thread optimisation obligations through rewrite passes

This commit is contained in:
2026-02-14 13:34:18 +00:00
parent 6164dcb7d9
commit 8fb7e8748e
2 changed files with 67 additions and 54 deletions
+54 -54
View File
@@ -42,30 +42,27 @@ let default_flags =
let obligation ?(kind = Preserve_relation) pass subject detail =
{ pass; kind; subject; detail }
let rec specialise_term obligations term =
let rec specialise_term note term =
match term with
| Source.TyApp (Source.TyLam (x, body), ty) ->
let body' = specialise_term obligations (Source.TyApp (Source.TyLam (x, body), ty)) in
begin match body' with
| Source.TyApp (Source.TyLam (x, body), ty) -> Source.(substitute_type x ty body)
| other -> other
end
| Source.Pair (a, b) -> Source.Pair (specialise_term obligations a, specialise_term obligations b)
| Source.Inl (ty, t) -> Source.Inl (ty, specialise_term obligations t)
| Source.Inr (ty, t) -> Source.Inr (ty, specialise_term obligations t)
| Source.Lam (x, a, b, body) -> Source.Lam (x, a, b, specialise_term obligations body)
| Source.App (f, a) -> Source.App (specialise_term obligations f, specialise_term obligations a)
| Source.TyLam (x, body) -> Source.TyLam (x, specialise_term obligations body)
| Source.TyApp (t, ty) -> Source.TyApp (specialise_term obligations t, ty)
| Source.Roll (ty, t) -> Source.Roll (ty, specialise_term obligations t)
| Source.Unroll t -> Source.Unroll (specialise_term obligations t)
| Source.Fix (f, ty, body) -> Source.Fix (f, ty, specialise_term obligations body)
| Source.Eq (g, a, b) -> Source.Eq (g, specialise_term obligations a, specialise_term obligations b)
| Source.If (c, t, e) -> Source.If (specialise_term obligations c, specialise_term obligations t, specialise_term obligations e)
| Source.Let (x, a, b) -> Source.Let (x, specialise_term obligations a, specialise_term obligations b)
| Source.LetPair (x, y, a, b) -> Source.LetPair (x, y, specialise_term obligations a, specialise_term obligations b)
note Preserve_relation "type application cloning" ("instantiated type binder " ^ x ^ " at " ^ Types.string_of_typ ty);
Source.(substitute_type x ty (specialise_term note body))
| Source.Pair (a, b) -> Source.Pair (specialise_term note a, specialise_term note b)
| Source.Inl (ty, t) -> Source.Inl (ty, specialise_term note t)
| Source.Inr (ty, t) -> Source.Inr (ty, specialise_term note t)
| Source.Lam (x, a, b, body) -> Source.Lam (x, a, b, specialise_term note body)
| Source.App (f, a) -> Source.App (specialise_term note f, specialise_term note a)
| Source.TyLam (x, body) -> Source.TyLam (x, specialise_term note body)
| Source.TyApp (t, ty) -> Source.TyApp (specialise_term note t, ty)
| Source.Roll (ty, t) -> Source.Roll (ty, specialise_term note t)
| Source.Unroll t -> Source.Unroll (specialise_term note t)
| Source.Fix (f, ty, body) -> Source.Fix (f, ty, specialise_term note body)
| Source.Eq (g, a, b) -> Source.Eq (g, specialise_term note a, specialise_term note b)
| Source.If (c, t, e) -> Source.If (specialise_term note c, specialise_term note t, specialise_term note e)
| Source.Let (x, a, b) -> Source.Let (x, specialise_term note a, specialise_term note b)
| Source.LetPair (x, y, a, b) -> Source.LetPair (x, y, specialise_term note a, specialise_term note b)
| Source.Case (s, (x, l), (y, r)) ->
Source.Case (specialise_term obligations s, (x, specialise_term obligations l), (y, specialise_term obligations r))
Source.Case (specialise_term note s, (x, specialise_term note l), (y, specialise_term note r))
| other -> other
let rec inline_cost = function
@@ -82,47 +79,55 @@ let rec inline_cost = function
| Source.LetPair (_, _, a, b) -> 1 + inline_cost a + inline_cost b
