w6c+selfhost: TK_AMP through chained N_DOT (closes #9)

Three shapes handled: value-struct chains (&o.i.a), pointer-field
(&p.f), slice/str pseudo-fields (&s.len). cstage inlines #6's spine
walker; wwstage reuses dotchainresolve unchanged. Silent-drop fallback
preserved.

Slice-header width mismatch in *&s.len writes filed as task #13.
This commit is contained in:
2026-05-13 23:17:15 +09:00
parent 5b098c4a99
commit d053560b80
6 changed files with 865 additions and 0 deletions

View File

@@ -217,6 +217,7 @@ TESTS = $(BIN)/test_smoke $(BIN)/test_lex $(BIN)/test_parse $(BIN)/test_check \
$(BIN)/test_e2e $(BIN)/test_ffi $(BIN)/test_dyn $(BIN)/test_stdlib \
$(BIN)/test_at_test $(BIN)/test_let_global \
$(BIN)/test_int_cast_signed $(BIN)/test_dot_chain \
$(BIN)/test_amp_dot \
$(BIN)/test_field_signed $(BIN)/test_frame_argcount \
$(BIN)/test_selfhost $(BIN)/test_w6a_ww $(BIN)/test_w6l_ww \
$(BIN)/test_w6c_ww $(BIN)/test_ww_ww $(BIN)/test_self_rebuild \
@@ -290,6 +291,12 @@ $(BIN)/test_dot_chain: test/wcc/650_dot_chain.c $(BIN)/ww \
$(LIB)/libwwrt.a | $(BIN)
$(CC) $(CFLAGS) -o $@ $<
$(BIN)/test_amp_dot: test/wcc/690_amp_dot.c $(BIN)/ww \
$(BIN)/w6c $(BIN)/w6a $(BIN)/w6l \
$(BIN)/ww_ww $(BIN)/w6c_ww $(BIN)/w6a_ww $(BIN)/w6l_ww \
$(LIB)/libwwrt.a | $(BIN)
$(CC) $(CFLAGS) -o $@ $<
$(BIN)/test_field_signed: test/wcc/660_field_signed.c $(BIN)/ww \
$(BIN)/w6c $(BIN)/w6a $(BIN)/w6l \
$(BIN)/ww_ww $(BIN)/w6c_ww $(BIN)/w6a_ww $(BIN)/w6l_ww \

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@@ -1287,6 +1287,134 @@ cgexpr(Cg *c, Node *n, Local *locals)
}
break;
}
if (opnd && opnd->kind == N_DOT) {
/* Address-of through a DOT chain. The early-exit
* above handled `&ident` and `&base[i]`; everything
* else was silently dropped. Three shapes converge
* here, all returning an 8B address (so no
* fldloadop dispatch — just LEAQ).
*
* 1. Value-struct fields, any depth (`&o.f`,
* `&o.i.a`, `&o.a.b.c`): walk the spine to a
* root ident, sum field offsets, emit LEAQ at
* base + sum. Mirror of the read at line 3722.
* 2. Slice/str pseudo-field tail (`&s.len`,
* `&b.buf.len`): folds into the spine walk
* with slice_delta 0/8/16.
* 3. Pointer-field (`&p.f` where p:*T): the spine
* walk aborts at the *T base; the fallback
* below loads p into AX and adds field_off.
*/
int amped = 0;
/* Spine walk — same shape as the read at 3722.
