Passing an aggregate BY VALUE as a call argument worked ONLY for a ≤16B
struct from an IDENT source; every non-ident source — CALL mk(), N_DOT
o.f, N_INDEX a[i], DEREF *p — and every array / >24B-struct (even as an
ident) fell to the scalar default: one PUSHQ for a multi-word aggregate,
stack-imbalancing against the type-based multi-word drain. cs!=ww, both
garbage (f(mk()) cs4/ww236, f(o.f) cs8/ww108, f(a[i]) cs4/ww28, f(*p)
cs4/ww140; arrays + 32B sret struct same).
The arg-pass twin of the #265/#268 let-init copy. A new aggregate-arg
push arm materialises the source into the arg convention: the source
ADDRESS in SI (ident LEAQ / deref operand / dotchainaddr #253 /
&base[i] spine #252-270) then its ceil(sz/8) words pushed high→low; a
CALL receives first — ≤24B in AX/DX/CX pushed straight, >24B sret'd
into a per-fn @aggargscr then pushed from there. The pop-forward drain
gained a matching array / >16B-struct arm and the callee prologue an
is_bigagg receive (ceil(sz/8) GP eightbytes), so caller and callee
agree on the multi-word layout. The ≤16B-struct-IDENT fast path is
untouched (byte-id preserved).
The new-arm exclusion is TYPE-keyed (the stamped tinfo, mirroring
cstage node_isstructarg over args[i]->type), not the name-keyed
structparamsize — a name-keyed gate re-opened the #211/#13 cross-module
same-leaf collision (784 symmetric: an 8B `sa.s` struct whose
name-resolution collides with `sb.s = *vtable` would miss the struct
fast path and wrongly enter the new arm, diverging from cstage's
1-word push). A float-bearing ≤16B struct from a non-ident source
loud-stops in both stages (the #165 SSE eightbyte transport the GP
push/drain can't model; out of scope). A const array/struct `def`
global as an aggregate arg is aligned DOWN to the leaner wwstage
(both loud-stop) per rule-10.
#110: cgen is compiler-imported by w6c + wwdump — main.combined.ww
regen'd for both.
949 rows: arg_{struct16,arr16,struct32}_{call,dot,idx,deref,ident},
full member readback (struct 16B reg-class + 32B sret-class + array
[4]u32, each non-ident source + ident control); byteid=1 throughout
(master both-broken-and-divergent → converge on the correct full
push, #263). All 111 dotbaseaddr + 3/3 784 pass; test-unit 241 green;
sizelint + smoke OK; the full w6c compiler source (214705 asm lines)
self-compiles cs==ww byte-id.
`let x: [2]inner = [inner{..}, inner{..}]` left the array unpopulated:
the N_ARRLIT per-element store handled scalar/str/float ONLY, so a
struct/array/tuple element hit the multi-word-store gap and stored just
the first 8 bytes (cs0/ww0). Both stages symmetric-broken; converge on
the populated result (#263).
Fix: an aggregate element of an array literal fills each element slot
from its source — cg_structlit_fill_bp for an N_STRUCTLIT element,
word-copy for an N_IDENT element (reusing COMMIT 2's per-element copy
shape). esz is the element's natural size (cstage esub->size). cgen.c
N_ARRLIT arm + cgenstmt.ww cglet. An aggregate `...` repeat and other
element shapes hard-stop loud (rule-7).
949 rows: arrlit_structlit, arrlit_structident (8B struct, byteid=1,
full readback). All 96 pass; test-unit 241 green; smoke OK.
The array-of-struct element store/copy family — one primitive (&(array
element) for an AGGREGATE element, used as address, never deref/truncate)
across three consumers. Both stages were symmetric-broken; converge on
the runtime-correct full-address/full-copy (#263).
(1a) `a[i].m[j] = v` (a:[N]struct) segfaulted: the `arr[i].field` arm
computed &a[i] then DEREF'd it (loaded the struct's first 8 bytes as a
value) for an `[N]T`-typed field → garbage base. Now an array-typed
field of an array element leaves the field ADDRESS (the #135 read-side,
applied to the array-element base). cgen.c arm + cgenexpr.ww cgdot
N_INDEX-lhs branch.
(1b) `a[i] = aggregateval` truncated the copy to an 8B MOVQ. New
aggregate (struct/array/tuple >8B) element-store branch word-copies the
element from the rhs source address (ident / N_DOT field / `*p` deref) —
the WRITE-twin of the #268 let-init loop. cgen.c N_INDEX store +
cgenexpr.ww cgassign.