| Source.Case (s, (_, l), (_, r)) -> 1 + inline_cost s + inline_cost l + inline_cost r
let rec inline_term obligations unsafe_repr_eq term =
let rec inline_term note unsafe_repr_eq term =
match term with
| Source.App (Source.Lam (x, _, _, body), arg) when inline_cost body <= 8 ->
Source.substitute x arg (inline_term obligations unsafe_repr_eq body)
note Preserve_relation "term beta inlining" ("inlined lambda argument " ^ x);
Source.substitute x arg (inline_term note unsafe_repr_eq body)
| Source.TyApp (Source.TyLam (x, body), ty) ->
Source.substitute_type x ty (inline_term obligations unsafe_repr_eq body)
note Preserve_relation "type beta inlining" ("inlined type argument " ^ Types.string_of_typ ty ^ " for " ^ x);
Source.substitute_type x ty (inline_term note unsafe_repr_eq body)
| Source.TyApp (Source.Var f, TInt) when unsafe_repr_eq && String.equal f "poly_const_false" ->
ignore obligations;
note Exposed_representation "parametric body exposure" "rewrote an abstract int instance into eq_int";
Source.Lam ("x", TInt, TArrow (TInt, TBool), Source.Lam ("y", TInt, TBool, Source.Eq (GInt, Source.Var "x", Source.Var "y")))
| Source.Pair (a, b) -> Source.Pair (inline_term obligations unsafe_repr_eq a, inline_term obligations unsafe_repr_eq b)
| Source.Inl (ty, t) -> Source.Inl (ty, inline_term obligations unsafe_repr_eq t)
| Source.Inr (ty, t) -> Source.Inr (ty, inline_term obligations unsafe_repr_eq t)
| Source.Lam (x, a, b, body) -> Source.Lam (x, a, b, inline_term obligations unsafe_repr_eq body)
| Source.Pair (a, b) -> Source.Pair (inline_term note unsafe_repr_eq a, inline_term note unsafe_repr_eq b)
| Source.Inl (ty, t) -> Source.Inl (ty, inline_term note unsafe_repr_eq t)
| Source.Inr (ty, t) -> Source.Inr (ty, inline_term note unsafe_repr_eq t)
| Source.Lam (x, a, b, body) -> Source.Lam (x, a, b, inline_term note unsafe_repr_eq body)
| Source.App (f, a) ->
let f' = inline_term obligations unsafe_repr_eq f in
let a' = inline_term obligations unsafe_repr_eq a in
let f' = inline_term note unsafe_repr_eq f in
let a' = inline_term note unsafe_repr_eq a in
begin match f' with
| Source.Lam (x, _, _, body) when inline_cost body <= 8 ->
inline_term obligations unsafe_repr_eq (Source.substitute x a' body)
note Preserve_relation "term beta inlining" ("inlined lambda argument " ^ x);
inline_term note unsafe_repr_eq (Source.substitute x a' body)
| _ -> Source.App (f', a')
end
| Source.TyLam (x, body) -> Source.TyLam (x, inline_term obligations unsafe_repr_eq body)
| Source.TyLam (x, body) -> Source.TyLam (x, inline_term note unsafe_repr_eq body)
| Source.TyApp (t, ty) ->
let t' = inline_term obligations unsafe_repr_eq t in
let t' = inline_term note unsafe_repr_eq t in
begin match t' with
| Source.TyLam (x, body) -> inline_term obligations unsafe_repr_eq (Source.substitute_type x ty body)
| Source.TyLam (x, body) ->
note Preserve_relation "type beta inlining" ("inlined type argument " ^ Types.string_of_typ ty ^ " for " ^ x);
inline_term note unsafe_repr_eq (Source.substitute_type x ty body)
| _ -> Source.TyApp (t', ty)
end
| Source.Roll (ty, t) -> Source.Roll (ty, inline_term obligations unsafe_repr_eq t)
| Source.Unroll t -> Source.Unroll (inline_term obligations unsafe_repr_eq t)
| Source.Fix (f, ty, body) -> Source.Fix (f, ty, inline_term obligations unsafe_repr_eq body)
| Source.Eq (g, a, b) -> Source.Eq (g, inline_term obligations unsafe_repr_eq a, inline_term obligations unsafe_repr_eq b)
| Source.Roll (ty, t) -> Source.Roll (ty, inline_term note unsafe_repr_eq t)
| Source.Unroll t -> Source.Unroll (inline_term note unsafe_repr_eq t)
