Hojun-Cho
5b212e51cf
A bare 'let x: T;' with 1 <= size(T) <= 7 matched no zero-fill arm in either stage (8B and >8B were already zeroed) - 'let c: [3]u8;' read stack garbage. User-ruled zero-value semantics: cstage gate sz>8 -> sz>0; wwstage zsz==8 arm hoisted above the fill-run arm (required - 8B would otherwise route into the run and diverge) and run gate zsz>0. New 840 pin: dirty-frame probe rows, dual-dim (run + cs/ww byte-id); discriminators fail exit-154 on pre-fix binaries. Fused with the lib/bytes test conversion (rule 11): either half alone turns 967 red. The old exit(signalled+10) wrapped a real 1782-count ltrim failure to exit 0 - green depended on the garbage. Converted to assert form (completes the 35/35 @test conversion); ltrim rows keep the bare 'let c: [3]u8;' as the consumer proof of the fix.
272 lines
9.3 KiB
C
272 lines
9.3 KiB
C
/*
|
||
* 840_zeroinit_run — task #16. A bare `let x: T;` (no initializer) must
|
||
* zero-fill its slot (Go zero-value, rob's ruling). Before the fix, cgen
|
||
* emitted the zero-fill ONLY for 8B-primitive slots and >8B composites; a
|
||
* SUB-8 aggregate (`let c: [3]u8;` = 3 bytes, a 3-byte struct, …) matched
|
||
* neither arm and fell through to NOTHING, so the slot read whatever the
|
||
* stack held.
|
||
*
|
||
* THE BUG (cstage == wwstage, BOTH wrong — shared gap, NOT rule-10):
|
||
* ken's bytes verdict (.ai/ken-bytes16-verdict.md) traced lib/bytes'
|
||
* green-but-broken 967 to ltrim_cases' `let c: [3]u8;` reading a prior
|
||
* deep-frame sibling's leftover bytes. The masking was a stack-zero
|
||
* accident: a bare let on a FRESH frame happens to read 0, so the bug
|
||
* only fires when a deep-framed fn ran first. byte-id was BLIND (#263):
|
||
* both stages emitted the identical no-store sequence.
|
||
*
|
||
* REPRO SHAPE (ken's bytes-independent minimal repro, generalised):
|
||
* dirty() writes a big local ([64]u8 = 222) to soil the stack region;
|
||
* probe() then declares the bare let as its FIRST local — reusing
|
||
* dirty()'s slot — and reads it. A correct zero-fill returns 0; the
|
||
* pre-fix garbage returned (222 * width) & 0xff (154 for [3]u8).
|
||
*
|
||
* THE FIX (#16, both stages): widen the no-rhs zero-fill gate from
|
||
* `sz > 8` to `sz > 0` (cgen.c N_LET) and add the symmetric `zsz > 0`
|
||
* run arm (cgenstmt.ww cglet), so 1..7-byte slots zero through the same
|
||
* MOVL/MOVB tail. sz == 8 keeps its immediate MOVQ $0; sz == 0 (`[0]T`)
|
||
* needs no stores.
|
||
*
|
||
* EACH ROW CARRIES BOTH DIMENSIONS (802 model):
|
||
* (a) cstage `ww build` + run, asserting exit 0 — pins that the bare let
|
||
* reads zero even after a dirtied frame (runtime correctness the
|
||
* byte-id gate cannot see).
|
||
* (b) w6c vs w6c_ww `.s` cmp — FAILS if the stages diverge (rule-10).
|
||
*
|
||
* GATE POLARITY: must stay GREEN. A nonzero exit means a bare-let slot
|
||
* regressed to reading stack garbage; a byte-id FAIL means the stages
|
||
* diverged on the zero-fill emission.
