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cgen: materialize and store all eightbytes of an aggregate unwrap success (#12)

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A struct/array success variant in an (S|e)! / r? unwrap dropped eightbytes on BOTH stages (byte-id blind). Two layers: (L1) the unwrap success shuffle (cgtrytaggedshift) matched no arm for a struct/array success and fell to a bare MOVQ DX,AX, materializing only w0 — widen the existing nested-TAGGED shift's gate to admit TY_STRUCT/TY_ARRAY (the in-cap union packs the payload as raw GP words past the tag, so that shift is exact); (L2) the aggregate store arms gated on rhs.kind==N_CALL and stored one word for an unwrap rhs — relax to also admit N_TRYUNW/N_TRYPROP at the three silent store shapes (arr[i]=, single-dot field, indexed-field), reusing the materialise scratch path (now #10-correct). Rule-7 LOUD-STOP for a float-bearing success variant (an SSE eightbyte cannot ride the GP {AX,DX,CX} shift, #165). The four already-loud unwrap consumers (let-receive #7, call-arg #271, assign-existing #49, resolver-field #24) stay loud; global/chained single-dot field (#16) and the sub-8-tail-through-unwrap union-maker frame clobber (#15) are separate follow-ups. Value-asserting pin, reddens under each stage's independent revert.
This commit is contained in:
Hojun-Cho
2026-06-28 01:10:31 +09:00
parent 3a0389ce60
commit 40872274d0
4 changed files with 269 additions and 17 deletions
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105
cmd/w6c/cgen.c
View File

@@ -557,6 +557,36 @@ struct_arg_size(Type *t)
return (int)t->size; return (int)t->size;
} }
/* agg_has_float — does an aggregate Type carry ANY float leaf
* (recursively through struct fields / array element / tuple
* positionals)? The #12 producer (N_TRYPROP/N_TRYUNW success shuffle)
* loud-stops a float-bearing aggregate success variant: the union
* return places a float eightbyte in the SSE class (X0/X1) which the GP
* AX/DX/CX payload shuffle cannot reach (mirror #11/#165). Conservative
* — ANY float, not a per-eightbyte SSE classify like struct_float_class
* — a loud-stop only needs to refuse, not transport. Mirrors wwstage
* tinfo_agg_float (cgenutil.ww). */
static int
agg_has_float(Type *t)
{
t = type_chase_named(t);
if (t == NULL) return 0;
if (cg_isfloat(t)) return 1;
if (t->kind == TY_STRUCT) {
for (Tfield *f = t->fields; f; f = f->next)
if (agg_has_float(f->type)) return 1;
return 0;
}
if (t->kind == TY_ARRAY)
return agg_has_float(t->sub);
if (t->kind == TY_TUPLE) {
for (Tparam *p = t->params; p; p = p->next)
if (agg_has_float(p->type)) return 1;
return 0;
}
return 0;
}
/* struct_float_class — SysV per-eightbyte classification for the #165 /* struct_float_class — SysV per-eightbyte classification for the #165
* float-bearing-struct param case (the param twin of #171's struct * float-bearing-struct param case (the param twin of #171's struct
* return, classifying per-eightbyte rather than #163's per-element). * return, classifying per-eightbyte rather than #163's per-element).
