An AOT-compiled app only needs the analyzer/back end at runtime to compile from
source — eval / load-string / load-file. Macros are expanded at build time and a
require of a baked namespace no-ops, so a closed app that never compiles at runtime
carries the compiler image (~0.8MB) as dead weight.
Under --tree-shake, when reachability is trustworthy (no bail) and no reachable code
references eval/load-string/load-file/load-reader/load, omit host/chez/seed/image.ss
+ compile-eval.ss from the runtime manifest. bld-tree-shake returns the flag
alongside the shaken forms; bld-emit-runtime filters the manifest.
Measured: build-app 9.84MB -> 9.05MB, still runs. Safety verified: an app that evals
keeps the compiler (eval is a bail + compile ref) and eval works at runtime.
build-smoke asserts the compiler is gone in the no-eval app; full make test green.
`jolt build --tree-shake` (or deps.edn :jolt/build {:tree-shake true}) does
reachability DCE over the re-emitted app + library namespaces: keep -main, every
side-effecting (non-def) top-level form, and every def reachable from those; drop
the rest. A macro (expanded at AOT, never called at runtime) is prunable too.
Sound: bails (keeps everything) if REACHABLE code resolves vars by name at runtime
(eval/resolve/ns-resolve/requiring-resolve/find-var/intern/load-string/...), which a
static call graph can't follow. Unreached eval-using library code is simply shaken
away and never triggers the bail. clojure.core and the compiler image stay baked
(prelude + image blobs), so only re-emitted namespaces are shaken for now.
The reachability machinery is in emit-image.ss (records: keep?/fqn/refs/str via
reduce-ir-children) + build.ss (BFS + bail check). build-smoke covers it (drops the
unreachable `twice` macro, output unchanged). Opt-in; default builds are untouched.
full make test green.
Scope note: this shakes the re-emitted app/lib code only. Measurement shows jolt's
compiled code is ~5.8MB of a ~9.8MB binary, dominated by the clojure.core prelude
(~1.5-2MB) and the compiler image (~0.8MB) — both baked blobs this pass doesn't
touch. Those (shake-core, drop-compiler-when-no-eval) are the larger footprint wins,
filed as follow-ups.
Release builds can legitimately want runtime dynamism (redefinition, eval,
load-string), so closed-world direct-linking shouldn't be forced on them. Gate it
behind an explicit --direct-link flag (or deps.edn :jolt/build {:direct-link
true}); off by default in every mode, including release and --opt.
build-binary takes an explicit direct-link? arg instead of deriving it from the
mode. build-smoke now covers the --direct-link path and asserts the cross-ns call
actually lowers to a jv$ binding; default release stays dynamically linked.
A built binary dropped its deps.edn :jolt/native declarations and its
resource roots, so an FFI+resources app (ring-app) failed at runtime:
sockets/sqlite gave 'no entry for socket' and io/resource returned nil.
The buildsmoke fixture is pure compute, so neither path was exercised.
The launcher now loads required + :process native libs before the app's
top-level forms (a library's defcfn resolves its foreign-procedure symbols
at top-level eval during startup, so the libs must be loaded first);
optional libs load in the scheme-start launcher, where a missing lib is
caught rather than aborting the heap build.
deps.edn :jolt/build {:embed [dirs]} bakes those dirs' files into the heap
(register-embedded-resource! at heap build), so io/resource serves them with
no files on disk. Non-embedded resources resolve at runtime against JOLT_PWD,
and io/file reads (e.g. config.edn) stay external.
build-binary now takes the encoded natives, embed dirs, and project paths
from cmd-build; deps/resolve-project surfaces them. Buildsmoke fixture grows
an embedded resource + a :process native to cover both paths.
The standalone-binary build needs Chez's kernel dev files (libkernel.a,
scheme.h) and a C compiler. A distro chezscheme package ships neither, so the
gate failed on CI (apt installs petite+scheme only). Preflight for the csv dir
and cc and skip cleanly when they're missing — same pattern as certify skipping
without Clojure. Where the toolchain exists (dev machines), it runs as before;
the discovered csv dir is pinned via JOLT_CHEZ_CSV so the build uses exactly it.
Wire the optimization gate to build mode. inline-enabled? (which gates the
inference + flatten-lets + scalar-replace passes in jolt.passes/run-passes) was
hardwired off, so those passes had never run on Chez at all. host-contract now
exposes a settable hc-optimize? flag; `jolt build --opt` flips it on during app
emission.
Kept off for the default release build for now: the passes are sound by design
(RFC 0005/0006) but unexercised on Chez, so release stays on the proven
var-deref codegen until they're validated against the corpus. --opt is the
opt-in fast path. buildsmoke checks both modes produce the same result.
This does not yet deliver direct call binding — the backend has no direct-link
emission path (every :var call still routes through jolt-invoke/var-deref) and
the inline-ir host stash is still a stub. Those are the remaining stage-4 levers.
Restores the standalone-binary capability the Janet host had. `bin/joltc build
-m NS -o OUT` AOT-compiles an app into a single self-contained executable — the
whole runtime, clojure.core, stdlib and compiler embedded, no Chez install or
jolt source needed at runtime.
Pipeline (host/chez/build.ss, host primitive jolt.host/build-binary driven by
jolt.main's build command): resolve deps, load the entry namespace recording the
app namespaces in dependency order, re-emit each to Scheme, textually inline the
cli.ss runtime load sequence into one flat source + the app + a launcher, then
compile-file -> make-boot-file -> embed the boot as C bytes -> cc-link against
libkernel.a.
Two non-obvious bits: the compile pass runs in a fresh Chez, not the loaded
runtime (regex.ss shadows top-level `error`, which otherwise bakes a broken
reference into the boot); and the launcher installs scheme-start rather than
running -main at top level, since boot top-level forms execute during heap build
before argv is set, so args only reach -main through scheme-start.
Loader: a require of an in-memory namespace with no source file now no-ops, so
AOT'd app namespaces satisfy require in a built binary.
Mode flags (--opt/--dev, default release) are plumbed; the optimization passes
they gate come in a later stage. RFC 0007 has the design. Gated by `make
buildsmoke`.
