test: port the match-dispatch asm observer to ww

728 -> test/asm/matchdispatch_test.ww. The distinct-CMPQ-tag
collection window over TEXT b.next preserved on both stages.
Strengthened: per-row byte-id legs added -- the C header claimed a
cmp -s its code never ran; all three rows verify green.
This commit is contained in:
2026-08-08 14:42:35 +09:00
parent 8c15ab5145
commit 5d100dbd42
3 changed files with 197 additions and 288 deletions

View File

@@ -1,287 +0,0 @@
/*
* 728_match_4arm_cross_module — Class A asm-presence + byte-id sentinel
* for task #31. Pins that the variant tag for each arm of a 4-arm match
* on a qualified `mod.fn(...)` call matches between cstage and wwstage
* even when the caller fn shadows the callee's fn-name across modules.
*
* Pre-fix wwstage's matchscrutt (selfhost/cmd/wcc/cgenutil.ww:2061-2074)
* resolved the scrutinee's tagged type via name-only fnretlookup. With
* `fn next` in two modules, collectfnrets' prepend ordering meant the
* last-declared `next` sat at the head, so `match (utf8.next(d))`
* inside a `fn next() (rune | done)` saw the 2-arm tagged instead of
* the callee's real 4-arm tagged. Arms 2/3 of the match dispatch then
* silently collapsed to CMPQ $0 (their case bodies were unreachable
* even when the tag matched). Sister of #27 (aliaslookupmod) and #28
* (fnparamslookupmod) — the third leaf in the same name-collision trio.
*
* Cstage carries module info through the checker-set callee type
* (cmd/w6c/cgen.c) so its match-scrutinee resolution is correct.
* Wwstage converges via fnretlookupmod (cgen.ww), called from
* matchscrutt's N_DOT branch.
*
* The repro requires:
* 1. callee fn declared first in module A, returning a 4+ arm tagged.
* 2. caller fn in module B, *same fn name*, returning a 2-arm tagged
* that is a subset of the callee's arms (so arms 0/1 still resolve
* and only 2+ surface the dispatch corruption).
* 3. The match scrutinee is the qualified `A.fn(...)` call.
*
* Asserts each arm of the canonical 4-arm match emits a *distinct*
* CMPQ tag in the wwstage asm AND cstage-vs-wwstage cmp -s holds.
*/
#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;
/* Function whose body holds the match-dispatch to inspect. The
* 4 arms must each emit a distinct `CMPQ $K, AX` between
* `TEXT <fn>` and the next TEXT directive. */
const char *fn;
int arms;
};
static const struct row rows[] = {
/* Canonical 4-arm: caller `next` in mod B shadows callee `next`
* in mod A. Pre-fix arms 2/3 → CMPQ $0; post-fix → $2/$3. */
{ "4arm_shadowed_callee",
"package a;\n"
"export type more = void;\n"
"export type invalid = !void;\n"
"export type done = void;\n"
"export fn next() (rune | done | more | invalid) = {\n"
" let r: rune;\n"
" return r;\n"
"};\n"
"package b;\n"
"import a;\n"
"type done = void;\n"
"fn next() (rune | done) = {\n"
" match (a.next()) {\n"
" case let r: rune => return r;\n"
" case let dn: a.done => { let v: done; return v; };\n"
" case let m: a.more => { abort(\"i\"); };\n"
" case let e: a.invalid => { abort(\"i\"); };\n"
" };\n"
"};\n"
"export fn main() i32 = { return 0; };\n",
"b.next", 4 },
/* Reverse arm order in the match source: pins that the bug
* follows variantindex (or in our case, the mod-disambiguated
* scrutinee type), not source order — arm 0 stays at idx 3 etc. */
{ "4arm_shadowed_reverse",
"package a;\n"
"export type more = void;\n"
"export type invalid = !void;\n"
"export type done = void;\n"
"export fn next() (rune | done | more | invalid) = {\n"
" let r: rune;\n"
" return r;\n"
"};\n"
"package b;\n"
"import a;\n"
"type done = void;\n"
"fn next() (rune | done) = {\n"
" match (a.next()) {\n"
" case let e: a.invalid => { abort(\"i\"); };\n"
" case let m: a.more => { abort(\"i\"); };\n"
" case let dn: a.done => { let v: done; return v; };\n"
" case let r: rune => return r;\n"
" };\n"
"};\n"
"export fn main() i32 = { return 0; };\n",
"b.next", 4 },
/* 3-arm boundary: confirm the issue is "arms ≥ caller's variant
* count collapse", not "≥ 2". Caller `next` returns 2-arm, callee
* returns 3-arm. Arm 2 must be CMPQ $2. */
{ "3arm_shadowed_callee",
"package a;\n"
"export type more = void;\n"
"export type done = void;\n"
