Theory TSO
theory TSO
imports
Heap
begin
section‹ Total store order (TSO)\label{sec:tso} ›
text‹
The total store order (TSO) memory model (\<^citet>‹"OwensSarkarSewell:2009"›; valid on multicore
x86) can be modelled as a closure as demonstrated by \<^citet>‹‹p182› in "JagadeesanEtAl:2012"›.
Essentially this is done by incorporating a write buffer into each thread's local state and adding
buffer draining opportunities before and after every command. The only subtlety is that the all
threads involved in a parallel composition need to start and end with empty write buffers (see
\S\ref{sec:tso-parallel}).
We configure the code generator in \S\ref{sec:tso-code_generation}.
Comparison with \<^citet>‹"JagadeesanEtAl:2012"›:
▪ We ignore mumbling-related issues and it doesn't make any difference
▪ in our model we commit writes one at a time; mumbling allows several to be committed at once (p182) which we model as an uninterrupted sequence of individual writes
▪ if we allowed ‹commit_writes› to commit multiple writes in a single step then ‹tso_closure› would not be idempotent
▪ their semantics is for terminating computations only; ours is for safety only
▪ their language is deterministic, ours is non-deterministic
▪ They do not provide many general laws for TSO
▪ Their claims that the semantics allows them to prove things (\S5) is not substantiated
›
type_synonym write_buffer = "heap.write list"
definition apply_writes :: "write_buffer ⇒ heap.t ⇒ heap.t" where
"apply_writes ws = fold (λw. (∘) (heap.apply_write w)) ws id"
lemma apply_write_present:
assumes "heap.present r s"
shows "heap.present r (heap.apply_write w s)"
using assms by (cases w) (simp split: heap.obj_at.splits)
lemma apply_writes_present:
assumes "heap.present r s"
shows "heap.present r (apply_writes wb s)"
using assms by (induct wb arbitrary: s) (simp_all add: apply_writes_def fold_fun apply_write_present)
setup ‹Sign.mandatory_path "raw"›
type_synonym 'v tso = "write_buffer ⇒ (heap.t, 'v × write_buffer) prog"
definition bind :: "'a raw.tso ⇒ ('a ⇒ 'b raw.tso) ⇒ 'b raw.tso" where
"bind f g = (λwb. f wb ⤜ uncurry g)"
adhoc_overloading
Monad_Syntax.bind ⇌ raw.bind
definition prim_return :: "'a ⇒ 'a raw.tso" where
"prim_return v = (λwb. prog.return (v, wb))"
setup ‹Sign.mandatory_path "bind"›
lemma mono:
assumes "f ≤ f'"
assumes "⋀x. g x ≤ g' x"
shows "raw.bind f g ≤ raw.bind f' g'"
using assms by (fastforce simp: raw.bind_def prog.bind.mono le_fun_def intro: prog.bind.mono)
lemma strengthen[strg]:
assumes "st_ord F f f'"
assumes "⋀x. st_ord F (g x) (g' x)"
shows "st_ord F (raw.bind f g) (raw.bind f' g')"
using assms by (cases F; clarsimp intro!: raw.bind.mono)
lemma mono2mono[cont_intro, partial_function_mono]:
assumes "monotone orda (≤) F"
assumes "⋀x. monotone orda (≤) (λy. G y x)"
shows "monotone orda (≤) (λf. raw.bind (F f) (G f))"
using assms unfolding monotone_def by (meson raw.bind.mono)
lemma botL:
shows "raw.bind ⊥ g = ⊥"
by (simp add: raw.bind_def fun_eq_iff prog.bind.botL)
lemma bind:
fixes f :: "_ raw.tso"
shows "f ⤜ g ⤜ h = f ⤜ (λx. g x ⤜ h)"
by (simp add: raw.bind_def fun_eq_iff split_def prog.bind.bind)
lemma prim_return:
shows prim_returnL: "raw.bind (raw.prim_return v) = (λg. g v)"
and prim_returnR: "f ⤜ raw.prim_return = f"
by (simp_all add: fun_eq_iff raw.prim_return_def raw.bind_def split_def prog.bind.return)
lemma supL:
fixes g :: "_ ⇒ _ raw.tso"
shows "f⇩1 ⊔ f⇩2 ⤜ g = (f⇩1 ⤜ g) ⊔ (f⇩2 ⤜ g)"
by (simp add: raw.bind_def fun_eq_iff prog.bind.supL)
lemma supR:
fixes f :: "_ raw.tso"
shows "f ⤜ (λv. g⇩1 v ⊔ g⇩2 v) = (f ⤜ g⇩1) ⊔ (f ⤜ g⇩2)"
by (simp add: raw.bind_def fun_eq_iff split_def prog.bind.supR)
lemma SUPL:
fixes X :: "_ set"
fixes f :: "_ ⇒ _ raw.tso"
shows "(⨆x∈X. f x) ⤜ g = (⨆x∈X. f x ⤜ g)"
by (simp add: raw.bind_def fun_eq_iff prog.bind.SUPL image_image)
lemma SUPR:
fixes X :: "_ set"
fixes f :: "_ raw.tso"
shows "f ⤜ (λv. ⨆x∈X. g x v) = (⨆x∈X. f ⤜ g x) ⊔ (f ⤜ ⊥)"
by (simp add: raw.bind_def split_def fun_eq_iff image_image bot_fun_def prog.bind.SUPR)
lemma SUPR_not_empty:
fixes f :: "_ raw.tso"
assumes "X ≠ {}"
shows "f ⤜ (λv. ⨆x∈X. g x v) = (⨆x∈X. f ⤜ g x)"
by (simp add: raw.bind_def split_def fun_eq_iff image_image prog.bind.SUPR_not_empty[OF assms])
lemma mcont2mcont[cont_intro]:
assumes "mcont luba orda Sup (≤) f"
assumes "⋀v. mcont luba orda Sup (≤) (λx. g x v)"
shows "mcont luba orda Sup (≤) (λx. raw.bind (f x) (g x))"
proof(rule ccpo.mcont2mcont'[OF complete_lattice_ccpo _ _ assms(1)])
show "mcont Sup (≤) Sup (≤) (λf. raw.bind f (g x))" for x
by (intro mcontI contI monotoneI) (simp_all add: raw.bind.mono flip: raw.bind.SUPL)
show "mcont luba orda Sup (≤) (λx. raw.bind f (g x))" for f
by (intro mcontI monotoneI contI)
(simp_all add: mcont_monoD[OF assms(2)] raw.bind.mono flip: raw.bind.SUPR_not_empty contD[OF mcont_cont[OF assms(2)]])
qed
setup ‹Sign.parent_path›
interpretation kleene: kleene "raw.prim_return ()" "λx y. raw.bind x ⟨y⟩"
by standard (simp_all add: raw.bind.prim_return raw.bind.botL raw.bind.bind raw.bind.supL raw.bind.supR)
primrec commit_write :: "unit raw.tso" where
"commit_write [] = prog.return ((), [])"
| "commit_write (w # wb) = prog.action {(((), wb), h, heap.apply_write w h) |h. True}"
definition commit_writes :: "unit raw.tso" where
"commit_writes = raw.kleene.star raw.commit_write"
setup ‹Sign.mandatory_path "tso"›
definition cl :: "'v raw.tso ⇒ 'v raw.tso" where
"cl P = raw.commit_writes ⪢ P ⤜ (λv. raw.commit_writes ⪢ raw.prim_return v)"