@@ -5385,10 +5415,21 @@ cgexpr(Cg *c, Node *n, Local *locals)
* store; for via_ptr/is_global the dst base addr * store; for via_ptr/is_global the dst base addr
* is reloaded into BX before each store so cgexpr * is reloaded into BX before each store so cgexpr
* can clobber AX/BX between fields. */ * can clobber AX/BX between fields. */
/* #12: an unwrap `b.f = mk()!` (direct) / `p.f =
* mk()!` (via-ptr) rides the same {AX,DX,CX} shape
* (producer shift) — admit it alongside N_CALL. Gated
* !is_global: the wwstage single-dot arms cover a direct
* / via-ptr base only; a global `g.f` unwrap stays on
* its pre-existing path in BOTH stages (out of scope,
* not regressed). Float/over-cap loud-stop at the
* producer. */
if (n->op == TK_ASSIGN && str_fu if (n->op == TK_ASSIGN && str_fu
&& str_fu->kind == TY_STRUCT && str_fu->kind == TY_STRUCT
&& (int)str_fu->size <= 24 && (int)str_fu->size <= 24
&& n->rhs && n->rhs->kind == N_CALL && n->rhs && (n->rhs->kind == N_CALL
|| ((n->rhs->kind == N_TRYUNW
|| n->rhs->kind == N_TRYPROP)
&& !is_global))
&& (str_fu->size % 8 == 0 && (str_fu->size % 8 == 0
|| str_fu->size % 8 == 1 || str_fu->size % 8 == 1
|| str_fu->size % 8 == 2 || str_fu->size % 8 == 2
@@ -5828,8 +5869,17 @@ cgexpr(Cg *c, Node *n, Local *locals)
* float return eightbyte rides X0/X1 which the GP * float return eightbyte rides X0/X1 which the GP
* AX/DX/CX cursor cannot read). Mirrors wwstage * AX/DX/CX cursor cannot read). Mirrors wwstage
* cgenexpr.ww. */ * cgenexpr.ww. */
/* #12: an unwrap `arr[i].f = mk()!` rides the
* same {AX,DX,CX} shape (producer shift) — admit
* it alongside N_CALL; the #11b non-call arm below
* excludes the unwrap kinds so this arm is the
* sole handler. cg_sret_retsize keys off ft (the
* field = success variant type), so an over-cap
* unwrap stays loud here too. */
if (n->op == TK_ASSIGN && n->rhs if (n->op == TK_ASSIGN && n->rhs
&& n->rhs->kind == N_CALL) { && (n->rhs->kind == N_CALL
|| n->rhs->kind == N_TRYUNW
|| n->rhs->kind == N_TRYPROP)) {
if (cg_sret_retsize(ft) > 0) if (cg_sret_retsize(ft) > 0)
fatal("#11c/#234: over-cap " fatal("#11c/#234: over-cap "
"(sret) aggregate field " "(sret) aggregate field "
@@ -5991,8 +6041,14 @@ cgexpr(Cg *c, Node *n, Local *locals)
* cg_aggcopy — the ONE copy emitter the non- * cg_aggcopy — the ONE copy emitter the non-
* indexed bases use (DRY). fsz natural * indexed bases use (DRY). fsz natural
* (ft->size). Mirrors wwstage cgenexpr.ww. */ * (ft->size). Mirrors wwstage cgenexpr.ww. */
/* #12: exclude the unwrap kinds — the #11 arm
* above is their sole handler (they ride the
* {AX,DX,CX} register cursor, NOT a source
* address). */
if (n->op == TK_ASSIGN && n->rhs if (n->op == TK_ASSIGN && n->rhs
&& n->rhs->kind != N_CALL && fu && n->rhs->kind != N_CALL
&& n->rhs->kind != N_TRYUNW
&& n->rhs->kind != N_TRYPROP && fu
&& (fu->kind == TY_STRUCT || fu->kind == TY_ARRAY && (fu->kind == TY_STRUCT || fu->kind == TY_ARRAY
|| fu->kind == TY_TUPLE) && fsz > 8) { || fu->kind == TY_TUPLE) && fsz > 8) {
cgexpr(c, idx, locals); cgexpr(c, idx, locals);
@@ -6986,12 +7042,20 @@ cgexpr(Cg *c, Node *n, Local *locals)
* copy scratch → dest. Scratch-first (not a dest spill across * copy scratch → dest. Scratch-first (not a dest spill across
* the call) keeps the call at the frame's natural alignment. * the call) keeps the call at the frame's natural alignment.
