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(*
* Copyright (c) Facebook, Inc. and its affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*)
(* Proofs about llvm to llair translation *)
open HolKernel boolLib bossLib Parse;
open listTheory arithmeticTheory pred_setTheory finite_mapTheory wordsTheory integer_wordTheory;
open settingsTheory miscTheory llvmTheory llairTheory llair_propTheory llvm_to_llairTheory;
new_theory "llvm_to_llair_prop";
numLib.prefer_num ();
Inductive v_rel:
(∀w. v_rel (FlatV (PtrV w)) (FlatV (IntV (w2i w) pointer_size)))
(∀w. v_rel (FlatV (W1V w)) (FlatV (IntV (w2i w) 1)))
(∀w. v_rel (FlatV (W8V w)) (FlatV (IntV (w2i w) 8)))
(∀w. v_rel (FlatV (W32V w)) (FlatV (IntV (w2i w) 32)))
(∀w. v_rel (FlatV (W64V w)) (FlatV (IntV (w2i w) 64)))
(∀vs1 vs2.
list_rel v_rel vs1 vs2
v_rel (AggV vs1) (AggV vs2))
End
(* Define when an LLVM state is related to a llair one. Parameterised over a
* relation on program counters, which chould be generated by the
* transformation. It is not trivial because the translation cuts up blocks at
* function calls and for remiving phi nodes.
*
* Also parameterised on a map for locals relating LLVM registers to llair
* expressions that compute the value in that register. This corresponds to part
* of the translation's state.
*)
Definition state_rel_def:
state_rel pc_rel emap (s:llvm$state) (s':llair$state)
pc_rel s.ip s'.bp
(* Unmapped registers in LLVM are unmapped in llair too *)
(∀r. flookup s.locals r = None flookup emap r = None)
(* Mapped LLVM registers have a related value in the emap (after
* evaluating) *)
(∀r v. flookup s.locals r = Some v
∃v' e.
v_rel v.value v'
flookup emap r = Some e eval_exp s' e v')
erase_tags s.heap = s'.heap
End
Theorem translate_arg_correct:
∀s a v pc_rel emap s'.
state_rel pc_rel emap s s'
eval s a = Some v
∃v'. eval_exp s' (translate_arg emap a) v' v_rel v.value v'
Proof
Cases_on `a` >> rw [eval_def, translate_arg_def]
>- cheat >>
CASE_TAC >> fs [PULL_EXISTS, state_rel_def] >>
res_tac >> rfs [] >> metis_tac []
QED
Theorem translate_constant_correct_lem:
(∀c s pc_rel emap s' (g : glob_var |-> β # word64).
state_rel pc_rel emap s s'
∃v'. eval_exp s' (translate_const c) v' v_rel (eval_const g c) v')
(∀(cs : (ty # const) list) s pc_rel emap s' (g : glob_var |-> β # word64).
state_rel pc_rel emap s s'
∃v'. list_rel (eval_exp s') (map (translate_const o snd) cs) v' list_rel v_rel (map (eval_const g o snd) cs) v')
(∀(tc : ty # const) s pc_rel emap s' (g : glob_var |-> β # word64).
state_rel pc_rel emap s s'
∃v'. eval_exp s' (translate_const (snd tc)) v' v_rel (eval_const g (snd tc)) v')
Proof
ho_match_mp_tac const_induction >> rw [translate_const_def] >>
simp [Once eval_exp_cases, eval_const_def]
>- (
Cases_on `s` >> simp [eval_const_def, translate_size_def, v_rel_cases] >>
metis_tac [truncate_2comp_i2w_w2i, dimindex_1, dimindex_8, dimindex_32, dimindex_64])
>- (
simp [v_rel_cases, PULL_EXISTS, MAP_MAP_o] >>
fs [combinTheory.o_DEF, pairTheory.LAMBDA_PROD] >>
metis_tac [])
>- (
simp [v_rel_cases, PULL_EXISTS, MAP_MAP_o] >>
fs [combinTheory.o_DEF, pairTheory.LAMBDA_PROD] >>
metis_tac [])
>- cheat
>- cheat
>- cheat
>- cheat
QED
Theorem translate_constant_correct:
∀c s pc_rel emap s' g.
