lh-l4v/lib/HaskellLemmaBucket.thy

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(*
* Copyright 2014, NICTA
*
* This software may be distributed and modified according to the terms of
* the BSD 2-Clause license. Note that NO WARRANTY is provided.
* See "LICENSE_BSD2.txt" for details.
*
* @TAG(NICTA_BSD)
*)
theory HaskellLemmaBucket
imports
HaskellLib_H
NonDetMonadLemmaBucket
begin
lemma map_bits_to_bl:
"map (op !! x) [0..<size x] = reverse (to_bl x)"
apply simp
apply (subst list_eq_iff_nth_eq)
apply rule
apply (simp add: word_size)
apply simp
apply rule
apply rule
apply (subst test_bit_bl)
apply (simp add: word_size)
done
lemma not_orList_is_replicate:
"\<not> orList ls \<Longrightarrow> ls = replicate (length ls) False"
proof (induct ls rule: rev_induct)
case Nil thus ?case unfolding orList_def by simp
next
case (snoc l ls)
from snoc.prems have ol: "\<not> orList ls" and nl: "\<not> l" unfolding orList_def by auto
have "ls = replicate (length ls) False" by (rule snoc.hyps [OF ol])
thus ?case
by (rule ssubst) (simp add: nl replicate_app_Cons_same [where xs = "[]", simplified])
qed
lemma andList_Cons:
assumes al: "andList $ map P (y # ys)"
shows "P y"
using al unfolding andList_def
by simp (induct rule: rev_induct, simp+)
lemma andList_mapE:
assumes al: "andList $ map P xs"
and xv: "x \<in> set xs"
shows "P x"
using al xv
proof (induct xs arbitrary: x rule: rev_induct)
case Nil thus ?case by simp
next
case (snoc y ys)
show ?case
proof (cases "x = y")
case True
with snoc.prems show ?thesis by (simp add: andList_def)
next
case False
with snoc.prems show ?thesis
by (auto simp: andList_def intro!: snoc.hyps)
qed
qed
lemma andList_to_aligned:
assumes al: "andList $ map (\<lambda>x. x && mask pageBits = 0) xs"
and xv: "x \<in> set xs"
shows "is_aligned x pageBits"
proof (subst is_aligned_mask)
from al show "x && mask pageBits = 0" by (rule andList_mapE) fact
qed
(* minimum/maximum *)
lemma maximum_ge: "x \<in> set b \<Longrightarrow> x \<le> maximum b"
unfolding maximum_def by (auto intro: Max_ge)
lemma less_minimum_not_in:
"\<lbrakk> ls \<noteq> []; x < minimum ls \<rbrakk> \<Longrightarrow> x \<notin> set ls"
unfolding minimum_def by auto
lemma minimum_le_member:
"\<lbrakk> x \<in> set ls; ls \<noteq> []\<rbrakk> \<Longrightarrow> minimum ls \<le> x"
unfolding minimum_def
apply (rule Min_le)
apply simp
apply simp
done
lemma minimum_map_distrib:
fixes f :: "('a :: linorder) \<Rightarrow> 'a" and ls :: "'a list"
assumes minf: "\<And>x y. \<lbrakk>x \<in> set ls; y \<in> set ls\<rbrakk> \<Longrightarrow> min (f x) (f y) = f (min x y)"
and lsn: "ls \<noteq> []"
shows "minimum (map f ls) = f (minimum ls)"
unfolding minimum_def
apply simp
apply (rule Min_image_distrib)
apply (erule (1) minf)
apply simp
apply (simp add: lsn)
done
lemma minimum_enum_upto:
fixes x :: "'a::len word"
assumes le: "x \<le> y"
shows "minimum [x .e. y] = x"
unfolding minimum_def using le
by (auto simp: upto_enum_set_conv intro!: MinI)