setup ‹Sign.parent_path›
definition action :: "(write_buffer ⇒ ('v × write_buffer × heap.t × heap.t) set) ⇒ 'v raw.tso" where
"action F = raw.tso.cl (λwb. prog.action {((v, wb @ ws), ss') |v ss' ws. (v, ws, ss') ∈ F wb})"
definition return :: "'v ⇒ 'v raw.tso" where
"return v = raw.action ⟨{v} × {[]} × Id⟩"
definition guard :: "(write_buffer ⇒ heap.t pred) ⇒ unit raw.tso" where
"guard g = raw.action (λwb. {()} × {[]} × Diag (g wb))"
definition MFENCE :: "unit raw.tso" where
"MFENCE = raw.guard (λwb s. wb = [])"
definition vmap :: "('v ⇒ 'w) ⇒ 'v raw.tso ⇒ 'w raw.tso" where
"vmap vf P = (λwb. prog.vmap (map_prod vf id) (P wb))"
definition t2p :: "'v raw.tso ⇒ (heap.t, 'v) prog" where
"t2p P = P [] ⤜ (λ(v, wb). raw.MFENCE wb ⪢ prog.return v)"
definition parallel :: "unit raw.tso ⇒ unit raw.tso ⇒ unit raw.tso" where
"parallel P Q = raw.MFENCE ⪢ ⟨(raw.t2p P ∥ raw.t2p Q) ⪢ prog.return ((), [])⟩"
lemma return_alt_def:
shows "raw.return = (λv. raw.tso.cl (raw.prim_return v))"
by (fastforce simp: raw.return_def raw.action_def raw.prim_return_def prog.return_def
intro: arg_cong[where f="λP. raw.tso.cl P wb" for wb] arg_cong[where f="prog.action"])
setup ‹Sign.mandatory_path "commit_writes"›
lemma return_le:
shows "raw.prim_return () ≤ raw.commit_writes"
unfolding raw.commit_writes_def by (subst raw.kleene.star.simps) simp
lemma return_le':
shows "prog.return ((), wb) ≤ raw.commit_writes wb"
using raw.commit_writes.return_le by (simp add: raw.prim_return_def le_fun_def)
lemma commit_writes:
shows "raw.commit_writes ⪢ raw.commit_writes = raw.commit_writes"
by (simp add: raw.commit_writes_def raw.kleene.star_comp_star)
lemma Nil:
shows "raw.commit_writes [] = prog.return ((), [])" (is "?lhs = ?rhs")
proof(rule antisym)
show "?lhs ≤ ?rhs"
unfolding raw.commit_writes_def
by (induct rule: raw.kleene.star.fixp_induct)
(simp_all add: raw.bind_def raw.prim_return_def prog.bind.returnL prog.p2s.bot spec.bind.mono)
show "?rhs ≤ ?lhs"
unfolding raw.commit_writes_def
by (subst raw.kleene.star.simps) (simp add: raw.bind_def raw.prim_return_def)
qed
lemma Cons:
shows "raw.commit_writes (w # wb)
= (raw.commit_write [w] ⪢ raw.commit_writes wb) ⊔ raw.prim_return () (w # wb)"
apply (simp add: raw.commit_writes_def)
apply (subst (1) raw.kleene.star.simps)
apply (subst (1) raw.bind_def)
apply simp
apply (subst prog.action.return_const[where F="{(s, heap.apply_write w s) |s. True}" and V="{((), wb)}" and W="{((), [])}", simplified Pair_image[symmetric] image_def, simplified])
apply (simp add: prog.bind.bind prog.bind.returnL)
done
lemma Cons_le:
shows "raw.commit_write [w] ⪢ raw.commit_writes wb ≤ raw.commit_writes (w # wb)"
by (simp add: raw.commit_writes.Cons)
setup ‹Sign.parent_path›
setup ‹Sign.parent_path›
setup ‹Sign.mandatory_path "spec.singleton.raw"›
lemma prim_return_Nil_le:
shows "⦉s, [], Some ((), wb)⦊ ≤ prog.p2s (raw.prim_return () wb)"
by (simp add: raw.prim_return_def prog.p2s.return spec.interference.cl.return
spec.bind.continueI[where xs="[]", simplified] spec.singleton.le_conv)
setup ‹Sign.parent_path›
setup ‹Sign.mandatory_path "spec.singleton.raw.commit_writes"›
lemma noop_le:
shows "⦉s, [], Some ((), wb)⦊ ≤ prog.p2s (raw.commit_writes wb)"
unfolding raw.commit_writes_def
by (rule order.trans[OF spec.singleton.raw.prim_return_Nil_le
prog.p2s.mono[OF le_funD[OF raw.kleene.epsilon_star_le]]])
lemma wb_suffix:
assumes "⦉s, xs, Some ((), wb')⦊ ≤ prog.p2s (raw.commit_writes wb)"
shows "suffix wb' wb"
using assms
by (induct wb arbitrary: s xs)
(auto simp: raw.commit_writes.Nil raw.commit_writes.Cons raw.prim_return_def
prog.p2s.simps prog.p2s.return spec.interference.cl.return
trace.split_all spec.singleton.le_conv
suffix_ConsI
elim!: spec.singleton.bind_le)
setup ‹Sign.parent_path›
setup ‹Sign.mandatory_path "raw"›
setup ‹Sign.mandatory_path "tso.cl"›
lemma bind_commit_writes_absorbL:
fixes P :: "'v raw.tso"
shows "raw.commit_writes ⪢ raw.tso.cl P = raw.tso.cl P"
by (simp add: raw.tso.cl_def raw.commit_writes.commit_writes flip: raw.bind.bind)
lemma bind_commit_writes_absorb_unitR:
fixes P :: "unit raw.tso"
shows "raw.tso.cl P ⪢ raw.commit_writes = raw.tso.cl P"
by (simp add: raw.tso.cl_def raw.bind.bind raw.commit_writes.commit_writes raw.bind.prim_returnR)
lemma bind_commit_writes_absorbR:
fixes P :: "'v raw.tso"
shows "raw.tso.cl P ⤜ (λv. raw.commit_writes ⪢ raw.prim_return v) = raw.tso.cl P"
by (simp add: raw.tso.cl_def raw.bind.bind raw.commit_writes.commit_writes raw.bind.prim_returnL)
(simp add: raw.commit_writes.commit_writes flip: raw.bind.bind)
lemma bot:
shows "raw.tso.cl ⊥ = raw.commit_writes ⤜ ⊥"
by (simp add: raw.tso.cl_def raw.bind.bind raw.bind.botL flip: bot_fun_def)
lemma prim_return:
shows "raw.tso.cl (raw.prim_return v) = raw.commit_writes ⪢ raw.prim_return v"
by (simp add: raw.tso.cl_def raw.bind.bind raw.bind.prim_returnL)
(simp add: raw.commit_writes.commit_writes flip: raw.bind.bind)
lemma Nil:
shows "raw.tso.cl P [] = P [] ⤜ (λv. raw.commit_writes (snd v) ⤜ (λw. prog.return (fst v, snd w)))"
by (simp add: raw.tso.cl_def raw.bind_def raw.prim_return_def raw.commit_writes.Nil prog.bind.returnL split_def)
lemma commit:
fixes wb :: write_buffer
shows "raw.commit_write [w] ⪢ f wb ≤ raw.tso.cl f (w # wb)"
apply (simp add: raw.tso.cl_def raw.bind_def raw.prim_return_def split_def)
apply (strengthen ord_to_strengthen[OF raw.commit_writes.Cons_le])
apply (simp add: prog.bind.bind)
apply (rule prog.bind.mono[OF order.refl])
