shoney.arickathil
4092074201
- monitor(watched, observer, msg): registration lives on the watched actor's home thread (kind-7 envelope cross-shard); actor_die walks the list; already-dead fires NOW; the notice msg moves; a full observer's notice drops with a stderr line (no fiber to trap) - time.after(ms, addr, msg): per-shard timer list riding the deadline machinery (uring tick min + epoll timeout both include timers; fired from the same sweep); ms <= 0 delivers now; NO cancel — the generation-counter idiom is pinned by run/timer-generation - runtime_notify: one runtime-sourced delivery path (notices, timers) — reserve-or-drop, cross-shard via kind-0 envelopes - compiler: monitor typed as a bespoke free fn (notice typed against the OBSERVER's mailbox — the three-argument deviation, disclosed); time.after as a stdlib row whose msg arg is EXEMPT from the module- call fresh-arg drop (it moves — the double-own bug the timer fixture caught); owner move slots for both - corpus: run/monitor-death (trap-death + already-dead notices), run/timer-delivery (armed + immediate), run/timer-generation - teardown drops undelivered notices and unfired timers; battery 13/13 Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2038 lines
92 KiB
OCaml
2038 lines
92 KiB
OCaml
(* owner.ml — the ownership pass (mutable value semantics), Task 7.
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This is the novel core of the design (spec section 3 rules 1-6 and
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section 4's "borrow enforcement split"). One forward dataflow walk per
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function body decides two things at once:
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1. the four MVS *rules*, each reported as a two-site diagnostic
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(WO-E301..WO-E304 — the codes are documented at their
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definitions below);
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2. the four *tables* plan 3's emitter consumes — moves, drops,
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rc sites, residual sites — rendered by Dump.dump_owner and
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pinned by goldens under compiler/test/golden/owner/.
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---- what a "borrow" is in this grammar --------------------------------
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There is no borrow *expression* syntax: `mut`/`take` are parameter
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conventions only (parser.ml's parse_param). So a borrow is created in
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exactly four ways, and every one of them is second-class (spec: "a
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borrow cannot escape its scope"):
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- a parameter declared without `take` (`p: T` shared, `mut p: T`
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exclusive) — a borrow of the *caller's* value, live for the whole
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body. Its source place is unknown here; the caller's own call site
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is where aliasing between two such borrows is checked.
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- `self` — always a borrow (spec rule 6: shared if the body only
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reads, exclusive if it writes; inferred, see method_writes_self).
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- `let r = <owned place with a projection>` (`let r = b.inner`) —
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milestone 1 has no syntax for moving a value *out of* a field or
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element, so this binds a borrow of that place, not a partial move.
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Consequence: `return r` is a borrow escape, and moving the place
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out from under `r` is a use-while-borrowed.
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- `for it in items` — `it` borrows an element of `items`, and the
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borrow is live for the whole loop body.
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Argument passing creates borrows too, but only for the duration of the
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call itself; that is the "region" of a call expression, and all of a
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call's argument borrows plus its receiver borrow are live
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simultaneously. Conflicts inside one region are checked pairwise.
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---- states, joins, loops ---------------------------------------------
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Per owned local: Live | Moved <site> | Borrowed <site> (the brief's
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three states). Join at an if/else merge takes Moved over Live (a value
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moved on one branch is treated as moved after the merge — the standard
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conservative rule; a diverging branch, i.e. one that returned, is
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dropped from the join instead of poisoning it). Loops are analyzed to
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a fixpoint the cheap way the brief prescribes: run the body once with
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diagnostics and table recording *off* (ctx.recording = false), join
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that result with the loop's entry state, then run it again for real.
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Two passes are enough because the lattice is three states tall and the
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only transition the body can make is Live -> Moved; the second pass
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therefore sees every loop-carried move (that is what catches
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`while c { consume(take b) }`).
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---- what is exempt ---------------------------------------------------
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`@gc` values (Types.is_gc_class) are exempt from every rule — aliasing
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them is legal by design (spec rule 5); they appear only in the rc
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table. Builtin scalars and `ref T` ids are copied, never moved, and
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are exempt too. `?T` follows T exactly
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(nil is just a value; null-narrowing does not change ownership state),
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so oclass_of unwraps Nullable first. An unknown type name is treated
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as Copy: types.ml already reported WO-E225 for it and a cascade of
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ownership errors on top would be noise.
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---- deliberate milestone-1 simplifications ---------------------------
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Each of these is a place where a *later* milestone adds precision, not
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a place where this pass is wrong-by-accident:
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- No partial moves. A move site must name a whole local (`x`), never
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a projection (`x.f`, `x[0]`); see the `let` case above.
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- Alias provability is syntactic *after canonicalization*: a place
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written through a borrow binding is first rewritten to the storage
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that borrow names (see canon), then two places overlap only if they
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share a root and every projection pair matches. Distinct roots are
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assumed disjoint — sound because a borrow can never be stored, so
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two distinct locals can only alias through parameters, and that
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aliasing is checked at the caller's call site. Canonicalization is
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what makes `swap(r, s)` after `let r = bag.items[i]; let s =
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bag.items[k]` behave identically to the direct
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`swap(bag.items[i], bag.items[k])`.
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- Two element accesses through *runtime* indices are neither proven
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equal nor proven distinct: they become residual sites, which is
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exactly the case runtime/src/borrow.c exists for.
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- Self-mutability (spec rule 6) is inferred from direct assignments
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to `self.…` in the method body only; a method that mutates self
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*indirectly*, by calling another mutating method on self, is read
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as read-only here. Types.method_info carries a `mutates` field but
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it is hardcoded `false` (types.ml never infers it), so this pass
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computes its own rather than trusting it.
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- Reassigning a live owned local (`x = other`) drops the overwritten
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value; that DROP is recorded in the drops table as OVERWRITE. The
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brief names the table "scope-end drop sets", but an overwritten
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value dies just as deterministically as one falling out of scope,
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and leaving it out would leak in plan 3.
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- A value moved on only one branch of an `if` is normalized rather
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than tracked per path: the branch that kept it drops it at its own
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end (JOIN-DROP), so the joined Moved state is true on both paths and
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nothing leaks. The cost is that the value dies earlier on that path
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than a drop-flag implementation would allow. Two drop caveats
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survive that fix, both deliberate: a `while`/`for` body that moves
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an outer local is an error anyway (the fixpoint's second pass
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reports WO-E301), so no normalization is attempted there; and a
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value whose *type* is unknown to the pass — the result of an
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unresolved builtin call — classifies as Copy and so is never
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dropped at all, which stays true until builtin signatures land. *)
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open Ast
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(* ============================================================
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Diagnostics (WO-E3xx). Task 8 catalogs these.
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============================================================ *)
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(* WO-E301 — a local is read (or moved again) after its value was moved
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away. Primary site: the use. Related site: the move. *)
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let use_after_move_code = Diag.ownership_prefix ^ "01"
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(* WO-E302 — a value is moved while a live borrow of it (or of something
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it contains) still exists. Primary site: the move. Related: the
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borrow. *)
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let move_while_borrowed_code = Diag.ownership_prefix ^ "02"
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(* WO-E303 — conflicting borrows of one place where the analysis can
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prove the two accesses alias, and at least one is exclusive (`mut`).
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Primary site: the second borrow. Related: the first. *)
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let conflicting_borrow_code = Diag.ownership_prefix ^ "03"
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(* WO-E304 — a borrow escapes its scope: returned, stored into a field,
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or moved out to a `take` parameter (spec rule 3). Primary site: the
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escape. Related: where the borrow was created. *)
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let borrow_escape_code = Diag.ownership_prefix ^ "04"
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(* ============================================================
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Ownership classes and places
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============================================================ *)
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(* Copy — scalars, `ref T`, unknown types: copied,
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never moved, no borrow rules, no drops.
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Owned — a non-@gc class/type instance, `multi T`, `map<K,V>`: one
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owner, moves, borrow-checked, dropped at scope end.
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Gc — a @gc class instance: freely aliased, refcounted. *)
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type oclass =
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| Copy
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| Owned
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| Gc
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(* A projection step. An index is split by what the analysis can prove
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about it: a literal (PConst) is comparable with other literals; a
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runtime index (PDyn) carries a *rendering* of the index expression, so
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two syntactically identical runtime indices compare equal (same
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element) and two different ones compare unknown (residual site). See
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idx_text for why the fallback rendering is node-unique. *)
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type proj =
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| PField of string
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| PConst of int
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| PDyn of string
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(* root is a local name ("self" included). ppos is the *root token's*
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position — a caret under `bag` reads better than one under the `.` or
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`[` that Ast.Field/Ast.Index carry. pnode is the outermost expression
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node's id: the emitter's key for this site. *)
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type place = {
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root : string;
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projs : proj list;
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ppos : Ast.pos;
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pnode : int;
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}
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let proj_text = function
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| PField f -> "." ^ f
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| PConst n -> "[" ^ string_of_int n ^ "]"
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| PDyn s -> "[" ^ s ^ "]"
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let place_text (p : place) : string =
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p.root ^ String.concat "" (List.map proj_text p.projs)
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(* How two places relate. Overlap = provably the same storage, or one
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contains the other (a prefix). Disjoint = provably different storage.
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Unknown = the analysis cannot decide; the VM must (residual site). *)
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type rel =
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| Overlap
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| Disjoint
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| Unknown
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let rec relate_projs (a : proj list) (b : proj list) : rel =
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match (a, b) with
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| [], _ | _, [] -> Overlap (* a prefix contains the longer path *)
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| PField x :: ta, PField y :: tb -> if x = y then relate_projs ta tb else Disjoint
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| PConst i :: ta, PConst j :: tb -> if i = j then relate_projs ta tb else Disjoint
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| PDyn x :: ta, PDyn y :: tb -> if x = y then relate_projs ta tb else Unknown
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| PConst _ :: _, PDyn _ :: _ | PDyn _ :: _, PConst _ :: _ -> Unknown
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| _ -> Unknown (* field vs index: ill-typed, stay conservative *)
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let relate (a : place) (b : place) : rel =
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if a.root <> b.root then Disjoint else relate_projs a.projs b.projs
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(* ============================================================
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The four tables (the plan-3 emitter contract)
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============================================================ *)
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(* Which MOVE is a real ownership transfer. Copy-classed assignments,
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returns and arguments are *not* here: for those the emitter's MOVE is
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a plain register copy. @gc transfers are not here either — they are rc
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sites. *)
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type move_kind =
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| MvLet
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| MvAssign
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| MvReturn
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| MvArg of string (* callee parameter name *)
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| MvCtorField of string (* field being initialized *)
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type move_site = {
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mv_node : int;
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mv_pos : Ast.pos;
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mv_place : string;
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mv_kind : move_kind;
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}
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(* An entry in a drop set / live mask. Owned values need DROP; @gc
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handles need a decrement, so masks tag them. *)
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type local_kind =
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| LOwned
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| LGc
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(* One name in a drop set / live mask. di_node is the *declaring* node id
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(a param's id, a `let`'s statement id, a `for`'s statement id, the
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method id for `self`) — carried because a name alone is ambiguous under
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shadowing: two nested scopes may each bind `x`, and the emitter must
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know which register it is being told to destroy. For an OVERWRITE entry
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there is no declaring node: di_name is the assigned place's text and
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di_node is that place expression's own node. *)
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type drop_item = {
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di_name : string;
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di_kind : local_kind;
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di_node : int;
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}
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(* DScope — every owned local of a scope that is still live where the
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scope ends (label names which block: BODY/THEN/ELSE/
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WHILE/FOR). Suppressed when the scope diverges (every path
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returned), because that scope end is unreachable.
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DReturn — every live owned local in *all* enclosing scopes at an
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early (or final) return, after the returned value's own
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move: the DROPs that must run before the frame leaves.
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DBreak/DContinue (haxe-parity Task 2) — every live owned local in
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every scope from here up to *and including* the nearest
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enclosing loop's own body scope (WHILE/FOR/DO — never
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beyond it, since a break/continue only exits the loop, not
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the function). Same "reuse DReturn's own machinery" shape,
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bounded to the loop instead of the whole function — see
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live_holders_upto.
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DOverwrite — the value an assignment overwrites (see the module doc).
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DBranchJoin — join normalization: the locals the *other* branch of an if
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moved and this one did not, dropped at this branch's end so
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both paths leave the merge in the same state (see
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branch_join_drops and the module doc's simplifications list).
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The label names the branch whose end they belong to; an `if`
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with no `else` anchors its implicit else at the `if` itself.