* In-cap only (cg_sret_retsize==0). */ * In-cap only (cg_sret_retsize==0). */
/* #12: an unwrap `mk()!` / `r?` whose success variant is
* an in-cap struct/array rides the SAME {AX,DX,CX} payload
* shape as the call return (the producer shift materialises
* it); admit it alongside N_CALL. cg_sret_retsize(esub)==0
* holds for an in-cap variant; the float/over-cap loud-
* stops live at the producer. */
if ((is_arr || is_sl || is_ptr) && n->op == TK_ASSIGN if ((is_arr || is_sl || is_ptr) && n->op == TK_ASSIGN
&& esubu && (esubu->kind == TY_STRUCT && esubu && (esubu->kind == TY_STRUCT
|| esubu->kind == TY_ARRAY || esubu->kind == TY_ARRAY
|| esubu->kind == TY_TUPLE) || esubu->kind == TY_TUPLE)
&& esz > 8 && esz > 8
&& n->rhs->kind == N_CALL && (n->rhs->kind == N_CALL
|| n->rhs->kind == N_TRYUNW
|| n->rhs->kind == N_TRYPROP)
&& cg_sret_retsize(esub) == 0) { && cg_sret_retsize(esub) == 0) {
int scr = cg_tagscr_slot(c, &locals, esz); int scr = cg_tagscr_slot(c, &locals, esz);
cgexpr(c, n->rhs, locals); /* call → AX/DX/CX */ cgexpr(c, n->rhs, locals); /* call → AX/DX/CX */
@@ -11113,8 +11177,24 @@ cgexpr(Cg *c, Node *n, Local *locals)
* standard AX=tag cursor. The scalar MOVQ DX,AX * standard AX=tag cursor. The scalar MOVQ DX,AX
* below carried only the inner tag and dropped the * below carried only the inner tag and dropped the
* payload (ken unw16). Nullable folds to one word * payload (ken unw16). Nullable folds to one word
* and stays on the scalar move. */ * and stays on the scalar move.
if (stu && stu->kind == TY_TAGGED && !stu->nullable) { *
* #12: a general-aggregate (struct/array) success
* variant rides the SAME in-cap {AX,DX,CX} payload
* shuffle — the union return packs the payload as raw
* GP words past the outer tag. Pre-#12 it matched no
* arm and fell to the bare MOVQ DX,AX below,
* materialising only w0 (w1/w2 dropped) — a SILENT
* both-stage word-drop. A float-bearing aggregate rides
* X0/X1 (the SSE return-class) which this GP cursor
* cannot reach, so LOUD-STOP it (mirror #11/#165). */
if (stu && ((stu->kind == TY_TAGGED && !stu->nullable)
|| stu->kind == TY_STRUCT || stu->kind == TY_ARRAY)) {
if (agg_has_float(stu))
fatal("#12/#165: float-bearing "
"aggregate success variant unwrap "
"(S|e)! rides SSE X0/X1; GP cursor "
"unwired");
ins2(c, A_MOVQ, areg(D_DX), areg(D_AX)); ins2(c, A_MOVQ, areg(D_DX), areg(D_AX));
if (stu->size > 8) if (stu->size > 8)
ins2(c, A_MOVQ, areg(D_CX), ins2(c, A_MOVQ, areg(D_CX),
@@ -11225,8 +11305,17 @@ cgexpr(Cg *c, Node *n, Local *locals)
} }
/* Family C (#35): TAGGED success = nested box on the /* Family C (#35): TAGGED success = nested box on the
* payload words — shift past the outer tag (see the * payload words — shift past the outer tag (see the
* N_TRYPROP twin). */ * N_TRYPROP twin). #12: a struct/array success variant
if (stu && stu->kind == TY_TAGGED && !stu->nullable) { * rides the same in-cap {AX,DX,CX} shuffle; a float-
* bearing aggregate LOUD-STOPS (X0/X1, GP cursor can't
* reach it). Full WHY at the N_TRYPROP twin. */
if (stu && ((stu->kind == TY_TAGGED && !stu->nullable)
|| stu->kind == TY_STRUCT || stu->kind == TY_ARRAY)) {
if (agg_has_float(stu))
fatal("#12/#165: float-bearing "
"aggregate success variant unwrap "
"(S|e)! rides SSE X0/X1; GP cursor "
"unwired");
ins2(c, A_MOVQ, areg(D_DX), areg(D_AX)); ins2(c, A_MOVQ, areg(D_DX), areg(D_AX));
if (stu->size > 8) if (stu->size > 8)
ins2(c, A_MOVQ, areg(D_CX), ins2(c, A_MOVQ, areg(D_CX),

68
selfhost/cmd/wcc/cgenexpr.ww
View File

@@ -240,8 +240,24 @@ fn cgtrytaggedshift(c: *cgen, n: *syntax.node) bool = {
let sv: *syntax.tinfo = successvariant(ou); let sv: *syntax.tinfo = successvariant(ou);
sv = tichase(sv); sv = tichase(sv);
if (sv == nil) { return false; }; if (sv == nil) { return false; };
if (sv.kind != syntax.tykind.TY_TAGGED) { return false; }; // #12: a general-aggregate (struct/array) success variant rides the
if (sv.nullable != 0) { return false; }; // SAME in-cap {AX=w0,DX=w1,CX=w2} payload shuffle as the nested-TAGGED
// box — the union return packs the payload as raw GP words past the
// outer tag. Pre-#12 it matched no arm and fell to the bare MOVQ DX,AX
// below, materialising only w0 (w1/w2 dropped) — a SILENT both-stage
// word-drop. A float-bearing aggregate rides X0/X1 instead (the SSE
// return-class), which this GP cursor cannot reach, so LOUD-STOP it
// (mirror #11/#165). Mirrors cstage N_TRYPROP/N_TRYUNW.