* Records (parent_struct, field_name) leaf-first,
* then iterates root-first to sum offsets. */
struct { Type *pu; const char *name; } steps[16];
int nsteps = 0;
Node *cur = opnd;
int abort = 0;
while (cur && cur->kind == N_DOT && cur->lhs) {
Type *pt = cur->lhs->type;
Type *pu = (pt && pt->kind == TY_NAMED)
? pt->under : pt;
if (!pu) { abort = 1; break; }
if (cur == opnd && (pu->kind == TY_SLICE
|| pu->kind == TY_STR)) {
/* leaf pseudo on slice/str header */
} else if (pu->kind != TY_STRUCT) {
abort = 1;
break;
}
if (nsteps >= 16) { abort = 1; break; }
steps[nsteps].pu = pu;
steps[nsteps].name = cur->str;
nsteps++;
cur = cur->lhs;
}
if (!abort && cur && cur->kind == N_IDENT
&& nsteps > 0) {
int total_off = 0;
int slice_delta = -1;
int ok = 1;
for (int i = nsteps - 1; i >= 0; i--) {
Type *pu = steps[i].pu;
if (pu->kind == TY_SLICE
|| pu->kind == TY_STR) {
if (strcmp(steps[i].name, "ptr") == 0)
slice_delta = 0;
else if (strcmp(steps[i].name, "len") == 0)
slice_delta = 8;
else if (strcmp(steps[i].name, "cap") == 0)
slice_delta = 16;
else { ok = 0; break; }
} else {
Tfield *f = NULL;
for (Tfield *fl = pu->fields; fl; fl = fl->next)
if (strcmp(fl->name, steps[i].name) == 0)
{ f = fl; break; }
if (!f) { ok = 0; break; }
total_off += (int)f->offset;
}
}
if (ok) {
int extra = (slice_delta >= 0)
? slice_delta : 0;
int root_off = localfind(locals, cur->str);
if (root_off != 0) {
ins2(c, A_LEAQ,
amem(D_BP,
root_off + total_off + extra),
areg(D_AX));
amped = 1;
} else if (let_islet(cur->str)) {
/* Two-step global form mirrors the
* read path's `LEAQ name,CX → MOVQ
* disp(CX),AX`, swapping the MOVQ
* for LEAQ. */
ins2(c, A_LEAQ,
masym(c, cur->str), areg(D_CX));
ins2(c, A_LEAQ,
amem(D_CX, total_off + extra),
areg(D_AX));
amped = 1;
}
}
}
/* Pointer-field fallback for `&p.f` where p:*T —
* the spine walker aborts on the *T base. Load p
* into AX, then LEAQ field_off(AX),AX. Mirror of
* the read at line 4033. */
if (!amped && opnd->lhs
&& opnd->lhs->kind == N_IDENT) {
Type *bt = opnd->lhs->type;
Type *bu = (bt && bt->kind == TY_NAMED)
? bt->under : bt;
if (bu && bu->kind == TY_PTR && bu->sub) {
Type *inner = bu->sub;
if (inner->kind == TY_NAMED)
inner = inner->under;
if (inner && inner->kind == TY_STRUCT) {
for (Tfield *f = inner->fields;
f; f = f->next) {
if (strcmp(f->name, opnd->str) != 0)
continue;
int off = localfind(locals,
opnd->lhs->str);
ins2(c, A_MOVQ,
amem(D_BP, off),
areg(D_AX));
ins2(c, A_LEAQ,
amem(D_AX, (int)f->offset),
areg(D_AX));
amped = 1;
break;
}
}
}
}
if (amped) break;
/* Fall through to silent-drop fallback below. */
}
if (opnd && opnd->kind == N_INDEX) {
/* &base[i] = base + i*esz, no dereference. */
Node *base = opnd->lhs;

View File

@@ -9918,6 +9918,169 @@ fn cgun(c: *cgen, n: *node) void = {
};
return;
};
// Address-of through a DOT chain. Mirror of cstage
// cgen.c TK_AMP N_DOT branch. Three shapes converge
// here, all returning an 8B address (no fldloadop —
// just LEAQ / MOVQ+LEAQ).
//
// 1. Value-struct fields, any depth (`&o.f`,
// `&o.i.a`, `&o.a.b.c`) and slice/str pseudo-field
// tail (`&s.len`, `&b.buf.len`): the chained
// (depth ≥ 2) case reuses dotchainresolve; the
// single-DOT case is handled below by inspecting
// the IDENT base's tnode. Byte-identical to the
// cstage spine walker for both depths.
// 2. Pointer-field (`&p.f` where p:*T): single-DOT
// only; spine walker aborts on the *T base. Load
// p into AX, then LEAQ field_off(AX), AX. Mirror
// of the read at cgdot 1144.
if (opnd.kind == nkind.N_DOT) {
// Shape 1 chained: depth-≥2 via dotchainresolve.