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DLiveMask — the frame's drop map at a call / DB_STUB site: everything
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live there, @gc handles included, taken *after* the call's
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own argument transfers because a moved-in value is the
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callee's responsibility, not this frame's. *)
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type drop_kind =
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| DScope of string
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| DReturn
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| DOverwrite
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| DBranchJoin of string
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| DLiveMask
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| DBreak
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| DContinue
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type drop_site = {
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dr_node : int;
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dr_pos : Ast.pos;
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dr_kind : drop_kind;
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dr_items : drop_item list;
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}
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(* iteration 7b: the rc-site machinery (acquire/release pairs, elision
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groups, the clobber rule) is gone with reference counting itself — a
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traced value's aliases need no bookkeeping, tracing owns the lifetime. *)
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type acc_kind =
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| AShared
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| AExcl
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| AMove
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(* Where static proof failed: the emitter wraps the region in
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BORROW_S/BORROW_X + RELEASE (runtime/src/borrow.c) and the VM traps on
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a real violation. *)
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type residual_site = {
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rs_node : int;
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rs_pos : Ast.pos;
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(* each side: its rendered place, its role, and the node of the
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expression the place came from — what the emitter needs to know
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*which* operand to wrap in BORROW_S/BORROW_X *)
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rs_a : string;
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rs_a_kind : acc_kind;
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rs_a_node : int;
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rs_b : string;
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rs_b_kind : acc_kind;
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rs_b_node : int;
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}
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type tables = {
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moves : move_site list;
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drops : drop_site list;
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residuals : residual_site list;
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}
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(* ============================================================
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Flow state
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============================================================ *)
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type state =
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| Live
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| Moved of Ast.pos
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| Borrowed of Ast.pos
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type local = {
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l_name : string;
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l_ty : Ast.field_ty;
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l_class : oclass;
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l_node : int; (* declaring node: param id / let stmt id / for stmt id / method id for self *)
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l_pos : Ast.pos;
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(* true when this frame holds the value (owned) or a counted handle
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(@gc) and must destroy it at scope end. False for borrows and for
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Copy-classed locals. *)
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l_holds : bool;
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(* for a borrow bound to a place in *this* frame (`let r = b.inner`,
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`for it in items`), the place borrowed; None for parameter borrows,
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whose source lives in the caller. Also set for a @gc alias, where it
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names the place the extra reference came from (rc elision needs it).
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This field is also what makes a place *canonical* — see canon. *)
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l_src : place option;
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(* only meaningful for a borrow: whether it is shared or exclusive. A
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`mut` parameter is an exclusive borrow; every borrow a `let` or a
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`for` can bind is shared, because the grammar has no `let mut`. Read
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when naming the *other* side of a residual site, so that side's role
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comes from data rather than from a literal at the reporting site. *)
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l_bkind : acc_kind;
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mutable l_state : state;
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}
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type scope = {
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sc_node : int;
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sc_pos : Ast.pos;
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sc_label : string;
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mutable sc_locals : local list; (* reverse declaration order = destruction order *)
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}
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(* Table accumulators, shared across all functions of a program. *)
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type sink = {
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mutable s_moves : move_site list;
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mutable s_drops : drop_site list;
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mutable s_res : residual_site list;
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}
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type ctx = {
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file : string;
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syms : Types.symbols;
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coll : Diag.Collector.t;
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sink : sink;
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fn_name : string;
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mutable scopes : scope list; (* innermost first *)
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(* haxe-parity Task 2: the enclosing While/For/DoWhile statement ids,
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innermost first — the nearest enclosing loop's own `s.s_id`, which
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is also its own scope's `sc_node` (analyze_block ~node:s.s_id).
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Empty outside any loop; a break/continue found there records no
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drop site at all (nothing to bound the drop to) and leaves the
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actual rejection to emit.ml, which has no jump target to lower it
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onto — the same WO-E403 "no legal target" convention as every
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other construct with nothing to lower to. *)
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mutable loop_stack : int list;
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(* false during a loop's probe pass: no diagnostics, no table entries *)
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mutable recording : bool;
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(* set when the current path has returned; a diverged path contributes
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no scope-end drops and drops out of if/else joins *)
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mutable diverged : bool;
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(* iteration 7b demand-promotion (Gcinfer): when Some, the pass runs in
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collect mode — a class value that would fail the escape rule records its
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class here instead of raising WO-E304, so inference can promote it to
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traced. None = normal report mode. *)
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promote : (string -> unit) option;
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}
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(* ============================================================
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Type/class resolution (reuses Types' symbol tables; derives nothing
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types.ml already exports)
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============================================================ *)
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let rec unwrap_nullable (ft : Ast.field_ty) : Ast.field_ty =
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match ft with Nullable inner -> unwrap_nullable inner | t -> t
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let oclass_of (ctx : ctx) (ft : Ast.field_ty) : oclass =
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match unwrap_nullable ft with
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(* `Text` is a HEAP value (runtime/src/obj.h's wo_str), so a binding that
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holds a fresh one owns it and must drop it at scope end. It was Copy
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until 2026-08-14 — grouped with Int/Bool because types.ml calls it a
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builtin scalar — and the consequence was that no Text local was ever
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dropped: every concatenation, interpolation and stdlib read accumulated
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in the arena for the life of the process. Invisible in the corpus (small
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|
strings live in the arena, which is freed wholesale at exit) and fatal in
|
|
a daemon (the workload's supervisor leaked a 1 MiB `fs.read_all` result
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|
per rescan, which is a plain malloc and so ASan-visible). A Text read out
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of a PLACE is still a borrow — analyze_let's own place logic decides
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that, exactly as it does for a record field. *)
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(* iteration 19: Bytes joins Text here — see Types.is_heap_scalar *)
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| Scalar n when Types.is_heap_scalar n -> Owned
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| Scalar n ->
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if Types.is_builtin_scalar n then Copy
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else if Types.is_gc_class ctx.syms n then Gc
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else if Types.StringMap.mem n ctx.syms.Types.classes then Owned
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else (
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(* haxe-parity Task 4: an all-bare union value is a plain integer
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|
tag — Copy, exactly like a builtin scalar (moving/aliasing it
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is copying an int). A payload union value is a heap variant
|
|
object — Owned, one owner, dropped at scope end like any other
|
|
non-@gc instance. *)
|
|
match Types.StringMap.find_opt n ctx.syms.Types.unions with
|
|
| Some u -> if u.Types.u_has_payload then Owned else Copy
|
|
| None -> Copy (* unknown type: WO-E225 already reported by types.ml *))
|
|
| Ref _ -> Copy
|
|
| Actor _ -> Copy (* an address is a copyable word; the runtime owns actors *)
|
|
| Backlink _ -> Copy (* a virtual collection of row ids read on demand *)
|
|
| Multi _ | Map _ -> Owned
|
|
| Nullable _ -> Copy (* unreachable: unwrapped above *)
|
|
|
|
let field_ty_of (ctx : ctx) (class_name : string) (fname : string) : Ast.field_ty option =
|
|
match Types.StringMap.find_opt class_name ctx.syms.Types.classes with
|
|
| None -> None
|
|
| Some (cls : Types.class_info) ->
|
|
let rec find = function
|
|
| [] -> None
|
|
| (n, ft, _, _) :: tl -> if n = fname then Some ft else find tl
|
|
in
|
|
find cls.Types.fields
|
|
|
|
let elem_ty (ft : Ast.field_ty) : Ast.field_ty option =
|
|
match unwrap_nullable ft with
|
|
| Multi n -> Some (Scalar n)
|
|
| Map (_, v) -> Some (Scalar v)
|
|
| _ -> None
|
|
|
|
let find_local (ctx : ctx) (name : string) : local option =
|
|
let rec go = function
|
|
| [] -> None
|
|
| sc :: tl -> (
|
|
match List.find_opt (fun l -> l.l_name = name) sc.sc_locals with
|
|
| Some l -> Some l
|
|
| None -> go tl)
|
|
in
|
|
go ctx.scopes
|
|
|
|
(* Does this method write `self`? Spec rule 6's inference, direct
|
|
assignments only (see the module doc's simplifications). *)
|
|
let rec root_name_of (e : Ast.expr) : string option =
|
|
match e.kind with
|
|
| Ident n -> Some n
|
|
| Field (base, _) | Index (base, _) -> root_name_of base
|
|
| _ -> None
|
|
|
|
let rec body_writes_self (body : Ast.stmt list) : bool =
|
|
List.exists stmt_writes_self body
|
|
|
|
and stmt_writes_self (s : Ast.stmt) : bool =
|
|
match s.s_kind with
|
|
| Assign { target; _ } -> root_name_of target = Some "self"
|
|
| If { then_body; else_body; _ } ->
|
|
body_writes_self then_body
|
|
|| (match else_body with Some (_, b) -> body_writes_self b | None -> false)
|
|
| While { body; _ } | For { body; _ } | DoWhile { body; _ } -> body_writes_self body
|
|
| Let _ | Return _ | ExprStmt _ | Break | Continue -> false
|
|
|
|
(* A resolved callee: its parameter conventions (positional), its return
|
|
type, and — for a method call — whether the receiver is borrowed
|
|
exclusively. Unresolved callees (a builtin such as `latest`, an
|
|
undeclared name) resolve to None and are then treated as taking every
|
|
argument by shared borrow: the conservative choice for *errors* (never
|
|
invent a move) and the honest one for the tables (no transfer to
|
|
record). *)
|
|
type callee = {
|
|
ce_params : (string * Ast.param_conv) list;
|
|
ce_ret : Ast.field_ty option;
|
|
ce_recv_excl : bool;
|
|
}
|
|
|
|
(* haxe-parity Task 4: a bare variant reference (`Pending`) or a variant
|
|
construction (`Failed("x")`) types as its union — locals always win
|
|
first (find_local / resolve_callee run before this), so a shadowing
|
|
binding is never mistaken for a variant. *)
|
|
let variant_union_ty (ctx : ctx) (n : string) : Ast.field_ty option =
|
|
match Types.find_variant ctx.syms n with
|
|
| Some (u, _) -> Some (Ast.Scalar u.Types.u_name)
|
|
| None -> None
|
|
|
|
let rec expr_ty (ctx : ctx) (e : Ast.expr) : Ast.field_ty option =
|
|
match e.kind with
|
|
| IntLit _ -> Some (Scalar "Int")
|
|
| FloatLit _ -> Some (Scalar "Float") (* iteration 19 *)
|
|
| StrLit _ -> Some (Scalar "Text")
|
|
| BoolLit _ -> Some (Scalar "Bool")
|
|
(* A non-empty list literal knows its element type, so an unannotated
|
|
`let names = ["a", "b"]` is still classified Owned and dropped. An
|
|
empty `[]`/`{}` is contextual: only the destination's declared type
|
|
says what it holds, so this stays None and the annotation (or the
|
|
field/parameter it is built into) decides. *)
|
|
| ListLit (first :: _) -> (
|
|
match expr_ty ctx first with Some (Scalar n) -> Some (Multi n) | _ -> None)
|
|
(* arc: a spawn's value is a typed address — a copyable scalar word *)
|
|
| Spawn (cn, _) -> (
|
|
match Types.StringMap.find_opt cn ctx.syms.Types.classes with
|
|
| Some cls -> (
|
|
match
|
|
List.find_opt (fun (m : Types.method_info) -> m.Types.name = "receive") cls.Types.methods
|
|
with
|
|
| Some { Types.params = [ (_, pty, _) ]; _ } -> (
|
|
match pty with Ast.Scalar mname -> Some (Ast.Actor mname) | _ -> None)
|
|
| _ -> None)
|
|
| None -> None)
|
|
| ListLit [] | MapLit -> None
|
|
(* haxe-parity Task 6: `nil` is the zero word — contextual on its
|
|
destination, and never something this frame owns. *)
|
|
| NilLit -> None
|
|
(* a checked decode's value is a fresh instance of the named type (or
|
|
nil) — owned, so the binding that holds it gets its drop *)
|
|
| As (_, ty) -> Some (Nullable ty)
|
|
(* haxe-parity Task 5: a `try` yields its try arm's type (types.ml has
|
|
already required the catch arm to agree). *)
|
|
| Try t -> expr_ty ctx t.body
|
|
| Ident n -> (
|
|
match find_local ctx n with
|
|
| Some l -> Some l.l_ty
|
|
| None -> variant_union_ty ctx n)
|
|
| Field (base, f) -> (
|
|
match expr_ty ctx base with
|
|
| Some bt -> ( match unwrap_nullable bt with Scalar cn -> field_ty_of ctx cn f | _ -> None)
|
|
| None -> None)
|
|
| Index (base, _) -> ( match expr_ty ctx base with Some bt -> elem_ty bt | None -> None)
|
|
| Call (callee, _) -> (
|
|
match resolve_callee ctx callee with
|
|
| Some c -> c.ce_ret
|
|
| None -> (
|
|
(* an unresolved Ident callee may be a variant construction — its
|
|
value is a fresh Owned variant object of the union's type, and
|
|
missing this here is a real leak (analyze_let's None-fallback
|
|
classifies as Copy, so the object would never be dropped). *)
|
|
match callee.kind with
|
|
| Ident n -> variant_union_ty ctx n
|
|
| _ -> None))
|
|
| Unary (_, o) -> expr_ty ctx o
|
|
(* `..` (CONCAT) always produces a FRESH Text, and interpolation desugars to
|
|
exactly such a chain — so this is what gives every interpolated or
|
|
concatenated binding an owner and a drop. Left as None before
|
|
2026-08-14, which made those bindings Copy and leaked every one. *)
|
|
| Binary (Concat, _, _) -> Some (Scalar "Text")
|
|
| Binary _ -> None (* arithmetic/comparison: Copy either way *)
|
|
| Ctor (cn, _) -> Some (Scalar cn)
|
|
| Insert _ -> Some (Scalar "Int") (* the new row's id — Copy, nothing to drop *)
|
|
| Query _ -> Some (Multi "Int") (* a query yields a fresh multi of ids — owned *)
|
|
| Delete _ -> Some (Scalar "Int") (* the deleted id — Copy *)
|
|
| Interp _ -> Some (Scalar "Text") (* an interpolation always produces Text *)
|
|
| DbStub _ -> None
|
|
| Switch (subject, arms) ->
|
|
(* review fix, Critical 3: this was `None` ("not chased", the same
|
|
call as `Binary`/`DbStub` above) — a real, reviewer-reproduced
|
|
leak, not a theoretical gap: `analyze_let`'s own fallback for
|
|
`expr_ty = None` is `Scalar "Int"` (Copy), so an *unannotated*
|
|
`let v = switch ... { case ...: SomeClass{...}; ... }` was
|
|
classified Copy and never dropped, even for a plain class with
|
|
no union involved. Mirrors emit.ml's own `ty_of_expr` Switch
|
|
case exactly (same shape, this file's own `Ast.field_ty`/`ctx`
|
|
types instead of `Types.typ`/`pctx`) rather than duplicating
|
|
types.ml's `typecheck_switch` unification: the first arm's
|
|
trailing `ExprStmt`'s own type wins — types.ml already proved
|
|
every other arm agrees, or reported WO-E201 if not, so trusting
|
|
the first arm here is not a second, weaker check, just this
|
|
file's own narrower deriver reading the same fact.
