w6c: fix global-ptr field-store SEGV via decline-to-resolver (#6)

A module-global pointer's field store/compound (`let gp:*S=nil; gp.f += 5`,
`gp.in = Inner{...}`) SEGV'd in cstage: the enumerated N_DOT-lhs arms load
the base pointer with `MOVQ boff(BP),BX`, valid only for a LOCAL ptr slot,
but a module-global ptr has no local slot (localfind=0) so it dereferenced
the saved BP. wwstage was correct -- it routes these through its F6
cgplaceaddr resolver (its dedicated arm is scalar-`=`-only by design,
#60/#61). The byte-id gate was blind (no global-ptr compound in the
bootstrap corpus) and the deferral note was stale: this is a live cs!=ww
divergence with wwstage as the oracle.

cstage already has an equivalent assign-resolver (cgen.c ~7488) that emits
byte-identically to wwstage's F6 route, but the enumerated arms intercepted
the global case first. Fix (align cstage UP, cstage-only): two precondition
entry-guards decline a module-global `*struct` base for the compound +
non-scalar-field cases so they fall through to the resolver. Plain-scalar
`=` stays in the enumerated arm (its #47 fix already matches wwstage). The
decline and resolver accept-sets exactly partition the global-base
N_DOT-lhs space (no gap, no overlap); tagged/float field stores now both
loud-stop symmetrically (were SEGV'ing). The discriminant keys on
localfind-presence + let_islet, so a param at offset 0 stays local.

New both-stage + byte-id test 689_globptr_field_store_run covers offset-0/8,
compound, struct/str field, chained gp.x.y, indexed gp.a[i].f, with local +
offset-0-param controls. The field-READ path is independently broken in
both stages (filed #15). make clean && make test: all 403 passed, byte-id
990-996 green.
This commit is contained in:
2026-06-23 01:12:27 +09:00
parent 30a4920ccf
commit 02967e04ce
3 changed files with 309 additions and 2 deletions

