`loadTransitiveHooks` loads a module only to register its hooks, macro-cache
replay and generic-instance offers. It is a dep-of-a-dep, not an import, so
none of its symbols are visible to the module being semchecked — yet it went
through the full `loadNifModule`, which builds the interface string tables by
calling `loadSymFromIndexEntry` on every index entry, and `processTopLevel`,
whose `export` branch calls `resolveSym` on every exported symbol. Both write
into an `interf`/`interfHidden` pair that is scratch, shared across all
iterations, and never read. Their only other effect is warming the name-keyed
`c.syms` cache, which `resolveSym` refills lazily from the same index on a miss.
New `LoadFlag.SkipInterfaceTables`, set only by `loadTransitiveHooks`, gates
both. Measured on a 219-module program: a one-line edit rebuild goes 5.58s ->
3.21s (-42%), and the compiler's own cold IC build 202s -> 164s (-19%), since
every `nim m` in a cold build pays this too. Profile of the `nim m` before:
direct imports 17 modules/1.40s, transitive hooks 209 modules/2.99s,
re-exports 39/0.23s.
This is NOT byte-inert, unlike the previous commit: skipping the eager stub
creation shifts the per-module load-order counter, so lazily-created stubs get
different serialized item ids and 44 of 238 `.s.bif` change. The artifacts stay
deterministic (238/238 reproducible across two independent cold builds) and
16/16 metamorphic tests pass, including `clean cache == incremental cache` and
`a no-op edit changes no artifact` — so an existing nimcache re-sems those
modules once and then converges. Also green: the 17-file `koch ic` suite, 13/13
differential edit checks against `nim c`, both `bootic` fixed points (debug and
release), and 482 tests across tests/arc, destructor, closure, iter, gc, async
with a failure set identical to the parent commit's.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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