lemma break_subsetsD:
"break f xs = (ys, zs) \<Longrightarrow> set ys \<subseteq> set xs \<and> set zs \<subseteq> set xs"
apply (induct xs arbitrary: ys zs)
apply simp
apply (case_tac "break f xs")
apply (elim meta_allE, drule(1) meta_mp)
apply (fastforce simp: split_def split: split_if_asm)
done
lemma distinct_prop_breakD:
"\<lbrakk> distinct_prop P xs; break f xs = (ys, zs) \<rbrakk>
\<Longrightarrow> \<forall>y \<in> set ys. \<forall>z \<in> set zs. P y z"
apply (induct xs arbitrary: ys zs)
apply simp
apply (simp add: split_def split: split_if_asm)
apply (case_tac "break f xs")
apply (elim meta_allE, drule(1) meta_mp)
apply (frule break_subsetsD)
apply fastforce
done
lemma stateAssert_wp:
"\<lbrace>\<lambda>s. P s \<longrightarrow> Q () s\<rbrace> stateAssert P e \<lbrace>Q\<rbrace>"
by (clarsimp simp: stateAssert_def) wp
lemma is_aligned_alignUp[simp]:
"is_aligned (alignUp p n) n"
by (simp add: alignUp_def complement_def
is_aligned_mask mask_def
word_bw_assocs)
lemma alignUp_le[simp]:
"alignUp p n \<le> p + 2 ^ n - 1"
unfolding alignUp_def
by (rule word_and_le2)
lemma complement_mask:
"complement (2 ^ n - 1) = ~~ mask n"
unfolding complement_def mask_def
by simp
lemma haskell_assert_wp:
"\<lbrace>\<lambda>s. Q \<longrightarrow> P s\<rbrace> haskell_assert Q xs \<lbrace>\<lambda>_. P\<rbrace>"
apply (simp add: haskell_assert_def)
apply wp
done
lemma init_append_last:
"xs \<noteq> [] \<Longrightarrow> init xs @ [last xs] = xs"
apply (induct xs rule: rev_induct)
apply simp
apply (simp add: init_def)
done
lemma no_fail_stateAssert:
"no_fail P (stateAssert P xs)"
apply (simp add: stateAssert_def)
apply (rule no_fail_pre, wp no_fail_bind)
apply simp
done
lemma empty_fail_stateAssert:
"empty_fail (stateAssert P s)"
by (simp add: stateAssert_def assert_def empty_fail_get)
lemma haskell_fail_wp:
"\<lbrace>\<top>\<rbrace> haskell_fail x \<lbrace>P\<rbrace>"
by (simp add: haskell_fail_def)
lemma no_fail_haskell_fail [simp, wp]:
"no_fail \<bottom> (haskell_fail xs)"
by simp
lemma in_assocs_is_fun:
"(x \<in> set (assocs f)) = (f (fst x) = snd x)"
by (cases x) (auto simp add: assocs_def)
lemma fun_is_in_assocs:
"(f x = y) = ((x,y) \<in> set (assocs f))"
by (simp add: in_assocs_is_fun)
lemma empty_set_is_null:
"(set xs = {}) = null xs"
by (clarsimp simp: null_def)
lemma assert_into_when:
"(assert P) = (when (\<not> P) (haskell_fail []))"
by (simp add: assert_def when_def)
lemma const_apply:
"const x y = x"
by (simp add: const_def)
lemma const_None_empty:
"const None = empty"
by (rule ext, simp add: const_apply)
lemma headM_tailM_Cons:
"headM (x # xs) = return x"
"tailM (x # xs) = return xs"
by (simp add: headM_def tailM_def)+
(* Moved by hand *)
lemma replicateM_mapM:
"replicateM n f = mapM (\<lambda>x. f) (replicate n ())"
by (simp add: replicateM_def mapM_def)
lemma alignUp_idem:
fixes a :: "'a::len word"
assumes al: "is_aligned a n"
and sz: "n < len_of TYPE('a)"
shows "alignUp a n = a"
