jolt/test/integration/phint-propagation-test.janet
Dmitri Sotnikov bd9e542c78
Propagate declared record hints through the whole-program fixpoint (jolt-3ko) (#134)
A ^Record param hint was applied only at the final re-emit (reinfer-def), not
during the inter-procedural fixpoint. So a hinted param with no callers stayed
:any while inference ran, and a field read off it (e.g. (:origin ^Ray r)) never
told a non-inlined callee that its arg is a Vec3 — the callee's params stayed
unproven and its field reads kept the dynamic guard.

Seed declared hints as a param-type floor in the fixpoint: phint-seed (passes/
types) resolves an arity's :phints to positional record types via the
record-shapes registry, and infer-unit! initializes each fn's fresh param slots
from them instead of nil. A fixed declared type can't poison the least-fixpoint
the way an early-iteration :any would, and a hinted param now propagates its
(and its field reads') types to its callees during inference.

Scope: this closes the hinted-propagation gap. It does NOT help the ray tracer,
which uses zero ^-hinted params (only hinted fields) — its remaining type gap is
unhinted record-param inference on recursive/non-inlined hot fns, and per the
jolt-15jq A/B it's allocation-bound regardless (jolt-8flj). Tracked on the bead.

Co-authored-by: Yogthos <yogthos@gmail.com>
2026-06-16 03:38:03 +00:00

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# Declared record param hints propagate THROUGH the whole-program fixpoint
# (jolt-3ko). A ^Record param's field reads type to the field's record type, and
# when such a field-read value is passed to a SHARED helper (no hints, inferred
# from call sites), the helper's params must pick up that record type so its own
# field reads bare-index. Before the fix, ^-hints were applied only at the final
# re-emit (reinfer-def), not during the fixpoint, so a hinted param with no
# callers stayed :any during inference and never propagated to its callees —
# exactly why the ray tracer's vec ops (called with (:origin ray) etc.) stayed
# unproven even under whole-program optimization.
(import ../../src/jolt/api :as api)
(import ../../src/jolt/backend :as backend)
(import ../../src/jolt/types :as types)
(print "phint propagation through the fixpoint (jolt-3ko)...")
(def dir (string (or (os/getenv "TMPDIR") "/tmp") "/jolt-phint-prop"))
(os/mkdir dir)
(spit (string dir "/pp.clj")
(string
"(ns pp)\n"
"(defrecord Vec3 [r g b])\n"
"(defrecord Ray [^Vec3 origin ^Vec3 direction])\n"
# shared ops, NO hints — must be inferred from the call sites below. A
# `loop` makes them inline-INELIGIBLE so they stay real calls (a small fn
# would be spliced into the caller, where the caller's hint already proves
# it); the point here is propagation to a separate callee's PARAMS.
"(defn dot [a b]\n"
" (loop [i 0 s 0.0]\n"
" (if (< i 1) (recur (inc i) (+ (+ (* (:r a) (:r b)) (* (:g a) (:g b))) (* (:b a) (:b b)))) s)))\n"
"(defn add [a b]\n"
" (loop [i 0 s nil]\n"
" (if (< i 1) (recur (inc i) (->Vec3 (+ (:r a) (:r b)) (+ (:g a) (:g b)) (+ (:b a) (:b b)))) s)))\n"
# callers pass field-read Vec3s from a ^Ray param into the shared ops
"(defn use-dot [^Ray r] (dot (:origin r) (:direction r)))\n"
"(defn use-add [^Ray r] (add (:origin r) (:direction r)))\n"))
(os/setenv "JOLT_DIRECT_LINK" "1")
(os/setenv "JOLT_WHOLE_PROGRAM" "1")
(os/setenv "JOLT_PATH" dir)
(def ctx (api/init {:compile? true}))
(api/eval-string ctx "(require '[pp])")
(def report (backend/infer-program! ctx))
(def pns (types/ctx-find-ns ctx "jolt.passes"))
(def reinfer (types/var-get (types/ns-find pns "reinfer-def")))
(def ppns (types/ctx-find-ns ctx "pp"))
(defn ptmap-for [fname params]
(def pts (get report (string "pp/" fname)))
(def m @{}) (when pts (var i 0) (each p params (put m p (get pts i)) (++ i))) m)
(defn guards [fname params]
(def cell (get (ppns :mappings) fname))
(length (string/find-all ":jolt/type"
(string/format "%p" (backend/emit-ir ctx (reinfer (get cell :infer-ir) (ptmap-for fname params)))))))
(var fails 0)
(defn check [label got expected]
(if (= got expected) (print " ok " label)
(do (++ fails) (printf " FAIL %s: want %p got %p" label expected got))))
# the shared ops' params get the Vec3 record type from the field-read call args,
# so all their field reads bare-index (no :jolt/type guard)
(check "dot params typed Vec3 -> reads bare" (guards "dot" ["a" "b"]) 0)
(check "add params typed Vec3 -> reads bare" (guards "add" ["a" "b"]) 0)
# the hinted callers were already fine (re-emit applies the phint)
(check "use-dot hinted reads bare" (guards "use-dot" ["r"]) 0)
# the report shows the shared ops' params as a Vec3 struct (has :shape / :type)
(def dot-a (get (get report "pp/dot") 0))
(check "dot param a is a struct type" (truthy? (and dot-a (or (get dot-a :shape) (get dot-a :struct)))) true)
# correctness: results are unchanged
(check "dot computes" (api/eval-string ctx "(pp/dot (pp/->Vec3 1 2 3) (pp/->Vec3 4 5 6))") 32)
(check "use-dot computes"
(api/eval-string ctx "(pp/use-dot (pp/->Ray (pp/->Vec3 1 2 3) (pp/->Vec3 4 5 6)))") 32)
(if (> fails 0) (do (printf "phint-propagation: %d FAILED" fails) (os/exit 1))
(print "phint propagation (jolt-3ko) passed!"))