state_rel pc_rel emap s s'
∃v'. eval_exp s' (translate_const c) v' v_rel (eval_const g c) v'
Proof
metis_tac [translate_constant_correct_lem]
QED
Theorem restricted_i2w_11:
∀i (w:'a word). INT_MIN (:'a) i i INT_MAX (:'a) (i2w i : 'a word) = i2w (w2i w) i = w2i w
Proof
rw [i2w_def]
>- (
Cases_on `n2w (Num (-i)) = INT_MINw` >>
rw [w2i_neg, w2i_INT_MINw] >>
fs [word_L_def] >>
`?j. 0 j i = -j` by intLib.COOPER_TAC >>
rw [] >>
fs [] >>
`INT_MIN (:'a) < dimword (:'a)` by metis_tac [INT_MIN_LT_DIMWORD] >>
`Num j MOD dimword (:'a) = Num j`
by (irule LESS_MOD >> intLib.COOPER_TAC) >>
fs []
>- intLib.COOPER_TAC
>- (
`Num j < INT_MIN (:'a)` by intLib.COOPER_TAC >>
fs [w2i_n2w_pos, integerTheory.INT_OF_NUM]))
>- (
fs [GSYM INT_MAX, INT_MAX_def] >>
`Num i < INT_MIN (:'a)` by intLib.COOPER_TAC >>
rw [w2i_n2w_pos, integerTheory.INT_OF_NUM] >>
intLib.COOPER_TAC)
QED
Theorem translate_extract_correct:
∀pc_rel emap s1 s1' a v v1' e1' cs ns result.
state_rel pc_rel emap s1 s1'
map (λci. signed_v_to_num (eval_const s1.globals ci)) cs = map Some ns
extract_value v ns = Some result
eval_exp s1' e1' v1'
v_rel v v1'
∃v2'.
eval_exp s1' (foldl (λe c. Select e (translate_const c)) e1' cs) v2'
v_rel result v2'
Proof
Induct_on `cs` >> rw [] >> fs [extract_value_def]
>- metis_tac [] >>
first_x_assum irule >>
Cases_on `ns` >> fs [] >>
qmatch_goalsub_rename_tac `translate_const c` >>
`?v2'. eval_exp s1' (translate_const c) v2' v_rel (eval_const s1.globals c) v2'`
by metis_tac [translate_constant_correct] >>
Cases_on `v` >> fs [extract_value_def] >>
qpat_x_assum `v_rel (AggV _) _` mp_tac >>
simp [Once v_rel_cases] >> rw [] >>
simp [Once eval_exp_cases, PULL_EXISTS] >>
fs [LIST_REL_EL_EQN] >>
qmatch_assum_rename_tac `_ = map Some is` >>
Cases_on `eval_const s1.globals c` >> fs [signed_v_to_num_def, signed_v_to_int_def] >> rw [] >>
`?i. v2' = FlatV i` by fs [v_rel_cases] >> fs [] >>
qmatch_assum_rename_tac `option_join _ = Some x` >>
`?size. i = IntV (&x) size` suffices_by metis_tac [] >> rw [] >>
qpat_x_assum `v_rel _ _` mp_tac >>
simp [v_rel_cases] >> rw [] >> fs [signed_v_to_int_def] >> rw [] >>
intLib.COOPER_TAC
QED
Theorem translate_update_correct:
∀pc_rel emap s1 s1' a v1 v1' v2 v2' e2 e2' e1' cs ns result.
state_rel pc_rel emap s1 s1'
map (λci. signed_v_to_num (eval_const s1.globals ci)) cs = map Some ns
insert_value v1 v2 ns = Some result
eval_exp s1' e1' v1'
v_rel v1 v1'
eval_exp s1' e2' v2'
v_rel v2 v2'
∃v3'.
eval_exp s1' (translate_updatevalue e1' e2' cs) v3'
v_rel result v3'
Proof
Induct_on `cs` >> rw [] >> fs [insert_value_def, translate_updatevalue_def]
>- metis_tac [] >>
simp [Once eval_exp_cases, PULL_EXISTS] >>
Cases_on `ns` >> fs [] >>
Cases_on `v1` >> fs [insert_value_def] >>
rename [`insert_value (el x _) _ ns`] >>
Cases_on `insert_value (el x l) v2 ns` >> fs [] >> rw [] >>
qpat_x_assum `v_rel (AggV _) _` mp_tac >> simp [Once v_rel_cases] >> rw [] >>
simp [v_rel_cases] >>
qmatch_goalsub_rename_tac `translate_const c` >>
qexists_tac `vs2` >> simp [] >>
`?v4'. eval_exp s1' (translate_const c) v4' v_rel (eval_const s1.globals c) v4'`
by metis_tac [translate_constant_correct] >>
`?idx_size. v4' = FlatV (IntV (&x) idx_size)`
by (
pop_assum mp_tac >> simp [Once v_rel_cases] >>
rw [] >> fs [signed_v_to_num_def, signed_v_to_int_def] >>
intLib.COOPER_TAC) >>
first_x_assum drule >>
disch_then drule >>
disch_then drule >>
disch_then (qspecl_then [`el x vs2`, `v2'`, `e2'`, `Select e1' (translate_const c)`] mp_tac) >>
simp [Once eval_exp_cases] >>
metis_tac [EVERY2_LUPDATE_same, LIST_REL_LENGTH, LIST_REL_EL_EQN]
QED
Theorem translate_instr_to_exp_correct:
∀emap instr r t s1 s1'.