let agg: bool = false;
if (sv.kind == syntax.tykind.TY_TAGGED && sv.nullable == 0) { agg = true; };
if (sv.kind == syntax.tykind.TY_STRUCT) { agg = true; };
if (sv.kind == syntax.tykind.TY_ARRAY) { agg = true; };
if (!agg) { return false; };
if (tinfoaggfloat(sv)) {
let m12f: str = "#12/#165: float-bearing aggregate success variant unwrap (S|e)! rides SSE X0/X1; GP cursor unwired\n";
os.write(2, m12f.ptr, m12f.len: u64);
os.exit(1);
};
emitline("\tMOVQ\tDX, AX\n"); emitline("\tMOVQ\tDX, AX\n");
if (sv.size: i32 > 8) { emitline("\tMOVQ\tCX, DX\n"); }; if (sv.size: i32 > 8) { emitline("\tMOVQ\tCX, DX\n"); };
if (sv.size: i32 > 16) { emitline("\tMOVQ\tR8, CX\n"); }; if (sv.size: i32 > 16) { emitline("\tMOVQ\tR8, CX\n"); };
@@ -9106,7 +9122,16 @@ fn cgassign(c: *cgen, n: *syntax.node) void = {
// alignment. esz>8 non-str/non-slice IS struct/array/tuple // alignment. esz>8 non-str/non-slice IS struct/array/tuple
// here (tagged returned above). In-cap only // here (tagged returned above). In-cap only
// (callsretsize==0). Mirror of cstage cgen.c C2c arm. // (callsretsize==0). Mirror of cstage cgen.c C2c arm.
if (n.rhs.kind == syntax.nkind.N_CALL && esz > 8 // #12: an unwrap `mk()!` / `r?` whose success variant
// is an in-cap struct/array rides the SAME {AX,DX,CX}
// payload shape as the call return (the producer shift
// at cgtrytaggedshift materialises it); admit it
// alongside N_CALL so the materialise + copy just works.
// callsretsize==0 holds (non-call → 0); the float/over-
// cap loud-stops live at the producer.
if ((n.rhs.kind == syntax.nkind.N_CALL
|| n.rhs.kind == syntax.nkind.N_TRYUNW
|| n.rhs.kind == syntax.nkind.N_TRYPROP) && esz > 8
&& !isstrtype(c, elemtn) && !isslicetype(c, elemtn) && !isstrtype(c, elemtn) && !isslicetype(c, elemtn)
&& callsretsize(c, n.rhs) == 0) { && callsretsize(c, n.rhs) == 0) {
let scrc2: i32 = tagscradd(c, esz); let scrc2: i32 = tagscradd(c, esz);
@@ -10014,9 +10039,17 @@ fn cgassign(c: *cgen, n: *syntax.node) void = {
// pure-float return eightbyte rides X0/X1 which // pure-float return eightbyte rides X0/X1 which
// the GP AX/DX/CX cursor cannot read). Mirrors // the GP AX/DX/CX cursor cannot read). Mirrors
// cstage cgen.c. // cstage cgen.c.