apply (strengthen ord_to_strengthen[OF raw.commit_writes.return_le'])
apply (simp add: prog.bind.returnL prog.bind.returnR)
done
setup ‹Sign.parent_path›
interpretation tso: closure_complete_distrib_lattice_distributive_class raw.tso.cl
proof standard
show "(x ≤ raw.tso.cl y) = (raw.tso.cl x ≤ raw.tso.cl y)" for x y :: "'a raw.tso"
proof(intro iffD2[OF order_class.order.closure_axioms_alt_def[unfolded closure_axioms_def], rule_format, simplified conj_explode] allI)
show "P ≤ raw.tso.cl P" for P :: "'a raw.tso"
unfolding raw.tso.cl_def
by (strengthen ord_to_strengthen[OF raw.commit_writes.return_le])
(simp add: raw.bind.prim_returnL raw.bind.prim_returnR)
show "mono raw.tso.cl"
proof(rule monotoneI)
fix P P' :: "'v raw.tso"
assume "P ≤ P'" show "raw.tso.cl P ≤ raw.tso.cl P'"
unfolding raw.tso.cl_def by (strengthen ord_to_strengthen(1)[OF ‹P ≤ P'›]) simp
qed
show "raw.tso.cl (raw.tso.cl P) = raw.tso.cl P" for P :: "'a raw.tso"
by (simp add: raw.tso.cl_def raw.bind.bind raw.commit_writes.commit_writes raw.bind.prim_returnL)
(simp add: raw.commit_writes.commit_writes flip: raw.bind.bind)
qed
show "raw.tso.cl (⨆X) ≤ ⨆ (raw.tso.cl ` X) ⊔ raw.tso.cl ⊥" for X :: "'a raw.tso set"
by (simp add: raw.tso.cl_def raw.bind.bind raw.bind.botL flip: bot_fun_def raw.bind.SUPR raw.bind.SUPL)
qed
setup ‹Sign.mandatory_path "tso.cl"›
lemma bind:
fixes f :: "'v raw.tso"
assumes "f ∈ raw.tso.closed"
shows "raw.tso.cl (f ⤜ g) = f ⤜ (λv. raw.tso.cl (g v))"
apply (simp add: raw.tso.cl_def raw.bind.bind)
apply (subst (1 2) raw.tso.closed_conv[OF assms(1)])
apply (simp add: raw.tso.cl.bind_commit_writes_absorbL flip: raw.bind.bind)
apply (subst (1) raw.tso.cl.bind_commit_writes_absorbR[symmetric])
apply (simp add: raw.bind.bind raw.bind.prim_returnL)
done
setup ‹Sign.parent_path›
setup ‹Sign.mandatory_path "bind"›
lemma commit_writes_absorbL:
assumes "f ∈ raw.tso.closed"
shows "raw.commit_writes ⪢ f = f"
by (metis assms raw.tso.closed_conv raw.tso.cl.bind_commit_writes_absorbL)
lemma commit_writes_absorb_unitR:
assumes "f ∈ raw.tso.closed"
shows "f ⪢ raw.commit_writes = f"
by (metis assms raw.tso.closed_conv raw.tso.cl.bind_commit_writes_absorb_unitR)
lemma returnL:
assumes "g v ∈ raw.tso.closed"
shows "raw.return v ⤜ g = g v"
by (simp add: assms raw.return_alt_def raw.bind.commit_writes_absorbL
raw.tso.cl.prim_return raw.bind.bind raw.bind.prim_returnL)
lemma returnR:
assumes "f ∈ raw.tso.closed"
shows "f ⤜ raw.return = f"
by (simp add: raw.return_alt_def raw.tso.cl.prim_return
raw.tso.cl.bind_commit_writes_absorbR[of f, simplified raw.tso.closed_conv[OF assms, symmetric]])
setup ‹Sign.parent_path›
setup ‹Sign.mandatory_path "tso.closed"›
lemma commit_writes:
shows "raw.commit_writes ∈ raw.tso.closed"
by (rule raw.tso.closed_clI)
(simp add: raw.tso.cl_def raw.commit_writes.commit_writes raw.bind.prim_returnR
flip: raw.bind.bind)
lemma bind[intro]:
fixes f :: "'v raw.tso"
fixes g :: "'v ⇒ 'w raw.tso"
assumes "f ∈ raw.tso.closed"
assumes "⋀x. g x ∈ raw.tso.closed"
shows "f ⤜ g ∈ raw.tso.closed"
by (simp add: assms raw.tso.closed_clI raw.tso.cl.bind flip: raw.tso.closed_conv)
lemma action[intro]:
shows "raw.action F ∈ raw.tso.closed"
by (simp add: raw.action_def)
lemma guard[intro]:
shows "raw.guard g ∈ raw.tso.closed"
by (simp add: raw.guard_def raw.tso.closed.action)
lemma MFENCE[intro]:
shows "raw.MFENCE ∈ raw.tso.closed"
by (simp add: raw.MFENCE_def raw.tso.closed.guard)
lemma parallel[intro]:
assumes "P ∈ raw.tso.closed"
assumes "Q ∈ raw.tso.closed"
shows "raw.parallel P Q ∈ raw.tso.closed"
apply (rule raw.tso.closed_clI)
apply (clarsimp simp: raw.parallel_def raw.tso.cl_def raw.bind.prim_returnR le_fun_def)
apply (subst (2) raw.bind.commit_writes_absorbL[OF raw.tso.closed.MFENCE, symmetric])
apply (simp add: raw.bind_def split_def prog.bind.bind prog.bind.mono[OF order.refl]
prog.bind.returnL raw.commit_writes.Nil)
done
lemma vmap[intro]:
assumes "P ∈ raw.tso.closed"
shows "raw.vmap vf P ∈ raw.tso.closed"
proof(rule raw.tso.closed_clI)
have "raw.tso.cl (raw.vmap vf P) ≤ raw.vmap vf (raw.tso.cl P)"
by (simp add: le_funI raw.tso.cl_def raw.vmap_def raw.bind_def raw.prim_return_def split_def comp_def
prog.vmap.eq_return prog.bind.bind prog.bind.returnL)
then show "raw.tso.cl (raw.vmap vf P) ≤ raw.vmap vf P"
by (simp flip: raw.tso.closed_conv[OF assms])
qed
setup ‹Sign.parent_path›
setup ‹Sign.mandatory_path "action"›
lemma bot:
shows "raw.action ⊥ = raw.tso.cl ⊥"
by (simp add: raw.action_def prog.action.empty bot_fun_def)
lemma monotone:
shows "mono raw.action"
unfolding raw.action_def
by (fastforce simp: le_fun_def intro: monoI prog.action.mono raw.tso.mono_cl)
lemmas strengthen[strg] = st_monotone[OF raw.action.monotone]
lemmas mono = monotoneD[OF raw.action.monotone]
lemma Sup:
shows "raw.action (⨆Fs) = ⨆(raw.action ` Fs) ⊔ raw.tso.cl ⊥" (is "?lhs = ?rhs")
proof -
have "?rhs = ⨆(raw.tso.cl ` (λF wb. prog.action {((v, wb @ ws), s, s') |v s s' ws. (v, ws, s, s') ∈ F wb}) ` Fs) ⊔ raw.tso.cl ⊥"
by (simp add: raw.action_def image_comp)
also have "… = raw.tso.cl (⨆F∈Fs. (λwb. prog.action {((v, wb @ ws), s, s') |v s s' ws. (v, ws, s, s') ∈ F wb}))"
by (simp add: raw.tso.cl_Sup)
also have "… = raw.tso.cl (λwb. ⨆(prog.action ` (λF. {((v, wb @ ws), s, s') |v s s' ws. (v, ws, s, s') ∈ F wb}) ` Fs))"
by (simp add: Sup_fun_def image_comp)
also have "… = ?lhs"
by (force simp: raw.action_def
simp flip: prog.action.Sup
intro: arg_cong[where f=raw.tso.cl] arg_cong[where f=prog.action])
finally show ?thesis ..