// `opnd.lhs.kind == N_DOT` gates the helper at
// nsteps ≥ 2 (matches the read path's gate).
if (opnd.lhs != nil) {
if (opnd.lhs.kind == nkind.N_DOT) {
let r: dotchain;
let pok: bool = dotchainresolve(c, opnd, &r);
if (pok) {
let extra: i64 = 0i64;
if (r.slicedelta >= 0i64) { extra = r.slicedelta; };
if (r.isglobal) {
emitline("\tLEAQ\t");
emitsymname(c, r.rootname);
emitline("(SB), CX\n");
emitline("\tLEAQ\t");
emitdispreg(r.totaloff + extra, "CX");
emitline(", AX\n");
} else {
emitline("\tLEAQ\t");
emitoff(r.rootoff + r.totaloff + extra);
emitline("(BP), AX\n");
};
return;
};
};
};
// Shape 1/2 single-DOT on an IDENT base. Inspect
// the base's tnode to pick value-struct vs slice/
// str pseudo vs pointer-field.
if (opnd.lhs != nil) {
if (opnd.lhs.kind == nkind.N_IDENT) {
let basenm: str = opnd.lhs.str;
let fld: str = opnd.str;
let lc: *local = localfindnode(c, basenm);
if (lc != nil) {
let tn: *node = lc.tnode;
let lkind: nkind = nkind.N_NONE;
if (tn != nil) { lkind = tn.kind; };
// Pointer-field: &p.f where p:*T.
if (lkind == nkind.N_TPTR) {
let inner: *node = tn.lhs;
let sname: str;
sname.ptr = nil; sname.len = 0;
if (inner != nil) {
if (inner.kind == nkind.N_TNAME) { sname = inner.str; };
};
if (sname.len > 0) {
let si: *structinfo = structlookup(c, sname);
if (si != nil) {
let fi: *fieldinfo = si.fields;
for (fi != nil) {
if (streq(fi.fname, fld)) {
emitline("\tMOVQ\t");
emitoff(lc.off: i64);
emitline("(BP), AX\n");
emitline("\tLEAQ\t");
emitdispreg(fi.foff: i64, "AX");
emitline(", AX\n");
return;
};
fi = fi.finext;
};
};
};
};
// Value-struct local: &o.f.
if (lkind == nkind.N_TNAME) {
let sname: str = tn.str;
let si: *structinfo = structlookup(c, sname);
if (si != nil) {
let fi: *fieldinfo = si.fields;
for (fi != nil) {
if (streq(fi.fname, fld)) {
emitline("\tLEAQ\t");
emitoff((lc.off + fi.foff): i64);
emitline("(BP), AX\n");
return;
};
fi = fi.finext;
};
};
};
// Slice/str pseudo-field on a local:
// &s.ptr / &s.len / &s.cap. Delta is
// 0/8/16 — matches the spine walker.
let delta: i32 = -1;
if (streq(fld, "ptr")) { delta = 0; };
if (streq(fld, "len")) { delta = 8; };
if (streq(fld, "cap")) { delta = 16; };
if (delta >= 0) {
let isslor: bool = false;
if (lkind == nkind.N_TSLICE) { isslor = true; };
if (lkind == nkind.N_TNAME) {
if (streq(tn.str, "str")) { isslor = true; };
};
if (isslor) {
emitline("\tLEAQ\t");
emitoff((lc.off + delta): i64);
emitline("(BP), AX\n");
return;
};
};
};
// Global root: top-level let, either a
// struct or a slice/str.
if (isletvar(c, basenm)) {
let gsi: *structinfo = letvarstructinfo(c, basenm);
if (gsi != nil) {
let fi: *fieldinfo = gsi.fields;
for (fi != nil) {
if (streq(fi.fname, fld)) {
emitline("\tLEAQ\t");
emitsymname(c, basenm);
emitline("(SB), CX\n");
emitline("\tLEAQ\t");
emitdispreg(fi.foff: i64, "CX");
emitline(", AX\n");
return;
};
fi = fi.finext;
};
};
let isstr: bool = letvarisstr(c, basenm);
let issl: bool = letvarisslice(c, basenm);
if (isstr || issl) {
let gdelta: i32 = -1;
if (streq(fld, "ptr")) { gdelta = 0; };
if (streq(fld, "len")) { gdelta = 8; };
if (issl) { if (streq(fld, "cap")) { gdelta = 16; }; };
if (gdelta >= 0) {
emitline("\tLEAQ\t");
emitsymname(c, basenm);
emitline("(SB), CX\n");
emitline("\tLEAQ\t");
emitdispreg(gdelta: i64, "CX");
emitline(", AX\n");
return;
};
};
};
};
};
// Fall through silently (mirrors cstage silent-
// drop fallback at the end of the TK_AMP block).
