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jolt/host/chez/seed
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Dmitri Sotnikov a31c1af8c4
Devirt: cache the resolved impl in a per-site cell (inline cache) (#237) 
A devirtualized protocol call resolved its impl with devirt-resolve on EVERY call
— but the tag/proto/method are compile-time constants, so the resolved fn is a
runtime constant (closed world). That per-call find-protocol-method (three
hashtable lookups) was the cost: on mono-dispatch, dispatch was ~75% of the time
(ablation: same arithmetic direct-call 166ms vs dispatch 673ms).

Resolve once. When emitting a direct-link def, each devirt site gets a fresh cache
cell, bound to #f in a let wrapping the def (so it persists across calls and is
shared by every invocation); the site resolves into it on first use ((or cell
(let ((_f (devirt-resolve ..))) (set! cell _f) _f))) and reuses it after — the
inline cache the JVM gets for free. First call still passes the real receiver, so
the Object/host-tag fallback (devirt-resolve) is unchanged.

mono-dispatch 673ms -> 214ms (~3.15x), 47.5x -> ~15x JVM, near the 166ms
direct-call floor. run-devirt.ss gains the cached-path checks (cell present, 1st
call caches + 2nd reuses, both == dispatch). make test / shakesmoke green, selfhost
holds, 0 new divergences.

Co-authored-by: Yogthos <yogthos@gmail.com>
2026-06-26 18:34:13 +00:00
..
image.ss Devirt: cache the resolved impl in a per-site cell (inline cache) (#237) 2026-06-26 18:34:13 +00:00
prelude.ss See through or/and in truthy-elision (#224) 2026-06-26 06:11:35 +00:00
README.md Docs: Chez-only, drop the Janet-era references and obsolete migration notes 2026-06-22 09:05:35 -04:00

README.md

Chez bootstrap seed

These two files are the bootstrap compiler for jolt — the seed that makes the build self-hosting:

  • prelude.ss — the clojure.core prelude (all tiers + clojure.string/walk/ template/edn/set/pprint) as Scheme def-var! forms.
  • image.ss — the compiler image (jolt.ir + jolt.analyzer + jolt.backend-scheme) as Scheme def-var! forms.

Both are generated, not hand-written. They are checked in because a fresh checkout must be able to build jolt-on-Chez using only Chez: host/chez/bootstrap.ss loads this seed, then rebuilds the prelude + image from the .clj/.ss sources via the on-Chez compiler (read → analyze → emit, all on Chez). The seed is a joint byte-fixpoint: rebuilding from an up-to-date seed reproduces it exactly. make selfhost (host/chez/selfcheck.sh) runs host/chez/bootstrap.ss and diffs the rebuilt artifacts against the checked-in seed.

Re-minting

When the seed sources change (the core tiers, the compiler namespaces, the host contract, the reader, emit-image.ss), the seed drifts and make selfhost fails. Re-mint it by running host/chez/bootstrap.ss and writing the freshly rebuilt prelude/image back to host/chez/seed/prelude.ss / host/chez/seed/image.ss, then commit the refreshed files.