "\<exists> l. x = [l]" by (cases x) auto
} note 0 = this
have "length a = Suc (Suc 0) \<Longrightarrow> \<exists>l l'. a = [l,l']" by (cases a) (auto dest: 0)
with * show ?thesis by (auto dest: 0)
qed
lemmas [simp] = app_def xcpt_app_def
text {*
\medskip
simp rules for @{term app}
*}
lemma appNone[simp]: "app i G maxs rT pc et None = True" by simp
lemma appLoad[simp]:
"(app (Load idx) G maxs rT pc et (Some s)) = (\<exists>ST LT. s = (ST,LT) \<and> idx < length LT \<and> LT!idx \<noteq> Err \<and> length ST < maxs)"
by (cases s, simp)
lemma appStore[simp]:
"(app (Store idx) G maxs rT pc et (Some s)) = (\<exists>ts ST LT. s = (ts#ST,LT) \<and> idx < length LT)"
by (cases s, cases "2 < length (fst s)", auto dest: 1 2)
lemma appLitPush[simp]:
"(app (LitPush v) G maxs rT pc et (Some s)) = (\<exists>ST LT. s = (ST,LT) \<and> length ST < maxs \<and> typeof (\<lambda>v. None) v \<noteq> None)"
by (cases s, simp)
lemma appGetField[simp]:
"(app (Getfield F C) G maxs rT pc et (Some s)) =
(\<exists> oT vT ST LT. s = (oT#ST, LT) \<and> is_class G C \<and>
field (G,C) F = Some (C,vT) \<and> G \<turnstile> oT \<preceq> (Class C) \<and> (\<forall>x \<in> set (match G NullPointer pc et). is_class G x))"
by (cases s, cases "2 <length (fst s)", auto dest!: 1 2)
lemma appPutField[simp]:
"(app (Putfield F C) G maxs rT pc et (Some s)) =
(\<exists> vT vT' oT ST LT. s = (vT#oT#ST, LT) \<and> is_class G C \<and>
field (G,C) F = Some (C, vT') \<and> G \<turnstile> oT \<preceq> (Class C) \<and> G \<turnstile> vT \<preceq> vT' \<and>
(\<forall>x \<in> set (match G NullPointer pc et). is_class G x))"
by (cases s, cases "2 <length (fst s)", auto dest!: 1 2)
lemma appNew[simp]:
"(app (New C) G maxs rT pc et (Some s)) =
(\<exists>ST LT. s=(ST,LT) \<and> is_class G C \<and> length ST < maxs \<and>
(\<forall>x \<in> set (match G OutOfMemory pc et). is_class G x))"
by (cases s, simp)
lemma appCheckcast[simp]:
"(app (Checkcast C) G maxs rT pc et (Some s)) =
(\<exists>rT ST LT. s = (RefT rT#ST,LT) \<and> is_class G C \<and>
(\<forall>x \<in> set (match G ClassCast pc et). is_class G x))"
by (cases s, cases "fst s", simp) (cases "hd (fst s)", auto)
lemma appPop[simp]:
"(app Pop G maxs rT pc et (Some s)) = (\<exists>ts ST LT. s = (ts#ST,LT))"
by (cases s, cases "2 <length (fst s)", auto dest: 1 2)
lemma appDup[simp]:
"(app Dup G maxs rT pc et (Some s)) = (\<exists>ts ST LT. s = (ts#ST,LT) \<and> 1+length ST < maxs)"
by (cases s, cases "2 <length (fst s)", auto dest: 1 2)
lemma appDup_x1[simp]:
"(app Dup_x1 G maxs rT pc et (Some s)) = (\<exists>ts1 ts2 ST LT. s = (ts1#ts2#ST,LT) \<and> 2+length ST < maxs)"
by (cases s, cases "2 <length (fst s)", auto dest: 1 2)
lemma appDup_x2[simp]:
"(app Dup_x2 G maxs rT pc et (Some s)) = (\<exists>ts1 ts2 ts3 ST LT. s = (ts1#ts2#ts3#ST,LT) \<and> 3+length ST < maxs)"
by (cases s, cases "2 <length (fst s)", auto dest: 1 2)
lemma appSwap[simp]:
"app Swap G maxs rT pc et (Some s) = (\<exists>ts1 ts2 ST LT. s = (ts1#ts2#ST,LT))"
by (cases s, cases "2 <length (fst s)") (auto dest: 1 2)
lemma appIAdd[simp]:
"app IAdd G maxs rT pc et (Some s) = (\<exists> ST LT. s = (PrimT Integer#PrimT Integer#ST,LT))"
(is "?app s = ?P s")
proof (cases s)
case (Pair a b)
