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(* *********************************************************************)
(* *)
(* The Compcert verified compiler *)
(* *)
(* Xavier Leroy, INRIA Paris-Rocquencourt *)
(* Prashanth Mundkur, SRI International *)
(* *)
(* Copyright Institut National de Recherche en Informatique et en *)
(* Automatique. All rights reserved. This file is distributed *)
(* under the terms of the INRIA Non-Commercial License Agreement. *)
(* *)
(* The contributions by Prashanth Mundkur are reused and adapted *)
(* under the terms of a Contributor License Agreement between *)
(* SRI International and INRIA. *)
(* *)
(* *********************************************************************)
Require Import Coqlib.
Require Import AST Integers Floats.
Require Import Values Memory Globalenvs.
Require Import Op RTL.
Require Import NeedDomain.
(** Neededness analysis for RISC-V operators *)
Definition op1 (nv: nval) := nv :: nil.
Definition op2 (nv: nval) := nv :: nv :: nil.
Definition needs_of_condition (cond: condition): list nval := nil.
Definition needs_of_operation (op: operation) (nv: nval): list nval :=
match op with
| Omove => op1 nv
| Ointconst n => nil
| Olongconst n => nil
| Ofloatconst n => nil
| Osingleconst n => nil
| Oaddrsymbol id ofs => nil
| Oaddrstack ofs => nil
| Ocast8signed => op1 (sign_ext 8 nv)
| Ocast16signed => op1 (sign_ext 16 nv)
| Oadd => op2 (modarith nv)
| Oaddimm n => op1 (modarith nv)
| Oneg => op1 (modarith nv)
| Osub => op2 (default nv)
| Omul => op2 (modarith nv)
| Omulhs | Omulhu | Odiv | Odivu | Omod | Omodu => op2 (default nv)
| Oand => op2 (bitwise nv)
| Oandimm n => op1 (andimm nv n)
| Oor => op2 (bitwise nv)
| Oorimm n => op1 (orimm nv n)
| Oxor => op2 (bitwise nv)
| Oxorimm n => op1 (bitwise nv)
| Oshl | Oshr | Oshru => op2 (default nv)
| Oshlimm n => op1 (shlimm nv n)
| Oshrimm n => op1 (shrimm nv n)
| Oshruimm n => op1 (shruimm nv n)
| Oshrximm n => op1 (default nv)
| Omakelong => op2 (default nv)
| Olowlong | Ohighlong => op1 (default nv)
| Ocast32signed => op1 (default nv)
| Ocast32unsigned => op1 (default nv)
| Oaddl => op2 (default nv)
| Oaddlimm n => op1 (default nv)
| Onegl => op1 (default nv)
| Osubl => op2 (default nv)
| Omull => op2 (default nv)
| Omullhs | Omullhu | Odivl | Odivlu | Omodl | Omodlu => op2 (default nv)
| Oandl => op2 (default nv)
| Oandlimm n => op1 (default nv)
| Oorl => op2 (default nv)
| Oorlimm n => op1 (default nv)
| Oxorl => op2 (default nv)
| Oxorlimm n => op1 (default nv)
| Oshll | Oshrl | Oshrlu => op2 (default nv)
| Oshllimm n => op1 (default nv)
| Oshrlimm n => op1 (default nv)
| Oshrluimm n => op1 (default nv)
| Oshrxlimm n => op1 (default nv)
| Onegf | Oabsf => op1 (default nv)
| Oaddf | Osubf | Omulf | Odivf => op2 (default nv)
| Onegfs | Oabsfs => op1 (default nv)
| Oaddfs | Osubfs | Omulfs | Odivfs => op2 (default nv)
| Ofloatofsingle | Osingleoffloat => op1 (default nv)
| Ointoffloat | Ointuoffloat | Ofloatofint | Ofloatofintu => op1 (default nv)
| Olongoffloat | Olonguoffloat | Ofloatoflong | Ofloatoflongu => op1 (default nv)
| Ointofsingle | Ointuofsingle | Osingleofint | Osingleofintu => op1 (default nv)
| Olongofsingle | Olonguofsingle | Osingleoflong | Osingleoflongu => op1 (default nv)
| Ocmp c => needs_of_condition c
| OEseqw _ => op2 (default nv)
| OEsnew _ => op2 (default nv)
| OEsequw _ => op2 (default nv)
| OEsneuw _ => op2 (default nv)
| OEsltw _ => op2 (default nv)
| OEsltuw _ => op2 (default nv)
| OEsltiw _ => op1 (default nv)
| OEsltiuw _ => op1 (default nv)
| OExoriw _ => op1 (bitwise nv)
| OEluiw _ => op1 (default nv)
| OEaddiw _ _ => op1 (default nv)
| OEandiw n => op1 (andimm nv n)
| OEoriw n => op1 (orimm nv n)
| OEseql _ => op2 (default nv)
| OEsnel _ => op2 (default nv)
| OEsequl _ => op2 (default nv)
| OEsneul _ => op2 (default nv)
| OEsltl _ => op2 (default nv)
| OEsltul _ => op2 (default nv)
| OEsltil _ => op1 (default nv)
| OEsltiul _ => op1 (default nv)
| OExoril _ => op1 (default nv)
| OEluil _ => op1 (default nv)
| OEaddil _ _ => op1 (default nv)
| OEandil _ => op1 (default nv)
| OEoril _ => op1 (default nv)
| OEloadli _ => op1 (default nv)
| OEmayundef _ => op2 (default nv)
| OEfeqd => op2 (default nv)
| OEfltd => op2 (default nv)
| OEfled => op2 (default nv)
| OEfeqs => op2 (default nv)
| OEflts => op2 (default nv)
| OEfles => op2 (default nv)
| Obits_of_single => op1 (default nv)
| Obits_of_float => op1 (default nv)
| Osingle_of_bits => op1 (default nv)
| Ofloat_of_bits => op1 (default nv)
| Oselectl => All :: nv :: nv :: nil
end.