using sz al unfolding alignUp_def
apply (simp add: complement_mask)
apply (subst x_power_minus_1)
apply (subst neg_mask_is_div)
apply (simp only: word_arith_nat_div unat_word_ariths)
apply (simp only: unat_power_lower)
apply (subst power_mod_div)
apply (erule is_alignedE)
apply simp
apply (subst unat_mult_power_lem)
apply simp
apply (subst unat_sub)
apply (subst unat_arith_simps)
apply (simp add: word_bits_def)
apply (simp add: word_bits_def del: unat_1)
apply simp
done
lemma alignUp_not_aligned_eq:
fixes a :: "'a :: len word"
assumes al: "\<not> is_aligned a n"
and sz: "n < len_of TYPE('a)"
shows "alignUp a n = (a div 2 ^ n + 1) * 2 ^ n"
proof -
have anz: "a mod 2 ^ n \<noteq> 0"
by (rule not_aligned_mod_nz) fact+
hence um: "unat (a mod 2 ^ n - 1) div 2 ^ n = 0" using sz
apply -
apply (rule div_less)
apply (simp add: unat_minus_one del: word_neq_0_conv)
apply (rule order_less_trans)
apply (rule diff_Suc_less)
apply (erule contrapos_np)
apply (simp add: unat_eq_zero)
apply (subst unat_power_lower [symmetric, OF sz[unfolded word_bits_def]])
apply (subst word_less_nat_alt [symmetric])
apply (rule word_mod_less_divisor)
apply (simp add: p2_gt_0)
done
have "a + 2 ^ n - 1 = (a div 2 ^ n) * 2 ^ n + (a mod 2 ^ n) + 2 ^ n - 1"
by (simp add: word_mod_div_equality)
also have "\<dots> = (a mod 2 ^ n - 1) + (a div 2 ^ n + 1) * 2 ^ n"
by (simp add: field_simps)
finally show "alignUp a n = (a div 2 ^ n + 1) * 2 ^ n" using sz
unfolding alignUp_def
apply (subst complement_mask)
apply (erule ssubst)
apply (subst neg_mask_is_div)
apply (simp add: word_arith_nat_div)
apply (subst unat_word_ariths(1) unat_word_ariths(2))+
apply (subst uno_simps)
apply (subst unat_1)
apply (subst mod_add_right_eq [symmetric])
apply (simp add: unat_power_lower)
apply (subst power_mod_div)
apply (subst div_mult_self1)
apply simp
apply (subst um)
apply simp
apply (subst mod_mod_power)
apply simp
apply (subst word_unat_power, subst Abs_fnat_hom_mult)
apply (subst mult_mod_left)
apply (subst power_add [symmetric])
apply simp
apply (subst Abs_fnat_hom_1)
apply (subst Abs_fnat_hom_add)
apply (subst word_unat_power, subst Abs_fnat_hom_mult)
apply (subst word_unat.Rep_inverse[symmetric], subst Abs_fnat_hom_mult)
apply simp
done
qed
lemma alignUp_ge:
fixes a :: "'a :: len word"
assumes sz: "n < len_of TYPE('a)"
and nowrap: "alignUp a n \<noteq> 0"
shows "a \<le> alignUp a n"
proof (cases "is_aligned a n")
case True
thus ?thesis using sz
by (subst alignUp_idem, simp_all)
next
case False
have lt0: "unat a div 2 ^ n < 2 ^ (len_of TYPE('a) - n)" using sz
apply -
apply (subst td_gal_lt [symmetric])
apply simp
apply (simp add: power_add [symmetric])
done
have"2 ^ n * (unat a div 2 ^ n + 1) \<le> 2 ^ len_of TYPE('a)" using sz
apply -
apply (rule nat_le_power_trans)
apply simp
apply (rule Suc_leI [OF lt0])
apply simp
done
moreover have "2 ^ n * (unat a div 2 ^ n + 1) \<noteq> 2 ^ len_of TYPE('a)" using nowrap sz
apply -
apply (erule contrapos_nn)