return;
};
if (opnd.kind == nkind.N_INDEX) {
// &base[i] = base + i*esz, no dereference.
let base: *node = opnd.lhs;

View File

@@ -1868,6 +1868,169 @@ fn cgun(c: *cgen, n: *node) void = {
};
return;
};
// Address-of through a DOT chain. Mirror of cstage
// cgen.c TK_AMP N_DOT branch. Three shapes converge
// here, all returning an 8B address (no fldloadop —
// just LEAQ / MOVQ+LEAQ).
//
// 1. Value-struct fields, any depth (`&o.f`,
// `&o.i.a`, `&o.a.b.c`) and slice/str pseudo-field
// tail (`&s.len`, `&b.buf.len`): the chained
// (depth ≥ 2) case reuses dotchainresolve; the
// single-DOT case is handled below by inspecting
// the IDENT base's tnode. Byte-identical to the
// cstage spine walker for both depths.
// 2. Pointer-field (`&p.f` where p:*T): single-DOT
// only; spine walker aborts on the *T base. Load
// p into AX, then LEAQ field_off(AX), AX. Mirror
// of the read at cgdot 1144.
if (opnd.kind == nkind.N_DOT) {
// Shape 1 chained: depth-≥2 via dotchainresolve.
// `opnd.lhs.kind == N_DOT` gates the helper at
// nsteps ≥ 2 (matches the read path's gate).
if (opnd.lhs != nil) {
if (opnd.lhs.kind == nkind.N_DOT) {
let r: dotchain;
let pok: bool = dotchainresolve(c, opnd, &r);
if (pok) {
let extra: i64 = 0i64;
if (r.slicedelta >= 0i64) { extra = r.slicedelta; };
if (r.isglobal) {
emitline("\tLEAQ\t");
emitsymname(c, r.rootname);
emitline("(SB), CX\n");
emitline("\tLEAQ\t");
emitdispreg(r.totaloff + extra, "CX");
emitline(", AX\n");
} else {
emitline("\tLEAQ\t");
emitoff(r.rootoff + r.totaloff + extra);
emitline("(BP), AX\n");
};
return;
};
};
};
// Shape 1/2 single-DOT on an IDENT base. Inspect
// the base's tnode to pick value-struct vs slice/
// str pseudo vs pointer-field.
if (opnd.lhs != nil) {
if (opnd.lhs.kind == nkind.N_IDENT) {
let basenm: str = opnd.lhs.str;
let fld: str = opnd.str;
let lc: *local = localfindnode(c, basenm);
if (lc != nil) {
let tn: *node = lc.tnode;
let lkind: nkind = nkind.N_NONE;
if (tn != nil) { lkind = tn.kind; };
// Pointer-field: &p.f where p:*T.
if (lkind == nkind.N_TPTR) {
let inner: *node = tn.lhs;
let sname: str;
sname.ptr = nil; sname.len = 0;
if (inner != nil) {
if (inner.kind == nkind.N_TNAME) { sname = inner.str; };
};
if (sname.len > 0) {
let si: *structinfo = structlookup(c, sname);
if (si != nil) {
let fi: *fieldinfo = si.fields;
for (fi != nil) {
if (streq(fi.fname, fld)) {
emitline("\tMOVQ\t");
emitoff(lc.off: i64);
emitline("(BP), AX\n");
emitline("\tLEAQ\t");
emitdispreg(fi.foff: i64, "AX");
emitline(", AX\n");
return;
};
fi = fi.finext;
};
};
};
};
// Value-struct local: &o.f.
if (lkind == nkind.N_TNAME) {
let sname: str = tn.str;
let si: *structinfo = structlookup(c, sname);
if (si != nil) {
let fi: *fieldinfo = si.fields;
for (fi != nil) {
if (streq(fi.fname, fld)) {
emitline("\tLEAQ\t");
emitoff((lc.off + fi.foff): i64);
emitline("(BP), AX\n");
return;
};
fi = fi.finext;
};
};
};
// Slice/str pseudo-field on a local:
// &s.ptr / &s.len / &s.cap. Delta is
// 0/8/16 — matches the spine walker.