qed
lemma sup:
shows "raw.action (F ⊔ G) = raw.action F ⊔ raw.action G"
using raw.action.Sup[where Fs="{F, G}"]
by (simp add: sup.absorb1 le_supI1 raw.action.mono flip: raw.action.bot)
setup ‹Sign.parent_path›
setup ‹Sign.mandatory_path "guard"›
lemma return_le:
shows "raw.guard g ≤ raw.return ()"
by (fastforce simp add: raw.guard_def raw.return_def intro: le_funI raw.action.mono)
lemma monotone:
shows "mono (raw.guard :: (write_buffer ⇒ heap.t pred) ⇒ _)"
proof(rule monoI)
show "raw.guard g ≤ raw.guard h" if "g ≤ h" for g h :: "write_buffer ⇒ heap.t pred"
unfolding raw.guard_def Diag_def
by (blast intro: raw.action.mono le_funI predicate2D[OF that])
qed
lemmas strengthen[strg] = st_monotone[OF raw.guard.monotone]
lemmas mono = monotoneD[OF raw.guard.monotone]
lemma less:
assumes "g < g'"
shows "raw.guard g < raw.guard g'"
proof(rule le_neq_trans)
show "raw.guard g ≤ raw.guard g'"
by (strengthen ord_to_strengthen(1)[OF order_less_imp_le[OF assms]]) simp
from assms obtain wb s where "g' wb s" "¬g wb s" by (metis leD predicate2I)
from ‹¬g wb s› have "¬⦉trace.T s [] (Some ((), wb))⦊ ≤ prog.p2s (raw.guard g wb)"
by (auto simp: raw.guard_def raw.action_def raw.tso.cl_def raw.bind_def raw.prim_return_def
split_def trace.split_all
prog.p2s.simps prog.p2s.action prog.p2s.return
spec.interference.cl.action spec.interference.cl.return
spec.singleton.le_conv spec.singleton.action_le_conv trace.steps'.step_conv
suffix_order.antisym_conv
elim!: spec.singleton.bind_le
dest!: spec.singleton.raw.commit_writes.wb_suffix)
moreover
from ‹g' wb s› have "⦉trace.T s [] (Some ((), wb))⦊ ≤ prog.p2s (raw.guard g' wb)"
by (force simp: raw.guard_def raw.action_def raw.prim_return_def raw.tso.cl_def raw.bind_def
spec.bind.bind spec.singleton.le_conv
prog.p2s.bind prog.p2s.action prog.p2s.return
spec.interference.cl.action spec.interference.cl.return
intro: spec.bind.continueI[where xs="[]", simplified] spec.action.stutterI
spec.singleton.raw.commit_writes.noop_le)
ultimately show "raw.guard g ≠ raw.guard g'" by metis
qed
setup ‹Sign.parent_path›
lemma MFENCE_alt_def:
shows "raw.MFENCE = raw.commit_writes ⪢ (λwb. prog.action ({((), wb)} × Diag ⟨wb = []⟩))"
proof -
have *: "prog.action {x. (∃a. x = (((), wb), a, a)) ∧ wb = []} ⤜ (λp. raw.commit_writes (snd p))
= prog.action ({((), wb)} × Diag (λs. wb = [])) ⤜ prog.return"
for wb
proof(induct rule: refinement.prog.eqI[case_names l2r r2l])
case l2r show ?case
apply (rule refinement.prog.rev_bind)
apply (rule refinement.prog.action[where Q="λv s. snd v = []"];
simp add: stable_def monotone_def; fail)
apply (rule refinement.gen_asm; clarsimp simp: raw.commit_writes.Nil)
apply (rule refinement.sort_of_refl)
apply (subst refinement.top, simp; fail)
apply (simp add: spec.idle.p2s_le; fail)
done
next
case r2l show ?case
apply (rule refinement.prog.rev_bind)
apply (rule refinement.prog.action[where Q="λv s. snd v = []"];
simp add: stable_def monotone_def; fail)
apply (rule refinement.gen_asm; clarsimp simp: raw.commit_writes.Nil)
apply (rule refinement.sort_of_refl)
apply (subst refinement.top, simp; fail)
apply (simp add: spec.idle.p2s_le; fail)
done
qed
show ?thesis
by (simp add: raw.MFENCE_def raw.guard_def raw.action_def raw.tso.cl_def
raw.bind.bind raw.bind.prim_returnR)
(simp add: * raw.bind_def raw.prim_return_def split_def prog.bind.return)
qed
setup ‹Sign.mandatory_path "MFENCE"›
lemma Nil:
shows "raw.MFENCE [] = prog.return ((), [])"
by (simp add: raw.MFENCE_alt_def raw.bind_def raw.commit_writes.Nil prog.bind.returnL
flip: Id_def prog.return_def)
setup ‹Sign.parent_path›
setup ‹Sign.parent_path›
setup ‹Sign.mandatory_path "refinement.raw"›
lemma MFENCE:
shows "prog.p2s (raw.MFENCE wb) ≤ ⦃P⦄, A ⊩ prog.p2s (raw.MFENCE wb), ⦃λv s. snd v = []⦄"
apply (simp add: raw.MFENCE_alt_def raw.bind_def split_def)
apply (rule refinement.prog.rev_bind)
apply (rule refinement.sort_of_refl)
apply (subst refinement.top, simp; fail)
apply (rule refinement.prog.action; simp add: stable_def monotone_def)
done
setup ‹Sign.parent_path›
setup ‹Sign.mandatory_path "raw"›
setup ‹Sign.mandatory_path "bind"›
lemma MFENCEL:
shows "raw.MFENCE wb ⤜ g = raw.MFENCE wb ⪢ g ((), [])" (is "?lhs = ?rhs")
proof(induct rule: refinement.prog.eqI[case_names l2r r2l])
case l2r show ?case
apply (rule refinement.prog.rev_bind)
apply (rule refinement.raw.MFENCE)
apply (rule refinement.gen_asm; clarsimp)
apply (rule refinement.sort_of_refl)
apply (subst refinement.top, simp; fail)
apply (rule spec.idle.p2s_le)
done
case r2l show ?case
apply (rule refinement.prog.rev_bind)
apply (rule refinement.raw.MFENCE)
apply (rule refinement.gen_asm; clarsimp)
apply (rule refinement.sort_of_refl)
apply (subst refinement.top, simp; fail)
apply (rule spec.idle.p2s_le)
done
qed
lemma MFENCE_return:
shows "raw.MFENCE wb ⪢ prog.return ((), []) = raw.MFENCE wb"
by (simp add: prog.bind.returnR flip: raw.bind.MFENCEL)
lemma MFENCE_MFENCE:
shows "raw.MFENCE ⪢ raw.MFENCE = raw.MFENCE"
by (simp add: raw.bind_def raw.prim_return_def raw.MFENCE.Nil raw.bind.MFENCE_return
raw.bind.MFENCEL[where g="(λ(_, y). raw.MFENCE y)"])
setup ‹Sign.parent_path›
setup ‹Sign.mandatory_path "t2p"›
lemma bot:
shows "raw.t2p ⊥ = ⊥"
by (simp add: raw.t2p_def prog.bind.botL)
lemma cl_bot:
shows "raw.t2p (raw.tso.cl ⊥) = ⊥"
by (simp add: raw.t2p_def raw.tso.cl.bot raw.bind_def raw.commit_writes.Nil
prog.bind.bind prog.bind.botL prog.bind.returnL)
lemma monotone:
shows "mono raw.t2p"
by (rule monotoneI) (simp add: raw.t2p_def le_fun_def prog.bind.mono)
lemmas strengthen[strg] = st_monotone[OF raw.t2p.monotone]
lemmas mono = monotoneD[OF raw.t2p.monotone]
lemmas mono2mono[cont_intro, partial_function_mono] = monotone2monotone[OF raw.t2p.monotone, simplified]
lemma Sup:
shows "raw.t2p (⨆X) = ⨆(raw.t2p ` X)"
by (simp add: raw.t2p_def prog.bind.SUPL)
lemma sup:
shows "raw.t2p (P ⊔ Q) = raw.t2p P ⊔ raw.t2p Q"
using raw.t2p.Sup[where X="{P, Q}"] by simp