(3a) `let c = x.arr[i]` (N_DOT base) / `let c = a[i][j]` (nested) dropped
the copy: the #268 let-init N_INDEX source-addr arm was N_IDENT-base-
gated. Now computes &base[idx] via cg_dotbase_addr (N_DOT field) or the
&abase[bidx] spine (nested N_IDENT-array base). cgen.c N_LET +
cgenstmt.ww cglet.
949 rows: elemfield_store, elem_struct_store, elem_arr_store,
letcopy_{dot,nest}_prim, letcopy_subarr (byteid=1); letcopy_{dot,nest}_
struct (byteid=0 — run-correct, byte-id blocked by the orthogonal
value-nested-struct frame divergence #254). All 94 pass; test-unit 241
green.
elemsizeofc drilled a 2D `[N][M]T` base's OUTER-index stride down to the
scalar T (the documented elemsizeof FOOTGUN: it bottoms out at the inner
prim size, 4 for [M]u32). The `direct != 8` short-circuit then returned
that scalar size, so wwstage emitted esz=$4 where cstage emits $12 (the
sub-array size, idx_eff(bt)->sub->size = sub.size*elen, type.c:121). The
runtime stayed self-consistent (write+read the same wrong stride) so it
masked until a CROSS-CELL access — a[0][j] and a[1][j] alias.
Fix: detect a nested-array element ([M]T inside [N][M]T) before the
short-circuit and return the element-array tinfo's natural .size, the
sub-array stride. wwstage-only; aligns up to cstage. w6c unchanged.
949 rows: nest2d_u32/u8/i32 (cross-cell write+readback, byte-id).
The fold-1b unified arm (bb2f4e1) added an N_IDENT addressable-rhs source
setup, but the two stages gated the GLOBAL case differently: cstage used
let_islet || def_isarraydef, wwstage used isletvar || deflookup (ANY def).
On a struct-typed `def` used as an aggregate-copy rhs (`let c: T = G`)
wwstage copied the whole value (correct) while cstage truncated to the 8B
scalar tail — a cs!=ww divergence (rule-10). A struct-LET global already
copies on both, so the def gap was also an internal cstage inconsistency.
Struct defs are first-class laid-out aggregates (DATA storage + field
load, #129 A.2/A.3), so converge on the correct full copy on both: add
def_isstructdef to cstage's predicate and replace wwstage's broad
deflookup with the def_is{array,struct}def pairing already held identical
in defisaddressable. 949 +2 rows (array-def + struct-def global, full
readback, byteid=1).
#265 fold-1 landed the deref-rhs aggregate copy as one slot→slot memcpy
loop fed from a source address in SI. fold-1b adds the remaining
addressable-rhs source-address setups, all routed into that SAME loop:
- array IDENT `let c: [N]T = s` — LEAQ the source slot into SI.
Pre-fix both stages truncated to the 8B scalar tail.
- N_DOT field `let c: A = o.i` — cg_dotchain_addr / dotchainaddr
(#253) lands &(o.i) in SI. Pre-fix truncated to 8B.
- N_INDEX element `let c: A = a[i]` — the &base[i] spine (#252:
scaled index + LEAQ base) lands the element address in SI. Pre-fix
scalar-loaded the element address as a value → segfault.
Size (the #254 non-slot-padded ABI extent) comes from the declared let
type for every shape (lu->size / structabisize|tinfo.size), independent
of the rhs; only the per-rhs address setup differs. The deref arm
becomes one branch of the unified arm. Struct-IDENT keeps its own #32
slot-copy arm above (unchanged). With those, the whole addressable-rhs
let-init-copy family is closed by construction: struct-ident / array-
ident / deref / N_DOT / N_INDEX all full-copy, both stages byte-identical
(rule-10).
949 gains 9 full-readback rows (every member written distinct + summed,
so a partial copy fails): array-ident 16B/32B + 12B(MOVL)/11B(MOVW+MOVB)
tails; N_DOT struct-field 16B + array-field 32B + 11B-tail struct field;
N_INDEX struct element 16B/32B. The N_INDEX source array is populated
through a `*inner` to `&a[i]` (the #135/#252 store path) because the
array-of-struct element direct store (`a[i].m[j]=v` / `a[i]=s` / struct-
array literal) segfaults on a SEPARATE pre-existing bug, reported
alongside this fold. w6c+wwdump combined.ww regen (#110). 70/70 949,
test-unit 241, sizelint, smoke green.