|
|
|
|
Task 4 fix round 1 (review Critical 1b): an arm may yield its own
|
|
payload BINDING (`case Boxed(b): b;` — the escape shape the
|
|
log-watcher's own return pattern uses). The binding is not a
|
|
local at derivation time (it exists only during the arm's own
|
|
walk), so the plain recursive call typed the whole switch `None`
|
|
-> the `Scalar "Int"` fallback -> Copy — a leak (unannotated
|
|
`let`) or a bogus downstream error. `binding_ty_of_arm` reads the
|
|
binding's type straight off the subject's variant declaration. *)
|
|
(match arms with
|
|
| [] -> None
|
|
| first :: _ -> (
|
|
match List.rev first.Ast.body with
|
|
| { Ast.s_kind = ExprStmt ve; _ } :: _ -> (
|
|
match ve.Ast.kind with
|
|
| Ident n -> (
|
|
match binding_ty_of_arm ctx subject first n with
|
|
| Some fty -> Some fty
|
|
| None -> expr_ty ctx ve)
|
|
| _ -> expr_ty ctx ve)
|
|
| _ -> None))
|
|
|
|
(* The declared type of payload binding [n], when [arm]'s pattern binds
|
|
it off [subject]'s union — None whenever this is not that shape. *)
|
|
and binding_ty_of_arm (ctx : ctx) (subject : Ast.expr) (arm : Ast.switch_arm) (n : string) :
|
|
Ast.field_ty option =
|
|
match expr_ty ctx subject with
|
|
| Some (Scalar sn) -> (
|
|
match Types.StringMap.find_opt sn ctx.syms.Types.unions with
|
|
| Some u when u.Types.u_has_payload -> (
|
|
match arm.Ast.values with
|
|
| [ { Ast.kind = Ast.Call ({ Ast.kind = Ast.Ident vname; _ }, bargs); _ } ] -> (
|
|
match
|
|
List.find_opt (fun (vi : Types.variant_info) -> vi.Types.vi_name = vname)
|
|
u.Types.u_variants
|
|
with
|
|
| Some vi when List.length bargs = List.length vi.Types.vi_fields ->
|
|
let rec zip (args : Ast.expr list) fields =
|
|
match (args, fields) with
|
|
| { Ast.kind = Ast.Ident bn; _ } :: _, (_, fty) :: _ when bn = n -> Some fty
|
|
| _ :: ta, _ :: tf -> zip ta tf
|
|
| _ -> None
|
|
in
|
|
zip bargs vi.Types.vi_fields
|
|
| _ -> None)
|
|
| _ -> None)
|
|
| _ -> None)
|
|
| _ -> None
|
|
|
|
and resolve_callee (ctx : ctx) (callee : Ast.expr) : callee option =
|
|
let params_of ps = List.map (fun (n, _, conv) -> (n, conv)) ps in
|
|
match callee.kind with
|
|
| Ident name -> (
|
|
match Types.StringMap.find_opt name ctx.syms.Types.free_fns with
|
|
| Some (f : Types.free_fn_info) ->
|
|
Some
|
|
{ ce_params = params_of f.Types.params; ce_ret = f.Types.ret; ce_recv_excl = false }
|
|
(* A BUILTIN's return type, from the table types.ml and emit.ml already
|
|
read. `split`/`split_ws`/`slice` hand back a fresh `multi` and
|
|
`substr`/`trim`/`join`/… a fresh Text; without this they resolved to
|
|
nothing, the binding fell back to Copy, and every one of those
|
|
containers leaked (measured: the workload's supervisor mode). A
|
|
user-declared fn of the same name wins above, the shadowing rule the
|
|
builtin surface already states. *)
|
|
| None -> (
|
|
let arg0 = None in
|
|
match Types.builtin_confident_ret name arg0 with
|
|
| Some t -> (
|
|
match Types.field_ty_of_typ t with
|
|
| Some ft -> Some { ce_params = []; ce_ret = Some ft; ce_recv_excl = false }
|
|
| None -> None)
|
|
| None -> None))
|
|
| Field (base, mname) -> (
|
|
match expr_ty ctx base with
|
|
| Some bt -> (
|
|
match unwrap_nullable bt with
|
|
| Scalar cn -> (
|
|
match Types.StringMap.find_opt cn ctx.syms.Types.classes with
|
|
| None -> None
|
|
| Some (cls : Types.class_info) -> (
|
|
match List.find_opt (fun (m : Types.method_info) -> m.Types.name = mname) cls.Types.methods with
|
|
| None -> None
|
|
| Some m ->
|
|
Some
|
|
{ ce_params = params_of m.Types.params; ce_ret = m.Types.ret;
|
|
ce_recv_excl = body_writes_self m.Types.body }))
|
|
| _ -> None)
|
|
(* The base is not a value: it names a reserved stdlib module
|
|
(`fs.read_all(path, cap)`) or a class with a static member
|
|
(`Tools.needle(cmd)`). Both shapes were unresolved here until
|
|
2026-08-14, and an unresolved callee is not a missing *type* — it is a
|
|
missing LIFETIME: analyze_let's None-fallback classifies the binding
|
|
`Scalar "Int"`, oclass_of calls that Copy, and the fresh Text or
|
|
`multi` the call returned is never dropped. That was the measured
|
|
>1 MB leak in eight seconds of the workload's supervisor mode (one
|
|
`fs.read_all` result per cron file). The tables read here are the same
|
|
ones types.ml and emit.ml already read; a local of the same name
|
|
shadows the module, exactly as it does everywhere else. *)
|
|
| None -> (
|
|
match base.kind with
|
|
| Ident head when find_local ctx head = None -> (
|
|
match Types.stdlib_member head mname with
|
|
| Some sm ->
|
|
Some
|
|
{ ce_params = [];
|
|
ce_ret = ( match sm.Types.sm_ret with Some t -> Types.field_ty_of_typ t | None -> None);
|
|
ce_recv_excl = false }
|
|
| None -> (
|
|
match Types.StringMap.find_opt head ctx.syms.Types.classes with
|
|
| None -> None
|
|
| Some (cls : Types.class_info) -> (
|
|
match
|
|
List.find_opt
|
|
(fun (m : Types.method_info) -> m.Types.name = mname && m.Types.is_static)
|
|
cls.Types.methods
|
|
with
|
|
| None -> None
|
|
| Some m ->
|
|
Some
|
|
{ ce_params = params_of m.Types.params; ce_ret = m.Types.ret;
|
|
ce_recv_excl = false })))
|
|
| _ -> None))
|
|
| _ -> None
|
|
|
|
(* ============================================================
|
|
Places
|
|
============================================================ *)
|
|
|
|
(* A runtime index's identity. Simple place-shaped indices render to
|
|
readable text so `items[i]` twice is recognized as the same element;
|
|
anything else falls back to a node-unique token, so two complex
|
|
indices are never mistaken for each other (Unknown -> residual site,
|
|
the safe side) even when they look identical in source. *)
|
|
let rec idx_text (e : Ast.expr) : string =
|
|
match e.kind with
|
|
| IntLit n -> string_of_int n
|
|
| Ident n -> n
|
|
| Field (base, f) -> idx_text base ^ "." ^ f
|
|
| _ -> "#" ^ string_of_int e.id
|
|
|
|
let idx_proj (e : Ast.expr) : proj =
|
|
match e.kind with IntLit n -> PConst n | _ -> PDyn (idx_text e)
|
|
|
|
(* Builtins that hand back a POINTER INTO their container rather than a fresh
|
|
value: binding one binds a borrow of that container, not a second owner.
|
|
`pop`/`shift` are deliberately absent — they remove the element, so the
|
|
caller really does take ownership. Now that Text is Owned (oclass_of), this
|
|
distinction is what keeps `let v = get(m, k)` from dropping a string the
|
|
map still holds. *)
|
|
let borrowing_builtin (name : string) : bool =
|
|
List.mem name [ "get"; "latest"; "key_at"; "val_at" ]
|
|
|
|
let rec place_of (e : Ast.expr) : place option =
|
|
match e.kind with
|
|
| Ident n -> Some { root = n; projs = []; ppos = e.pos; pnode = e.id }
|
|
| Call ({ kind = Ident bname; _ }, (container :: rest)) when borrowing_builtin bname -> (
|
|
match place_of container with
|
|
| Some p ->
|
|
let proj = match rest with idx :: _ -> idx_proj idx | [] -> PDyn ("#" ^ string_of_int e.id) in
|
|
Some { p with projs = p.projs @ [ proj ]; pnode = e.id }
|
|
| None -> None)
|
|
| Field (base, f) -> (
|
|
match place_of base with
|
|
| Some p -> Some { p with projs = p.projs @ [ PField f ]; pnode = e.id }
|
|
| None -> None)
|
|
| Index (base, idx) -> (
|
|
match place_of base with
|
|
| Some p -> Some { p with projs = p.projs @ [ idx_proj idx ]; pnode = e.id }
|
|
| None -> None)
|
|
| _ -> None
|
|
|
|
let place_ty (ctx : ctx) (p : place) : Ast.field_ty option =
|
|
match find_local ctx p.root with
|
|
| None -> None
|
|
| Some l ->
|
|
List.fold_left
|
|
(fun acc pr ->
|
|
match acc with
|
|
| None -> None
|
|
| Some t -> (
|
|
match (pr, unwrap_nullable t) with
|
|
| PField f, Scalar cn -> field_ty_of ctx cn f
|
|
| (PConst _ | PDyn _), t' -> elem_ty t'
|
|
| _ -> None))
|
|
(Some l.l_ty) p.projs
|
|
|
|
let place_class (ctx : ctx) (p : place) : oclass =
|
|
match place_ty ctx p with Some t -> oclass_of ctx t | None -> Copy
|
|
|
|
(* ============================================================
|
|
Canonical places
|
|
============================================================ *)
|
|
|
|
(* A place written through a borrow binding names the *same storage* as the
|
|
place that borrow came from, so alias questions must be asked about the
|
|
canonical form, never the syntax. `let r = bag.items[i]` makes `r`
|
|
canonically `bag.items[i]`, and `r.n` canonically `bag.items[i].n`;
|
|
substitution is transitive (`let s = r.inner`). Without this,
|
|
`swap(r, s)` would compare roots `r` and `s`, conclude Disjoint, and
|
|
emit neither an error nor a residual site — the exact hole a syntactic
|
|
root check leaves open, and the one case where nobody (not the compiler,
|
|
not the VM) would be enforcing the rule.