lemma mcont2mcont[cont_intro]:
fixes P :: "_ ⇒ _ raw.tso"
assumes "mcont luba orda Sup (≤) F"
shows "mcont luba orda Sup (≤) (λx. raw.t2p (F x))"
proof -
from assms have "mcont luba orda Sup (≤) (λx. F x [])"
by (fastforce intro!: mcontI contI monotoneI
dest: mcont_contD mcont_monoD
simp: le_funD
simp flip: SUP_apply)
then show ?thesis
by (simp add: raw.t2p_def split_def)
qed
lemma return:
shows "raw.t2p (raw.return v) = prog.return v"
by (simp add: raw.t2p_def raw.return_alt_def raw.tso.cl_def raw.bind_def raw.prim_return_def
prog.p2s.simps prog.p2s.return
spec.interference.cl.action spec.interference.cl.return
spec.bind.bind spec.bind.return
raw.commit_writes.Nil raw.MFENCE.Nil
flip: prog.p2s_inject)
(simp add: spec.rel.wind_bind flip: spec.bind.bind)
lemma MFENCE_bind:
shows "raw.t2p (raw.MFENCE ⤜ P) = raw.t2p (P ())"
by (simp add: raw.t2p_def raw.bind_def split_def prog.bind.returnL raw.MFENCE.Nil)
lemma bind_return_unit:
shows "raw.t2p (λwb. prog.bind P (λ_::unit. prog.return ((), []))) = P"
by (simp add: raw.t2p_def raw.bind_def split_def
prog.bind.bind prog.bind.returnL prog.bind.returnR raw.MFENCE.Nil)
setup ‹Sign.parent_path›
setup ‹Sign.mandatory_path "parallel"›
lemma commute:
shows "raw.parallel P Q = raw.parallel Q P"
by (simp add: raw.parallel_def prog.parallel.commute)
lemma assoc:
shows "raw.parallel P (raw.parallel Q R) = raw.parallel (raw.parallel P Q) R"
by (simp add: raw.parallel_def raw.t2p.MFENCE_bind raw.t2p.bind_return_unit prog.parallel.assoc)
lemma mono:
assumes "P ≤ P'"
assumes "Q ≤ Q'"
shows "raw.parallel P Q ≤ raw.parallel P' Q'"
unfolding raw.parallel_def
apply (strengthen ord_to_strengthen(1)[OF assms(1)])
apply (strengthen ord_to_strengthen(1)[OF assms(2)])
apply (rule order.refl)
done
lemma botL:
shows "raw.parallel (raw.tso.cl ⊥) f = raw.MFENCE ⪢ f ⪢ raw.MFENCE ⪢ raw.tso.cl ⊥"
apply (simp add: raw.parallel_def raw.t2p.cl_bot prog.parallel.bot prog.bind.bind prog.bind.botL)
apply (simp add: raw.t2p_def split_def raw.bind_def prog.bind.bind prog.bind.returnL)
apply (subst (3 4) raw.bind.MFENCEL)
apply (simp add: raw.tso.cl.Nil prog.bind.botL)
done
lemma returnL:
shows "raw.parallel (raw.return ()) P = raw.MFENCE ⤜ (λ_. P) ⤜ (λ_. raw.MFENCE)"
apply (simp add: raw.parallel_def raw.t2p.return prog.parallel.return)
apply (simp add: raw.t2p_def split_def raw.bind_def prog.bind.bind prog.bind.returnL raw.bind.MFENCE_return)
apply (subst (2) raw.bind.MFENCEL)
apply simp
done
lemma SupL_not_empty:
assumes "∀x∈X. x ∈ raw.tso.closed"
assumes "Q ∈ raw.tso.closed"
assumes "X ≠ {}"
shows "raw.parallel (⨆X ⊔ raw.tso.cl ⊥) Q = (⨆P∈X. raw.parallel P Q) ⊔ raw.tso.cl ⊥"
proof -
from ‹X ≠ {}›
have "raw.parallel (⨆ X) Q = (⨆P∈X. raw.parallel P Q)"
by (simp add: raw.parallel_def raw.t2p.Sup raw.t2p.sup
prog.parallel.SupL_not_empty prog.parallel.supL prog.bind.SUPL prog.bind.supL)
(simp add: raw.bind_def split_def fun_eq_iff prog.bind.SUPR_not_empty image_image)
moreover
from assms have "raw.tso.cl ⊥ ≤ (⨆P∈X. raw.parallel P Q)"
by (force intro: less_eq_Sup raw.tso.least[OF _ raw.tso.closed.parallel])
moreover note assms
ultimately show ?thesis
by (simp add: sup.absorb1 less_eq_Sup raw.tso.least)
qed
setup ‹Sign.parent_path›
setup ‹Sign.parent_path›
typedef 'v tso = "raw.tso.closed :: 'v raw.tso set"
morphisms t2p' Abs_tso
by blast
setup_lifting type_definition_tso
instantiation tso :: (type) complete_distrib_lattice
begin
lift_definition bot_tso :: "'v tso" is "raw.tso.cl ⊥" ..
lift_definition top_tso :: "'v tso" is "⊤" ..
lift_definition sup_tso :: "'v tso ⇒ 'v tso ⇒ 'v tso" is sup ..
lift_definition inf_tso :: "'v tso ⇒ 'v tso ⇒ 'v tso" is inf ..
lift_definition less_eq_tso :: "'v tso ⇒ 'v tso ⇒ bool" is less_eq .
lift_definition less_tso :: "'v tso ⇒ 'v tso ⇒ bool" is less .
lift_definition Inf_tso :: "'v tso set ⇒ 'v tso" is Inf ..
lift_definition Sup_tso :: "'v tso set ⇒ 'v tso" is "λX. Sup X ⊔ raw.tso.cl ⊥" ..
instance by (standard; transfer; auto simp: InfI Inf_lower le_supI1 SupI SupE raw.tso.least)
end
setup ‹Sign.mandatory_path "tso"›
lift_definition bind :: "'v tso ⇒ ('v ⇒ 'w tso) ⇒ 'w tso" is raw.bind ..
lift_definition action :: "(write_buffer ⇒ ('v × write_buffer × heap.t × heap.t) set) ⇒ 'v tso" is raw.action ..
lift_definition MFENCE :: "unit tso" is raw.MFENCE ..
lift_definition parallel :: "unit tso ⇒ unit tso ⇒ unit tso" is raw.parallel ..
lift_definition vmap :: "('v ⇒ 'w) ⇒ 'v tso ⇒ 'w tso" is raw.vmap ..
lift_definition t2p :: "'v tso ⇒ (heap.t, 'v) prog" is raw.t2p .
adhoc_overloading
Monad_Syntax.bind ⇌ tso.bind
adhoc_overloading
parallel ⇌ tso.parallel
definition return :: "'v ⇒ 'v tso" where
"return v = tso.action ⟨{v} × {[]} × Id⟩"
definition guard :: "(write_buffer ⇒ heap.t pred) ⇒ unit tso" where
"guard g = tso.action (λwb. {()} × {[]} × Diag (g wb))"
abbreviation (input) read :: "(heap.t ⇒ 'v) ⇒ 'v tso" where
"read f ≡ tso.action (λwb. {(f (apply_writes wb s), [], s, s) |s. True})"
abbreviation (input) "write" :: "(heap.t ⇒ heap.write) ⇒ unit tso" where
"write f ≡ tso.action ⟨{((), [f s], s, s) |s. True}⟩"
lemma return_alt_def:
shows "tso.return v = tso.read ⟨v⟩"
by (auto simp: tso.return_def intro: arg_cong[where f="tso.action"])
declare tso.bind_def[code drop]
declare tso.action_def[code drop]
declare tso.return_def[code drop]
declare tso.MFENCE_def[code drop]
declare tso.parallel_def[code drop]
declare tso.vmap_def[code drop]
setup ‹Sign.mandatory_path "return"›
lemma transfer[transfer_rule]:
shows "rel_fun (=) cr_tso raw.return tso.return"
unfolding raw.return_def tso.return_def by transfer_prover
setup ‹Sign.parent_path›
setup ‹Sign.mandatory_path "action"›
lemma empty:
shows bot: "tso.action ⊥ = ⊥"
and "tso.action (λ_. {}) = ⊥"
by (simp_all add: raw.action.bot[transferred, unfolded bot_fun_def] bot_fun_def)
lemmas monotone = raw.action.monotone[transferred]
lemmas strengthen[strg] = st_monotone[OF tso.action.monotone]