View File

@@ -325,6 +325,7 @@ TESTS = $(BIN)/test_smoke $(BIN)/test_lex $(BIN)/test_parse $(BIN)/test_check \
$(BIN)/test_global_arr_elem_field \
$(BIN)/test_structlit_slice_field \
$(BIN)/test_arrglob_nodup_run \
$(BIN)/test_globptr_field_store_run \
$(BIN)/test_dot_str_chained_arg \
$(BIN)/test_dot_slice_arg \
$(BIN)/test_dot_tagged_source \
@@ -1448,6 +1449,15 @@ $(BIN)/test_arrglob_nodup_run: test/wcc/689_arrglob_nodup_run.c $(BIN)/ww \
$(LIB)/libwwrt.a | $(BIN)
$(CC) $(CFLAGS) -o $@ $<
# 689_globptr_field_store_run (#6): a module-global *struct ptr base field
# store (compound / non-scalar / chained / indexed) no longer SEGVs in cstage
# and is byte-identical to wwstage (cstage aligned UP via decline-to-resolver).
$(BIN)/test_globptr_field_store_run: test/wcc/689_globptr_field_store_run.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_dot_str_chained_arg: test/wcc/692_dot_str_chained_arg.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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@@ -2406,6 +2406,74 @@ cgplaceaddr(Cg *c, Node *n, int dst_reg, Local *locals)
return 0;
}
/* #6 — a module-GLOBAL `*struct` pointer base (`gp.f = v`, `gp.f += v`)
* carries via_ptr=1 but has NO local slot: localfind returns 0, so the
* enumerated via_ptr field-store arms emit `MOVQ (BP),BX` (deref the
* saved BP = garbage → SEGV). wwstage routes every such case EXCEPT
* plain-scalar-`=` through its F6 cgplaceaddr resolver (the scalar-only
* dedicated arm, selfhost cgenexpr.ww; compound + non-scalar = the
* deferred #60/#61). cstage's own F6 assign-resolver (cgen.c N_ASSIGN,
* via cgplaceaddr) emits byte-identically. So decline those cases at the
* enumerated arm's dispatch — they fall to the resolver, aligning cstage
* UP to wwstage and restoring byte-id (handle where the resolver handles;
* loud-stop, same message, where it loud-stops on tagged/float). The
* plain-scalar-`=` struct-field case STAYS in the enumerated arm — its
* #47 fix already matches wwstage's dedicated arm. Discriminant is
* localfind-ABSENCE + let_islet (storage class), NEVER a boff==0
* sentinel: a param at offset 0 has localfind != 0 and stays local. */
static int
global_ptr_field_decline(Node *lhs, int op, Local *locals)
{
if (lhs == NULL || lhs->kind != N_DOT || lhs->lhs == NULL)
return 0;
Node *base = lhs->lhs;
if (base->kind == N_UN && base->op == TK_STAR) base = base->lhs;
if (base == NULL || base->kind != N_IDENT) return 0;
if (localfind(locals, base->str) != 0 || !let_islet(base->str))
return 0;
Type *bu = type_chase_named(base->type);
if (bu == NULL || bu->kind != TY_PTR) return 0;
Type *su = type_chase_named(bu->sub);
if (su == NULL) return 0;
/* `(*gp).ptr/.len/.cap` pseudo-field: no struct field, always
* resolver (wwstage loud-stops "unsupported assign target shape"). */
if (su->kind == TY_SLICE || su->kind == TY_STR) return 1;
if (su->kind != TY_STRUCT) return 0;
if (op != TK_ASSIGN) return 1;
for (Tfield *fl = su->fields; fl; fl = fl->next)
if (strcmp(fl->name, lhs->str) == 0) {
Type *fu = type_chase_named(fl->type);
int isf32 = 0;
if (fld_isfloat(fl->type, &isf32)) return 1;
if (fu && (fu->kind == TY_STRUCT
|| fu->kind == TY_ARRAY || fu->kind == TY_TUPLE
|| fu->kind == TY_STR || fu->kind == TY_SLICE
|| fu->kind == TY_TAGGED))
return 1;
return 0;
}
return 0;
}
/* #6 (chained twin) — a multi-dot LHS (`gp.x.y = v`) rooted at a module-
* GLOBAL pointer the walk dereferences: the chained value-struct walker
* (cgen.c N_ASSIGN) conflates is_global with ptr_root and emits the same
* `MOVQ (BP),CX` SEGV for plain `=`. Decline at entry → the F6 resolver
* (byte-id with wwstage). A global VALUE-struct root (`gv.x.y`, root type
* TY_STRUCT) and a LOCAL pointer root (localfind != 0) both stay in the
* walker — they are already correct. */
static int
global_ptr_chain_root_decline(Node *lhs, Local *locals)
{
Node *cur = lhs;
while (cur && cur->kind == N_DOT) cur = cur->lhs;
if (cur == NULL || cur->kind != N_IDENT) return 0;
if (localfind(locals, cur->str) != 0 || !let_islet(cur->str))
return 0;
Type *u = type_chase_named(cur->type);
return (u != NULL && u->kind == TY_PTR);
}
/* FA1 (#15): append() header-place access, cgplaceaddr's append
* consumer. direct = ident-local header in the frame (BP-disp — the
* legacy emission, kept byte-identical); indirect = header address
@@ -5078,7 +5146,8 @@ cgexpr(Cg *c, Node *n, Local *locals)
* `p.f = v`. v1 scope: bare-IDENT inner only; (*expr).f
* (non-IDENT inner) falls through to the existing drop
* behaviour pending follow-up task. */
if (n->lhs && n->lhs->kind == N_DOT && n->lhs->lhs &&
if (!global_ptr_field_decline(n->lhs, n->op, locals)
&& n->lhs && n->lhs->kind == N_DOT && n->lhs->lhs &&
(n->lhs->lhs->kind == N_IDENT ||
(n->lhs->lhs->kind == N_UN && n->lhs->lhs->op == TK_STAR
&& n->lhs->lhs->lhs
@@ -6080,7 +6149,8 @@ cgexpr(Cg *c, Node *n, Local *locals)
* (the existing 1-deep branch only fires for `ident.field = …`).
* Only plain `=` is wired — compound on a chained value-struct
* field is rare and stays unhandled. */
if (n->lhs && n->lhs->kind == N_DOT && n->lhs->lhs
if (!global_ptr_chain_root_decline(n->lhs, locals)
&& n->lhs && n->lhs->kind == N_DOT && n->lhs->lhs
&& n->lhs->lhs->kind == N_DOT && n->op == TK_ASSIGN) {
struct { Type *pu; const char *name; } steps[16];
int nsteps = 0;