// #12: an unwrap `arr[i].f = mk()!` rides the same
// {AX,DX,CX} shape (producer shift) — admit it
// alongside N_CALL; the #11b non-call arm below
// excludes the unwrap kinds so this arm is the SOLE
// handler. callsretsize==0 for a non-call, so an
// over-cap unwrap stays loud at the producer.
if (n.op == syntax.tkind.TK_ASSIGN if (n.op == syntax.tkind.TK_ASSIGN
&& n.rhs != nil && n.rhs != nil
&& n.rhs.kind == syntax.nkind.N_CALL) { && (n.rhs.kind == syntax.nkind.N_CALL
|| n.rhs.kind == syntax.nkind.N_TRYUNW
|| n.rhs.kind == syntax.nkind.N_TRYPROP)) {
if (callsretsize(c, n.rhs) > 0) { if (callsretsize(c, n.rhs) > 0) {
let m11o: str = "#11c/#234: over-cap (sret) aggregate field receive arr[i].f=mk() unwired (cs!=ww; task #8)\n"; let m11o: str = "#11c/#234: over-cap (sret) aggregate field receive arr[i].f=mk() unwired (cs!=ww; task #8)\n";
os.write(2, m11o.ptr, m11o.len: u64); os.write(2, m11o.ptr, m11o.len: u64);
@@ -10179,9 +10212,16 @@ fn cgassign(c: *cgen, n: *syntax.node) void = {
// through aggargsrcaddr (src -> SI) + aggcopy — the ONE // through aggargsrcaddr (src -> SI) + aggcopy — the ONE
// copy emitter the non-indexed bases use (DRY, rule 8). // copy emitter the non-indexed bases use (DRY, rule 8).
// tsz natural (fi.fsz, type table). Mirrors cstage cgen.c. // tsz natural (fi.fsz, type table). Mirrors cstage cgen.c.
// #12: exclude the unwrap kinds — the #11 arm above is
// their sole handler (they ride the {AX,DX,CX} register
// cursor, NOT a source address, so aggargsrcaddr can't
// reach them). Pre-#12 an N_TRYUNW matched != N_CALL and
// loud-stopped here; now it materialises in the #11 arm.
if (n.op == syntax.tkind.TK_ASSIGN if (n.op == syntax.tkind.TK_ASSIGN
&& n.rhs != nil && n.rhs != nil
&& n.rhs.kind != syntax.nkind.N_CALL) { && n.rhs.kind != syntax.nkind.N_CALL
&& n.rhs.kind != syntax.nkind.N_TRYUNW
&& n.rhs.kind != syntax.nkind.N_TRYPROP) {
let fk11b: *syntax.tinfo = tichase(fi.tnode.type_: *syntax.tinfo); let fk11b: *syntax.tinfo = tichase(fi.tnode.type_: *syntax.tinfo);
let isagg11b: bool = false; let isagg11b: bool = false;
if (fk11b != nil) { if (fk11b != nil) {
@@ -10458,10 +10498,15 @@ fn cgassign(c: *cgen, n: *syntax.node) void = {
// register RECV reads AX/DX/CX at 8-byte // register RECV reads AX/DX/CX at 8-byte
// granularity — size via structabisize (cstage // granularity — size via structabisize (cstage
// SSoT lu->size, check.c:760; cgen.c:7720 // SSoT lu->size, check.c:760; cgen.c:7720
// sz=lu->size at the receive twin). // sz=lu->size at the receive twin). #12: an
// unwrap `p.f = mk()!` rides the same {AX,DX,CX}
// shape (producer shift) — admit it alongside
// N_CALL; float/over-cap loud-stop at the producer.
if (n.op == syntax.tkind.TK_ASSIGN if (n.op == syntax.tkind.TK_ASSIGN
&& n.rhs != nil && n.rhs != nil
&& n.rhs.kind == syntax.nkind.N_CALL && (n.rhs.kind == syntax.nkind.N_CALL
|| n.rhs.kind == syntax.nkind.N_TRYUNW
|| n.rhs.kind == syntax.nkind.N_TRYPROP)
&& fi.tnode != nil && fi.tnode != nil
&& fi.tnode.kind == syntax.nkind.N_TNAME && fi.tnode.kind == syntax.nkind.N_TNAME
&& aliasprimsize(c, fi.tnode.str) == 0) { && aliasprimsize(c, fi.tnode.str) == 0) {
@@ -10702,10 +10747,15 @@ fn cgassign(c: *cgen, n: *syntax.node) void = {
// directly at (lc.off+fi.foff)(BP). // directly at (lc.off+fi.foff)(BP).