classify_instr instr = Exp r t
state_rel pc_rel emap s1 s1'
(∀s2. step_instr prog s1 instr s2
(∃v pv. eval_exp s1' (translate_instr_to_exp emap instr) v
flookup s2.locals r = Some pv v_rel pv.value v))
Proof
recInduct translate_instr_to_exp_ind >>
simp [translate_instr_to_exp_def, classify_instr_def] >>
conj_tac
>- ( (* Sub *)
rw [step_instr_cases, Once eval_exp_cases, do_sub_def, PULL_EXISTS] >>
simp [inc_pc_def, update_result_def, FLOOKUP_UPDATE] >>
simp [v_rel_cases, PULL_EXISTS] >>
first_x_assum (mp_then.mp_then mp_then.Any mp_tac translate_arg_correct) >>
disch_then drule >>
first_x_assum (mp_then.mp_then mp_then.Any mp_tac translate_arg_correct) >>
disch_then drule >>
BasicProvers.EVERY_CASE_TAC >> fs [translate_ty_def, translate_size_def] >>
rfs [v_rel_cases] >>
pairarg_tac >> fs [] >>
fs [pairTheory.PAIR_MAP, wordsTheory.FST_ADD_WITH_CARRY] >>
qmatch_goalsub_abbrev_tac `eval_exp _ _ (FlatV (IntV i1 _))` >> strip_tac >>
qmatch_goalsub_abbrev_tac `eval_exp _ _ (FlatV (IntV i2 _))` >> strip_tac >>
qexists_tac `i1` >> qexists_tac `i2` >> simp [] >>
unabbrev_all_tac >>
rw []
>- (
irule restricted_i2w_11 >> simp [word_sub_i2w] >>
`dimindex (:1) = 1` by rw [] >>
drule truncate_2comp_i2w_w2i >>
rw [word_sub_i2w] >>
metis_tac [w2i_ge, w2i_le, SIMP_CONV (srw_ss()) [] ``INT_MIN (:1)``,
SIMP_CONV (srw_ss()) [] ``INT_MAX (:1)``])
>- (
irule restricted_i2w_11 >> simp [word_sub_i2w] >>
`dimindex (:8) = 8` by rw [] >>
drule truncate_2comp_i2w_w2i >>
rw [word_sub_i2w] >>
metis_tac [w2i_ge, w2i_le, SIMP_CONV (srw_ss()) [] ``INT_MIN (:8)``,
SIMP_CONV (srw_ss()) [] ``INT_MAX (:8)``])
>- (
irule restricted_i2w_11 >> simp [word_sub_i2w] >>
`dimindex (:32) = 32` by rw [] >>
drule truncate_2comp_i2w_w2i >>
rw [word_sub_i2w] >>
metis_tac [w2i_ge, w2i_le, SIMP_CONV (srw_ss()) [] ``INT_MIN (:32)``,
SIMP_CONV (srw_ss()) [] ``INT_MAX (:32)``])
>- (
irule restricted_i2w_11 >> simp [word_sub_i2w] >>
`dimindex (:64) = 64` by rw [] >>
drule truncate_2comp_i2w_w2i >>
rw [word_sub_i2w] >>
metis_tac [w2i_ge, w2i_le, SIMP_CONV (srw_ss()) [] ``INT_MIN (:64)``,
SIMP_CONV (srw_ss()) [] ``INT_MAX (:64)``])) >>
conj_tac
>- (
rw [step_instr_cases] >>
simp [inc_pc_def, update_result_def, FLOOKUP_UPDATE] >>
metis_tac [translate_arg_correct, translate_extract_correct]) >>
conj_tac
>- (
rw [step_instr_cases] >>
simp [inc_pc_def, update_result_def, FLOOKUP_UPDATE] >>
metis_tac [translate_arg_correct, translate_update_correct]) >>
cheat
QED
export_theory ();