|
|
|
|
Termination: each substitution step records the root it replaced, so a
|
|
self-referential chain created by shadowing (`let r = r.inner` in an
|
|
inner scope, where the inner `r` shadows the outer one that the source
|
|
place names) stops instead of looping. Such a chain stays partially
|
|
canonicalized; it is the one imprecise case, and it cannot hang. *)
|
|
let canon_walk (ctx : ctx) (p : place) : place * string list =
|
|
let rec go seen (p : place) =
|
|
if List.mem p.root seen then (p, seen)
|
|
else
|
|
match find_local ctx p.root with
|
|
| Some { l_src = Some src; _ } ->
|
|
go (p.root :: seen) { p with root = src.root; projs = src.projs @ p.projs }
|
|
| _ -> (p, p.root :: seen)
|
|
in
|
|
go [] p
|
|
|
|
let canon (ctx : ctx) (p : place) : place = fst (canon_walk ctx p)
|
|
|
|
(* Every root a place is reached *through*: the binding names it was written
|
|
with, plus the root it finally lands on. `is_own_binding`'s test lives on
|
|
this list, so a reborrow chain (`let t = r` where `r` borrows
|
|
`bag.items[i]`) is treated the same as a direct binding — otherwise using
|
|
`t` would be reported as conflicting with `r`, a borrow it *is*. *)
|
|
let canon_roots (ctx : ctx) (p : place) : string list = snd (canon_walk ctx p)
|
|
|
|
let relate_places (ctx : ctx) (a : place) (b : place) : rel =
|
|
relate (canon ctx a) (canon ctx b)
|
|
|
|
(* `outer` is a proper container of `inner` (`bag` of `bag.items[i]`), not
|
|
the same storage. *)
|
|
let is_strict_prefix (outer : place) (inner : place) : bool =
|
|
outer.root = inner.root
|
|
&& List.length outer.projs < List.length inner.projs
|
|
&& relate_projs outer.projs inner.projs = Overlap
|
|
|
|
|
|
(* ============================================================
|
|
Diagnostics
|
|
============================================================ *)
|
|
|
|
let report (ctx : ctx) ~code ~(pos : Ast.pos) ~message ~(rel : Ast.pos) ~label : unit =
|
|
if ctx.recording then
|
|
Diag.Collector.add ctx.coll
|
|
(Diag.error ~code ~file:ctx.file ~line:pos.line ~col:pos.col ~message
|
|
~related:[ Diag.related_site ~file:ctx.file ~line:rel.line ~col:rel.col ~label ]
|
|
())
|
|
|
|
(* "borrowed here" wording, chosen from how the borrow was created —
|
|
the second half of every two-site borrow error. *)
|
|
let borrow_label (l : local) : string =
|
|
match l.l_src with
|
|
| Some src -> Printf.sprintf "`%s` borrows `%s` here" l.l_name (place_text src)
|
|
| None ->
|
|
Printf.sprintf "`%s` is borrowed here — declare it `take %s: T` to pass ownership in" l.l_name
|
|
l.l_name
|
|
|
|
(* ============================================================
|
|
Table recording
|
|
============================================================ *)
|
|
|
|
let record_move (ctx : ctx) (p : place) (kind : move_kind) : unit =
|
|
if ctx.recording then
|
|
ctx.sink.s_moves <-
|
|
{ mv_node = p.pnode; mv_pos = p.ppos; mv_place = place_text p; mv_kind = kind }
|
|
:: ctx.sink.s_moves
|
|
|
|
let record_drop (ctx : ctx) ~node ~(pos : Ast.pos) ~kind ~items : unit =
|
|
if ctx.recording && items <> [] then
|
|
ctx.sink.s_drops <-
|
|
{ dr_node = node; dr_pos = pos; dr_kind = kind; dr_items = items } :: ctx.sink.s_drops
|
|
|
|
let record_residual (ctx : ctx) ~node ~(pos : Ast.pos) ~(a : place) ~a_kind ~(b : place) ~b_kind :
|
|
unit =
|
|
if ctx.recording then
|
|
ctx.sink.s_res <-
|
|
(* canonical text, so two accesses that reach the same container
|
|
through different borrow bindings read as what they are; the node
|
|
ids stay the precise key *)
|
|
{ rs_node = node; rs_pos = pos; rs_a = place_text (canon ctx a); rs_a_kind = a_kind;
|
|
rs_a_node = a.pnode; rs_b = place_text (canon ctx b); rs_b_kind = b_kind;
|
|
rs_b_node = b.pnode }
|
|
:: ctx.sink.s_res
|
|
|
|
(* ============================================================
|
|
Scopes, live sets, snapshots
|
|
============================================================ *)
|
|
|
|
let push_scope (ctx : ctx) ~node ~pos ~label : unit =
|
|
ctx.scopes <- { sc_node = node; sc_pos = pos; sc_label = label; sc_locals = [] } :: ctx.scopes
|
|
|
|
let declare (ctx : ctx) (l : local) : unit =
|
|
match ctx.scopes with
|
|
| [] -> ()
|
|
| sc :: _ -> sc.sc_locals <- l :: sc.sc_locals
|
|
|
|
let is_live_holder (l : local) : bool =
|
|
l.l_holds && match l.l_state with Live -> true | Moved _ | Borrowed _ -> false
|
|
|
|
(* Every live holder, innermost scope first, destruction order inside
|
|
each scope. *)
|
|
let live_holders (ctx : ctx) : local list =
|
|
List.concat_map (fun sc -> List.filter is_live_holder sc.sc_locals) ctx.scopes
|
|
|
|
(* haxe-parity Task 2: every live holder from the innermost scope up to
|
|
and including the scope whose sc_node is [loop_node] (the nearest
|
|
enclosing loop's own body scope) — DBreak/DContinue's own bound
|
|
version of live_holders, which goes all the way to the function's
|
|
own outermost scope (return's job: leave the whole frame). A
|
|
break/continue only leaves the loop, so scopes *outside* it are
|
|
untouched — their own DScope drop still runs later, at the loop's
|
|
normal exit. *)
|
|
let live_holders_upto (ctx : ctx) (loop_node : int) : local list =
|
|
let rec go = function
|
|
| [] -> []
|
|
| (sc : scope) :: rest ->
|
|
let here = List.filter is_live_holder sc.sc_locals in
|
|
if sc.sc_node = loop_node then here else here @ go rest
|
|
in
|
|
go ctx.scopes
|
|
|
|
let owned_items (ls : local list) : drop_item list =
|
|
ls
|
|
|> List.filter (fun l -> l.l_class = Owned)
|
|
|> List.map (fun l -> { di_name = l.l_name; di_kind = LOwned; di_node = l.l_node })
|
|
|
|
let mask_items (ls : local list) : drop_item list =
|
|
List.map
|
|
(fun l ->
|
|
{ di_name = l.l_name; di_kind = (if l.l_class = Gc then LGc else LOwned); di_node = l.l_node })
|
|
ls
|
|
|
|
let pop_scope (ctx : ctx) : unit =
|
|
match ctx.scopes with
|
|
| [] -> ()
|
|
| sc :: rest ->
|
|
if not ctx.diverged then begin
|
|
let live = List.filter is_live_holder sc.sc_locals in
|
|
record_drop ctx ~node:sc.sc_node ~pos:sc.sc_pos ~kind:(DScope sc.sc_label)
|
|
~items:(owned_items live)
|
|
end;
|
|
ctx.scopes <- rest
|
|
|
|
type snapshot = (local * state) list
|
|
|
|
let snapshot (ctx : ctx) : snapshot =
|
|
List.concat_map (fun sc -> List.map (fun l -> (l, l.l_state)) sc.sc_locals) ctx.scopes
|
|
|
|
let restore (s : snapshot) : unit = List.iter (fun (l, st) -> l.l_state <- st) s
|
|
|
|
let earlier (a : Ast.pos) (b : Ast.pos) : Ast.pos =
|
|
if (a.line, a.col) <= (b.line, b.col) then a else b
|
|
|
|
let join_state (a : state) (b : state) : state =
|
|
match (a, b) with
|
|
| Moved p1, Moved p2 -> Moved (earlier p1 p2)
|
|
| Moved p, _ | _, Moved p -> Moved p
|
|
| Borrowed p, _ | _, Borrowed p -> Borrowed p
|
|
| Live, Live -> Live
|
|
|
|
(* Both snapshots come from the same physical local records (branch-local
|
|
locals are gone by the time a branch is joined), so keys are compared
|
|
with physical equality. *)
|
|
let join (a : snapshot) (b : snapshot) : snapshot =
|
|
List.map
|
|
(fun (l, sa) ->
|
|
let sb = try List.assq l b with Not_found -> sa in
|
|
(l, join_state sa sb))
|
|
a
|
|
|
|
(* ============================================================
|
|
Borrow bookkeeping
|
|
============================================================ *)
|
|
|
|
(* Borrows of a place in this frame that are still live: let-bound
|
|
aliases and loop cursors. Parameter borrows are excluded — their
|
|
source is the caller's, and the caller checks it. @gc aliases are
|
|
excluded because @gc is exempt. *)
|
|
let outstanding_borrows (ctx : ctx) : (local * place) list =
|
|
List.concat_map
|
|
(fun sc ->
|
|
List.filter_map
|
|
(fun l ->
|
|
match (l.l_src, l.l_class, l.l_state) with
|
|
| Some src, Owned, Borrowed _ -> Some (l, src)
|
|
| _ -> None)
|
|
sc.sc_locals)
|
|
ctx.scopes
|
|
|
|
(* An access through a borrow's own binding (`it.touch()` inside
|
|
`for it in items`) is what the borrow is *for*, so it never conflicts
|
|
with that same borrow — nor with any borrow further up the chain the
|
|
access is reached through. Checked on the roots the place was *written*
|
|
with, since after canonicalization an access and its own borrow are the
|
|
same place by construction. *)
|
|
let is_own_binding (ctx : ctx) (l : local) (p : place) : bool =
|
|
List.mem l.l_name (canon_roots ctx p)
|
|
|
|
(* [skip_roots] names borrow bindings that another access in the same
|
|
region already stands for; without it, `swap(r, s)` (both borrow
|
|
bindings) would be reported once by the region's pairwise check and then
|
|
twice more here, once per (access, other binding) pair. *)
|
|
let check_against_borrows (ctx : ctx) ~(node : int) ~(pos : Ast.pos) ?(skip_roots = [])
|
|
(p : place) (kind : acc_kind) : unit =
|
|
List.iter
|
|
(fun ((l : local), src) ->
|
|
if not (is_own_binding ctx l p || List.mem l.l_name skip_roots) then
|
|
match relate_places ctx p src with
|
|
| Overlap ->
|
|
let code, message =
|
|
match kind with
|
|
| AMove ->
|
|
( move_while_borrowed_code,
|
|
Printf.sprintf "cannot move `%s` while `%s` is borrowed" (place_text p)
|
|
(place_text src) )
|
|
| AExcl | AShared ->
|
|
(* "mutate" covers both exclusive accesses this reaches: a
|
|
`mut` argument and an assignment to the place *)
|
|
( conflicting_borrow_code,
|
|
Printf.sprintf "cannot mutate `%s` while `%s` is borrowed" (place_text p)
|
|
(place_text src) )
|
|
in
|
|
report ctx ~code ~pos ~message ~rel:l.l_pos ~label:(borrow_label l)
|
|
| Unknown ->
|
|
record_residual ctx ~node ~pos ~a:p ~a_kind:kind ~b:src ~b_kind:l.l_bkind
|
|
| Disjoint -> ())
|
|
(outstanding_borrows ctx)
|
|
|
|
(* ============================================================
|
|
Moves and escapes
|
|
============================================================ *)
|
|
|
|
let root_local (ctx : ctx) (p : place) : local option = find_local ctx p.root
|
|
|
|
let is_borrow_root (ctx : ctx) (p : place) : local option =
|
|
match root_local ctx p with
|
|
| Some l -> ( match l.l_state with Borrowed _ -> Some l | Live | Moved _ -> None)
|
|
| None -> None
|
|
|
|
(* Reading a place: the one place use-after-move is reported. When the
|
|
move site *is* the use site, the move happened on an earlier turn
|
|
through a loop (the fixpoint's second pass found it) — say so, because
|
|
"moved here" pointing at the line you are already looking at is
|
|
otherwise baffling. *)
|
|
let use_place (ctx : ctx) (p : place) : unit =
|
|
match root_local ctx p with
|
|
| Some { l_state = Moved mpos; l_name; _ } ->
|
|
let same_site = mpos.line = p.ppos.line && mpos.col = p.ppos.col in
|
|
report ctx ~code:use_after_move_code ~pos:p.ppos
|
|
~message:
|
|
(if same_site then
|
|
Printf.sprintf "use of `%s` after it was moved on the previous loop iteration" l_name
|
|
else Printf.sprintf "use of `%s` after it was moved" l_name)
|
|
~rel:mpos
|
|
~label:
|
|
(if same_site then Printf.sprintf "`%s` is moved here, once per iteration" l_name
|
|
else Printf.sprintf "`%s` moved here" l_name)
|
|
| _ -> ()
|
|
|
|
(* The user class an escaping value's type resolves to, if any (unwrapping `?`).
|
|
A class value that escapes is the demand-promotion signal: second-class
|
|
borrows cannot be stored or returned, so a class that must escape has to be
|
|
traced. Scalars, builtins, and non-class names are genuine escape errors. *)
|
|
let class_of_ty (syms : Types.symbols) (t : Ast.field_ty) : string option =
|
|
let rec base = function Ast.Nullable ft -> base ft | ft -> ft in
|
|
match base t with
|
|
| Ast.Scalar n when Types.StringMap.mem n syms.Types.classes -> Some n
|
|
| _ -> None
|
|
|
|
let escape (ctx : ctx) (l : local) ~(pos : Ast.pos) ~message
|
|
~(promote_class : string option) : unit =
|
|
(* `promote_class` is the class of the value that actually escapes (the
|
|
escaping place's type), not the borrow-root local's — so `return h.box`
|
|
promotes `Box`, never `Holder`. In collect mode with a class in hand, record
|
|
it; otherwise report WO-E304. *)
|
|
match (ctx.promote, promote_class) with
|
|
| Some record, Some c -> record c
|
|
| _ ->
|
|
report ctx ~code:borrow_escape_code ~pos ~message ~rel:l.l_pos
|
|
~label:(borrow_label l)
|
|
|
|
(* Whether passing/assigning this place would be a *real* transfer — the
|
|
positive half of `transfer`'s decision below, needed one step earlier by
|
|
analyze_call: an argument that cannot transfer (a borrow, a projection,
|
|
an already-moved local) must be classified as a read, or the region's
|
|
pairwise check reports a bogus move conflict on top of the escape error
|
|
`transfer` is about to give. *)
|
|
(* A `Text` stored into a field or a record is COPIED by the VM (SETF's own
|
|
rule, the same one push/set follow) — so it is neither a move out of the
|
|
source nor a borrow escaping its scope. Without this, `fn rename(name: Text)
|
|
{ self.name = name }` — the most ordinary line in the workload — is
|
|
WO-E304, and the only way to write it would be `take name: Text`. Copying
|
|
is what keeps a field's owner the object itself. *)
|
|
let stores_by_copy (ctx : ctx) (p : place) : bool =
|
|
match place_ty ctx p with
|
|
| Some t -> ( match unwrap_nullable t with
|
|
| Scalar n -> Types.is_heap_scalar n
|
|
| _ -> false)
|
|
| None -> false
|
|
|
|
let is_real_transfer (ctx : ctx) (p : place) : bool =
|
|
p.projs = []
|
|
&& match root_local ctx p with Some l -> l.l_holds && l.l_state = Live | None -> false
|
|
|
|
(* The one gate every ownership transfer goes through. Returns true when
|
|
a real transfer happened (the caller then records the move site with
|
|
the right kind). `what` names the escape flavour for the E304 message.