"export fn next() (rune | done | more) = {\n"
" let r: rune;\n"
" return r;\n"
"};\n"
"package b;\n"
"import a;\n"
"type done = void;\n"
"fn next() (rune | done) = {\n"
" match (a.next()) {\n"
" case let r: rune => return r;\n"
" case let dn: a.done => { let v: done; return v; };\n"
" case let m: a.more => { abort(\"i\"); };\n"
" };\n"
"};\n"
"export fn main() i32 = { return 0; };\n",
"b.next", 3 },
};
static int
slurp(const char *path, char *buf, size_t cap)
{
FILE *f = fopen(path, "rb");
if (!f) return -1;
size_t n = fread(buf, 1, cap - 1, f);
fclose(f);
buf[n] = '\0';
return (int)n;
}
static int
emit_s(const char *w6c, const struct row *r, int i, char *out_s, size_t cap)
{
char src[64], cmd[1024];
snprintf(src, sizeof src, "/tmp/m4cm_%d_%d.ww", getpid(), i);
snprintf(out_s, cap, "/tmp/m4cm_%d_%d_%s.s",
getpid(), i, w6c[strlen(w6c) - 1] == 'w' ? "ww" : "c");
FILE *f = fopen(src, "wb");
if (!f) return -1;
fputs(r->src, f);
fclose(f);
snprintf(cmd, sizeof cmd, "%s -o %s %s 2>/dev/null", w6c, out_s, src);
int rc = runwait(cmd);
unlink(src);
return rc;
}
/* Inside TEXT <fn>, walk every `CMPQ $K, AX` line that precedes the
* next TEXT directive and assert at least `arms` of them and that
* the first `arms` such tags are pairwise distinct AND cover [0..arms). */
static int
check_distinct_cmpq(const char *spath, const struct row *r, const char *stage)
{
char buf[1 << 14];
if (slurp(spath, buf, sizeof buf) < 0) {
fprintf(stderr, "row[%s][%s]: cannot read %s\n",
r->label, stage, spath);
return -1;
}
char fnhdr[128];
snprintf(fnhdr, sizeof fnhdr, "TEXT %s", r->fn);
const char *fn = strstr(buf, fnhdr);
if (!fn) {
fprintf(stderr, "row[%s][%s]: no `%s` in %s\n",
r->label, stage, fnhdr, spath);
return -1;
}
const char *end = strstr(fn + strlen(fnhdr), "\nTEXT ");
if (!end) end = buf + strlen(buf);
int seen[16] = {0};
int got = 0;
const char *p = fn;
while (p < end) {
const char *m = strstr(p, "CMPQ\t$");
if (!m || m >= end) break;
const char *digits = m + strlen("CMPQ\t$");
if (*digits < '0' || *digits > '9') { p = m + 1; continue; }
int k = 0;
while (*digits >= '0' && *digits <= '9') {
k = k * 10 + (*digits - '0');
digits++;
}
if (strncmp(digits, ", AX", 4) == 0) {
if (got < 16 && k < 16) seen[got++] = k;
}
p = m + 1;
}
if (got < r->arms) {
fprintf(stderr,
"row[%s][%s]: only %d `CMPQ $K, AX` in %s body (want %d)\n",
r->label, stage, got, r->fn, r->arms);
return -1;
}
int bitmap = 0;
for (int i = 0; i < r->arms; i++) {
if (seen[i] < 0 || seen[i] >= r->arms) {
fprintf(stderr,
"row[%s][%s]: arm %d emits CMPQ $%d (out of [0, %d))\n",
r->label, stage, i, seen[i], r->arms);
return -1;
}
if (bitmap & (1 << seen[i])) {
fprintf(stderr,
"row[%s][%s]: arm %d repeats tag $%d (collapse)\n",
r->label, stage, i, seen[i]);
return -1;
}
bitmap |= 1 << seen[i];
}
return 0;
}
int
main(void)
{
const char *bin = getenv("BIN");
if (!bin) bin = "out/bin";
char absbin[512];
if (bin[0] != '/') {
char cwd[256];
if (getcwd(cwd, sizeof cwd) == NULL) return 1;
snprintf(absbin, sizeof absbin, "%s/%s", cwd, bin);
bin = absbin;
}
char w6c[640], w6c_ww[640];
snprintf(w6c, sizeof w6c, "%s/w6c", bin);
snprintf(w6c_ww, sizeof w6c_ww, "%s/w6c_ww", bin);
int have_ww = (access(w6c_ww, X_OK) == 0);
int n = (int)(sizeof rows / sizeof rows[0]);
int total = 0, fail = 0;
for (int i = 0; i < n; i++) {
char cs_path[128], ws_path[128];
if (emit_s(w6c, &rows[i], i, cs_path, sizeof cs_path) != 0) {
fprintf(stderr,
"match_4arm_cross_module[cstage][%s]: w6c failed\n",
rows[i].label);
fail++; total++; continue;
}
total++;
if (check_distinct_cmpq(cs_path, &rows[i], "cstage") != 0)
fail++;
if (!have_ww) { unlink(cs_path); continue; }
if (emit_s(w6c_ww, &rows[i], i, ws_path, sizeof ws_path) != 0) {
fprintf(stderr,
"match_4arm_cross_module[wwstage][%s]: w6c_ww failed\n",
rows[i].label);
fail++; total++;
unlink(cs_path); continue;
}
total++;
if (check_distinct_cmpq(ws_path, &rows[i], "wwstage") != 0)
fail++;
unlink(cs_path); unlink(ws_path);
}
if (fail) {
fprintf(stderr,
"match_4arm_cross_module: %d/%d fixtures failed\n",
fail, total);
return 1;
}
printf("match_4arm_cross_module: %d/%d ok\n", total, total);
return 0;
}