let delta: i32 = -1;
if (streq(fld, "ptr")) { delta = 0; };
if (streq(fld, "len")) { delta = 8; };
if (streq(fld, "cap")) { delta = 16; };
if (delta >= 0) {
let isslor: bool = false;
if (lkind == nkind.N_TSLICE) { isslor = true; };
if (lkind == nkind.N_TNAME) {
if (streq(tn.str, "str")) { isslor = true; };
};
if (isslor) {
emitline("\tLEAQ\t");
emitoff((lc.off + delta): i64);
emitline("(BP), AX\n");
return;
};
};
};
// Global root: top-level let, either a
// struct or a slice/str.
if (isletvar(c, basenm)) {
let gsi: *structinfo = letvarstructinfo(c, basenm);
if (gsi != nil) {
let fi: *fieldinfo = gsi.fields;
for (fi != nil) {
if (streq(fi.fname, fld)) {
emitline("\tLEAQ\t");
emitsymname(c, basenm);
emitline("(SB), CX\n");
emitline("\tLEAQ\t");
emitdispreg(fi.foff: i64, "CX");
emitline(", AX\n");
return;
};
fi = fi.finext;
};
};
let isstr: bool = letvarisstr(c, basenm);
let issl: bool = letvarisslice(c, basenm);
if (isstr || issl) {
let gdelta: i32 = -1;
if (streq(fld, "ptr")) { gdelta = 0; };
if (streq(fld, "len")) { gdelta = 8; };
if (issl) { if (streq(fld, "cap")) { gdelta = 16; }; };
if (gdelta >= 0) {
emitline("\tLEAQ\t");
emitsymname(c, basenm);
emitline("(SB), CX\n");
emitline("\tLEAQ\t");
emitdispreg(gdelta: i64, "CX");
emitline(", AX\n");
return;
};
};
};
};
};
// Fall through silently (mirrors cstage silent-
// drop fallback at the end of the TK_AMP block).
return;
};
if (opnd.kind == nkind.N_INDEX) {
// &base[i] = base + i*esz, no dereference.
let base: *node = opnd.lhs;

View File

@@ -9918,6 +9918,169 @@ fn cgun(c: *cgen, n: *node) void = {
};
return;
};
// Address-of through a DOT chain. Mirror of cstage
// cgen.c TK_AMP N_DOT branch. Three shapes converge
// here, all returning an 8B address (no fldloadop —
// just LEAQ / MOVQ+LEAQ).
//
// 1. Value-struct fields, any depth (`&o.f`,
// `&o.i.a`, `&o.a.b.c`) and slice/str pseudo-field
// tail (`&s.len`, `&b.buf.len`): the chained
// (depth ≥ 2) case reuses dotchainresolve; the
// single-DOT case is handled below by inspecting
// the IDENT base's tnode. Byte-identical to the
// cstage spine walker for both depths.
// 2. Pointer-field (`&p.f` where p:*T): single-DOT
// only; spine walker aborts on the *T base. Load
// p into AX, then LEAQ field_off(AX), AX. Mirror
// of the read at cgdot 1144.
if (opnd.kind == nkind.N_DOT) {
// Shape 1 chained: depth-≥2 via dotchainresolve.
// `opnd.lhs.kind == N_DOT` gates the helper at
// nsteps ≥ 2 (matches the read path's gate).
if (opnd.lhs != nil) {
if (opnd.lhs.kind == nkind.N_DOT) {
let r: dotchain;
let pok: bool = dotchainresolve(c, opnd, &r);
if (pok) {
let extra: i64 = 0i64;
if (r.slicedelta >= 0i64) { extra = r.slicedelta; };
if (r.isglobal) {
emitline("\tLEAQ\t");
emitsymname(c, r.rootname);
emitline("(SB), CX\n");
emitline("\tLEAQ\t");
emitdispreg(r.totaloff + extra, "CX");
emitline(", AX\n");
} else {
emitline("\tLEAQ\t");
emitoff(r.rootoff + r.totaloff + extra);
emitline("(BP), AX\n");
};
return;
};
};
};
// Shape 1/2 single-DOT on an IDENT base. Inspect
// the base's tnode to pick value-struct vs slice/
// str pseudo vs pointer-field.
