The wcc test drivers ran `ww build <bare-/tmp src>` with no -o, so the
compiler's <stem>.sepwork scratch landed beside the source and was never
cleaned: unbounded /tmp growth (2195 stale dirs observed) that fills tmpfs
and fabricates phantom test failures + silent harness aborts, and for
in-repo fixture builds leaked .sepwork into the tracked tree.
Each leaking build now writes its source + output inside a per-invocation
tmpdir, passes -o <tmpdir>/<stem> so the .sepwork lands inside it, and
rm -rf's the tmpdir on every exit path -- including fopen-fail and the
expected-fail reject builds (scratch is mkdir'd before the build can fail).
`ww run` and explicit-`-o`/byte-id helpers are left as-is; the 990/993
byte-id comparison logic is byte-for-byte unchanged.
Two items filed separately (this commit holds the no-Makefile / no-main.c
rail):
- #13: a stale <src>.s byte-id readback (749) silently no-ops since
separate-compile emits .s to <ostem>.sepwork/__root.s; documented inline.
- #14: build-system Makefile recipes build selfhost/cmd/*/main.ww with no
-o and leak main.sepwork in-tree (bounded, gitignored; own commit).
One concern -- sepwork leak hygiene -- across 228 drivers; uniform
transform applied per-file and two-round reviewed. make test: all 402
passed, zero net-new /tmp scratch, zero test-driven in-repo .sepwork.
The original #37 symptom (worker-34's `..findflag` mangle) cannot
reproduce on master — was a runtime miscompile misattributed to a
link-time issue. Investigation surfaced three real wwstage cgen
gaps in the N_INDEX-through-struct-field family, sister bugs to
#34 (N_INDEX N_IDENT-base) and #36 (primsize-default-to-8).
1. `indexbaseesz` slice-element stride defaulted to 8 for named-
struct elements. `&opts.ptr[i]` for `opts: *[]option` computed
MOVQ $8 instead of $24. Fix: route slice case through
`elemsizeofc(c, innert)`; ptr-to-named-struct via structlookup.
2. `cgun TK_AMP N_INDEX` ignored N_DOT base. `&p.ptr[i]` left
esz=8 because only N_IDENT base was handled. Mirror cgindex's
existing N_DOT arm.
3. `nodeisstr` N_INDEX arm only walked N_IDENT bases. `cmd.argsptr[i]`
for `argsptr: *str` returned false; pushargsrev dropped the
.len half at call sites. Add N_DOT-base arm that walks the
struct field's pointee.
Test 713 (struct_field_index): 3 rows × 2 stages = 6 fixtures, one
per fix shape. Runtime-only; bootstrap byte-id (995_self_rebuild)
covers cross-stage drift.
Residual: getopttest's errortable still fails through wwstage with
a slice-of-str-via-&arr[expr] miscompile. Filed as task #38.