|
||
*/
|
||
#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_exit; };
|
||
|
||
/* Every row shares the dirty()→probe() spine: dirty soils the frame,
|
||
* probe declares the bare let FIRST and reads it. want_exit is 0 (all
|
||
* reads zero). The discriminating rows are the SUB-8 aggregates ([3]u8,
|
||
* [5]u8, [7]u8, the 3-byte struct) — the exact gap #16 closed; the
|
||
* scalar / [20]u8 / str / slice rows are controls (already zeroed pre-#16
|
||
* via the sz==8 and sz>8 arms) pinning no-regression. */
|
||
static const struct row rows[] = {
|
||
/* the exact ken repro: [3]u8 sub-8 array. Pre-fix returned 154. */
|
||
{ "arr3_u8",
|
||
"package main;\n"
|
||
"fn dirty() void = {\n"
|
||
" let big: [64]u8; let i: i32 = 0;\n"
|
||
" for (i < 64) { big[i] = 222u8; i += 1; };\n"
|
||
"};\n"
|
||
"fn probe() i32 = {\n"
|
||
" let c: [3]u8;\n"
|
||
" return (c[0]: i32) + (c[1]: i32) + (c[2]: i32);\n"
|
||
"};\n"
|
||
"export fn main() i32 = { dirty(); return probe(); };\n", 0 },
|
||
/* sub-8, width 5 — exercises the MOVL+MOVB tail split (4 + 1). */
|
||
{ "arr5_u8",
|
||
"package main;\n"
|
||
"fn dirty() void = {\n"
|
||
" let big: [64]u8; let i: i32 = 0;\n"
|
||
" for (i < 64) { big[i] = 222u8; i += 1; };\n"
|
||
"};\n"
|
||
"fn probe() i32 = {\n"
|
||
" let c: [5]u8; let acc: i32 = 0; let j: i32 = 0;\n"
|
||
" for (j < 5) { acc += (c[j]: i32); j += 1; };\n"
|
||
" return acc;\n"
|
||
"};\n"
|
||
"export fn main() i32 = { dirty(); return probe(); };\n", 0 },
|
||
/* sub-8, width 7 — the widest sub-8 extent (MOVL + MOVW + MOVB is
|
||
* unreachable under the run's 4/1 tail, so this is MOVL + 3×MOVB). */
|
||
{ "arr7_u8",
|
||
"package main;\n"
|
||
"fn dirty() void = {\n"
|
||
" let big: [64]u8; let i: i32 = 0;\n"
|
||
" for (i < 64) { big[i] = 222u8; i += 1; };\n"
|
||
"};\n"
|
||
"fn probe() i32 = {\n"
|
||
" let c: [7]u8; let acc: i32 = 0; let j: i32 = 0;\n"
|
||
" for (j < 7) { acc += (c[j]: i32); j += 1; };\n"
|
||
" return acc;\n"
|
||
"};\n"
|
||
"export fn main() i32 = { dirty(); return probe(); };\n", 0 },
|
||
/* sub-8 STRUCT (3 bytes) — the non-array half of the gap. Read each
|
||
* field; a garbage slot would sum nonzero. */
|
||
{ "struct3_u8",
|
||
"package main;\n"
|
||
"type S = struct { a: u8, b: u8, c: u8 };\n"
|
||
"fn dirty() void = {\n"
|
||
" let big: [64]u8; let i: i32 = 0;\n"
|
||
" for (i < 64) { big[i] = 222u8; i += 1; };\n"
|
||
"};\n"
|
||
"fn probe() i32 = {\n"
|
||
" let s: S;\n"
|
||
" return (s.a: i32) + (s.b: i32) + (s.c: i32);\n"
|
||
"};\n"
|
||
"export fn main() i32 = { dirty(); return probe(); };\n", 0 },
|
||
/* CONTROL: scalar i32 (sz==8) — zeroed pre-#16 by the MOVQ $0 arm. */
|
||
{ "scalar_i32",
|
||
"package main;\n"
|
||
"fn dirty() void = {\n"
|
||
" let big: [64]u8; let i: i32 = 0;\n"
|
||
" for (i < 64) { big[i] = 222u8; i += 1; };\n"
|
||
"};\n"
|
||
"fn probe() i32 = { let x: i32; return x; };\n"
|
||
"export fn main() i32 = { dirty(); return probe(); };\n", 0 },
|
||
/* CONTROL: [20]u8 (>8) — zeroed pre-#16 by the #84 sz>8 run. */
|
||
{ "arr20_u8",
|
||
"package main;\n"
|
||
"fn dirty() void = {\n"
|
||
" let big: [64]u8; let i: i32 = 0;\n"
|
||
" for (i < 64) { big[i] = 222u8; i += 1; };\n"
|
||
"};\n"
|
||
"fn probe() i32 = {\n"
|
||
" let c: [20]u8; let acc: i32 = 0; let j: i32 = 0;\n"
|
||
" for (j < 20) { acc += (c[j]: i32); j += 1; };\n"
|
||
" return acc;\n"
|
||
"};\n"
|
||
"export fn main() i32 = { dirty(); return probe(); };\n", 0 },
|
||
/* CONTROL: bare str header (24B) — rob's declmod `let empty: str;`
|
||
* shape. .len must read 0 (zeroed pre-#16 by the sz>8 run). */
|
||
{ "str_hdr",
|
||
"package main;\n"
|
||
"fn dirty() void = {\n"
|
||
" let big: [64]u8; let i: i32 = 0;\n"
|
||