if (opnd.lhs != nil) {
if (opnd.lhs.kind == nkind.N_IDENT) {
let basenm: str = opnd.lhs.str;
let fld: str = opnd.str;
let lc: *local = localfindnode(c, basenm);
if (lc != nil) {
let tn: *node = lc.tnode;
let lkind: nkind = nkind.N_NONE;
if (tn != nil) { lkind = tn.kind; };
// Pointer-field: &p.f where p:*T.
if (lkind == nkind.N_TPTR) {
let inner: *node = tn.lhs;
let sname: str;
sname.ptr = nil; sname.len = 0;
if (inner != nil) {
if (inner.kind == nkind.N_TNAME) { sname = inner.str; };
};
if (sname.len > 0) {
let si: *structinfo = structlookup(c, sname);
if (si != nil) {
let fi: *fieldinfo = si.fields;
for (fi != nil) {
if (streq(fi.fname, fld)) {
emitline("\tMOVQ\t");
emitoff(lc.off: i64);
emitline("(BP), AX\n");
emitline("\tLEAQ\t");
emitdispreg(fi.foff: i64, "AX");
emitline(", AX\n");
return;
};
fi = fi.finext;
};
};
};
};
// Value-struct local: &o.f.
if (lkind == nkind.N_TNAME) {
let sname: str = tn.str;
let si: *structinfo = structlookup(c, sname);
if (si != nil) {
let fi: *fieldinfo = si.fields;
for (fi != nil) {
if (streq(fi.fname, fld)) {
emitline("\tLEAQ\t");
emitoff((lc.off + fi.foff): i64);
emitline("(BP), AX\n");
return;
};
fi = fi.finext;
};
};
};
// Slice/str pseudo-field on a local:
// &s.ptr / &s.len / &s.cap. Delta is
// 0/8/16 — matches the spine walker.
let delta: i32 = -1;
if (streq(fld, "ptr")) { delta = 0; };
if (streq(fld, "len")) { delta = 8; };
if (streq(fld, "cap")) { delta = 16; };
if (delta >= 0) {
let isslor: bool = false;
if (lkind == nkind.N_TSLICE) { isslor = true; };
if (lkind == nkind.N_TNAME) {
if (streq(tn.str, "str")) { isslor = true; };
};
if (isslor) {
emitline("\tLEAQ\t");
emitoff((lc.off + delta): i64);
emitline("(BP), AX\n");
return;
};
};
};
// Global root: top-level let, either a
// struct or a slice/str.
if (isletvar(c, basenm)) {
let gsi: *structinfo = letvarstructinfo(c, basenm);
if (gsi != nil) {
let fi: *fieldinfo = gsi.fields;
for (fi != nil) {
if (streq(fi.fname, fld)) {
emitline("\tLEAQ\t");
emitsymname(c, basenm);
emitline("(SB), CX\n");
emitline("\tLEAQ\t");
emitdispreg(fi.foff: i64, "CX");
emitline(", AX\n");
return;
};
fi = fi.finext;
};
};
let isstr: bool = letvarisstr(c, basenm);
let issl: bool = letvarisslice(c, basenm);
if (isstr || issl) {
let gdelta: i32 = -1;
if (streq(fld, "ptr")) { gdelta = 0; };
if (streq(fld, "len")) { gdelta = 8; };
if (issl) { if (streq(fld, "cap")) { gdelta = 16; }; };
if (gdelta >= 0) {
emitline("\tLEAQ\t");
emitsymname(c, basenm);
emitline("(SB), CX\n");
emitline("\tLEAQ\t");
emitdispreg(gdelta: i64, "CX");
emitline(", AX\n");
return;
};
};
};
};
};
// Fall through silently (mirrors cstage silent-
// drop fallback at the end of the TK_AMP block).
return;
};
if (opnd.kind == nkind.N_INDEX) {
// &base[i] = base + i*esz, no dereference.
let base: *node = opnd.lhs;

241
test/wcc/690_amp_dot.c Normal file
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@@ -0,0 +1,241 @@
/*
* 690_amp_dot — address-of through a DOT chain.