lemmas mono = monotoneD[OF tso.action.monotone]
lemmas mono2mono[cont_intro, partial_function_mono] = monotone2monotone[OF tso.action.monotone, simplified]
lemma Sup:
shows "tso.action (⨆Fs) = ⨆(tso.action ` Fs)"
by transfer (simp add: raw.action.Sup)
lemmas sup = tso.action.Sup[where Fs="{F, G}" for F G, simplified]
setup ‹Sign.parent_path›
setup ‹Sign.mandatory_path "bind"›
lemmas if_distrL = if_distrib[where f="λf. tso.bind f g" for g]
lemmas mono = raw.bind.mono[transferred]
lemma strengthen[strg]:
assumes "st_ord F f f'"
assumes "⋀x. st_ord F (g x) (g' x)"
shows "st_ord F (tso.bind f g) (tso.bind f' g')"
using assms by (cases F; clarsimp intro!: tso.bind.mono)
lemmas mono2mono[cont_intro, partial_function_mono] = raw.bind.mono2mono[transferred]
lemma bind:
shows "f ⤜ g ⤜ h = tso.bind f (λx. g x ⤜ h)"
by transfer (simp add: raw.bind.bind)
lemma return:
shows returnL: "tso.return v ⤜ g = g v"
and returnR: "f ⤜ tso.return = f"
by (transfer; simp add: raw.bind.returnL raw.bind.returnR)+
lemma botL:
shows "tso.bind ⊥ g = ⊥"
by transfer (simp add: raw.tso.cl.bot raw.bind.bind raw.bind.botL flip: bot_fun_def)
lemma botR_le:
shows "tso.bind f ⟨⊥⟩ ≤ f" (is ?thesis1)
and "tso.bind f ⊥ ≤ f" (is ?thesis2)
proof -
show ?thesis1
by (metis bot.extremum dual_order.refl tso.bind.mono tso.bind.returnR)
then show ?thesis2
by (simp add: bot_fun_def)
qed
lemma
fixes f :: "_ tso"
fixes f⇩1 :: "_ tso"
shows supL: "(f⇩1 ⊔ f⇩2) ⤜ g = (f⇩1 ⤜ g) ⊔ (f⇩2 ⤜ g)"
and supR: "f ⤜ (λx. g⇩1 x ⊔ g⇩2 x) = (f ⤜ g⇩1) ⊔ (f ⤜ g⇩2)"
by (transfer; blast intro: raw.bind.supL raw.bind.supR)+
lemma SUPL:
fixes X :: "_ set"
fixes f :: "_ ⇒ _ tso"
shows "(⨆x∈X. f x) ⤜ g = (⨆x∈X. f x ⤜ g)"
by transfer
(simp add: raw.bind.supL raw.bind.SUPL raw.tso.cl.bot raw.bind.bind raw.bind.botL
flip: bot_fun_def)
lemma SUPR:
fixes X :: "_ set"
fixes f :: "_ tso"
shows "f ⤜ (λv. ⨆x∈X. g x v) = (⨆x∈X. f ⤜ g x) ⊔ (f ⤜ ⊥)"
unfolding bot_fun_def
by transfer
(simp add: raw.bind.supR raw.bind.SUPR ac_simps
sup.absorb2 le_supI1 raw.bind.mono raw.tso.closed.bind raw.tso.least)
lemma SupR:
fixes X :: "_ set"
fixes f :: "_ tso"
shows "f ⪢ (⨆X) = (⨆x∈X. f ⪢ x) ⊔ (f ⤜ ⊥)"
by (simp add: tso.bind.SUPR[where g="λx v. x", simplified])
lemma SUPR_not_empty:
fixes f :: "_ tso"
assumes "X ≠ {}"
shows "f ⤜ (λv. ⨆x∈X. g x v) = (⨆x∈X. f ⤜ g x)"
using iffD2[OF ex_in_conv assms]
by (subst trans[OF tso.bind.SUPR sup.absorb1]; force intro: SUPI tso.bind.mono)
lemma mcont2mcont[cont_intro]:
assumes "mcont luba orda Sup (≤) f"
assumes "⋀v. mcont luba orda Sup (≤) (λx. g x v)"
shows "mcont luba orda Sup (≤) (λx. tso.bind (f x) (g x))"
proof(rule ccpo.mcont2mcont'[OF complete_lattice_ccpo _ _ assms(1)])
show "mcont Sup (≤) Sup (≤) (λf. tso.bind f (g x))" for x
by (intro mcontI contI monotoneI) (simp_all add: tso.bind.mono flip: tso.bind.SUPL)
show "mcont luba orda Sup (≤) (λx. tso.bind f (g x))" for f
by (intro mcontI monotoneI contI)
(simp_all add: mcont_monoD[OF assms(2)] tso.bind.mono
flip: tso.bind.SUPR_not_empty contD[OF mcont_cont[OF assms(2)]])
qed
setup ‹Sign.parent_path›
setup ‹Sign.mandatory_path "guard"›
lemma transfer[transfer_rule]:
shows "rel_fun (=) cr_tso raw.guard tso.guard"
unfolding raw.guard_def tso.guard_def by transfer_prover
lemma bot:
shows "tso.guard ⊥ = ⊥"
and "tso.guard (λ_ _ .False) = ⊥"
by (simp_all add: tso.guard_def tso.action.empty)
lemma top:
shows "tso.guard ⊤ = tso.return ()" (is ?thesis1)
and "tso.guard (λ_. ⊤) = tso.return ()" (is ?thesis2)
and "tso.guard (λ_ _. True) = tso.return ()" (is ?thesis3)
proof -
show ?thesis1
by (simp add: tso.guard_def tso.return_def flip: Id_def)
then show ?thesis2 and ?thesis3
by (simp_all add: top_fun_def)
qed
lemma return_le:
shows "tso.guard g ≤ tso.return ()"
by transfer (rule raw.guard.return_le)
lemma monotone:
shows "mono tso.guard"
by transfer (rule raw.guard.monotone)
lemmas strengthen[strg] = st_monotone[OF tso.guard.monotone]
lemmas mono = monotoneD[OF tso.guard.monotone]
lemmas mono2mono[cont_intro, partial_function_mono] = monotone2monotone[OF tso.guard.monotone, simplified]
lemma less:
assumes "g < g'"
shows "tso.guard g < tso.guard g'"
using assms by transfer (rule raw.guard.less)
setup ‹Sign.parent_path›
setup ‹Sign.mandatory_path "parallel"›
lemma commute:
shows "tso.parallel P Q = tso.parallel Q P"
by transfer (rule raw.parallel.commute)
lemma assoc:
shows "tso.parallel P (tso.parallel Q R) = tso.parallel (tso.parallel P Q) R"
by transfer (rule raw.parallel.assoc)
lemmas mono = raw.parallel.mono[transferred]
lemma strengthen[strg]:
assumes "st_ord F P P'"
assumes "st_ord F Q Q'"
shows "st_ord F (tso.parallel P Q) (tso.parallel P' Q')"
using assms by (cases F; simp add: tso.parallel.mono)
lemma mono2mono[cont_intro, partial_function_mono]:
assumes "monotone orda (≤) F"
assumes "monotone orda (≤) G"
shows "monotone orda (≤) (λf. tso.parallel (F f) (G f))"
using assms by (simp add: monotone_def tso.parallel.mono)
lemma bot:
shows parallel_botL: "tso.parallel ⊥ f = tso.MFENCE ⪢ f ⪢ tso.MFENCE ⤜ ⊥" (is ?thesis1)
and parallel_botR: "tso.parallel f ⊥ = tso.MFENCE ⪢ f ⪢ tso.MFENCE ⤜ ⊥" (is ?thesis2)
proof -
show ?thesis1
unfolding bot_fun_def by transfer (simp add: raw.parallel.botL raw.bind.bind)
then show ?thesis2
by (simp add: tso.parallel.commute)
qed
lemma return:
shows returnL: "tso.return () ∥ P = tso.MFENCE ⪢ P ⪢ tso.MFENCE" (is ?thesis1)
and returnR: "P ∥ tso.return () = tso.MFENCE ⪢ P ⪢ tso.MFENCE" (is ?thesis2)
proof -
show ?thesis1
by transfer (rule raw.parallel.returnL)
then show ?thesis2
by (simp add: tso.parallel.commute)
qed
lemma Sup_not_empty:
fixes X :: "unit tso set"
assumes "X ≠ {}"
shows SupL_not_empty: "⨆X ∥ Q = (⨆P∈X. P ∥ Q)" (is "?thesis1 Q")
and SupR_not_empty: "P ∥ ⨆X = (⨆Q∈X. P ∥ Q)" (is ?thesis2)
proof -
from assms show "?thesis1 Q" for Q
by transfer (rule raw.parallel.SupL_not_empty)
then show ?thesis2
by (simp add: tso.parallel.commute)
qed
lemma sup:
fixes P :: "unit tso"