// N_STRUCTLIT: field-walk; each inner // N_STRUCTLIT: field-walk; each inner
// field stored at +fi.foff+inner_foff(BP). // field stored at +fi.foff+inner_foff(BP).
// BP-rel direct, no addr scratch needed. // BP-rel direct, no addr scratch needed. #12: an
// unwrap `b.f = mk()!` rides the same {AX,DX,CX}
// shape (producer shift) — admit it alongside
// N_CALL; float/over-cap loud-stop at the producer.
if (n.op == syntax.tkind.TK_ASSIGN if (n.op == syntax.tkind.TK_ASSIGN
&& n.rhs != nil && n.rhs != nil
&& n.rhs.kind == syntax.nkind.N_CALL && (n.rhs.kind == syntax.nkind.N_CALL
|| n.rhs.kind == syntax.nkind.N_TRYUNW
|| n.rhs.kind == syntax.nkind.N_TRYPROP)
&& fi.tnode != nil && fi.tnode != nil
&& fi.tnode.kind == syntax.nkind.N_TNAME && fi.tnode.kind == syntax.nkind.N_TNAME
&& aliasprimsize(c, fi.tnode.str) == 0) { && aliasprimsize(c, fi.tnode.str) == 0) {

36
selfhost/cmd/wcc/cgenutil.ww
View File

@@ -3013,6 +3013,42 @@ fn aggargfloatstop(n: *syntax.node) bool = {
return false; return false;
}; };
// tinfoaggfloat — does an aggregate tinfo carry ANY float leaf
// (recursively through struct fields / array element / tuple
// positionals)? The #12 producer (cgtrytaggedshift) loud-stops a
// float-bearing aggregate success variant: the union return places a
// float eightbyte in the SSE class (X0/X1) which the GP {AX,DX,CX}
// payload shuffle cannot reach (mirror #11/#165). Conservative — ANY
// float, not a per-eightbyte SSE classify like structfloatclass — a
// loud-stop only needs to refuse, not transport. Mirrors cstage
// agg_has_float (cmd/w6c/cgen.c).
fn tinfoaggfloat(t: *syntax.tinfo) bool = {
if (t == nil) { return false; };
let u: *syntax.tinfo = tichase(t);
if (u == nil) { return false; };
if (syntax.typeisfloat(u)) { return true; };
if (u.kind == syntax.tykind.TY_STRUCT) {
let fi: *syntax.tfield = u.fields;
for (fi != nil) {
if (tinfoaggfloat(fi.type_)) { return true; };
fi = fi.tnext;
};
return false;
};
if (u.kind == syntax.tykind.TY_ARRAY) {
return tinfoaggfloat(u.sub);
};
if (u.kind == syntax.tykind.TY_TUPLE) {
let pe: *syntax.ttupleelem = u.tupleelems;
for (pe != nil) {
if (tinfoaggfloat(pe.type_)) { return true; };
pe = pe.tnext;
};
return false;
};
return false;
};
// structfloatclass — SysV per-eightbyte classification for the #165 // structfloatclass — SysV per-eightbyte classification for the #165
// float-bearing-struct param case (param twin of #171's struct return; // float-bearing-struct param case (param twin of #171's struct return;
// classifies per-eightbyte, not #163's per-element). Returns 0 when the // classifies per-eightbyte, not #163's per-element). Returns 0 when the

77
test/lang/struct_unwrap_test.ww Normal file
View File

@@ -0,0 +1,77 @@
// struct_unwrap_test — #12: an aggregate (struct) success-variant unwrap
// `(S|e)!` / `r?` dropped payload words (SILENT, both stages, byte-id-BLIND).
