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wcc: converge let-IDENT memcpy, IDENT-assign recv, nested struct call-recv onto structabisize

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Three more wwstage cgen sites still used unrounded structnaturalsize where
cstage rounds via lu->size — pre-existing gate-blind cs!=ww latents the #169b
reviewer surfaced: cgenstmt N_LET struct-IDENT memcpy (let p2: T = p1; twin
cgen.c:7869), cgenexpr N_ASSIGN N_IDENT-lhs register RECV (s = mk(); twin
cgen.c:4700-4737), and cgenutil's nested struct N_CALL recv inside
cgstructlitfill (twin cgen.c:2121).

Converge all three onto structabisize, completing the same-class closure
started by #169 and continued by #169b. Also corrected the inline comment at
cgenutil.ww:3273-3286 that wrongly claimed fl->type->size was natural
(check.c:760 sets ABI). sretretsize at cgenutil.ww:1301 is gate-equivalent
natural and is left alone.

Probe 698 +3 rows (one per converged site) with cs==ww .s byte-cmp and a
pre-fix-rebuild discriminator. 990-997 byte-id hold.
This commit is contained in:
Hojun-Cho
2026-05-28 14:07:58 +09:00
parent 39f9267bc9
commit 66a91c8969
6 changed files with 142 additions and 60 deletions
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52
selfhost/cmd/wwdump/main.combined.ww
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@@ -17337,21 +17337,22 @@ fn cgstructlitfill(c: *cgen, si: *structinfo, lit: *node,
if (primsize(fi.tnode.str) == 0) {
let csi: *structinfo = structlookup(c, fi.tnode.str);
if (csi != nil) {
// Use the inner struct's
// NATURAL size (no 8B slot
// rounding) so MOVL/MOVW/
// MOVB tail dispatch matches
// cstage's fl->type->size
// (which is natural per
// check.c). fi.fsz here is
// Inner struct's ABI size
// (maxalign-rounded) — cstage
// reads fl->type->size at the
// nested-call branch
// (cgen.c:2121); check.c:760
// sets that to the
// maxalign-rounded ABI extent
// (NOT natural). fi.fsz is
// wwstage's slot-padded
// totsize — using it would
// emit 2× MOVQ where cstage
// emits MOVQ+MOVL for a
// 12B inner, etc. (task #15
// territory; sidestepped
// locally.)
let cfsz: i32 = structnaturalsize(csi);
// totsize (round-to-8); the
// pre-#169 structnaturalsize
// shorts struct{i64,i32}
// (natural 12, ABI 16) to
// MOVQ+MOVL where cstage
// writes MOVQ+MOVQ.
let cfsz: i32 = structabisize(csi);
let crem: i32 = cfsz - (cfsz / 8) * 8;
if (cfsz <= 24) {
if (crem == 0 || crem == 1
@@ -24267,9 +24268,14 @@ fn cgassign(c: *cgen, n: *node) void = {
if (lcsname.len > 0) {
let lcsi: *structinfo = structlookup(c, lcsname);
if (lcsi != nil) {
// si.totsize is slot-padded (rounded to 8);
// receive ABI needs the TYPE's natural size.
let lcnsz: i32 = structnaturalsize(lcsi);
// register RECV reads AX/DX/CX at 8-byte
// granularity — size via structabisize (cstage
// N_ASSIGN-IDENT branch sets sz = lu->size,
// cgen.c:4704; check.c:760 SSoT). The pre-
// #169 structnaturalsize shorts struct{i64,i32}
// (natural 12, ABI 16) to MOVQ+MOVL where
// cstage writes MOVQ+MOVQ.
let lcnsz: i32 = structabisize(lcsi);
if (n.op == tkind.TK_ASSIGN) {
if (n.rhs != nil
&& n.rhs.kind == nkind.N_STRUCTLIT) {
@@ -25876,8 +25882,8 @@ fn cglet(c: *cgen, n: *node) void = {
// Struct ident copy: `let p2: T = p1;` where T is a struct
// >8B and rhs is a local ident. Per-qword MOVQ from src
// slot to dst slot, with a sized tail (MOVL/MOVB) for
// natural sizes that aren't 8-aligned (e.g. `struct
// { i32, i32, i32 }` is 12B). Pre-fix this path fell
// ABI sizes that aren't 8-aligned (e.g. `struct
// { i32, i32, i32 }`, maxalign 4 → ABI 12B). Pre-fix this path fell
// through to `cgexpr + MOVQ AX, off(BP)` which stored
// only the first qword (and a stale BX for sz==16 lets
// via the str-init tail) — silent partial copy. Mirrors
@@ -25891,7 +25897,13 @@ fn cglet(c: *cgen, n: *node) void = {
if (sname.len > 0) {
let lsi: *structinfo = structlookup(c, sname);
if (lsi != nil) {
let lsz: i32 = structnaturalsize(lsi);
// memcpy run sizes on the maxalign-rounded ABI
// size — cstage N_LET sets sz = lu->size
// (cgen.c:7533, struct-IDENT branch :7869),
// check.c:760 SSoT. structnaturalsize would
// short struct{i64,i32} (natural 12, ABI 16)
// to MOVQ+MOVL where cstage writes MOVQ+MOVQ.
let lsz: i32 = structabisize(lsi);
if (lsz > 8) {
let lc: *local = localfindnode(c, rhs.str);
if (lc != nil) {