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.
Passing a module-global struct by value -- let g: pt = pt{...}; take(g)
-- was silently miscompiled, mirror-opposite on the two stages. cstage's
by-value struct-arg arm hit localfind(g)->0 and read 2 words from the
frame (MOVQ (BP)), never main.g(SB) -> returned garbage. wwstage used the
correct main.g(SB) base but fell through to the scalar single-PUSHQ
default, pushing one word for a 2-word struct -> dropped a field.
Both stages now take the off==0 global branch: LEAQ main.NAME(SB) and copy
all struct-size/8 eightbytes (reusing the GAP-A.ptr/#231 global-base
predicate), converging to one byte-identical sequence. The local path
(off!=0) is unchanged; >16B aggregates (#271) already resolved globals.
Commit A of the cluster; the cstage-only inferred-global-type Sym-repoint
(every let g = ... module-global yields <nil> downstream) is Commit B
(#18). Slice/str global-by-value args have the same wwstage field-drop --
filed (#10 G-valglobal-arg; struct closed here). byte-id 990-997 8/8.
test/wcc/822 table-driven, byte-id per stage.