|
|
|
|
Order of decisions matters: a moved-from local was already reported by
|
|
use_place, a borrow can never be moved out of, and a projection is not
|
|
a move at all in milestone 1 (see the module doc). *)
|
|
let transfer (ctx : ctx) (p : place) ~(what : string) : bool =
|
|
match place_class ctx p with
|
|
| Copy -> false
|
|
| Gc -> false (* traced values alias freely; tracing owns the lifetime *)
|
|
| Owned -> (
|
|
match is_borrow_root ctx p with
|
|
| Some l ->
|
|
escape ctx l ~pos:p.ppos
|
|
~message:
|
|
(Printf.sprintf "borrow of `%s` %s — borrows cannot outlive their scope" (place_text p)
|
|
what)
|
|
~promote_class:
|
|
(match place_ty ctx p with Some t -> class_of_ty ctx.syms t | None -> None);
|
|
false
|
|
| None -> (
|
|
match root_local ctx p with
|
|
| None -> false
|
|
| Some l -> (
|
|
match l.l_state with
|
|
| Moved _ -> false (* already reported at the read *)
|
|
| Borrowed _ -> false (* unreachable: is_borrow_root covered it *)
|
|
| Live ->
|
|
if p.projs <> [] then false (* no partial moves in milestone 1 *)
|
|
else begin
|
|
check_against_borrows ctx ~node:p.pnode ~pos:p.ppos p AMove;
|
|
l.l_state <- Moved p.ppos;
|
|
true
|
|
end)))
|
|
|
|
(* ============================================================
|
|
The walk
|
|
============================================================ *)
|
|
|
|
(* One access inside a call's region. Its position is the accessed
|
|
place's own root token (place.ppos), so no separate field. *)
|
|
type access = {
|
|
ac_place : place;
|
|
ac_kind : acc_kind;
|
|
}
|
|
|
|
let rec read_expr (ctx : ctx) (e : Ast.expr) : unit =
|
|
match e.kind with
|
|
(* iteration 19: a Float literal owns nothing — it is a word in a register,
|
|
exactly like an Int. (A Bytes value DOES own its heap object, but Bytes
|
|
has no literal form, so nothing new lands in this arm.) *)
|
|
| IntLit _ | FloatLit _ | StrLit _ | BoolLit _ -> ()
|
|
| Ident _ | Field _ | Index _ ->
|
|
(match place_of e with Some p -> use_place ctx p | None -> ());
|
|
read_place_parts ctx e
|
|
| Call (callee, args) -> analyze_call ctx e callee args
|
|
| Ctor (cn, fields) -> analyze_ctor ctx cn fields
|
|
(* arc: spawn's ctor half moves fields exactly as a ctor literal does;
|
|
the result (an address) is Copy, so no drop for the spawn itself *)
|
|
| Spawn (cn, fields) -> analyze_ctor ctx cn fields
|
|
| Insert (_, fields) ->
|
|
(* iteration 9 Task 3: the engine copies every field value at the row
|
|
API (the two-worlds bulkhead), so an insert BORROWS its values —
|
|
no transfer, no E304, the source keeps what it had. Trap-capable
|
|
(unique violations arrive with Task 4), so the drop map is
|
|
recorded exactly like DbStub's. *)
|
|
List.iter (fun (_, fe) -> read_expr ctx fe) fields;
|
|
record_drop ctx ~node:e.id ~pos:e.pos ~kind:DLiveMask ~items:(mask_items (live_holders ctx))
|
|
| Unary (_, o) -> read_expr ctx o
|
|
| Binary (_, a, b) ->
|
|
read_expr ctx a;
|
|
read_expr ctx b
|
|
| Interp inner -> read_expr ctx inner
|
|
(* A list literal reads each element and hands it to the fresh
|
|
container, exactly as `push(m, v)` does — so it inherits `push`'s own
|
|
open gap, recorded in docs/plan/oop-vm/08-builtin-surface.md: an
|
|
element that is a *borrowed* non-constant Text (or any borrowed
|
|
owned value) is stored by pointer while the container's declared
|
|
element kind makes it the container's to free. The workload's own
|
|
literals are string constants (never freed) plus borrowed params
|
|
handed straight to a stdlib call, so nothing reachable today hits
|
|
it; it is a runtime-semantics gap to close with `push`, not a
|
|
literal-specific one. *)
|
|
| ListLit items -> List.iter (read_expr ctx) items
|
|
| MapLit | NilLit -> ()
|
|
| As (inner, _) -> read_expr ctx inner
|
|
| Try t -> analyze_try ctx e t.body t.ename t.handler
|
|
| DbStub _ ->
|
|
(* trap-capable: the frame needs its drop map here *)
|
|
record_drop ctx ~node:e.id ~pos:e.pos ~kind:DLiveMask ~items:(mask_items (live_holders ctx))
|
|
| Delete t ->
|
|
read_expr ctx t;
|
|
record_drop ctx ~node:e.id ~pos:e.pos ~kind:DLiveMask ~items:(mask_items (live_holders ctx))
|
|
| Query q ->
|
|
(* iteration 9b: the sub-expressions only READ (engine field-reads copy
|
|
out at the boundary); the query is trap-capable (engine faults), so
|
|
the frame needs its drop map here, exactly like DbStub. *)
|
|
(match q.q_src with QNav e2 -> read_expr ctx e2 | QTable _ -> ());
|
|
List.iter (read_expr ctx) q.q_wheres;
|
|
(match q.q_group with Some (_, k) -> read_expr ctx k | None -> ());
|
|
(match q.q_order with Some (k, _) -> read_expr ctx k | None -> ());
|
|
(match q.q_take with Some t -> read_expr ctx t | None -> ());
|
|
read_expr ctx q.q_select;
|
|
record_drop ctx ~node:e.id ~pos:e.pos ~kind:DLiveMask ~items:(mask_items (live_holders ctx))
|
|
| Switch (subject, arms) -> analyze_switch ctx e.id subject arms
|
|
|
|
(* The root of a place expression is already accounted for by use_place;
|
|
what still needs walking are index subexpressions and a non-place base
|
|
(`f().x`). *)
|
|
and read_place_parts (ctx : ctx) (e : Ast.expr) : unit =
|
|
match e.kind with
|
|
| Ident _ -> ()
|
|
| Field (base, _) -> read_place_parts ctx base
|
|
| Index (base, idx) ->
|
|
read_place_parts ctx base;
|
|
read_expr ctx idx
|
|
| _ -> read_expr ctx e
|
|
|
|
and analyze_ctor (ctx : ctx) (cn : string) (fields : (string * Ast.expr) list) : unit =
|
|
List.iter
|
|
(fun (fname, fe) ->
|
|
read_expr ctx fe;
|
|
match place_of fe with
|
|
| None -> ()
|
|
| Some p ->
|
|
if stores_by_copy ctx p then () (* the field gets its own copy *)
|
|
else if transfer ctx p ~what:(Printf.sprintf "cannot be stored in `%s.%s`" cn fname) then
|
|
record_move ctx p (MvCtorField fname))
|
|
fields
|
|
|
|
(* A call is one region: the receiver borrow and every argument borrow
|
|
are live at the same time, so they are checked pairwise against each
|
|
other and against any outstanding borrow in the frame. Reads happen
|
|
first (against the pre-call state), then the conflict checks, then the
|
|
transfers — that ordering is what makes `f(x, take x)` a
|
|
move-while-borrowed rather than a use-after-move. *)
|
|
and analyze_call (ctx : ctx) (call_e : Ast.expr) (callee : Ast.expr) (args : Ast.expr list) : unit =
|
|
(* haxe-parity Task 4: a variant construction is not a call — it
|
|
lowers to NEW + SETF, no CALL instruction — so every place-shaped
|
|
payload argument is a ctor-field ESCAPE (analyze_ctor's own rule:
|
|
the value is stored into the fresh object, which owns it from
|
|
here), never a borrow-for-the-duration-of-the-call. Getting this
|
|
wrong is a double free, not an imprecision: a local moved into the
|
|
payload would otherwise stay Live and be dropped at scope end on
|
|
top of the variant object's own recursive drop. No LIVE-MASK is
|
|
recorded either — there is no trap-capable call site to sync a
|
|
drop map at. A declared free fn of the same name shadows the
|
|
variant (the same flat-table resolution resolve_callee itself
|
|
uses). *)
|
|
let variant_ctor =
|
|
match callee.kind with
|
|
| Ident n when not (Types.StringMap.mem n ctx.syms.Types.free_fns) ->
|
|
Types.find_variant ctx.syms n
|
|
| _ -> None
|
|
in
|
|
match variant_ctor with
|
|
| Some (_, vi) ->
|
|
List.iteri
|
|
(fun i (fe : Ast.expr) ->
|
|
read_expr ctx fe;
|
|
match place_of fe with
|
|
| None -> ()
|
|
| Some p ->
|
|
let fname =
|
|
match List.nth_opt vi.Types.vi_fields i with
|
|
| Some (n, _) -> n
|
|
| None -> Printf.sprintf "arg%d" (i + 1)
|
|
in
|
|
if
|
|
transfer ctx p
|
|
~what:(Printf.sprintf "cannot be stored in `%s.%s`" vi.Types.vi_name fname)
|
|
then record_move ctx p (MvCtorField fname))
|
|
args
|
|
| None ->
|
|
let resolved = resolve_callee ctx callee in
|
|
(* receiver *)
|
|
let recv =
|
|
match callee.kind with
|
|
| Ident _ -> None
|
|
| Field (base, _) ->
|
|
read_expr ctx base;
|
|
let excl = match resolved with Some c -> c.ce_recv_excl | None -> false in
|
|
(match place_of base with
|
|
| Some p ->
|
|
if place_class ctx p = Owned then
|
|
Some { ac_place = p; ac_kind = (if excl then AExcl else AShared) }
|
|
else None
|
|
| None -> None)
|
|
| _ ->
|
|
read_expr ctx callee;
|
|
None
|
|
in
|
|
List.iter (fun a -> read_expr ctx a) args;
|
|
(* argument conventions, positionally; unresolved or over-supplied
|
|
arguments fall back to a shared borrow *)
|
|
let conv_of i =
|
|
match resolved with
|
|
| None -> (Printf.sprintf "arg%d" (i + 1), Borrow)
|
|
| Some c -> ( match List.nth_opt c.ce_params i with Some p -> p | None -> ("_", Borrow))
|
|
in
|
|
let arg_accesses =
|
|
List.concat
|
|
(List.mapi
|
|
(fun i a ->
|
|
match place_of a with
|
|
| None -> []
|
|
| Some p -> (
|
|
let _, conv = conv_of i in
|
|
match (place_class ctx p, conv) with
|
|
| Copy, _ | Gc, _ -> []
|
|
| Owned, Take ->
|
|
let kind = if is_real_transfer ctx p then AMove else AShared in
|
|
[ { ac_place = p; ac_kind = kind } ]
|
|
| Owned, Mut -> [ { ac_place = p; ac_kind = AExcl } ]
|
|
| Owned, Borrow -> [ { ac_place = p; ac_kind = AShared } ]))
|
|
args)
|
|
in
|
|
let accesses = (match recv with Some r -> [ r ] | None -> []) @ arg_accesses in
|
|
(* pairwise, in argument order *)
|
|
let rec pairs = function
|
|
| [] -> ()
|
|
| a :: tl ->
|
|
List.iter (fun b -> check_pair ctx call_e a b) tl;
|
|
pairs tl
|
|
in
|
|
pairs accesses;
|
|
(* An exclusive borrow also has to clear the frame's outstanding borrows
|
|
(moves do that inside `transfer`) — minus the bindings this region's
|
|
own accesses already stand for, which the pairwise check just
|
|
covered. *)
|
|
let region_roots = List.map (fun a -> a.ac_place.root) accesses in
|
|
List.iter
|
|
(fun a ->
|
|
if a.ac_kind = AExcl then
|
|
check_against_borrows ctx ~node:call_e.id ~pos:a.ac_place.ppos ~skip_roots:region_roots
|
|
a.ac_place AExcl)
|
|
accesses;
|
|
(* transfers last *)
|
|
(* iteration 7b deleted the `push`-of-a-gc-value special case (an RC_INC
|
|
escape site): a traced value stored into a container needs no
|
|
bookkeeping — tracing finds it through the container.