A `let c: T = *p` (T a struct or array, >8B) copied no full aggregate:
cstage dropped the init entirely (c read garbage); wwstage emitted only
the scalar `MOVQ AX,off(BP)` tail (first 8 bytes). Both wrong, differently
— converge BOTH stages on a size-driven slot-to-slot memcpy: cgexpr the
deref operand to the source address in AX, MOVQ AX,SI, then a MOVQ run
plus a sized MOVL/MOVW/MOVB tail over the #254 non-slot-padded ABI extent
(lu->size / structabisize for a struct, tinfo.size for an array). Mirror
arms in cgen.c N_LET and cgenstmt.ww cglet, byte-identical (rule-10).
Unblocks sha256's faithful `let copy = *h`. The by-value aggregate RETURN
ABI (array/struct return truncates to AX) is fold-2 (#267, deferred).
949 gains 6 full-readback rows (every member written distinct + summed,
so a truncated copy fails): struct{[4]u32} 16B, struct{[8]u32} 32B via
both *(&s) and *p (sha256 shape), bare [4]u32, and non-8-mult tails
([3]u32 12B → MOVL, [11]u8 11B → MOVW+MOVB). w6c+wwdump combined.ww regen
(#110). 61/61 949, test-unit 240, sizelint, smoke green.
cgreturn's passthrough predicate was TYPE-only (istagged && type-eq), with
no source-kind filter. It forwarded the source's AX/DX/CX unchanged, which
is correct ONLY when the source already materialized the full tagged slot
into registers — N_CALL / N_INDEX / N_DOT (the #261-broadened set). For a
tagged LOCAL ident, cgexpr loads only word0 (the tag) into AX, never the
payload into DX, so passthrough dropped the payload: `return v` of a
`(i32|void)=7i32` exited 0 instead of 7. wwstage was already correct — its
forwardtagged kind filter excludes N_IDENT, routing it through the
scratch-widen path. The runtime oracle (cstage 0, wwstage 7) proved cstage
is the bug; this aligns cstage UP.
Gate passthrough to {N_CALL,N_INDEX,N_DOT}; a tagged-ident return now falls
to the existing scratch-slot widen path (cg_widen_tagged_store tagged-subset
N_IDENT arm), byte-identical to wwstage's return scratch-widen. cstage-only
(no combined.ww regen — combined.ww embeds the unchanged wwstage source;
byte-id is blind here, the new 949 rows are the net).
test/949: tagged_ident_ret_i32 (7) + tagged_ident_ret_void (void tag
survives) + register-resident controls tagged_call_ret_ctrl /
tagged_dot_ret_ctrl (passthrough must still fire); INDEX control already
present. All dual-stage run + cs==ww byte-id.
The #259 store fix unmasked a pre-existing latent cs!=ww in the tagged-
element READ via an N_DOT base (`x.o[i]`) / chained N_INDEX base
(`m[i][j]`): wwstage materialized the element as a SCALAR one-word load +
zeroed tag where cstage copies the full tagged slot — silently dropping
the tag/payload-high word (wrong variant). Three sites all keyed off the
same N_IDENT-only gate; cstage classifies TY_TAGGED for ANY base off the
checker-stamped element type. Align wwstage UP:
- cgindex (cgenexpr.ww): the N_DOT/N_INDEX-base arm now sets
elem_tagged/elem_slot_sz from n.type_ (the stamped element tinfo),
mirroring cstage cgen.c:8101 — the full-slot copy arms then fire.
- rhstaggedabicall (cgenutil.ww): the N_INDEX branch reads
typeistagged(src.type_) for any base instead of an N_IDENT-only
structural lookup, mirroring cstage's src->type keying — fixes the
let-init / call-arg widen-source spill.
- forwardtagged (cgenstmt.ww): the return-path passthrough gate now
accepts N_INDEX/N_DOT tagged rhs (which cgexpr materializes into the
tagged ABI), not just N_CALL — fixes `return x.o[i]`.
read + call-arg + return + chained 2D all close by construction (one
materialization path). cstage unchanged (pure wwstage-align-up). 949
gains 9 #261 rows (i32 + explicit-void variant per shape proves the tag
survives) and flips the two #259 read-back rows to byteid=1.
