simon/jolt
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Tree-shake the clojure.core prelude too (whole-program DCE)

Browse source 
--tree-shake now shakes the clojure.core/stdlib prelude in the same reachability
graph as the app + libraries — only core fns actually reached from -main ship.

dce-blob-records reads prelude.ss with Chez `read`, unwraps each
(guard ... (def-var! "ns" "name" V)) and builds the core->core call graph from the
(var-deref/jolt-var "ns" "name") refs in V — the real emitted edges, no
re-analysis. bld-shake-all merges core + app records into one BFS; roots are -main,
side-effecting forms, and the clojure.core fns the runtime .ss shims reference by
name (enumerated in dce-runtime-core-roots). The shaken core is spliced where the
prelude.ss blob was, in original (tier) order, so load-time deps are preserved.
Bail (reachable runtime resolve) keeps the prelude whole.

Soundness follows Stalin's rule (any reference, value or call, keeps a def live):
dce-collect-refs counts :var and :the-var; non-def registration forms are always
kept (covers protocol/multimethod dispatch). Validated by make shakesmoke: the four
deps.edn git-lib apps build byte-identical output shaken vs not.

Wins (binary): build-app 9.84MB -> 8.12MB (dropped 403/457 core defs); malli-app
10.0MB -> 8.1MB; markdown 9.9 -> 8.3; commonmark 9.8 -> 8.1 — all output-identical.
build-smoke asserts an unused core fn (group-by) is dropped; full make test green.
This commit is contained in:
Yogthos 2026-06-23 20:42:23 -04:00
parent f7fd73c448
commit 298ac66fb1
3 changed files with 96 additions and 38 deletions
Download patch file Download diff file Expand all files Collapse all files

