Six bottom-up IR rewrites (const-fold, inline-node, subst, flatten-lets,
subst-lookup, scalar-replace) each hand-listed every op's child positions —
~250 lines of identical "recurse children, rebuild" arms that had to be kept in
sync whenever an op was added. Extract one map-ir-children into ir.clj that
knows each op's child layout; each walk keeps only its genuine specials
(const-fold's invoke/if, inline-node's invoke, subst's local/let alpha-rename,
scalar-replace's invoke/let folds) and delegates the rest.
The combinator is total over the op set, so the walks are now total too: a
couple soundly gain coverage they previously skipped (const-fold now folds
inside :try; subst-lookup now recurses :def inits, which fixes a latent dangling
ref where a dropped const-key-map binding was referenced inside a def). These
are sound — all six are result-preserving optimizations — and 3-mode conformance
+ fixpoint confirm identical program behavior.
map-ir-children is shape-preserving for :try (recurses :catch-body/:finally only
when present, never assoc's nil) so it can't turn a struct node into a phm.
Written with cond/get only, matching the passes' tier, so no new load-order dep.
Predicates (body-closed?/pure?/local-escapes?), the type-threading infer, and the
Janet backend emit stay as-is: their conservative :else defaults / [type node]
threading / host language don't fit a node-rebuilding combinator.
Adds ir-passes-test coverage for folding reaching fn/loop/try bodies. Full gate
green (conformance x3, suite >=4695/88, fixpoint stage1==2==3, inline-sra + devirt).
passes.clj was a 1486-line grab-bag mixing three weakly-coupled concerns. Split
along the clusters the review mapped (only run-passes + the dirty flag were
shared):
jolt.passes.fold const-fold + the shared scalar-const? predicate (base)
jolt.passes.inline inline + flatten-lets + scalar-replace
jolt.passes.types collection-type inference + success checker + driver API
jolt.passes façade: run-passes + :refer re-exports of the driver fns
the back end looks up by name
scalar-const? was used by both the inline pass and the inference walk, so it
moves to fold (the base layer) and both refer it. The check-mode state stays
private to jolt.passes.types behind a new run-inference fn; run-passes calls it.
build-compiler! loads the three in dependency order before the façade, mirroring
the existing jolt.ir -> jolt.analyzer bootstrap. No behavior change. Also fixed
the stale ns docstring that listed four passes and omitted the type system.
Gate green: conformance 355x3, clojure-test-suite 4718 pass (>= 4695 baseline),
full jpm test exit 0.