| Source.Fix (f, ty, body) -> Source.Fix (f, ty, inline_term note unsafe_repr_eq body)
| Source.Eq (g, a, b) -> Source.Eq (g, inline_term note unsafe_repr_eq a, inline_term note unsafe_repr_eq b)
| Source.If (c, t, e) ->
Source.If (inline_term obligations unsafe_repr_eq c, inline_term obligations unsafe_repr_eq t, inline_term obligations unsafe_repr_eq e)
Source.If (inline_term note unsafe_repr_eq c, inline_term note unsafe_repr_eq t, inline_term note unsafe_repr_eq e)
| Source.Let (x, a, b) ->
let a' = inline_term obligations unsafe_repr_eq a in
let b' = inline_term obligations unsafe_repr_eq b in
if inline_cost a' <= 4 then Source.substitute x a' b' else Source.Let (x, a', b')
| Source.LetPair (x, y, a, b) -> Source.LetPair (x, y, inline_term obligations unsafe_repr_eq a, inline_term obligations unsafe_repr_eq b)
let a' = inline_term note unsafe_repr_eq a in
let b' = inline_term note unsafe_repr_eq b in
if inline_cost a' <= 4 then begin
note Preserve_relation "let inlining" ("inlined binding " ^ x);
Source.substitute x a' b'
end else Source.Let (x, a', b')
| Source.LetPair (x, y, a, b) -> Source.LetPair (x, y, inline_term note unsafe_repr_eq a, inline_term note unsafe_repr_eq b)
| Source.Case (s, (x, l), (y, r)) ->
Source.Case (inline_term obligations unsafe_repr_eq s, (x, inline_term obligations unsafe_repr_eq l), (y, inline_term obligations unsafe_repr_eq r))
Source.Case (inline_term note unsafe_repr_eq s, (x, inline_term note unsafe_repr_eq l), (y, inline_term note unsafe_repr_eq r))
| other -> other
let rec repr_of_typ = function
@@ -198,17 +203,12 @@ let compile flags source_type source_program =
obligations := obligation ~kind pass subject detail :: !obligations
in
let specialised =
if flags.specialise then begin
note "specialise" Preserve_relation "type application cloning" "specialisation preserves source typing but requires instantiation closedness";
specialise_term obligations source_program
end else source_program
if flags.specialise then specialise_term (note "specialise") source_program
else source_program
in
let inlined =
if flags.inline then begin
if flags.unsafe_repr_eq then
note "inline" Exposed_representation "parametric body exposure" "inlining may replace an abstract constant relation with eq_int at specialised int instances";
inline_term obligations flags.unsafe_repr_eq specialised
end else specialised
if flags.inline then inline_term (note "inline") flags.unsafe_repr_eq specialised
else specialised
in
let target_program =
if flags.repr_lower then begin
+13
View File
@@ -18,6 +18,9 @@ let find_case name =
| Some case -> case
| None -> failwith ("missing case " ^ name)
let has_obligation kind obligations =
List.exists (fun (o : Pipeline.obligation) -> o.kind = kind) obligations
let () =
List.iter
(fun (case : Corpus.case) ->
@@ -33,6 +36,16 @@ let () =
assert_true
"expected representation exposure witness"
(repr.failure_mode = Audit.Representation_exposure);
assert_true
"expected unsafe inlining to emit representation exposure obligation"
(has_obligation Pipeline.Exposed_representation repr.compiled.obligations);
let safe = Audit.audit_case (find_case "safe-polymorphic-instantiation") in
assert_true
"safe instantiation should not emit representation exposure obligation"
(not (has_obligation Pipeline.Exposed_representation safe.compiled.obligations));
assert_true
"safe instantiation should emit preserve relation obligations at rewrite sites"
(has_obligation Pipeline.Preserve_relation safe.compiled.obligations);
let strict = Audit.audit_case (find_case "strictness-induced-termination-change") in
assert_true
"expected strictness shift witness"