#259: the tagged-union array-field indexed STORE arm computed &arr[i]
from a non-ident base (`x.o[1]=v` where o:[N](T|void)) with a plain
cgexpr(base) — the N_DOT array field auto-derefs (loads the field's
first 8 bytes AS a pointer) -> garbage dest -> SEGFAULT. Route the base
through the array-gated helper cg_dotbase_addr/dotbaseaddr (dst BX keeps
the scaled index live in AX; viaptr + chained handled by the shared
helper), mirroring #257. Symmetric both stages. This was the last
unrouted cgexpr(base) cell in the array-field-base-address family
(#135/#252/#253/#255/#257) — proof-grep of both stages now shows ZERO
unrouted base cells in the slice/decay/addr/index/store builders, so the
family is closed by construction. (The chained-ptr-field scalar/str/
float store sites at cgenexpr.ww:6489+ / cgen.c:4379+ correctly cgexpr
the pointer spine and are the #133 family, not array-field-address.)
#256: align wwstage dotchainaddr's N_IDENT non-local arm to carry
cstage cg_dotchain_addr's `let_islet || def_isstructdef` guard (here
isletvar || deflookup) instead of emitting LEAQ name(SB) unconditionally.
Unreachable on valid input (a struct-typed chain root is always local /
let-global / struct def) so zero divergent asm — never-silent ethos only.
Tests (949): store-only byte-id rows (tagged_store_own/_ptr) gate the
#259 store base-address emission cs==ww; store+readback rows
(tagged_store_*_rd) are run-only (cstage) proving the store wrote the
right slot (66/77) and no longer segfaults. byte-id on the readback rows
is blocked by an ORTHOGONAL newly-surfaced divergence in the N_DOT-base
tagged-element READ materialization (sibling of #255: wwstage loads one
word + zeroes the tag where cstage copies the full 16-byte slot) — the
store base is already byte-id; only the read-back diverges. Reported
separately for triage.
combined.ww regen'd (w6c + wwdump embed cgen).
The #257 call-arg fix routes the N_SLICE base through the array-gated
cg_dotbase_addr/dotbaseaddr helper. Add the load-bearing deviation
guard: a slice of a []T field and of a str field passed straight as a
call arg must FALL THROUGH the gate to cgexpr (header .ptr load), not
take the field address. Both also exercise the N_DOT esz extension on
the fall-through arm (re-slice by element width). cs==ww byte-id.
An inline slice of a struct `[N]T`-field passed DIRECTLY as a call
argument (`rd(x.o[lo:hi])`) materialized the slice .ptr from the field
VALUE, not its ADDRESS: the pushargs/pushargsrev N_SLICE inline builder's
non-ident else-arm did plain cgexpr(base), so the N_DOT field auto-derefs
(MOVL field,AX used as .ptr) -> callee derefs garbage -> SEGFAULT. The
let-init / assign-rhs / return / hoist-to-local contexts already routed
through the cgslice #252 choke-point; only this call-arg builder kept a
private duplicate. cs==ww both segfaulted identically pre-fix (gate-blind).
Fix (symmetric both stages):
- route the else-arm through cg_dotbase_addr / dotbaseaddr (the cgslice
#252 choke-point: array-field-gated, so `[]T`/str/`*T` fields fall
through to cgexpr; chained inner `o.p.m` handled via its #253 arm);
- extend the N_IDENT-only esz gate to N_DOT bases, taking the element
width from the checker-stamped base->type (rule-13 type table), so
non-u8 call-arg slices scale stride.
Before: `MOVL -8(BP),AX; PUSHQ AX` (field value as .ptr). After:
`LEAQ -8(BP),AX; PUSHQ AX` (field address). cs==ww byte-identical.
Helper note: used dotbaseaddr (not dotchainaddr as first scoped) — it is
the established cgslice choke-point and is array-field-gated, so a slice/
str-typed field base keeps the correct cgexpr header-ptr load; bare
dotchainaddr lacks that gate and would mis-emit the field address for
those. dotbaseaddr already handles the chained `o.p.m` inner via #253.
Tests: test/wcc/949 gains 6 call-arg rows (u8, i32-esz-stride, via-*struct,
chained, + hoist-to-local and bare-local-array controls), each run-
correctness AND cs==ww byte-id.
PROOF-GREP residual: the tagged-union-element indexed-STORE arm
(cgen.c:~4972 / cgenexpr.ww:~5024) is the same N_DOT-base auto-deref shape,
still unrouted in BOTH stages (symmetric, segfaults) — a distinct
consumption axis filed separately; NOT fixed here.