View File

@@ -0,0 +1,227 @@
/*
* 689_globptr_field_store_run (#6) — a module-GLOBAL `*struct` pointer base
* (`gp.f = v` / `gp.f += v` / `gp.x.y = v` / `gp.a[i].f = v`) stores
* correctly AND cstage / wwstage agree byte-for-byte.
*
* THE BUG (cstage only): a global `*struct` ptr base carries via_ptr=1 but
* has no local slot — localfind returns 0, so the enumerated via_ptr field-
* store arms emitted `MOVQ (BP),BX` (deref the saved BP = garbage → SEGV).
* The plain-scalar-`=` STORE half was already correct (the #47/#8 fix, LEAQ
* gp(SB)), so load/store were asymmetric. wwstage routes every case EXCEPT
* plain-scalar-`=` through its F6 cgplaceaddr resolver and was correct.
*
* THE FIX (align cstage UP): decline the global-`*struct`-ptr base at the
* enumerated arm's dispatch for compound + non-scalar (and a chained
* `gp.x.y` root), so cstage falls to its OWN F6 assign-resolver — byte-
* identical to wwstage. Plain-scalar-`=` stays in the enumerated arm (its
* #47 byte-id is undisturbed); a local ptr and a param at offset 0
* (localfind != 0) also stay local.
*
* shape | want
* ------------------------------+------
* gp.f += 5 (compound off 8) | 5
* gp.f += 7 (compound off 0) | 7
* gp.in = Inner{7,9} (struct) | 16
* gp.sf = "hi" (str field) | 2
* gp.x.y=11; gp.x.z+=7 (chain) | 18
* gp.a[1].f=5; gp.a[1].g+=8 | 13
* lp.f += 5 (LOCAL ptr ctrl) | 5
* bump(&s): p.f/p.g (param ctrl)| 10
* Each row also asserts w6c .s == w6c_ww .s byte-identical.
* Pre-fix: cstage SEGV(139) on every global-ptr row; cs vs ww .s differed.
*/
#include <stdio.h>
#include <stdlib.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 *name;
const char *src;
int want;
};
static const struct row ROWS[] = {
{ "compound_off8",
"package main;\n"
"type S = struct { a: i64, f: i64 };\n"
"let gp: *S = nil;\n"
"export fn main() i32 = { let s: S = S{a=0,f=0}; gp = &s;"
" gp.f += 5; return s.f: i32; };\n", 5 },
{ "compound_off0",
"package main;\n"
"type S = struct { f: i64, g: i64 };\n"
"let gp: *S = nil;\n"
"export fn main() i32 = { let s: S = S{f=0,g=0}; gp = &s;"
" gp.f += 7; return s.f: i32; };\n", 7 },
{ "struct_field",
"package main;\n"
"type I = struct { x: i64, y: i64 };\n"
"type S = struct { a: i64, in: I };\n"
"let gp: *S = nil;\n"
"export fn main() i32 = { let s: S = S{a=0,in=I{x=0,y=0}}; gp = &s;"
" gp.in = I{x=7,y=9}; return (s.in.x+s.in.y): i32; };\n", 16 },
{ "str_field",
"package main;\n"
"type S = struct { a: i64, sf: str };\n"
"let gp: *S = nil;\n"
"export fn main() i32 = { let s: S = S{a=0,sf=\"\"}; gp = &s;"
" gp.sf = \"hi\"; return (s.sf.len): i32; };\n", 2 },
{ "chained",
"package main;\n"
"type I = struct { y: i64, z: i64 };\n"
"type S = struct { a: i64, x: I };\n"
"let gp: *S = nil;\n"
"export fn main() i32 = { let s: S = S{a=0,x=I{y=0,z=0}}; gp = &s;"
" gp.x.y = 11; gp.x.z += 7; return (s.x.y+s.x.z): i32; };\n", 18 },
{ "indexed",
"package main;\n"
"type E = struct { f: i64, g: i64 };\n"
"type S = struct { n: i64, a: [3]E };\n"
"let gp: *S = nil;\n"
"export fn main() i32 = { let s: S; gp = &s;"
" gp.a[1].f = 5; gp.a[1].g += 8; return (s.a[1].f+s.a[1].g): i32; };\n", 13 },
{ "local_ptr_ctrl",
"package main;\n"
"type S = struct { a: i64, f: i64 };\n"
"export fn main() i32 = { let s: S = S{a=0,f=0}; let lp: *S = &s;"