apply (subst alignUp_not_aligned_eq [OF False sz])
apply (subst unat_arith_simps)
apply (subst unat_word_ariths)
apply (subst unat_word_ariths)
apply simp
apply (subst mult_mod_left)
apply (simp add: unat_div field_simps power_add[symmetric] mod_mod_power
min.absorb2 unat_power_lower)
done
ultimately have lt: "2 ^ n * (unat a div 2 ^ n + 1) < 2 ^ len_of TYPE('a)" by simp
have "a = a div 2 ^ n * 2 ^ n + a mod 2 ^ n" by (rule word_mod_div_equality [symmetric])
also have "\<dots> < (a div 2 ^ n + 1) * 2 ^ n" using sz lt
apply (simp add: field_simps)
apply (rule word_add_less_mono1)
apply (rule word_mod_less_divisor)
apply (simp add: word_less_nat_alt unat_power_lower)
apply (subst unat_word_ariths)
apply (simp add: unat_div unat_power_lower)
done
also have "\<dots> = alignUp a n"
by (rule alignUp_not_aligned_eq [symmetric]) fact+
finally show ?thesis by (rule order_less_imp_le)
qed
lemma alignUp_le_greater_al:
fixes x :: "'a :: len word"
assumes le: "a \<le> x"
and sz: "n < len_of TYPE('a)"
and al: "is_aligned x n"
shows "alignUp a n \<le> x"
proof (cases "is_aligned a n")
case True
thus ?thesis using sz le by (simp add: alignUp_idem)
next
case False
hence anz: "a mod 2 ^ n \<noteq> 0"
by (rule not_aligned_mod_nz)
from al obtain k where xk: "x = 2 ^ n * of_nat k" and kv: "k < 2 ^ (len_of TYPE('a) - n)"
by (auto elim!: is_alignedE)
hence kn: "unat (of_nat k :: 'a word) * unat ((2::'a word) ^ n) < 2 ^ len_of TYPE('a)"
using sz
apply (subst unat_of_nat_eq)
apply (erule order_less_le_trans)
apply simp
apply (subst mult.commute)
apply (simp add: unat_power_lower)
apply (rule nat_less_power_trans)
apply simp
apply simp
done
have au: "alignUp a n = (a div 2 ^ n + 1) * 2 ^ n"
by (rule alignUp_not_aligned_eq) fact+
also have "\<dots> \<le> of_nat k * 2 ^ n"
proof (rule word_mult_le_mono1 [OF inc_le _ kn])
show "a div 2 ^ n < of_nat k" using kv xk le sz anz
by (simp add: alignUp_div_helper)
show "(0:: 'a word) < 2 ^ n" using sz by (simp add: p2_gt_0 sz)
qed
finally show ?thesis using xk by (simp add: field_simps)
qed
lemma alignUp_is_aligned_nz:
fixes a :: "'a :: len word"
assumes al: "is_aligned x n"
and sz: "n < len_of TYPE('a)"
and ax: "a \<le> x"
and az: "a \<noteq> 0"
shows "alignUp (a::'a :: len word) n \<noteq> 0"
proof (cases "is_aligned a n")
case True
hence "alignUp a n = a" using sz by (simp add: alignUp_idem)
thus ?thesis using az by simp
next
case False
hence anz: "a mod 2 ^ n \<noteq> 0"
by (rule not_aligned_mod_nz)
{
assume asm: "alignUp a n = 0"
have lt0: "unat a div 2 ^ n < 2 ^ (len_of TYPE('a) - n)" using sz
apply -
apply (subst td_gal_lt [symmetric])
apply simp
apply (simp add: power_add [symmetric])
done
have leq: "2 ^ n * (unat a div 2 ^ n + 1) \<le> 2 ^ len_of TYPE('a)" using sz
apply -
apply (rule nat_le_power_trans)
apply simp
apply (rule Suc_leI [OF lt0])
apply simp
done
from al obtain k where kv: "k < 2 ^ (len_of TYPE('a) - n)" and xk: "x = 2 ^ n * of_nat k"