|
|
|
|
Storing an OWNED, non-copied value into a container is a MOVE, exactly
|
|
like a `take` argument: the container owns the element and frees it in
|
|
its own drop plan (runtime/src/gc.c multi_free/map_free), so the caller
|
|
dropping it too was a double free. This was the disclosed
|
|
"move-on-push" gap — it stayed latent while pushed elements were Texts
|
|
(copied at the boundary, 2026-08-14) and detonated the moment iteration
|
|
16's route-table pattern pushed a CLASS value (`push(self.routes, r)`
|
|
plus the take-param's scope-end DROP = the container's element freed
|
|
twice). `push`'s value slot and `set`'s key/value slots transfer;
|
|
Text/json.Value stay copy-stored (`stores_by_copy`), so their fresh-
|
|
value drop is still the caller's. A user-declared fn of the same name
|
|
wins, exactly like the builtin table's shadowing rule. *)
|
|
let container_store_slot (i : int) : bool =
|
|
match callee.kind with
|
|
| Ident "push" -> i = 1 && Types.StringMap.find_opt "push" ctx.syms.Types.free_fns = None
|
|
| Ident "set" ->
|
|
(i = 1 || i = 2) && Types.StringMap.find_opt "set" ctx.syms.Types.free_fns = None
|
|
(* arc: send(addr, msg) MOVES the message to the runtime — the sender's
|
|
binding dies (compile-time move, iteration 8's criterion).
|
|
iteration 24: call(addr, msg) moves its message identically. *)
|
|
| Ident "send" -> i = 1 && Types.StringMap.find_opt "send" ctx.syms.Types.free_fns = None
|
|
| Ident "call" -> i = 1 && Types.StringMap.find_opt "call" ctx.syms.Types.free_fns = None
|
|
(* T4/T5: the notice / timer message moves to the runtime too *)
|
|
| Ident "monitor" ->
|
|
i = 2 && Types.StringMap.find_opt "monitor" ctx.syms.Types.free_fns = None
|
|
| Field ({ kind = Ident "time"; _ }, "after") -> i = 2
|
|
| _ -> false
|
|
in
|
|
List.iteri
|
|
(fun i a ->
|
|
match place_of a with
|
|
| None -> ()
|
|
| Some p ->
|
|
let pname, conv = conv_of i in
|
|
if conv = Take then
|
|
(if transfer ctx p ~what:(Printf.sprintf "cannot be passed to `take %s`" pname) then
|
|
record_move ctx p (MvArg pname))
|
|
else if container_store_slot i && place_class ctx p = Owned
|
|
&& not (stores_by_copy ctx p) then
|
|
(if
|
|
transfer ctx p
|
|
~what:
|
|
(match callee.kind with
|
|
| Ident "send" | Ident "call" | Ident "monitor"
|
|
| Field ({ kind = Ident "time"; _ }, "after") ->
|
|
"cannot be sent — a message moves to the receiver"
|
|
| _ -> "cannot be stored in a container")
|
|
then record_move ctx p (MvArg "element"))
|
|
)
|
|
args;
|
|
record_drop ctx ~node:call_e.id ~pos:call_e.pos ~kind:DLiveMask
|
|
~items:(mask_items (live_holders ctx))
|
|
|
|
(* The pairwise equivalent of is_own_binding: one side reaches the storage
|
|
through a borrow binding, the other names the place that borrow came
|
|
from (`bag.eat(it)` inside `for it in bag.items`). Using a borrow
|
|
alongside the thing it borrows from is what the binding is for, so it is
|
|
not a conflict — and after canonicalization the two would otherwise
|
|
always Overlap. Two *different* bindings of the same container (`r` and
|
|
`s`) are not this case and stay checked. *)
|
|
and reuses_binding (ctx : ctx) (a : place) (b : place) : bool =
|
|
(* narrow on purpose: only when one side is written through a borrow
|
|
binding *and* the other side names a proper container of what that
|
|
borrow points at. Two bindings of the same container (`r` and `s`), or
|
|
a binding against the very element it borrows, are not this case and
|
|
stay checked. *)
|
|
let through (p : place) (other : place) =
|
|
match find_local ctx p.root with
|
|
| Some { l_src = Some _; _ } -> is_strict_prefix (canon ctx other) (canon ctx p)
|
|
| _ -> false
|
|
in
|
|
through a b || through b a
|
|
|
|
and check_pair (ctx : ctx) (call_e : Ast.expr) (a : access) (b : access) : unit =
|
|
if a.ac_kind = AShared && b.ac_kind = AShared then ()
|
|
else if reuses_binding ctx a.ac_place b.ac_place then ()
|
|
else
|
|
match relate_places ctx a.ac_place b.ac_place with
|
|
| Disjoint -> ()
|
|
| Unknown ->
|
|
record_residual ctx ~node:call_e.id ~pos:call_e.pos ~a:a.ac_place ~a_kind:a.ac_kind
|
|
~b:b.ac_place ~b_kind:b.ac_kind
|
|
| Overlap -> (
|
|
match (a.ac_kind, b.ac_kind) with
|
|
| AMove, AMove ->
|
|
report ctx ~code:use_after_move_code ~pos:b.ac_place.ppos
|
|
~message:
|
|
(Printf.sprintf "use of `%s` after it was moved" (place_text b.ac_place))
|
|
~rel:a.ac_place.ppos
|
|
~label:(Printf.sprintf "`%s` moved here" (place_text a.ac_place))
|
|
| AMove, _ ->
|
|
report ctx ~code:move_while_borrowed_code ~pos:a.ac_place.ppos
|
|
~message:
|
|
(Printf.sprintf "cannot move `%s` while `%s` is borrowed in the same call"
|
|
(place_text a.ac_place) (place_text b.ac_place))
|
|
~rel:b.ac_place.ppos
|
|
~label:(Printf.sprintf "`%s` borrowed here" (place_text b.ac_place))
|
|
| _, AMove ->
|
|
report ctx ~code:move_while_borrowed_code ~pos:b.ac_place.ppos
|
|
~message:
|
|
(Printf.sprintf "cannot move `%s` while `%s` is borrowed in the same call"
|
|
(place_text b.ac_place) (place_text a.ac_place))
|
|
~rel:a.ac_place.ppos
|
|
~label:(Printf.sprintf "`%s` borrowed here" (place_text a.ac_place))
|
|
| _ ->
|
|
report ctx ~code:conflicting_borrow_code ~pos:b.ac_place.ppos
|
|
~message:
|
|
(Printf.sprintf "cannot borrow `%s` as `mut` twice in the same call"
|
|
(place_text b.ac_place))
|
|
~rel:a.ac_place.ppos
|
|
~label:(Printf.sprintf "`%s` first borrowed here" (place_text a.ac_place)))
|
|
|
|
(* ---- statements ------------------------------------------------------ *)
|
|
|
|
(* Join normalization. A value moved on one branch of an `if` and not the
|
|
other leaves the merge in two different real states while the join can
|
|
record only one — and it records Moved, so nothing would ever drop the
|
|
value on the path that did *not* move it: a leak. Rather than spend a
|
|
runtime drop flag, the non-moving branch drops it at its own end, which
|
|
makes the joined Moved state true on both paths. Sound because the join
|
|
already marked it Moved, so a later use is WO-E301 either way. *)
|
|
and branch_join_drops (ctx : ctx) ~(node : int) ~(label : string) ~(pos : Ast.pos)
|
|
~(moving : snapshot) ~(other : snapshot) : unit =
|
|
let items =
|
|
List.filter_map
|
|
(fun ((l : local), st_other) ->
|
|
let st_moving = try List.assq l moving with Not_found -> st_other in
|
|
match (st_other, st_moving) with
|
|
| Live, Moved _ when l.l_holds && l.l_class = Owned ->
|
|
Some { di_name = l.l_name; di_kind = LOwned; di_node = l.l_node }
|
|
| _ -> None)
|
|
other
|
|
in
|
|
record_drop ctx ~node ~pos ~kind:(DBranchJoin label) ~items
|
|
|
|
(* haxe-parity Task 3: `switch`'s own arms are alternate flows joining
|
|
back together after the switch — exactly what `if`/`else` already
|
|
is, generalized from two branches to N (one per arm). Reused, not
|
|
reinvented, per the brief's own instruction: each arm is its own
|
|
`analyze_block` (so an arm-local owned value that is never moved
|
|
still gets its ordinary DScope drop at that arm's own end — nothing
|
|
special to write for that half); a diverging arm (every path inside
|
|
it returned) drops out of the join exactly like a diverging `if`
|
|
branch does; and a value moved in *some* arms but not others gets
|
|
`branch_join_drops`'s own JOIN-DROP treatment, called once per kept
|
|
arm against the join of every *other* (non-diverging) arm's ending
|
|
state — the N-way shape of the same "the branch that kept it drops
|
|
it at its own end" rule the module doc above states for two.
|
|
|
|
The subject is read (`read_expr`, never `transfer`) exactly once,
|
|
before any arm runs: it is compared against, never consumed — "the
|
|
SUBJECT's ownership — borrowed for the comparison, not consumed" per
|
|
this task's own brief. Case values are read the same way; for this
|
|
task's scalar/Text subjects they are always literals, so this is a
|
|
no-op today and only matters once a union variant tag becomes a real
|
|
bound reference (Task 4). *)
|
|
and analyze_switch (ctx : ctx) (node : int) (subject : Ast.expr) (arms : Ast.switch_arm list) :
|
|
unit =
|
|
read_expr ctx subject;
|
|
(* haxe-parity Task 4: over a union-typed subject the case "values"
|
|
are variant PATTERNS (`case Ok:`, `case Failed(reason):`), not
|
|
expressions — never read as such (a pattern's binding names are
|
|
unbound on purpose; reading them would be noise at best). The
|
|
subject's own union-ness comes from this pass's own expr_ty,
|
|
deliberately NOT unwrapped through `?T` (types.ml's subj_union
|
|
makes the same call — a `?Union` subject stays on the plain-value
|
|
path until Task 6). *)
|
|
let subj_union =
|
|
match expr_ty ctx subject with
|
|
| Some (Scalar n) -> Types.StringMap.find_opt n ctx.syms.Types.unions
|
|
| _ -> None
|
|
in
|
|
(match subj_union with
|
|
| Some _ -> ()
|
|
| None ->
|
|
List.iter (fun (a : Ast.switch_arm) -> List.iter (read_expr ctx) a.Ast.values) arms);
|
|
(* A payload pattern's bindings are BORROWS of the subject's own
|
|
fields (`case Failed(reason):` reads `reason` straight out of the
|
|
variant object via GETF — the subject keeps owning the payload, so
|
|
the binding must never be dropped by the arm or the subject's own
|
|
drop double-frees). Declared into the arm's own scope, exactly like
|
|
a `for` cursor is into its loop's (same Borrowed state, same
|
|
l_holds = false); when the subject is a place, the binding's source
|
|
place is that place plus the field projection, so moving the
|
|
subject out from under a live binding is the ordinary WO-E302. *)
|
|
let arm_bindings (a : Ast.switch_arm) : local list =
|
|
match subj_union with
|
|
| None -> []
|
|
| Some u -> (
|
|
match a.Ast.values with
|
|
| [ { Ast.kind = Ast.Call ({ Ast.kind = Ast.Ident vname; _ }, args); _ } ] -> (
|
|
match
|
|
List.find_opt (fun (v : Types.variant_info) -> v.Types.vi_name = vname)
|
|
u.Types.u_variants
|
|
with
|
|
| Some vi when List.length args = List.length vi.Types.vi_fields ->
|
|
let subj_place = place_of subject in
|
|
List.concat
|
|
(List.map2
|
|
(fun (arg : Ast.expr) (fname, fty) ->
|
|
match arg.Ast.kind with
|
|
| Ast.Ident bn ->
|
|
let src =
|
|
match subj_place with
|
|
| Some p ->
|
|
Some { p with projs = p.projs @ [ PField fname ]; pnode = arg.Ast.id }
|
|
| None -> None
|
|
in
|
|
[ { l_name = bn; l_ty = fty; l_class = oclass_of ctx fty;
|
|
l_node = arg.Ast.id; l_pos = arg.Ast.pos; l_holds = false; l_src = src;
|
|
l_bkind = AShared; l_state = Borrowed arg.Ast.pos } ]
|
|
| _ -> [])
|
|
args vi.Types.vi_fields)
|
|
| _ -> [])
|
|
| _ -> [])
|
|
in
|
|
let entry = snapshot ctx in
|
|
let div0 = ctx.diverged in
|
|
(* review fix, Critical 1: walk the *lowering* order (default last),
|
|
not raw source order — see Ast.switch_lowering_order's own doc
|
|
comment. "ARM<i>" must be the same index emit.ml's own
|
|
emit_switch hands the owner tables, or every DScope/JOIN-DROP
|
|
lookup below silently misses. *)
|
|
let results =
|
|
List.mapi
|
|
(fun i (a : Ast.switch_arm) ->
|
|
restore entry;
|
|
ctx.diverged <- div0;
|
|
let label = Printf.sprintf "ARM%d" i in
|
|
analyze_block ctx ~pre:(arm_bindings a) ~node ~pos:a.Ast.arm_pos ~label a.Ast.body;
|
|
(label, a.Ast.arm_pos, snapshot ctx, ctx.diverged))
|
|
(Ast.switch_lowering_order arms)
|
|
in
|
|
let non_diverged = List.filter (fun (_, _, _, d) -> not d) results in
|
|
match non_diverged with
|
|
| [] ->
|
|
(* every arm diverged (or there were no arms at all — a malformed
|
|
switch types.ml already reports on): nothing reachable follows,
|
|
so — mirroring analyze_stmt's own `If` case, which restores
|
|
*some* snapshot purely for hygiene even though it is provably
|
|
unobservable — restore the last arm's ending state, if any. *)
|
|
(match List.rev results with (_, _, sn, _) :: _ -> restore sn | [] -> ());
|
|
ctx.diverged <- true
|
|
| (_, _, first_sn, _) :: rest ->
|
|
List.iter
|
|
(fun (label, pos, sn, _) ->
|
|
match List.filter (fun (l, _, _, _) -> l <> label) non_diverged with
|
|
| [] -> () (* the only non-diverging arm: nothing else could have moved anything *)
|
|
| (_, _, first_other, _) :: rest_other ->
|
|
let moved_elsewhere =
|
|
List.fold_left (fun acc (_, _, s, _) -> join acc s) first_other rest_other
|
|
in
|
|
branch_join_drops ctx ~node ~label ~pos ~moving:moved_elsewhere ~other:sn)
|
|
non_diverged;
|
|
restore (List.fold_left (fun acc (_, _, s, _) -> join acc s) first_sn rest);
|
|
ctx.diverged <- div0
|
|
|
|
and analyze_stmt (ctx : ctx) (s : Ast.stmt) : unit =
|
|
match s.s_kind with
|
|
