TODO

Cleanup / symmetry items noticed during the Round-6 perf work. None are blocking; recorded so they aren't lost. (Forward-looking perf levers — copy-and-patch codegen, 16B Tok, the writev object-output micro-lever — live in doc/plan/PERF.md, not here.)

Container facility symmetry

• KIT_HASHSET_DEFINE lacks _reserve. Round-6 added NAME##_reserve(m, n) to KIT_HASHMAP_DEFINE (include/kit/support/hashmap.h) so a bulk insert with a known count skips the resize cascade. The hashset variant in the same file was not given the matching primitive. Mirror it (same body: grow cap to hold n at the load factor, power-of-two) if/when a set needs it — don't ship it unused.

• SegVec has no _reserve. The object readers now pre-size the SymNameIndex hashmap (obj_reserve_symbols), but the parallel Symbols (src/obj) / LinkSyms (src/link) segvecs still grow one 64-entry segment at a time — ~16k small allocations for a 1M-symbol object. A SEGVEC reserve (pre-allocate ⌈n/seg⌉ segments) would cut that alloc churn on large ingests. Touch points: src/core/segvec.h, the readers in src/obj/*/read.c, and link_resolve_symbols.

Linker symbol-map pre-sizing (partial)

• Only img->globals got symhash_reserve (link_resolve.c). The other symhash_init-without-capacity maps — alias_map (link_resolve.c:~401), defined/undefs (link_resolve.c:~1139), globals_by_name (link_relocatable.c:~451) — could pre-size from a known count for consistency. Lower value (the measured resize churn was img->globals + the reader SymNameIndex); do it if a profile shows them.

Object-emitter de-duplication (macho / elf / coff)

• The three src/obj/*/emit.c carry near-identical code: the strtab_add linear-dedup (flatten-to-search), the final strtab flatten+write, and the section-bytes write loop. A small shared src/obj helper would de-triplicate them. NB: streaming each section's Buf chunks instead of flatten-to-one write() was tried and is slower (more syscalls) — keep the single big write; only the dedup is wanted here.