*
* cstage's TK_AMP early-exit historically only handled `&ident` and
* `&base[i]`; everything else fell through to a silent-drop fallback,
* so `&o.i.a` left AX undefined (not even the value — undefined).
* Filed as task #9 from worker-chained-dot judgement #3. Pinned here:
*
* - single-DOT `&o.f` on a value-struct local AND a global root,
* - chained `&o.i.a` on a value-struct (depth 2),
* - 3-deep `&o.a.b.c` (confirms the walker is loop-shaped, not
* hardcoded to depth 2),
* - pointer-field `&p.f` where p:*T,
* - slice-header `&s.len`: write through it (`*&s.len = 0;`) and
* read back via `s.len`. This is the motivating Hare-slice-header
* poke pattern — the whole reason this gap got filed.
* - address agrees with read: `*&o.i.a == o.i.a` round-trips so the
* spine walk's offset arithmetic matches the read path's.
*
* Exercises both stages via `ww` (cstage) and `ww_ww` (wwstage) when
* present.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/wait.h>
static int
runwait(const char *cmd)
{
int rc = system(cmd);
if (rc == -1) return -1;
if (WIFEXITED(rc)) return WEXITSTATUS(rc);
return -1;
}
struct row { const char *label; const char *src; int want; };
static const struct row rows[] = {
/* &o.f single-DOT on a value-struct local. Round-trips a write
* through the address, returns the field directly. */
{ "amp_dot_single_local",
"type pt = struct { x: i32, y: i32 };\n"
"fn main() i32 = {\n"
" let o: pt;\n"
" let p: *i32 = &o.x;\n"
" *p = 21;\n"
" return o.x;\n"
"};\n",
21 },
/* &g.f single-DOT on a global (top-level let) struct root.
* Pins the LEAQ name(SB), CX → LEAQ disp(CX), AX form. */
{ "amp_dot_single_global",
"type pt = struct { x: i32, y: i32 };\n"
"let g: pt;\n"
"fn main() i32 = {\n"
" let p: *i32 = &g.x;\n"
" *p = 33;\n"
" return g.x;\n"
"};\n",
33 },
/* &o.i.a — Drew's chained value-struct shape. Address-of side
* of task #6's read fix. */
{ "amp_dot_chain_2deep",
"type inner = struct { a: i32, b: i32 };\n"
"type outer = struct { i: inner, x: i32 };\n"
"fn main() i32 = {\n"
" let o: outer;\n"
" let p: *i32 = &o.i.a;\n"
" *p = 17;\n"
" return o.i.a;\n"
"};\n",
17 },
/* 3-deep chain: confirms the spine walker is loop-shaped, not
* hardcoded to depth 2. Same shape as 650's value_struct_3deep
* but going through &. */
{ "amp_dot_chain_3deep",
"type a3 = struct { a: i32 };\n"
"type a2 = struct { a: a3 };\n"
"type a1 = struct { a: a2 };\n"
"fn main() i32 = {\n"
" let v: a1;\n"
" let p: *i32 = &v.a.a.a;\n"
" *p = 9;\n"
" return v.a.a.a;\n"
"};\n",
9 },
/* &p.f where p:*T (pointer-field). Spine walker aborts on the
* *T base; the pointer-field fallback should fire. */
{ "amp_dot_ptr_field",
"type pt = struct { x: i32, y: i32 };\n"
"fn main() i32 = {\n"
" let o: pt;\n"
" o.x = 0; o.y = 0;\n"
" let p: *pt = &o;\n"
" let q: *i32 = &p.y;\n"
" *q = 55;\n"
" return o.y;\n"
"};\n",
55 },
/* The motivating idiom: write through `&s.len` on a slice header
* to truncate without re-allocating. Mirrors the Hare slice-
* header poke pattern that bufio will eventually want. Test:
* fill a slice's len to 5, then *&s.len = 0; assert s.len == 0. */
{ "amp_dot_slice_len_writethrough",
"fn main() i32 = {\n"
" let arr: [4]u8;\n"
" let s: []u8;\n"
" s.ptr = &arr[0];\n"
" s.len = 4;\n"
