Bare-index field reads for statically-known records (#228)

When the inference types a keyword-lookup receiver as a record — it carries the
field-order :shape and :hint :struct from the whole-program fixpoint — the back
end reads the field by its declared slot via jrec-field-at instead of jolt-get.
That skips the jolt-get case-lambda, the dispatch fn, and the field-key
hashtable lookup, leaving a jrec? check + a static-index vector-ref.

jrec-field-at falls back to jolt-get when the receiver isn't the expected record
(a map downgraded by dissoc, or a value the inference mistyped), so it stays
correct if the static type is wrong. Only the no-default form takes the bare
path (a declared field is always present).

Sound only for non-nil records: a self-recursive param that can be nil (e.g.
binary-trees check-tree, whose untagged child is nil at leaves) types :any and
keeps jolt-get — the whole-program fixpoint demotes it. The target is non-nil
record params, like a Vec3 dot product (~5% there; boxed-flonum arithmetic
dominates the rest, a separate numeric lever).

run-fieldread.ss gate: emitted form uses jrec-field-at at the right slot and
matches jolt-get for each declared field; a non-field key and a default-arg form
keep the generic path. make test / shakesmoke green, 0 new divergences.

Co-authored-by: Yogthos <yogthos@gmail.com>
This commit is contained in:
Dmitri Sotnikov 2026-06-26 11:29:14 +00:00 committed by GitHub
parent af11aaa7ff
commit de31221573
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5 changed files with 188 additions and 80 deletions

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@ -4,7 +4,7 @@
# build step. `make test` is the full gate. `make remint` rebuilds the seed after a
# source change.
.PHONY: test ci values corpus unit smoke buildsmoke selfhost sci certify ffi transient infer wp devirt directlink numeric inline shakesmoke remint
.PHONY: test ci values corpus unit smoke buildsmoke selfhost sci certify ffi transient infer wp devirt fieldread directlink numeric inline shakesmoke remint
# Full gate (dev machine). Includes the self-host byte-fixpoint, which only holds
# on the same Chez that minted the seed.
@ -15,7 +15,7 @@ test: selfhost ci
# lockfile) — it RUNS correctly on any Chez, but `selfhost` rebuilds it and a
# different Chez version may emit byte-different (gensym/order) output, so the
# byte-fixpoint is a dev-machine check, not a CI one (jolt-8479).
ci: values corpus unit smoke buildsmoke sci ffi transient infer wp devirt directlink numeric inline certify
ci: values corpus unit smoke buildsmoke sci ffi transient infer wp devirt fieldread directlink numeric inline certify
@echo "OK: CI gates passed"
# Self-host fixpoint: bootstrap.ss rebuild == checked-in seed.
@ -73,6 +73,12 @@ wp:
devirt:
@chez --script host/chez/run-devirt.ss
# Native record field reads: a keyword lookup on a statically-known record reads
# the field by its declared slot (jrec-field-at) instead of jolt-get; the value
# must match, and a non-field key / default-arg form keeps the generic path.
fieldread:
@chez --script host/chez/run-fieldread.ss
# Direct-linking emission: a closed-world build binds top-level app defs to jv$
# Scheme bindings and routes app->app calls/refs to them, skipping var-deref +
# jolt-invoke; ^:dynamic/^:redef and nested defs opt out.