| Let { name; ty; value } -> analyze_let ctx s name ty value
|
|
| Assign { target; value } -> analyze_assign ctx s target value
|
|
| ExprStmt e -> read_expr ctx e
|
|
| Return opt -> analyze_return ctx s opt
|
|
| If { cond; then_body; else_body } ->
|
|
read_expr ctx cond;
|
|
let entry = snapshot ctx in
|
|
let div0 = ctx.diverged in
|
|
analyze_block ctx ~node:s.s_id ~pos:s.s_pos ~label:"THEN" then_body;
|
|
let after_then = snapshot ctx in
|
|
let div_then = ctx.diverged in
|
|
restore entry;
|
|
ctx.diverged <- div0;
|
|
let after_else, div_else =
|
|
match else_body with
|
|
| None -> (entry, div0)
|
|
| Some (epos, body) ->
|
|
analyze_block ctx ~node:s.s_id ~pos:epos ~label:"ELSE" body;
|
|
let sn = snapshot ctx in
|
|
let dv = ctx.diverged in
|
|
restore entry;
|
|
(sn, dv)
|
|
in
|
|
(* a branch that returned contributes no state to the merge *)
|
|
if div_then && div_else then begin
|
|
restore after_then;
|
|
ctx.diverged <- true
|
|
end
|
|
else if div_then then begin
|
|
restore after_else;
|
|
ctx.diverged <- div0
|
|
end
|
|
else if div_else then begin
|
|
restore after_then;
|
|
ctx.diverged <- div0
|
|
end
|
|
else begin
|
|
(* neither branch returned: normalize a one-sided move by dropping on
|
|
the side that kept the value. An `if` without `else` anchors its
|
|
implicit else at the `if` token — there is no other position to
|
|
name. *)
|
|
let else_anchor = match else_body with Some (epos, _) -> epos | None -> s.s_pos in
|
|
branch_join_drops ctx ~node:s.s_id ~label:"ELSE" ~pos:else_anchor ~moving:after_then
|
|
~other:after_else;
|
|
branch_join_drops ctx ~node:s.s_id ~label:"THEN" ~pos:s.s_pos ~moving:after_else
|
|
~other:after_then;
|
|
restore (join after_then after_else);
|
|
ctx.diverged <- div0
|
|
end
|
|
| While { cond; body } ->
|
|
ctx.loop_stack <- s.s_id :: ctx.loop_stack;
|
|
fixpoint ctx
|
|
(fun () ->
|
|
read_expr ctx cond;
|
|
analyze_block ctx ~node:s.s_id ~pos:s.s_pos ~label:"WHILE" body);
|
|
ctx.loop_stack <- List.tl ctx.loop_stack
|
|
| For { var; var2; iter; body } ->
|
|
read_expr ctx iter;
|
|
let src = place_of iter in
|
|
let iter_ty = expr_ty ctx iter in
|
|
(* `for k, v in m` binds the map's key and value types; the one-name
|
|
form binds the element type (elem_ty). Both cursors are BORROWS of
|
|
what the container owns, so neither is ever dropped by the body. *)
|
|
let key_ty, item_ty =
|
|
match (iter_ty, var2) with
|
|
| Some (Map (k, v)), Some _ -> (Some (Scalar k), Scalar v)
|
|
| Some (Nullable (Map (k, v))), Some _ -> (Some (Scalar k), Scalar v)
|
|
| Some t, _ -> (None, ( match elem_ty t with Some e -> e | None -> t))
|
|
| None, _ -> (None, Scalar "Int")
|
|
in
|
|
(* A cursor over Text elements holds a COPY, not a borrow: the emitter
|
|
copies each element as it loads it (the same boundary rule containers,
|
|
fields and returns follow), so the body owns its cursor and drops it per
|
|
iteration. That is also what lets `for k, v in m { v.field = … }` work —
|
|
a borrowing key cursor made every mutation through the value cursor a
|
|
WO-E303 against the container's own borrow. Any other element type is
|
|
still a borrow: records are not copied. *)
|
|
let cursor (n : string) (t : Ast.field_ty) : local =
|
|
let copied =
|
|
match unwrap_nullable t with
|
|
| Scalar cn -> Types.is_heap_scalar cn
|
|
| _ -> false
|
|
in
|
|
if copied then
|
|
{ l_name = n; l_ty = t; l_class = Owned; l_node = s.s_id; l_pos = s.s_pos; l_holds = true;
|
|
l_src = None; l_bkind = AShared; l_state = Live }
|
|
else
|
|
{ l_name = n; l_ty = t; l_class = oclass_of ctx t; l_node = s.s_id; l_pos = s.s_pos;
|
|
l_holds = false; l_src = src; l_bkind = AShared; l_state = Borrowed s.s_pos }
|
|
in
|
|
ctx.loop_stack <- s.s_id :: ctx.loop_stack;
|
|
fixpoint ctx
|
|
(fun () ->
|
|
push_scope ctx ~node:s.s_id ~pos:s.s_pos ~label:"FOR";
|
|
(* the cursor borrows an element of the iterable for the whole
|
|
body: moving the container out from under it is E302 *)
|
|
(match (key_ty, var2) with
|
|
| Some kt, Some v2 ->
|
|
declare ctx (cursor var kt);
|
|
declare ctx (cursor v2 item_ty)
|
|
| _ -> declare ctx (cursor var item_ty));
|
|
List.iter (analyze_stmt ctx) body;
|
|
pop_scope ctx);
|
|
ctx.loop_stack <- List.tl ctx.loop_stack
|
|
| DoWhile { body; cond } ->
|
|
(* `do { body } while cond` — body always runs before the condition
|
|
is ever consulted, so it is analyzed first; still wrapped in
|
|
`fixpoint` for the same reason `while`/`for` are (a *second*
|
|
iteration's move state must be joined against the first's, the
|
|
brief's own loop rule — see fixpoint's doc comment). *)
|
|
ctx.loop_stack <- s.s_id :: ctx.loop_stack;
|
|
fixpoint ctx
|
|
(fun () ->
|
|
analyze_block ctx ~node:s.s_id ~pos:s.s_pos ~label:"DO" body;
|
|
read_expr ctx cond);
|
|
ctx.loop_stack <- List.tl ctx.loop_stack
|
|
| Break -> analyze_break ctx s
|
|
| Continue -> analyze_continue ctx s
|
|
|
|
(* The brief's loop rule: probe the body once with recording off, join
|
|
that with the entry state, then analyze for real against the joined
|
|
state. The exit state joins the entry again — a `while` may run zero
|
|
times — and a `return` inside the body does not make the loop diverge
|
|
for the same reason. *)
|
|
and fixpoint (ctx : ctx) (run : unit -> unit) : unit =
|
|
let entry = snapshot ctx in
|
|
let div0 = ctx.diverged in
|
|
let was_recording = ctx.recording in
|
|
ctx.recording <- false;
|
|
run ();
|
|
ctx.recording <- was_recording;
|
|
ctx.diverged <- div0;
|
|
restore (join entry (snapshot ctx));
|
|
run ();
|
|
let after = snapshot ctx in
|
|
restore (join entry after);
|
|
ctx.diverged <- div0
|
|
|
|
(* `~pre` (haxe-parity Task 4): locals to declare into the fresh scope
|
|
before its statements run — a payload pattern's bindings, and nothing
|
|
else today. Borrows only (l_holds = false), so pop_scope's drop
|
|
recording never sees them; every pre-existing call site passes
|
|
nothing and is byte-identical. *)
|
|
(* haxe-parity Task 5: `try body catch (e) handler`. The two arms are
|
|
alternate flows joining at one point — the same shape `if`/`switch`
|
|
already have, so the same join machinery applies: whatever one arm
|
|
moved out, the arm that still holds it drops at its own end
|
|
(branch_join_drops), and the state after the whole expression is the
|
|
join of both.
|
|
|
|
What is genuinely different from a branch is WHERE the catch arm starts
|
|
from: a trap can be raised anywhere inside the body, so the handler may
|
|
run after *any prefix* of it. Taking the entry state as the handler's
|
|
starting point is the conservative reading — it never claims the body's
|
|
moves happened — and the join then makes the surviving path responsible
|
|
for the drop. The frame also needs a live mask at the try itself (like
|
|
every other trap-capable site): that mask is what the VM's unwind uses
|
|
to release the body's own values before landing in the handler.
|
|
|
|
`e` is a local of the predeclared `Error` record, owned by the handler
|
|
scope (the record and its two Texts are freshly allocated at landing),
|
|
so pop_scope records its drop like any other owned local's. *)
|
|
and analyze_try (ctx : ctx) (e : Ast.expr) (body : Ast.expr) (ename : string)
|
|
(handler : Ast.stmt list) : unit =
|
|
record_drop ctx ~node:e.id ~pos:e.pos ~kind:DLiveMask ~items:(mask_items (live_holders ctx));
|
|
let entry = snapshot ctx in
|
|
let div0 = ctx.diverged in
|
|
read_expr ctx body;
|
|
let body_sn = snapshot ctx in
|
|
let body_div = ctx.diverged in
|
|
restore entry;
|
|
ctx.diverged <- div0;
|
|
let ety = Ast.Scalar Types.error_record_name in
|
|
let ebind =
|
|
{ l_name = ename; l_ty = ety; l_class = oclass_of ctx ety; l_node = e.id; l_pos = e.pos;
|
|
l_holds = (match oclass_of ctx ety with Copy -> false | _ -> true); l_src = None;
|
|
l_bkind = AShared; l_state = Live }
|
|
in
|
|
analyze_block ctx ~pre:[ ebind ] ~node:e.id ~pos:e.pos ~label:"CATCH" handler;
|
|
let catch_sn = snapshot ctx in
|
|
let catch_div = ctx.diverged in
|
|
if (not body_div) && not catch_div then begin
|
|
branch_join_drops ctx ~node:e.id ~label:"TRYBODY" ~pos:e.pos ~moving:catch_sn ~other:body_sn;
|
|
branch_join_drops ctx ~node:e.id ~label:"CATCHJOIN" ~pos:e.pos ~moving:body_sn ~other:catch_sn
|
|
end;
|
|
restore (if body_div then catch_sn else if catch_div then body_sn else join body_sn catch_sn);
|
|
ctx.diverged <- body_div && catch_div
|
|
|
|
and analyze_block (ctx : ctx) ?(pre = []) ~node ~pos ~label (body : Ast.stmt list) : unit =
|
|
push_scope ctx ~node ~pos ~label;
|
|
List.iter (declare ctx) pre;
|
|
List.iter (analyze_stmt ctx) body;
|
|
pop_scope ctx
|
|
|
|
and analyze_let (ctx : ctx) (s : Ast.stmt) (name : string) (ty : Ast.field_ty option)
|
|
(value : Ast.expr)
|
|
: unit =
|
|
read_expr ctx value;
|
|
let vty =
|
|
match ty with
|
|
| Some t -> t
|
|
| None -> ( match expr_ty ctx value with Some t -> t | None -> Scalar "Int")
|
|
in
|
|
let cls = oclass_of ctx vty in
|
|
(* A container read that yields a Text is COPIED by the emitter — the fourth
|
|
ownership boundary, and the one that keeps `let cl = headers["x"]` from
|
|
borrowing the map for the rest of the scope (which then forbade moving
|
|
that map into a record, WO-E302). For any other element type the read is
|
|
still a borrow of the container: records are not copied. *)
|
|
let reads_container =
|
|
match value.Ast.kind with
|
|
| Ast.Index _ -> true
|
|
| Ast.Call ({ Ast.kind = Ast.Ident bn; _ }, _) -> borrowing_builtin bn
|
|
| _ -> false
|
|
in
|
|
let copies_out = reads_container && (match unwrap_nullable vty with
|
|
| Scalar n -> Types.is_heap_scalar n
|
|
| _ -> false) in
|
|
let vplace = if copies_out then None else place_of value in
|
|
(* A `@gc` value read out of a container is neither a copy nor a new
|
|
reference: the container holds the count, and the reader only looks. It
|
|
must NOT take the Gc-alias path below (which records an RC_INC/RC_DEC
|
|
pair) — doing so double-released the element and segfaulted both `gc/`
|
|
fixtures. Reading it as a plain borrow of the container is what the pass
|
|
did before container reads became places, now with the right type. *)
|
|
let gc_container_read = reads_container && cls = Gc in
|
|
let holds, src, state =
|
|
match (cls, vplace) with
|
|
| Gc, _ when gc_container_read -> (false, vplace, Borrowed s.s_pos)
|
|
(* Binding a Text from a PLACE copies it — the same boundary rule as a
|
|
field store, a container element, a loop cursor and a return. The
|
|
source stays live and keeps its own value; this binding owns the copy
|
|
and drops it at scope end. Without it `let range = part` MOVED `part`,
|
|
and the next line's `index_of(part, "/")` was a use-after-move. *)
|
|
| (Owned | Gc), Some p when stores_by_copy ctx p -> (true, None, Live)
|
|
| Copy, _ -> (false, None, Live)
|
|
| Owned, None -> (true, None, Live) (* fresh value: constructor or call result *)
|
|
| Owned, Some p -> (
|
|
(* a whole owned local moves; a projection binds a *borrow* of that
|
|
place instead — milestone 1 has no partial moves, so
|
|
`let r = b.inner` is an alias, not a transfer *)
|
|
match root_local ctx p with
|
|
| None -> (true, None, Live) (* root is not a local: treat as a fresh value *)
|
|
| Some l -> (
|
|
match l.l_state with
|
|
| Moved _ -> (true, None, Live) (* use-after-move already reported *)
|
|
| Borrowed _ -> (false, Some p, Borrowed s.s_pos) (* reborrow *)
|
|
| Live ->
|
|
if p.projs = [] && l.l_holds then begin
|
|
if transfer ctx p ~what:"cannot be moved out" then record_move ctx p MvLet;
|
|
(true, None, Live)
|
|
end
|
|
else (false, Some p, Borrowed s.s_pos)))
|
|
| Gc, None -> (true, None, Live) (* traced: no bookkeeping (7b) *)
|
|
| Gc, Some p -> (true, Some p, Live)
|
|
in
|
|
declare ctx
|
|
{ l_name = name; l_ty = vty; l_class = cls; l_node = s.s_id; l_pos = s.s_pos; l_holds = holds;
|
|
l_src = src; l_bkind = AShared; l_state = state }
|
|
|
|
and analyze_assign (ctx : ctx) (s : Ast.stmt) (target : Ast.expr) (value : Ast.expr) : unit =
|
|
read_expr ctx value;
|
|
let tplace = place_of target in
|
|
let vplace = place_of value in
|
|
(* `a = a` (or `self.box = self.box`) replaces a place with itself: the
|
|
old value and the new one are the same storage, so recording a drop for
|
|
the "overwritten" value would destroy the value the assignment just
|
|
stored — a double free with no diagnostic. Overlap is deliberately a
|
|
hair wider than the exact test (which would be `canon tp = canon vp`):
|
|
it also holds when one side *contains* the other, as in `a = a.inner`.