" lp.f += 5; return s.f: i32; };\n", 5 },
{ "param_off0_ctrl",
"package main;\n"
"type S = struct { f: i64, g: i64 };\n"
"fn bump(p: *S) void = { p.f += 3; p.g += 4; };\n"
"export fn main() i32 = { let s: S = S{f=1,g=2}; bump(&s);"
" return (s.f+s.g): i32; };\n", 10 },
};
#define NROWS ((int)(sizeof ROWS / sizeof ROWS[0]))
/* build+run one row through `driver`; return exit code or -1. */
static int
run_driver(const char *driver, const char *src, int idx)
{
char tmpdir[64], srcf[128], outbin[160], rmcmd[192], cmd[2400];
snprintf(tmpdir, sizeof tmpdir, "/tmp/gpfs_%d_%d_d", getpid(), idx);
mkdir(tmpdir, 0755);
snprintf(srcf, sizeof srcf, "%s/t.ww", tmpdir);
snprintf(outbin, sizeof outbin, "%s/t", tmpdir);
snprintf(rmcmd, sizeof rmcmd, "rm -rf %s", tmpdir);
FILE *f = fopen(srcf, "wb");
if (!f) { runwait(rmcmd); return -1; }
fputs(src, f);
fclose(f);
snprintf(cmd, sizeof cmd, "%s build -o %s %s 2>/dev/null",
driver, outbin, srcf);
if (runwait(cmd) != 0) { runwait(rmcmd); return -1; }
int got = runwait(outbin);
runwait(rmcmd);
return got;
}
/* emit .s for `tool` (w6c / w6c_ww) into asmf; 0 ok, -1 on compile fail. */
static int
emit_asm(const char *bin, const char *tool, const char *src, int idx,
const char *asmf)
{
char srcf[80], cmd[2400];
snprintf(srcf, sizeof srcf, "/tmp/gpfs_asm_%d_%d.ww", getpid(), idx);
FILE *f = fopen(srcf, "wb");
if (!f) return -1;
fputs(src, f);
fclose(f);
snprintf(cmd, sizeof cmd, "%s/%s -o %s %s 2>/dev/null",
bin, tool, asmf, srcf);
int rc = runwait(cmd);
unlink(srcf);
return rc == 0 ? 0 : -1;
}
static int
files_identical(const char *a, const char *b)
{
FILE *fa = fopen(a, "rb"), *fb = fopen(b, "rb");
if (!fa || !fb) { if (fa) fclose(fa); if (fb) fclose(fb); return 0; }
int ca, cb, same = 1;
do {
ca = fgetc(fa); cb = fgetc(fb);
if (ca != cb) { same = 0; break; }
} while (ca != EOF);
fclose(fa); fclose(fb);
return same;
}
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[1024], wdrv[1024];
snprintf(cdrv, sizeof cdrv, "%s/ww", bin);
snprintf(wdrv, sizeof wdrv, "%s/ww_ww", bin);
int have_ww = (access(wdrv, X_OK) == 0);
int fail = 0, total = 0;
for (int i = 0; i < NROWS; i++) {
const struct row *r = &ROWS[i];
total++;
int gc = run_driver(cdrv, r->src, i);
if (gc != r->want) {
fprintf(stderr, "globptr_field_store[%s,cstage]: run=%d want=%d\n",
r->name, gc, r->want);
fail++;
}
if (have_ww) {
total++;
int gw = run_driver(wdrv, r->src, i);
if (gw != r->want) {
fprintf(stderr, "globptr_field_store[%s,wwstage]: run=%d want=%d\n",
r->name, gw, r->want);
fail++;
}
}
/* byte-id: w6c .s == w6c_ww .s */
if (have_ww) {
char csf[80], wwf[80];
snprintf(csf, sizeof csf, "/tmp/gpfs_cs_%d_%d.s", getpid(), i);
snprintf(wwf, sizeof wwf, "/tmp/gpfs_ww_%d_%d.s", getpid(), i);
total++;
int ec = emit_asm(bin, "w6c", r->src, i, csf);
int ew = emit_asm(bin, "w6c_ww", r->src, i, wwf);
if (ec != 0 || ew != 0 || !files_identical(csf, wwf)) {
fprintf(stderr, "globptr_field_store[%s]: cs/ww .s NOT "
"byte-identical (ec=%d ew=%d)\n", r->name, ec, ew);
fail++;
}
unlink(csf); unlink(wwf);
}
}
if (fail) {
fprintf(stderr, "globptr_field_store_run: %d/%d checks failed\n",
fail, total);
return 1;
}
printf("globptr_field_store_run: %d/%d ok\n", total, total);
return 0;
}