84
host/chez/build.ss
View file

@ -140,11 +140,16 @@
;; Inline the runtime manifest. When drop-compiler? (a closed AOT app that never
;; compiles from source at runtime), omit the compiler image + compile-eval shim —
;; the analyzer/back end are dead weight in the binary (~0.8MB).
(define (bld-emit-runtime out drop-compiler?)
(define (bld-emit-runtime out drop-compiler? core-strs)
(for-each (lambda (l)
(unless (and drop-compiler?
(or (bld-contains? l "seed/image.ss") (bld-contains? l "compile-eval.ss")))
(bld-inline-line l out 0)))
(cond
;; core-shake: emit the shaken clojure.core defs in place of the blob.
((and core-strs (bld-contains? l "seed/prelude.ss"))
(for-each (lambda (s) (put-string out s) (put-string out "\n")) core-strs))
((and drop-compiler?
(or (bld-contains? l "seed/image.ss") (bld-contains? l "compile-eval.ss")))
#f)
(else (bld-inline-line l out 0))))
bld-runtime-manifest))
;; --- app emission -----------------------------------------------------------
@ -153,21 +158,24 @@
;; The loop itself is emit-image's ei-emit-ns* (optimize? #t, guard? #f).
(define (bld-emit-ns ns-name src) (ei-emit-ns* ns-name src #t #f))
;; Tree-shake the re-emitted forms: keep every non-def form (side effects) + every
;; def reachable from -main and from those forms; drop the rest. Bails to keep-all
;; if any form resolves vars by name at runtime. `records` is the ei-emit-ns-records
;; output across all app namespaces; returns the kept Scheme strings in order.
(define (bld-tree-shake records entry-main)
(let ((edges (make-hashtable string-hash string=?))
(roots '()))
;; Tree-shake the whole closed program — the clojure.core prelude (read into records
;; by dce-blob-records) AND the re-emitted app + library namespaces — over one
;; reachability graph: keep every non-def form (side effects), -main, the core fns the
;; runtime shims need, and every def reachable from those; drop the rest. Bails to
;; keep-all if reachable code resolves vars by name at runtime (closed-world
;; violation). Returns (values core-strs app-strs drop-compiler?); core-strs is #f on
;; a bail, signalling "inline prelude.ss unshaken".
(define (bld-shake-all core-records app-records entry-main)
(let ((all (append core-records app-records))
(edges (make-hashtable string-hash string=?))
(roots (cons entry-main dce-runtime-core-roots)))
(for-each (lambda (r)
(if (vector-ref r 0)
(set! roots (append (vector-ref r 2) roots))
(hashtable-set! edges (vector-ref r 1) (vector-ref r 2))))
records)
;; reachability from -main + every side-effecting form's refs.
all)
(let ((reached (make-hashtable string-hash string=?)))
(let bfs ((work (cons entry-main roots)))
(let bfs ((work roots))
(unless (null? work)
(let ((fq (car work)))
(if (hashtable-ref reached fq #f)
@ -177,31 +185,31 @@
(let ((kept? (lambda (r) (or (vector-ref r 0) (hashtable-ref reached (vector-ref r 1) #f))))
(refs-any (lambda (r set) (ormap (lambda (b) (and (member b (vector-ref r 2)) #t)) set)))
(bail #f) (needs-compiler #f))
;; bail only if REACHABLE code resolves vars by name — then the static call
;; graph is incomplete and dropping anything is unsound. Unreached eval-using
;; library code is simply shaken away and never triggers the bail. Track
;; whether any reachable code needs the compiler at runtime (eval/load).
(for-each (lambda (r)
(when (kept? r)
(when (refs-any r dce-bail-refs) (set! bail #t))
(when (refs-any r dce-compile-refs) (set! needs-compiler #t))))
records)
;; the compiler image can be dropped only when reachability is trustworthy
;; (no bail) and no reachable code compiles from source at runtime.
(let ((drop-compiler? (and (not bail) (not needs-compiler))))
all)
(let ((drop-compiler? (and (not bail) (not needs-compiler)))
;; -> (values strs n-defs n-kept)
(pick (lambda (recs)
(let loop ((rs recs) (acc '()) (n 0) (k 0))
(if (null? rs)
(values (reverse acc) n k)
(let* ((r (car rs)) (isdef (and (vector-ref r 1) #t)))
(if (kept? r)
(loop (cdr rs) (cons (vector-ref r 3) acc)
(if isdef (+ n 1) n) (if isdef (+ k 1) k))
(loop (cdr rs) acc (if isdef (+ n 1) n) k))))))))
(if bail
(begin (display "jolt build: tree-shake skipped (reachable code resolves vars at runtime)\n")
(values (map (lambda (r) (vector-ref r 3)) records) drop-compiler?))
(let ((kept '()) (ndef 0) (nkeep 0))
(for-each (lambda (r)
(when (vector-ref r 1) (set! ndef (+ ndef 1)))
(when (kept? r)
(when (vector-ref r 1) (set! nkeep (+ nkeep 1)))
(set! kept (cons (vector-ref r 3) kept))))
records)
(display (string-append "jolt build: tree-shake kept " (number->string nkeep)
" of " (number->string ndef) " defs\n"))
(values (reverse kept) drop-compiler?))))))))
(values #f (map (lambda (r) (vector-ref r 3)) app-records) drop-compiler?))
(let-values (((core-strs cn ck) (pick core-records))
((app-strs an ak) (pick app-records)))
(display (string-append "jolt build: tree-shake kept " (number->string (+ ck ak))
" of " (number->string (+ cn an)) " defs (core "
(number->string ck) "/" (number->string cn) ")\n"))
(values core-strs app-strs drop-compiler?))))))))
;; --- bundling: native libs + resources --------------------------------------
;; A jolt seq of jolt strings -> a Scheme list of Scheme strings.
@ -295,13 +303,15 @@
((var-deref "jolt.backend-scheme" "set-direct-link!") #t)
((var-deref "jolt.backend-scheme" "direct-link-reset!")))
(let*-values
(((app-strs drop-compiler?)
(((core-strs app-strs drop-compiler?)
(if tree-shake?
(bld-tree-shake
(bld-shake-all
(dce-blob-records "host/chez/seed/prelude.ss")
(apply append
(map (lambda (nf) (ei-emit-ns-records (car nf) (read-file-string (cdr nf)))) ordered))
(string-append entry-ns "/-main"))
(values (apply append
(values #f
(apply append
(map (lambda (nf) (bld-emit-ns (car nf) (read-file-string (cdr nf)))) ordered))
#f))))
(set-optimize! #f)
@ -316,7 +326,7 @@
(bld-system (string-append "mkdir -p '" builddir "'"))
;; 3. flat source = runtime + app + launcher.
(let ((out (open-output-file flat-ss 'replace)))
(bld-emit-runtime out drop-compiler?)
(bld-emit-runtime out drop-compiler? core-strs)
;; Load native libs, bake embedded resources, and point source roots at
;; the build-time app roots — all BEFORE the app forms. The app's
;; top-level forms run at binary startup (Sbuild_heap), and they include