// A struct success variant rides the in-cap {AX=w0,DX=w1,CX=w2} GP ABI — a
// DIFFERENT shuffle from #6's str/slice {ptr,len,cap} header. Two layers:
// L1 PRODUCER (cgtrytaggedshift / cgen.c N_TRYPROP+N_TRYUNW): a struct/array
// success variant matched no arm and fell to the bare `MOVQ DX,AX`,
// materialising only w0 — w1/w2 (in CX/R8) dropped.
// L2 CONSUMER (the aggregate-STORE arms): gated rhs.kind==N_CALL and stored
// one word for an N_TRYUNW/N_TRYPROP rhs — admitting the unwrap kinds
// reuses the #10-correct scratch materialise.
// Both layers are silent both-stage, so the byte-id gate is BLIND to the drop —
// these VALUE asserts are the sole tooth. Reverting either stage's L2 relax (or
// the shared L1 producer) reverts the dropped word to the poison sentinel 9 and
// reddens. POISON-SEED every dest member to 9 so a dropped w1/w2 reads 9 != the
// expected nonzero value (a fresh-frame 0 would also mismatch, but 9 is robust).
//
// Coverage = the three SILENT store shapes (arr-elem C2c, single-dot field
// direct + via-ptr, indexed-field #11) for a clean 2-eightbyte s2 (w1 tooth)
// plus a 3-eightbyte s24 (w2 tooth — exercises the producer's R8->CX shift).
// The sub-8-tail-THROUGH-unwrap case (#10's tail) is NOT pinnable: an ARRAY
// success variant is checker-rejected (`([7]i16|e)`, task #5/#60) and a sub-8-
// tail STRUCT success variant trips a SEPARATE pre-existing bug — the union-
// return struct-lit fill overruns saved BP when the variant ends at the frame
// edge (g's MOVQ writes past the 14B struct into [BP]); filed for the lead.
package struct_unwrap_test;
type e = !i32;
type s2 = struct { a: i64, b: i64 }; // 2 eightbytes: w0=a, w1=b
type s24 = struct { a: i64, b: i64, c: i64 }; // 3 eightbytes: w0,w1,w2
type box = struct { f: s2, g: i64 };
fn mk2() (s2 | e) = { return s2 { a = 111i64, b = 222i64 }; };
fn mk24() (s24 | e) = { return s24 { a = 111i64, b = 222i64, c = 333i64 }; };
@test fn arr_elem() void = { // L2 site: C2c whole-element arr[i]=mk()!
let arr: [2]s2;
arr[1].a = 9i64; arr[1].b = 9i64; // poison: w1 sentinel 9 != 222
arr[1] = mk2()!;
assert(arr[1].a == 111i64);
assert(arr[1].b == 222i64); // w1 — the dropped-word tooth
};
@test fn arr_elem_w2() void = { // C2c, 3 eightbytes — w2 (R8->CX) tooth
let arr: [2]s24;
arr[1].a = 9i64; arr[1].b = 9i64; arr[1].c = 9i64;
arr[1] = mk24()!;
assert(arr[1].a == 111i64);
assert(arr[1].b == 222i64);
assert(arr[1].c == 333i64); // w2 tooth (>16B producer shift)
};
@test fn field_direct() void = { // L2 site: single-dot direct b.f=mk()!
let b: box = box { f = s2{a=9i64,b=9i64}, g = 7i64 };
b.f = mk2()!;
assert(b.f.a == 111i64);
assert(b.f.b == 222i64); // w1 tooth
assert(b.g == 7i64); // neighbour field intact
};
@test fn field_via_ptr() void = { // L2 site: single-dot via *struct p.f=mk()!
let b: box = box { f = s2{a=9i64,b=9i64}, g = 7i64 };
let p: *box = &b;
p.f = mk2()!;
assert(b.f.a == 111i64);
assert(b.f.b == 222i64); // w1 tooth
assert(b.g == 7i64);
};
@test fn field_of_indexed() void = { // L2 site: #11 indexed-field arr[i].f=mk()!
let arr: [2]box;
arr[1].g = 5i64; arr[1].f.a = 9i64; arr[1].f.b = 9i64;
arr[1].f = mk2()!;
assert(arr[1].f.a == 111i64);
assert(arr[1].f.b == 222i64); // w1 tooth
assert(arr[1].g == 5i64); // neighbour field intact
};