Definition operation_is_redundant (op: operation) (nv: nval): bool :=
match op with
| Ocast8signed => sign_ext_redundant 8 nv
| Ocast16signed => sign_ext_redundant 16 nv
| Oandimm n => andimm_redundant nv n
| Oorimm n => orimm_redundant nv n
| _ => false
end.
Ltac InvAgree :=
match goal with
| [H: vagree_list nil _ _ |- _ ] => inv H; InvAgree
| [H: vagree_list (_::_) _ _ |- _ ] => inv H; InvAgree
| _ => idtac
end.
Ltac TrivialExists :=
match goal with
| [ |- exists v, Some ?x = Some v /\ _ ] => exists x; split; auto
| _ => idtac
end.
Section SOUNDNESS.
Variable ge: genv.
Variable sp: block.
Variables m m': mem.
Hypothesis PERM: forall b ofs k p, Mem.perm m b ofs k p -> Mem.perm m' b ofs k p.
Lemma needs_of_condition_sound:
forall cond args b args',
eval_condition cond args m = Some b ->
vagree_list args args' (needs_of_condition cond) ->
eval_condition cond args' m' = Some b.
Proof.
intros. unfold needs_of_condition in H0.
eapply default_needs_of_condition_sound; eauto.
Qed.
Lemma needs_of_operation_sound:
forall op args v nv args',
eval_operation ge (Vptr sp Ptrofs.zero) op args m = Some v ->
vagree_list args args' (needs_of_operation op nv) ->
nv <> Nothing ->
exists v',
eval_operation ge (Vptr sp Ptrofs.zero) op args' m' = Some v'
/\ vagree v v' nv.
Proof.
unfold needs_of_operation; intros; destruct op; try (eapply default_needs_of_operation_sound; eauto; fail);
simpl in *; FuncInv; InvAgree; TrivialExists.
- apply sign_ext_sound; auto. compute; auto.
- apply sign_ext_sound; auto. compute; auto.
- apply add_sound; auto.
- apply add_sound; auto with na.
- apply neg_sound; auto.
- apply mul_sound; auto.
- apply and_sound; auto.
- apply andimm_sound; auto.
- apply or_sound; auto.
- apply orimm_sound; auto.
- apply xor_sound; auto.
- apply xor_sound; auto with na.
- apply shlimm_sound; auto.
- apply shrimm_sound; auto.
- apply shruimm_sound; auto.
- fold (Val.and (Vint n) v0);
fold (Val.and (Vint n) v2);
rewrite (Val.and_commut (Vint n) v0);
rewrite (Val.and_commut (Vint n) v2);
apply andimm_sound; auto.
- fold (Val.or (Vint n) v0);
fold (Val.or (Vint n) v2);
rewrite (Val.or_commut (Vint n) v0);
rewrite (Val.or_commut (Vint n) v2);
apply orimm_sound; auto.
- apply xor_sound; auto with na.
- (* selectl *)
unfold ExtValues.select01_long.
destruct v0; auto with na.
assert (Val.lessdef (Vint i) v4) as LESSDEF by auto with na.
inv LESSDEF.
destruct (Int.eq i Int.one).
{ apply normalize_sound; auto. }
destruct (Int.eq i Int.zero).
{ apply normalize_sound; auto. }
cbn. auto with na.
Qed.
Lemma operation_is_redundant_sound:
forall op nv arg1 args v arg1' args',
operation_is_redundant op nv = true ->
eval_operation ge (Vptr sp Ptrofs.zero) op (arg1 :: args) m = Some v ->
vagree_list (arg1 :: args) (arg1' :: args') (needs_of_operation op nv) ->
vagree v arg1' nv.
Proof.
intros. destruct op; simpl in *; try discriminate; inv H1; FuncInv; subst.
- apply sign_ext_redundant_sound; auto. lia.
- apply sign_ext_redundant_sound; auto. lia.
- apply andimm_redundant_sound; auto.
- apply orimm_redundant_sound; auto.
Qed.
End SOUNDNESS.
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