by (auto elim!: is_alignedE)
hence "a div 2 ^ n < of_nat k" using ax sz anz
by (rule alignUp_div_helper)
hence r: "unat a div 2 ^ n < k" using sz
apply (simp add: unat_div word_less_nat_alt)
apply (subst (asm) unat_of_nat)
apply (subst (asm) mod_less)
apply (rule order_less_le_trans [OF kv])
apply (simp add: unat_power_lower)+
done
have "alignUp a n = (a div 2 ^ n + 1) * 2 ^ n"
by (rule alignUp_not_aligned_eq) fact+
hence "\<dots> = 0" using asm by simp
hence "unat a div 2 ^ n = 2 ^ (len_of TYPE('a) - n) - 1" using sz leq
apply -
apply (rule nat_diff_add)
apply simp
apply (subst nat_mult_eq_cancel1 [where k = "2 ^ n", symmetric])
apply simp
apply (subst power_add [symmetric])
apply simp
apply (drule unat_cong)
apply simp
apply (subst (asm) unat_word_ariths)
apply (subst (asm) unat_word_ariths)
apply (simp add: unat_div mult_mod_left power_add [symmetric] mod_mod_power
min.absorb2)
apply (clarsimp simp: field_simps)
apply (rule ccontr)
apply (drule (1) order_le_neq_trans)
apply (simp add: unat_power_lower)
done
hence "2 ^ (len_of TYPE('a) - n) - 1 < k" using r
by simp
hence False using kv by simp
} thus ?thesis by (clarsimp simp del: word_neq_0_conv)
qed
lemma alignUp_ar_helper:
fixes a :: "'a :: len word"
assumes al: "is_aligned x n"
and sz: "n < len_of TYPE('a)"
and sub: "{x..x + 2 ^ n - 1} \<subseteq> {a..b}"
and anz: "a \<noteq> 0"
shows "a \<le> alignUp a n \<and> alignUp a n + 2 ^ n - 1 \<le> b"
proof
from al have xl: "x \<le> x + 2 ^ n - 1" by (simp add: is_aligned_no_overflow)
from xl sub have ax: "a \<le> x"
by (clarsimp elim!: range_subset_lower [where x = x])
show "a \<le> alignUp a n"
proof (rule alignUp_ge)
show "alignUp a n \<noteq> 0" using al sz ax anz
by (rule alignUp_is_aligned_nz)
qed fact+
show "alignUp a n + 2 ^ n - 1 \<le> b"
proof (rule order_trans)
from xl show tp: "x + 2 ^ n - 1 \<le> b" using sub
by (clarsimp elim!: range_subset_upper [where x = x])
from ax have "alignUp a n \<le> x"
by (rule alignUp_le_greater_al) fact+
hence "alignUp a n + (2 ^ n - 1) \<le> x + (2 ^ n - 1)" using xl
apply -
apply (erule word_plus_mono_left)
apply (subst olen_add_eqv)
apply (simp add: field_simps)
done
thus "alignUp a n + 2 ^ n - 1 \<le> x + 2 ^ n - 1"
by (simp add: field_simps)
qed
qed
lemma orList_False:
"(\<not> orList bs) = (set bs \<subseteq> {False})"
apply (induct bs)
apply (simp_all add: orList_def foldl_True)
apply (case_tac a)
apply (simp_all add: orList_def foldl_True)
done
lemma Cons_eq_tails:
"((xs # xxs) = tails ys) = (ys = xs \<and> xxs = tl (tails ys))"
by (case_tac ys, auto)
lemma findM_on_outcome':
assumes x: "\<And>x xs. \<lbrace>\<lambda>s. Q None s \<and> x \<in> fn s \<and> set xs \<subseteq> fn s\<rbrace> f x
\<lbrace>\<lambda>rv s. (rv \<longrightarrow> Q (Some x) s) \<and> (\<not> rv \<longrightarrow> Q None s \<and> set xs \<subseteq> fn s)\<rbrace>"
shows "\<lbrace>\<lambda>s. Q None s \<and> set xs \<subseteq> fn s\<rbrace> findM f xs \<lbrace>Q\<rbrace>"
apply (induct xs)