" s.cap = 4;\n"
" let q: *i32 = &s.len;\n"
" *q = 0;\n"
" return s.len: i32;\n"
"};\n",
0 },
/* &o.s.ptr — slice-FIELD of a struct: combines shape 1 (walk
* into struct field at .s) and shape 3 (slice pseudo-tail
* .ptr at offset 0 of the header). Proves the spine walker's
* slice_delta fold composes with the struct-field offset; the
* write through `*&o.s.ptr` must land at the slice header's
* ptr slot inside the enclosing struct. */
{ "amp_dot_slice_field_ptr",
"type wrap = struct { s: []u8, x: i32 };\n"
"fn main() i32 = {\n"
" let arr: [4]u8;\n"
" let w: wrap;\n"
" w.s.len = 4; w.s.cap = 4;\n"
" let pp: **u8 = &w.s.ptr;\n"
" *pp = &arr[0];\n"
" arr[0] = 71;\n"
" return w.s.ptr[0]: i32;\n"
"};\n",
71 },
/* Address agrees with read: `*&o.i.a == o.i.a`. The deref load
* of the address must reproduce the same value the read path
* lowers — proves the spine walker's offset sum is identical
* across both directions. */
{ "amp_dot_addr_eq_read",
"type inner = struct { a: i32, b: i32 };\n"
"type outer = struct { i: inner, x: i32 };\n"
"fn main() i32 = {\n"
" let o: outer;\n"
" o.i.a = 41;\n"
" let p: *i32 = &o.i.a;\n"
" if (*p == o.i.a) { return 42; };\n"
" return 0;\n"
"};\n",
42 },
};
static int
run_driver(const char *driver, const struct row *r, int i)
{
char src[64], tmpdir[64], cmd[1024];
snprintf(src, sizeof src, "/tmp/wad_%d_%d.ww", getpid(), i);
snprintf(tmpdir, sizeof tmpdir, "/tmp/wad_%d_d_%d", getpid(), i);
FILE *f = fopen(src, "wb");
if (!f) return -1;
fputs(r->src, f);
fclose(f);
mkdir(tmpdir, 0755);
snprintf(cmd, sizeof cmd, "cd %s && %s build %s",
tmpdir, driver, src);
if (runwait(cmd) != 0) {
fprintf(stderr, "row[%s]: build via %s failed\n",
r->label, driver);
unlink(src); rmdir(tmpdir);
return -1;
}
const char *base = strrchr(src, '/');
base = base ? base + 1 : src;
char outbin[128];
snprintf(outbin, sizeof outbin, "%s/%s", tmpdir, base);
char *dot = strrchr(outbin, '.');
if (dot && strcmp(dot, ".ww") == 0) *dot = '\0';
int got = runwait(outbin);
unlink(src); unlink(outbin); rmdir(tmpdir);
return got;
}
int
main(void)
{
const char *bin = getenv("BIN");
if (!bin) bin = "out/bin";
char absbin[1024];
if (bin[0] != '/') {
char cwd[1024];
if (getcwd(cwd, sizeof cwd) == NULL) return 1;
snprintf(absbin, sizeof absbin, "%s/%s", cwd, bin);
bin = absbin;
}
char cdrv[1100];
snprintf(cdrv, sizeof cdrv, "%s/ww", bin);
char wdrv[1100];
snprintf(wdrv, sizeof wdrv, "%s/ww_ww", bin);
struct { const char *name; const char *path; int gated_on_existence; }
drivers[] = {
{ "cstage", cdrv, 0 },
{ "wwstage", wdrv, 1 },
{ NULL, NULL, 0 },
};
int n = (int)(sizeof rows / sizeof rows[0]);
int total = 0, fail = 0;
for (int d = 0; drivers[d].name; d++) {
if (drivers[d].gated_on_existence
&& access(drivers[d].path, X_OK) != 0) {
fprintf(stderr, "amp_dot: skip %s (no %s)\n",
drivers[d].name, drivers[d].path);
continue;
}
for (int i = 0; i < n; i++) {
int got = run_driver(drivers[d].path, &rows[i], i);
total++;
if (got != rows[i].want) {
fprintf(stderr,
"amp_dot[%s][%s]: exit=%d want=%d\n",
drivers[d].name, rows[i].label,
got, rows[i].want);
fail++;
}
}
}
if (fail) {
fprintf(stderr,
"amp_dot: %d/%d fixtures failed\n", fail, total);
return 1;
}
printf("amp_dot: %d/%d ok\n", total, total);
return 0;
}