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.
Sister fix to #17. The BP-rel helper from #17 covered N_LET /
N_ASSIGN N_IDENT-lhs / N_RETURN; the four N_ASSIGN N_DOT-lhs
structlit walks still went through the inline `cgexpr(field.lhs);
store-AX-sized` shape and silently dropped trailing bytes when a
struct-typed field's value was itself an N_STRUCTLIT. Affected dot
flavors: single-dot via_ptr / global / BP-rel and the chained-dot
walker (depth >= 2, all three root flavors).
Extend `cg_structlit_fill_bp` / `cgstructlitfillbp` into
`cg_structlit_fill` / `cgstructlitfill` taking a destination mode
(DST_BP / DST_PTR_LOCAL / DST_GLOBAL = 0/1/2), srcoff (PTR_LOCAL),
srcname (GLOBAL), and disp accumulator. `disp` grows by foff on
descent; srcoff/srcname stay constant across the call tree. The
pre-#17 wrappers are preserved byte-identically by delegating with
mode=DST_BP — 995_self_rebuild byte-identity holds for the no-
nested-STRUCTLIT case that selfhost source actually uses.
The non-BP modes reload BX before the ELLIPSIS zero-fill loop AND
before every field store (tagged, scalar, and the cgexpr leaf).
This is correctness-by-construction — cgexpr clobbers BX between
fields, and the redundant reload only fires on shapes that didn't
compile before. The four dot-flavor sites in each stage now compute
their dst mode + disp and call the shared helper (reducing each
from ~80-130 inline lines to ~5-12 lines of dispatch).
Stage signature asymmetry: cstage threads Local** for cgexpr; ww-
stage takes explicit totsize because #15 (split totsize into
naturalsize + slotsize) is still pending and the dot sites need
structnaturalsize while the BP-rel sites need si.totsize. Both
asymmetries are documented in the helper docstrings.
704 covers 8 rows (24 checks: 8 cstage exits, 8 wwstage exits, 8
cstage-vs-wwstage .s byte-identity diffs): 6 dst-flavors (single-
dot local/ptr/global, chained-dot local/ptr/global) plus single-
local 3-deep and single-ptr 3-deep to pin disp threading through
the helper's recursion and through DST_PTR_LOCAL BX reloads.
The nested struct-typed CALL rhs in field-walks has the same shape
as the STRUCTLIT bug fixed here but the helper only handles
STRUCTLIT — tracked as task #20.