apply (simp, wp)
apply (simp, wp)
apply assumption
apply (rule x)
done
lemma findM_on_outcome:
assumes x: "\<And>x ys. x \<in> set xs \<Longrightarrow> \<lbrace>Q None and I\<rbrace> f x \<lbrace>\<lambda>rv s. (rv \<longrightarrow> Q (Some x) s) \<and> (\<not> rv \<longrightarrow> Q None s \<and> I s)\<rbrace>"
shows "\<lbrace>Q None and I\<rbrace> findM f xs \<lbrace>Q\<rbrace>"
apply (rule hoare_vcg_precond_imp)
apply (rule findM_on_outcome' [where fn="\<lambda>s. if I s then set xs else {}"])
apply (case_tac "x \<notin> set xs")
apply simp
apply (simp cong: rev_conj_cong)
apply (case_tac "\<not> set xsa \<subseteq> set xs")
apply simp
apply simp
apply (rule hoare_vcg_precond_imp)
apply (rule hoare_post_imp [OF _ x])
apply clarsimp
apply assumption
apply simp
apply simp
done
lemma in_set_tailsD: "xs \<in> set (tails ys) \<Longrightarrow> set xs \<subseteq> set ys"
apply (induct ys)
apply simp
apply simp
apply (erule disjE)
apply simp
apply simp
apply blast
done
lemma notin_set_tails_set:
"x \<notin> set xs \<Longrightarrow> \<forall>xs' \<in> set (tails xs). \<forall>x' \<in> set xs'. x \<noteq> x'"
by (fastforce dest!: in_set_tailsD)
lemma set_tails_set: "(set (tails v) \<subseteq> {x. set x \<subseteq> S}) = (set v \<subseteq> S)"
apply (induct v, simp_all)
done
lemma filter_assocs_Cons:
fixes v :: "('a :: len) word" shows
"\<lbrakk> f (v, g v); \<forall>x < v. \<not> f (x, g x) \<rbrakk> \<Longrightarrow>
filter f (assocs g) = (v, g v) # tl (filter f (assocs g))"
apply (simp add: assocs_def)
apply (cut_tac v=v in enum_word_div)
apply clarsimp
apply (subst map_cong [OF _ refl], assumption)+
apply (simp(no_asm))
apply simp
done
lemma snd_stateAssert_after:
"\<not> snd ((do _ \<leftarrow> f; stateAssert R vs od) s) \<Longrightarrow>
\<not>snd (f s) \<and> (\<forall>(rv, s') \<in> fst (f s). R s')"
apply (clarsimp simp: bind_def stateAssert_def get_def assert_def
return_def fail_def split_def split: split_if_asm)
done
lemma oblivious_stateAssert [simp]:
"oblivious f (stateAssert g xs) = (\<forall>s. g (f s) = g s)"
apply (simp add: oblivious_def stateAssert_def exec_get
assert_def return_def fail_def split: split_if)
apply auto
done
lemma stateAssert_def2:
"stateAssert f xs = do v \<leftarrow> gets f; if v then return () else fail od"
by (simp add: stateAssert_def gets_def assert_def)
lemma findM_is_mapME:
"(findM f xs >>= g)
= liftM (\<lambda>_. ())
(doE ys \<leftarrow> mapME_x (\<lambda>x. do v \<leftarrow> f x;
if v then do g (Some x); throwError () od
else returnOk () od) xs;
liftE (g None) odE)"
apply (induct xs)
apply (simp add: mapME_x_def sequenceE_x_def liftM_def returnOk_bind)
apply (simp add: liftE_def)
apply (simp add: mapME_x_Cons bindE_assoc liftE_bindE[symmetric]
liftM_def cong: if_cong)
apply (simp add: liftE_bindE bind_assoc)
apply (rule bind_cong[OF refl])
apply (simp add: bindE_assoc split: split_if)
apply (simp add: liftE_bindE bind_assoc throwError_bind)
done
end