|
|
Such a shape cannot type-check upstream today, so the two tests agree
|
|
on every reachable program; if containment ever became expressible,
|
|
suppressing the drop would still be the safe direction — the
|
|
overwritten value and the stored one overlap, so dropping either is
|
|
the double free. *)
|
|
let self_assign =
|
|
match (tplace, vplace) with
|
|
| Some tp, Some vp -> relate_places ctx tp vp = Overlap
|
|
| _ -> false
|
|
in
|
|
(* Writing a place is an exclusive access to it (so it may not be
|
|
borrowed elsewhere), and the value it held dies here. Table entries and
|
|
the diagnostic point at the place written, not at the statement (they
|
|
coincide today — an assignment starts at its target — but the place is
|
|
what the entry is about). *)
|
|
(match tplace with
|
|
| None -> read_expr ctx target
|
|
| Some p ->
|
|
check_against_borrows ctx ~node:s.s_id ~pos:p.ppos p AExcl;
|
|
if p.projs = [] then begin
|
|
match root_local ctx p with
|
|
| Some l when l.l_holds && l.l_state = Live && not self_assign ->
|
|
if l.l_class = Owned then
|
|
record_drop ctx ~node:s.s_id ~pos:p.ppos ~kind:DOverwrite
|
|
~items:[ { di_name = place_text p; di_kind = LOwned; di_node = p.pnode } ]
|
|
| _ -> ()
|
|
end
|
|
else begin
|
|
(* a projection target is also a read of its root *)
|
|
use_place ctx p;
|
|
read_place_parts ctx target;
|
|
match if self_assign then Copy else place_class ctx p with
|
|
| Owned ->
|
|
record_drop ctx ~node:s.s_id ~pos:p.ppos ~kind:DOverwrite
|
|
~items:[ { di_name = place_text p; di_kind = LOwned; di_node = p.pnode } ]
|
|
| Gc -> () (* traced: tracing owns the old value's lifetime (7b) *)
|
|
| Copy -> ()
|
|
end);
|
|
(* the incoming value *)
|
|
(match vplace with
|
|
| None -> ()
|
|
| Some vp ->
|
|
let into_field = match tplace with Some tp -> tp.projs <> [] | None -> true in
|
|
let what =
|
|
if into_field then
|
|
Printf.sprintf "cannot be stored in `%s`"
|
|
(match tplace with Some tp -> place_text tp | None -> "a field")
|
|
else "cannot be moved out"
|
|
in
|
|
if into_field && stores_by_copy ctx vp then () (* the field gets its own copy *)
|
|
else if transfer ctx vp ~what then record_move ctx vp MvAssign);
|
|
(* Whatever the value was — a fresh constructor, a call result, another
|
|
local — assigning to a whole local re-initializes it: a local that had
|
|
been moved out of is live again afterwards. *)
|
|
match tplace with
|
|
| Some tp when tp.projs = [] -> (
|
|
match root_local ctx tp with Some l when l.l_holds -> l.l_state <- Live | _ -> ())
|
|
| _ -> ()
|
|
|
|
and analyze_return (ctx : ctx) (s : Ast.stmt) (opt : Ast.expr option) : unit =
|
|
(match opt with
|
|
| None -> ()
|
|
| Some e -> (
|
|
read_expr ctx e;
|
|
match place_of e with
|
|
| None -> ()
|
|
| Some p ->
|
|
(* Returning a Text is the third ownership boundary that COPIES (the
|
|
other two are a container element and a field): the caller gets its
|
|
own string, the callee's borrow stays the borrow it was. emit.ml
|
|
emits that copy. Without this the workload's own level classifier —
|
|
`for lv in [...] { … return lv }` — cannot be written at all. *)
|
|
if stores_by_copy ctx p then ()
|
|
else if transfer ctx p ~what:(Printf.sprintf "escapes `%s`" ctx.fn_name) then
|
|
record_move ctx p MvReturn));
|
|
let live = live_holders ctx in
|
|
record_drop ctx ~node:s.s_id ~pos:s.s_pos ~kind:DReturn ~items:(owned_items live);
|
|
ctx.diverged <- true
|
|
|
|
(* haxe-parity Task 2: `break`/`continue` reuse analyze_return's own
|
|
drop machinery verbatim, bounded to the nearest enclosing loop
|
|
instead of the whole function (live_holders_upto vs. live_holders —
|
|
see that function's doc comment) — this is "the one non-trivial bit"
|
|
the brief calls out: an owned value still alive in the loop body at
|
|
a `break`/`continue` gets its DROP recorded right here, at the jump,
|
|
not left to leak. `ctx.diverged <- true` afterward mirrors
|
|
analyze_return's own reasoning exactly: the rest of *this* block is
|
|
unreachable, and the surrounding if/fixpoint machinery already knows
|
|
how to fold that into a branch join or a loop's own entry/exit meet
|
|
(the same normalization a `return` inside a loop or an `if` already
|
|
gets, unchanged by this task). Outside any loop, `loop_stack` is
|
|
empty and nothing is recorded — see that field's own doc comment for
|
|
why emit.ml, not this pass, is the actual gate for that case. *)
|
|
and analyze_break (ctx : ctx) (s : Ast.stmt) : unit =
|
|
(match ctx.loop_stack with
|
|
| [] -> ()
|
|
| loop_node :: _ ->
|
|
let live = live_holders_upto ctx loop_node in
|
|
record_drop ctx ~node:s.s_id ~pos:s.s_pos ~kind:DBreak ~items:(owned_items live));
|
|
ctx.diverged <- true
|
|
|
|
and analyze_continue (ctx : ctx) (s : Ast.stmt) : unit =
|
|
(match ctx.loop_stack with
|
|
| [] -> ()
|
|
| loop_node :: _ ->
|
|
let live = live_holders_upto ctx loop_node in
|
|
record_drop ctx ~node:s.s_id ~pos:s.s_pos ~kind:DContinue ~items:(owned_items live));
|
|
ctx.diverged <- true
|
|
|
|
(* ============================================================
|
|
Per-function driver
|
|
============================================================ *)
|
|
|
|
let param_local (ctx : ctx) (p : Ast.param) : local =
|
|
let cls = oclass_of ctx p.ty in
|
|
match cls with
|
|
| Copy -> { l_name = p.name; l_ty = p.ty; l_class = Copy; l_node = p.id; l_pos = p.pos;
|
|
l_holds = false; l_src = None; l_bkind = AShared; l_state = Live }
|
|
| Owned | Gc -> (
|
|
match p.conv with
|
|
| Take ->
|
|
{ l_name = p.name; l_ty = p.ty; l_class = cls; l_node = p.id; l_pos = p.pos; l_holds = true;
|
|
l_src = None; l_bkind = AShared; l_state = Live }
|
|
| Borrow | Mut ->
|
|
(* @gc parameters are aliases, not borrows: no borrow rules apply,
|
|
and the caller's reference keeps the object alive for the call *)
|
|
let state = if cls = Gc then Live else Borrowed p.pos in
|
|
{ l_name = p.name; l_ty = p.ty; l_class = cls; l_node = p.id; l_pos = p.pos; l_holds = false;
|
|
l_src = None; l_bkind = (if p.conv = Mut then AExcl else AShared); l_state = state })
|
|
|
|
let analyze_fn ~(file : string) ?(promote : (string -> unit) option = None)
|
|
(syms : Types.symbols) (coll : Diag.Collector.t) (sink : sink)
|
|
~(self_class : string option) (m : Ast.method_decl) : unit =
|
|
let ctx =
|
|
{ file; syms; coll; sink; fn_name = m.name; scopes = []; loop_stack = []; recording = true;
|
|
diverged = false; promote }
|
|
in
|
|
push_scope ctx ~node:m.id ~pos:m.pos ~label:"BODY";
|
|
(* `self` is always a borrow (spec rule 6) *)
|
|
(match self_class with
|
|
| None -> ()
|
|
| Some cn ->
|
|
let ty = Scalar cn in
|
|
let cls = oclass_of ctx ty in
|
|
declare ctx
|
|
{ l_name = "self"; l_ty = ty; l_class = cls; l_node = m.id; l_pos = m.pos; l_holds = false;
|
|
l_src = None; l_bkind = (if body_writes_self m.body then AExcl else AShared);
|
|
l_state = (if cls = Gc then Live else Borrowed m.pos) });
|
|
List.iter (fun p -> declare ctx (param_local ctx p)) m.params;
|
|
List.iter (analyze_stmt ctx) m.body;
|
|
pop_scope ctx
|
|
|
|
(* ============================================================
|
|
Entry point
|
|
============================================================ *)
|
|
|
|
let pos_key (p : Ast.pos) = (p.line, p.col)
|
|
|
|
let analyze ~(file : string) ?(promote : (string -> unit) option = None)
|
|
(prog : Ast.program) (syms : Types.symbols) (coll : Diag.Collector.t) : tables =
|
|
let sink = { s_moves = []; s_drops = []; s_res = [] } in
|
|
List.iter
|
|
(function
|
|
| Ast.Class c ->
|
|
List.iter
|
|
(fun m -> analyze_fn ~file ~promote syms coll sink ~self_class:(Some c.name) m)
|
|
c.methods
|
|
| Ast.Interface _ -> ()
|
|
| Ast.Fn f -> analyze_fn ~file ~promote syms coll sink ~self_class:None f
|
|
| Ast.Use _ -> ()
|
|
| Ast.Const _ -> ()
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| Ast.Union _ -> () (* haxe-parity Task 4: no bodies to analyze *))
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prog.decls;
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(* Source order: sort by position, stably, so entries sharing a
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position keep the order the walk produced. Node ids can *not* be
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used for ordering (ast.ml: expression ids are unique but not
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parent-before-child). *)
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let sort_by key l = List.stable_sort (fun a b -> compare (key a) (key b)) (List.rev l) in
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{ moves = sort_by (fun m -> pos_key m.mv_pos) sink.s_moves;
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drops = sort_by (fun d -> pos_key d.dr_pos) sink.s_drops;
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residuals = sort_by (fun r -> pos_key r.rs_pos) sink.s_res }
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