have "?app (a,b) = ?P (a,b)"
proof (cases a)
fix t ts assume a: "a = t#ts"
show ?thesis
proof (cases t)
fix p assume p: "t = PrimT p"
show ?thesis
proof (cases p)
assume ip: "p = Integer"
show ?thesis
proof (cases ts)
fix t' ts' assume t': "ts = t' # ts'"
show ?thesis
proof (cases t')
fix p' assume "t' = PrimT p'"
with t' ip p a
show ?thesis by (cases p') auto
qed (auto simp add: a p ip t')
qed (auto simp add: a p ip)
qed (auto simp add: a p)
qed (auto simp add: a)
qed auto
with Pair show ?thesis by simp
qed
lemma appIfcmpeq[simp]:
"app (Ifcmpeq b) G maxs rT pc et (Some s) =
(\<exists>ts1 ts2 ST LT. s = (ts1#ts2#ST,LT) \<and> 0 \<le> int pc + b \<and>
((\<exists> p. ts1 = PrimT p \<and> ts2 = PrimT p) \<or> (\<exists>r r'. ts1 = RefT r \<and> ts2 = RefT r')))"
by (cases s, cases "2 <length (fst s)", auto dest!: 1 2)
lemma appReturn[simp]:
"app Return G maxs rT pc et (Some s) = (\<exists>T ST LT. s = (T#ST,LT) \<and> (G \<turnstile> T \<preceq> rT))"
by (cases s, cases "2 <length (fst s)", auto dest: 1 2)
lemma appGoto[simp]:
"app (Goto b) G maxs rT pc et (Some s) = (0 \<le> int pc + b)"
by simp
lemma appThrow[simp]:
"app Throw G maxs rT pc et (Some s) =
(\<exists>T ST LT r. s=(T#ST,LT) \<and> T = RefT r \<and> (\<forall>C \<in> set (match_any G pc et). is_class G C))"
by (cases s, cases "2 < length (fst s)", auto dest: 1 2)
lemma appInvoke[simp]:
"app (Invoke C mn fpTs) G maxs rT pc et (Some s) = (\<exists>apTs X ST LT mD' rT' b'.
s = ((rev apTs) @ (X # ST), LT) \<and> length apTs = length fpTs \<and> is_class G C \<and>
G \<turnstile> X \<preceq> Class C \<and> (\<forall>(aT,fT)\<in>set(zip apTs fpTs). G \<turnstile> aT \<preceq> fT) \<and>
method (G,C) (mn,fpTs) = Some (mD', rT', b') \<and>
(\<forall>C \<in> set (match_any G pc et). is_class G C))" (is "?app s = ?P s")
proof (cases s)
note list_all2_iff [simp]
case (Pair a b)
have "?app (a,b) \<Longrightarrow> ?P (a,b)"
proof -
assume app: "?app (a,b)"
hence "a = (rev (rev (take (length fpTs) a))) @ (drop (length fpTs) a) \<and>
length fpTs < length a" (is "?a \<and> ?l")
by auto
hence "?a \<and> 0 < length (drop (length fpTs) a)" (is "?a \<and> ?l")
by auto
hence "?a \<and> ?l \<and> length (rev (take (length fpTs) a)) = length fpTs"
by (auto)
hence "\<exists>apTs ST. a = rev apTs @ ST \<and> length apTs = length fpTs \<and> 0 < length ST"
by blast
hence "\<exists>apTs ST. a = rev apTs @ ST \<and> length apTs = length fpTs \<and> ST \<noteq> []"
by blast
hence "\<exists>apTs ST. a = rev apTs @ ST \<and> length apTs = length fpTs \<and>
(\<exists>X ST'. ST = X#ST')"
by (simp add: neq_Nil_conv)
hence "\<exists>apTs X ST. a = rev apTs @ X # ST \<and> length apTs = length fpTs"
by blast
with app
show ?thesis by clarsimp blast
qed
with Pair
have "?app s \<Longrightarrow> ?P s" by (simp only:)
moreover
have "?P s \<Longrightarrow> ?app s" by (clarsimp simp add: min.absorb2)
ultimately
show ?thesis by (rule iffI)
qed
lemma effNone:
"(pc', s') \<in> set (eff i G pc et None) \<Longrightarrow> s' = None"
by (auto simp add: eff_def xcpt_eff_def norm_eff_def)
lemma xcpt_app_lemma [code]:
"xcpt_app i G pc et = list_all (is_class G) (xcpt_names (i, G, pc, et))"
by (simp add: list_all_iff)
lemmas [simp del] = app_def xcpt_app_def
end