The cgindex N_DOT-base arm set esz from the checker-stamped element
tinfo but skipped signedness, so loadopsz saw signed_elem=false and
emitted MOVL/MOVZ* (zero-extend) where cstage's fldloadop reads
signedness from the element type and emits MOVSXD/MOVSWQ/MOVSBQ. A
negative i8/i16/i32 read of `x.o[k]` (struct `[N]T` field) round-tripped
with the wrong upper bits — silent cs!=ww, byte-id-blind since bootstrap
never indexes signed-narrow struct array-fields.
Mirror the sibling N_INDEX-base arm: signed_elem = typeissigned(dt).
loadopsz already keys on (signed,sz), so this closes all three narrow
widths at once. Pure wwstage-up; cstage unchanged.
949 gains nload_i32/i16/i8 negative-read rows (run + cs==ww byte-id).
combined.ww regen'd for w6c + wwdump (the cgen embedders).
cg_dotbase_addr / dotbaseaddr rejected a non-ident inner, so a chained
base (`o.p.m[i]` / `o.i.m[i]` / `o.a.b.m[i]`) fell to cgexpr(base) which
auto-derefs the array field's first 8 bytes AS a pointer -> garbage base
-> segfault (base64 fillobuf `s.enc.encmap[...]` blocker). Extend the one
helper per stage to accept a chained inner: a new cg_dotchain_addr /
dotchainaddr recovers the container base via the dot-chain spine (recurse
to &x, deref when x is a *struct, sum field offsets), keeping the same
no-AX/no-stack spill contract. dotbaseaddr then takes the pointer VALUE of
inner when viaptr, else its ADDRESS, and adds the field offset. One fix
closes every op (index r/w, addr-of, slice, compound) since all route
through the helper. Symmetric cs==ww byte-id.
test/949: +22 rows. Chained-PTR (rd/wr/addr/slice x2/compound), deeper
(value+ptr leaf links, triple-pointer exercising the internal deref),
non-u8 esz stride (i32 addr+slice), and single-level controls — all
byte-id. The chained VALUE-container arm (`o.i.m`) is run-only (byteid=0):
it needs a value nested-struct instance, which trips THREE orthogonal
pre-existing cs!=ww emission divergences (bare-let zero-init policy,
global DATAW byte count, i32 element-load opcode in the index fallback)
unrelated to #253. Run correctness proves the segfault is gone for that
cell; byte-id there awaits the separate wwstage value-nested-struct fix.
The 7-row table covered u8 addr-of (local + *struct param) and the
non-u8 stride only on the slice path. Two coverage gaps closed:
addr_i32 &x.o[2] on a [4]i32 field, *p read -> 88. The addr-of
complex-base arm scales the index by esz=sizeof(elem)
independent of the base-address path; only u8 (esz=1)
rows exercised it before. Proves IMULQ $4 stride
composes with the dotbaseaddr LEAQ base.
slice_ptr_u8 x.o[1:4] via a *e param. dotbaseaddr's viaptr arm
(MOVQ (BP) deref) on the slice base was untested — all
slice rows used a value-struct (LEAQ) base.
Both run-correct + cs==ww byte-identical.
Taking &x.o[i] (address-of) or slicing x.o[lo:hi] / x.o[lo:] of a
struct's [N]T-typed FIELD computed the field's VALUE as the base
address (MOVL off(BP),AX) instead of its ADDRESS (LEAQ off(BP),AX) ->
garbage pointer -> segfault. The index read/write path was fixed in
#135; this is the unwired addr-of + slice sibling — both base-address
paths fell to the generic cgexpr(base) auto-deref.
Wire the #135 cg_dotbase_addr / dotbaseaddr helper into the addr-of
N_INDEX complex-base arm and the N_SLICE base arm, symmetric on both
stages (guarded if(!dotbase) cgexpr(base)). Extend the slice element
stride (esz) and default-hi length to an N_DOT array-field base too,
read from the field's element tinfo / array length via the type table
(rule-13) — so non-u8 element slices scale correctly and s.obuf[lo:]
gets the array's element count.
cstage already derived default-hi via base->type (alen); only wwstage
needed the N_DOT default-hi arm. cs==ww byte-identical on every shape.
test/949_dotbase_addr_slice_run: 7 dual-stage rows (addr-of local +
*struct param, explicit + default-hi u8 slice, non-u8 [4]i32 stride,
bare-local control), run + cs==ww byte-id. Regen w6c/wwdump combined.ww.