" for (i < 64) { big[i] = 222u8; i += 1; };\n"
|
||
"};\n"
|
||
"fn probe() i32 = { let empty: str; return empty.len; };\n"
|
||
"export fn main() i32 = { dirty(); return probe(); };\n", 0 },
|
||
/* CONTROL: bare slice header (24B) — .len must read 0. */
|
||
{ "slice_hdr",
|
||
"package main;\n"
|
||
"fn dirty() void = {\n"
|
||
" let big: [64]u8; let i: i32 = 0;\n"
|
||
" for (i < 64) { big[i] = 222u8; i += 1; };\n"
|
||
"};\n"
|
||
"fn probe() i32 = { let xs: []i32; return xs.len; };\n"
|
||
"export fn main() i32 = { dirty(); return probe(); };\n", 0 },
|
||
{ NULL, NULL, 0 }
|
||
};
|
||
|
||
static int
|
||
slurp_eq(const char *a, const char *b)
|
||
{
|
||
FILE *fa = fopen(a, "rb");
|
||
FILE *fb = fopen(b, "rb");
|
||
if (!fa || !fb) { if (fa) fclose(fa); if (fb) fclose(fb); return -1; }
|
||
int rc = 0;
|
||
for (;;) {
|
||
int ca = fgetc(fa);
|
||
int cb = fgetc(fb);
|
||
if (ca != cb) { rc = -1; break; }
|
||
if (ca == EOF) break;
|
||
}
|
||
fclose(fa); fclose(fb);
|
||
return rc;
|
||
}
|
||
|
||
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 w6c[1100], w6c_ww[1100];
|
||
snprintf(w6c, sizeof w6c, "%s/w6c", bin);
|
||
snprintf(w6c_ww, sizeof w6c_ww, "%s/w6c_ww", bin);
|
||
if (access(w6c_ww, X_OK) != 0) {
|
||
fprintf(stderr, "zeroinit: w6c_ww missing — cannot run the "
|
||
"cs==ww byte-id gate\n");
|
||
return 1;
|
||
}
|
||
|
||
int n = 0, fail = 0;
|
||
for (int i = 0; rows[i].src; i++, n++) {
|
||
char src[64];
|
||
snprintf(src, sizeof src, "/tmp/wwzi_%d_%d.ww", getpid(), i);
|
||
FILE *f = fopen(src, "wb");
|
||
if (f == NULL) { fail++; continue; }
|
||
fputs(rows[i].src, f);
|
||
fclose(f);
|
||
|
||
/* (a) cstage build + run in a scratch dir. */
|
||
char tmpdir[64];
|
||
snprintf(tmpdir, sizeof tmpdir, "/tmp/wwzi_%d_d_%d", getpid(), i);
|
||
mkdir(tmpdir, 0755);
|
||
|
||
char cmd[2048];
|
||
snprintf(cmd, sizeof cmd, "cd %s && %s/ww build %s",
|
||
tmpdir, bin, src);
|
||
if (runwait(cmd) != 0) {
|
||
fprintf(stderr, "row[%s]: cstage build failed\n",
|
||
rows[i].label);
|
||
fail++;
|
||
unlink(src); rmdir(tmpdir);
|
||
continue;
|
||
}
|
||
|
||
char outbin[128];
|
||
const char *base = strrchr(src, '/');
|
||
base = base ? base + 1 : src;
|
||
snprintf(outbin, sizeof outbin, "%s/%s", tmpdir, base);
|
||
char *dot = strrchr(outbin, '.');
|
||
if (dot && strcmp(dot, ".ww") == 0) *dot = '\0';
|
||
|
||
int got = runwait(outbin);
|
||
if (got != rows[i].want_exit) {
|
||
fprintf(stderr, "row[%s]: cstage exit %d, want %d "
|
||
"(bare let read stack garbage?)\n",
|
||
rows[i].label, got, rows[i].want_exit);
|
||
fail++;
|
||
}
|
||
unlink(outbin); rmdir(tmpdir);
|
||
|
||
/* (b) cs==ww byte-id gate. */
|
||
char cs_s[64], ws_s[64];
|
||
snprintf(cs_s, sizeof cs_s, "/tmp/wwzi_%d_%d_cs.s", getpid(), i);
|
||
snprintf(ws_s, sizeof ws_s, "/tmp/wwzi_%d_%d_ww.s", getpid(), i);
|
||
|
||
snprintf(cmd, sizeof cmd, "%s -o %s %s 2>/dev/null", w6c, cs_s, src);
|
||
if (runwait(cmd) != 0) {
|
||
fprintf(stderr, "row[%s]: w6c failed\n", rows[i].label);
|
||
fail++; unlink(src); continue;
|
||
}
|
||
snprintf(cmd, sizeof cmd, "%s -o %s %s 2>/dev/null",
|
||
w6c_ww, ws_s, src);
|
||
if (runwait(cmd) != 0) {
|
||
fprintf(stderr, "row[%s]: w6c_ww failed\n", rows[i].label);
|
||
fail++; unlink(src); unlink(cs_s); continue;
|
||
}
|
||
if (slurp_eq(cs_s, ws_s) != 0) {
|
||
fprintf(stderr, "row[%s]: cstage/wwstage .s DIFFER "
|
||
"(rule-10 byte-id violation)\n", rows[i].label);
|
||
fail++;
|
||
}
|
||
unlink(src); unlink(cs_s); unlink(ws_s);
|
||
}
|
||
|
||
if (fail) {
|
||
fprintf(stderr, "%d/%d zeroinit tests failed\n", fail, n);
|
||
return 1;
|
||
}
|
||
printf("zeroinit: %d/%d ok (cstage run + cs==ww byte-id)\n", n, n);
|
||
return 0;
|
||
}
|