shows supL: "P ⊔ Q ∥ R = (P ∥ R) ⊔ (Q ∥ R)"
and supR: "P ∥ Q ⊔ R = (P ∥ Q) ⊔ (P ∥ R)"
using tso.parallel.SupL_not_empty[where X="{P, Q}"] tso.parallel.SupR_not_empty[where X="{Q, R}"]
by simp_all
lemma mcont2mcont[cont_intro]:
assumes "mcont luba orda Sup (≤) P"
assumes "mcont luba orda Sup (≤) Q"
shows "mcont luba orda Sup (≤) (λx. tso.parallel (P x) (Q x))"
proof(rule ccpo.mcont2mcont'[OF complete_lattice_ccpo _ _ assms(1)])
show "mcont Sup (≤) Sup (≤) (λy. tso.parallel y (Q x))" for x
by (intro mcontI contI monotoneI) (simp_all add: tso.parallel.mono tso.parallel.SupL_not_empty)
show "mcont luba orda Sup (≤) (λx. tso.parallel y (Q x))" for y
by (simp add: mcontI monotoneI contI mcont_monoD[OF assms(2)]
spec.parallel.mono mcont_contD[OF assms(2)] tso.parallel.SupR_not_empty image_image)
qed
setup ‹Sign.parent_path›
setup ‹Sign.mandatory_path "bind"›
lemmas MFENCE_MFENCE = raw.bind.MFENCE_MFENCE[transferred]
setup ‹Sign.parent_path›
setup ‹Sign.mandatory_path "t2p'"›
lemma monotone:
shows "mono (λt. t2p' t wb)"
by (simp add: le_fun_def less_eq_tso.rep_eq monotone_def)
lemmas strengthen[strg] = st_monotone[OF tso.t2p'.monotone]
lemmas mono = monotoneD[OF tso.t2p'.monotone]
lemmas action = tso.action.rep_eq
lemma return:
shows "t2p' (tso.return v) = raw.return v"
by transfer simp
setup ‹Sign.parent_path›
setup ‹Sign.parent_path›
paragraph‹ Combinators ›
setup ‹Sign.mandatory_path "tso"›
abbreviation guardM :: "bool ⇒ unit tso" where
"guardM b ≡ if b then ⊥ else tso.return ()"
abbreviation unlessM :: "bool ⇒ unit tso ⇒ unit tso" where
"unlessM b c ≡ if b then tso.return () else c"
abbreviation whenM :: "bool ⇒ unit tso ⇒ unit tso" where
"whenM b c ≡ if b then c else tso.return ()"
definition app :: "('a ⇒ unit tso) ⇒ 'a list ⇒ unit tso" where
"app f xs = foldr (λx m. f x ⪢ m) xs (tso.return ())"
primrec fold_mapM :: "('a ⇒ 'b tso) ⇒ 'a list ⇒ 'b list tso" where
"fold_mapM f [] = tso.return []"
| "fold_mapM f (x # xs) = do {
y ← f x;
ys ← fold_mapM f xs;
tso.return (y # ys)
}"
partial_function (lfp) while :: "('k ⇒ ('k + 'v) tso) ⇒ 'k ⇒ 'v tso" where
"while c k = c k ⤜ (λrv. case rv of Inl k' ⇒ while c k' | Inr v ⇒ tso.return v)"
abbreviation (input) while' :: "((unit + 'v) tso) ⇒ 'v tso" where
"while' c ≡ tso.while ⟨c⟩ ()"
definition raise :: "String.literal ⇒ 'v tso" where
"raise s = ⊥"
definition assert :: "bool ⇒ unit tso" where
"assert P = (if P then tso.return () else tso.raise STR ''assert'')"
declare tso.raise_def[code drop]
setup ‹Sign.mandatory_path "fold_mapM"›
lemma bot:
shows "tso.fold_mapM ⊥ = (λxs. case xs of [] ⇒ tso.return [] | _ ⇒ ⊥)"
by (simp add: fun_eq_iff tso.bind.botL split: list.split)
lemma append:
shows "tso.fold_mapM f (xs @ ys) = tso.fold_mapM f xs ⤜ (λxs. tso.fold_mapM f ys ⤜ (λys. tso.return (xs @ ys)))"
by (induct xs) (simp_all add: tso.bind.bind tso.bind.returnL tso.bind.returnR)
setup ‹Sign.parent_path›
setup ‹Sign.mandatory_path "app"›
lemma bot:
shows "tso.app ⊥ = (λxs. case xs of [] ⇒ tso.return () | _ ⇒ ⊥)"
and "tso.app (λ_. ⊥) = (λxs. case xs of [] ⇒ tso.return () | _ ⇒ ⊥)"
by (simp_all add: fun_eq_iff tso.app_def tso.bind.botL split: list.split)
lemma Nil:
shows "tso.app f [] = tso.return ()"
by (simp add: tso.app_def)
lemma Cons:
shows "tso.app f (x # xs) = f x ⪢ tso.app f xs"
by (simp add: tso.app_def)
lemmas simps =
tso.app.bot
tso.app.Nil
tso.app.Cons
lemma append:
shows "tso.app f (xs @ ys) = tso.app f xs ⪢ tso.app f ys"
by (induct xs arbitrary: ys) (simp_all add: tso.app.simps tso.bind.returnL tso.bind.bind)
lemma monotone:
shows "mono (λf. tso.app f xs)"
by (induct xs) (simp_all add: tso.app.simps le_fun_def monotone_on_def tso.bind.mono)
lemmas strengthen[strg] = st_monotone[OF tso.app.monotone]
lemmas mono = monotoneD[OF tso.app.monotone]
lemmas mono2mono[cont_intro, partial_function_mono] = monotone2monotone[OF tso.app.monotone, simplified, of orda P for orda P]
lemma Sup_le:
shows "(⨆f∈X. tso.app f xs) ≤ tso.app (⨆X) xs"
by (simp add: SUP_le_iff SupI tso.app.mono)
setup ‹Sign.parent_path›
setup ‹Sign.parent_path›
subsection‹ References\label{sec:tso-refs} ›
text‹
Observe that allocation is global in this model. We allow the memory location to have an arbitrary
value and enqueue the initialising write in the TSO buffer.
›
setup ‹Sign.mandatory_path "tso.Ref"›
definition ref :: "'a::heap.rep ⇒ 'a ref tso" where
"ref v = tso.action (λwb. {(r, [heap.Write (ref.addr_of r) 0 (heap.rep.to v)], s, s')
|r s s' v'. (r, s') ∈ Ref.alloc v' s})"
definition lookup :: "'a::heap.rep ref ⇒ 'a tso" (‹!_› 61) where
"lookup r = tso.read (Ref.get r)"
definition update :: "'a ref ⇒ 'a::heap.rep ⇒ unit tso" (‹_ := _› 62) where
"update r v = tso.write ⟨heap.Write (ref.addr_of r) 0 (heap.rep.to v)⟩"
declare tso.Ref.ref_def[code drop]
declare tso.Ref.lookup_def[code drop]
declare tso.Ref.update_def[code drop]
setup ‹Sign.parent_path›
subsection‹ Inhabitation\label{sec:tso-inhabitation} ›
text‹ In order to obtain compositional rules we need to make the write buffer explicit. ›
setup ‹Sign.mandatory_path "tso"›
definition t2s :: "write_buffer ⇒ 'v tso ⇒ (sequential, heap.t, 'v × write_buffer) spec" where
"t2s wb P = prog.p2s (tso.t2p' P wb)"
setup ‹Sign.parent_path›
setup ‹Sign.mandatory_path "spec.singleton.tso"›
lemma t2s_commit:
assumes "⦉heap.apply_write w s, xs, v⦊ ≤ tso.t2s wb f"
shows "⦉s, (self, heap.apply_write w s) # xs, v⦊ ≤ tso.t2s (w # wb) f"
unfolding tso.t2s_def
by (subst raw.tso.closed_conv[OF tso.t2p'])
(fastforce simp: prog.p2s.action simp add: prog.p2s.simps simp flip: tso.t2s_def
intro: order.trans[OF _ prog.p2s.mono[OF raw.tso.cl.commit]]
spec.bind.continueI[where xs="[(self, heap.apply_write w s)]" and v="((), [])", simplified, OF _ assms]
order.trans[OF spec.action.stepI spec.interference.expansive])
setup ‹Sign.parent_path›
setup ‹Sign.mandatory_path "spec.idle.tso"›
lemma t2s_le:
shows "spec.idle ≤ tso.t2s wb P"
by (simp add: tso.t2s_def spec.idle.p2s_le)
setup ‹Sign.parent_path›
setup ‹Sign.mandatory_path "spec.t2s"›
lemmas minimal[iff] = order.trans[OF spec.idle.minimal_le spec.idle.tso.t2s_le]
setup ‹Sign.parent_path›
setup ‹Sign.mandatory_path "spec.interference.tso"›
lemma t2s_le:
shows "spec.rel ({env} × UNIV) ⤜ (λ_::unit. tso.t2s wb P) ≤ tso.t2s wb P"
by (simp add: tso.t2s_def prog.p2s.interference_wind_bind)
setup ‹Sign.parent_path›
setup ‹Sign.mandatory_path "prog.p2s"›
lemma t2p[prog.p2s.simps]:
shows "prog.p2s (tso.t2p P)
= tso.t2s [] P ⤜ (λvwb. prog.p2s (raw.MFENCE (snd vwb) ⪢ prog.return (fst vwb)))"
by transfer (simp add: tso.t2p_def tso.t2s_def raw.t2p_def prog.p2s.simps split_def)
setup ‹Sign.parent_path›
setup ‹Sign.mandatory_path "tso.t2s"›
lemma bind:
shows "tso.t2s wb (f ⤜ g) = tso.t2s wb f ⤜ (λx. tso.t2s (snd x) (g (fst x)))"
unfolding tso.t2s_def by transfer (simp add: raw.bind_def split_def prog.p2s.simps)
lemma parallel:
shows "tso.t2s [] (P ∥ Q) = prog.p2s ((tso.t2p P ∥ tso.t2p Q) ⪢ prog.return ((), []))"
unfolding tso.t2s_def
by transfer (simp add: raw.parallel_def raw.bind_def raw.MFENCE.Nil prog.bind.returnL)
lemma return:
shows "tso.t2s [] (tso.return v) = prog.p2s (prog.return (v, []))"
unfolding tso.t2s_def
by transfer
(simp add: raw.return_alt_def raw.tso.cl.Nil raw.prim_return_def prog.bind.returnL raw.commit_writes.Nil)
setup ‹Sign.parent_path›
paragraph‹ Inhabitation rules. ›
setup ‹Sign.mandatory_path "inhabits.tso"›
lemma bind:
assumes "tso.t2s wb f -s, xs→ tso.t2s wb' f'"
shows "tso.t2s wb (f ⤜ g) -s, xs→ tso.t2s wb' (f' ⤜ g)"
by (simp add: tso.t2s.bind inhabits.spec.bind assms)
lemma commit:
shows "tso.t2s (w # wb) f -s, [(self, heap.apply_write w s)]→ tso.t2s wb f"
by (clarsimp simp: inhabits_def spec.bind.singletonL spec.term.none.singleton trace.split_all
spec.singleton.tso.t2s_commit)
setup ‹Sign.mandatory_path "Ref"›
lemma ref:
fixes r :: "'a::heap.rep ref"
fixes s :: "heap.t"
fixes v :: "'a"
fixes v' :: "'a"
assumes "¬heap.present r s"
shows "tso.t2s wb (tso.Ref.ref v)
-s, [(self, Ref.set r v' s)]→
tso.t2s (wb @ [heap.Write (ref.addr_of r) 0 (heap.rep.to v)]) (tso.return r)" (is "?lhs -s, ?step→ ?rhs")
proof -
have rhs: "?rhs = prog.p2s (raw.commit_writes (wb @ [heap.Write (ref.addr_of r) 0 (heap.rep.to v)])
⤜ (λv. raw.prim_return r (snd v)))"
apply (simp add: tso.t2s_def tso.t2p'.return raw.return_def raw.action_def)
apply (subst (1) prog.return.cong)
apply (simp_all add: image_iff split_def Sup_fst fst_image raw.tso.cl.prim_return raw.bind_def
flip: raw.prim_return_def)
done
note * = order.trans[OF _ spec.bind.mono[OF prog.p2s.mono[OF
raw.commit_writes.return_le[unfolded le_fun_def raw.prim_return_def, rule_format]]
order.refl]]
note ** = spec.bind.mono[OF spec.action.stepI[where a=self and s=s
and v="(r, wb @ [heap.Write (ref.addr_of r) 0 (heap.rep.to v)])"
and s'="Ref.set r v' s"
and w="Some (r, wb @ [heap.Write (ref.addr_of r) 0 (heap.rep.to v)])"]
order.refl]
have lhs: "⦉s, [(self, Ref.set r v' s)], Some (r, wb @ [heap.Write (ref.addr_of r) 0 (heap.rep.to v)])⦊
⤜ (λv. prog.p2s (raw.commit_writes (snd v))
⤜ (λx. prog.p2s (raw.prim_return (fst v) (snd x))))
≤ ?lhs"
apply (simp add: tso.Ref.ref_def tso.t2s_def split_def tso.t2p'.action
raw.action_def raw.tso.cl_def raw.bind_def prog.p2s.bind prog.bind.bind)
apply (rule * )
apply (simp flip: prog.p2s.bind)
apply (force simp: assms Ref.alloc_def prog.p2s.simps prog.p2s.action prog.bind.returnL
intro: ** order.trans[OF _ spec.bind.mono[OF spec.interference.expansive order.refl]])
done
show ?thesis
unfolding inhabits_def
by (rule order.trans[OF _ lhs])
(simp add: rhs prog.p2s.simps spec.bind.singletonL spec.term.none.singleton)
qed
lemma lookup:
fixes r :: "'a::heap.rep ref"
shows "tso.t2s wb (!r) -s, []→ tso.t2s wb (tso.return (Ref.get r (apply_writes wb s)))"
apply (clarsimp simp: tso.Ref.lookup_def inhabits_def trace.split_all
tso.t2s_def tso.t2p'.action tso.t2p'.return
raw.action_def raw.return_alt_def raw.tso.cl.prim_return
spec.bind.singletonL spec.term.none.singleton)
apply (clarsimp simp: raw.tso.cl_def raw.bind_def split_def prog.bind.bind)
apply (rule order.trans[OF _ prog.p2s.mono[OF
prog.bind.mono[OF raw.commit_writes.return_le[unfolded raw.prim_return_def le_fun_def, rule_format]
order.refl]]])
apply (force simp: prog.bind.return prog.p2s.bind prog.p2s.action
intro: order.trans[OF spec.bind.continueI[where xs="[]", simplified, OF spec.action.stutterI]
spec.bind.mono[OF spec.interference.expansive order.refl]])
done
lemma update:
fixes r :: "'a::heap.rep ref"
shows "tso.t2s wb (r := v)
-s, []→
tso.t2s (wb @ [heap.Write (ref.addr_of r) 0 (heap.rep.to v)]) (tso.return ())"
proof -
have *: "(λp. raw.prim_return () (snd p)) = prog.return"
by (simp add: raw.prim_return_def fun_eq_iff)
have "raw.tso.cl (λwb. prog.return ((), wb)) (wb @ [heap.Write (ref.addr_of r) 0 (heap.rep.to v)])
≤ raw.tso.cl (λwb. prog.action {(((), wb @ [heap.Write (ref.addr_of r) 0 (heap.rep.to v)]), s, s) |s. True}) wb"
apply (simp add: raw.tso.cl_def raw.bind.prim_returnR raw.commit_writes.commit_writes
flip: raw.prim_return_def
cong: order.assms_cong)
apply (simp add: * raw.tso.cl_def raw.bind_def split_def prog.bind.bind)
apply (rule order.trans[OF _
prog.bind.mono[OF raw.commit_writes.return_le[unfolded raw.prim_return_def le_fun_def, rule_format]
order.refl]])
apply (simp add: prog.bind.returnL flip: prog.p2s.bind)
apply (subst (1) prog.return.cong, force, force)
apply (simp add: split_def Sup_fst fst_image prog.bind.return)
done
from prog.p2s.mono[OF this] show ?thesis
by (fastforce simp: tso.Ref.update_def raw.action_def tso.t2s_def inhabits_def
tso.t2p'.return tso.t2p'.action
raw.return_alt_def raw.prim_return_def
spec.bind.singletonL spec.term.none.singleton)
qed
setup ‹Sign.parent_path›
lemmas bind' = inhabits.trans[OF inhabits.tso.bind]
lemmas commit' = inhabits.trans[OF inhabits.tso.commit]
setup ‹Sign.parent_path›
end