ww/test/wcc/944_array_zeroinit_run.c

/*
 * 944_array_zeroinit_run — #84: uninit `[N]T` ARRAY locals were NEVER
 * zero-filled. The bare-let no-rhs zero-fill (cmd/w6c/cgen.c N_LET else
 * + selfhost/cmd/wcc/cgenstmt.ww cglet) was gated `sz>8 && !TY_ARRAY`,
 * so `let a: [3]int;` read whatever the stack held — BOTH stages,
 * both-wrong-IDENTICAL, byte-id-blind (#263-class): the cs==ww gate
 * cannot see a shared-garbage read. The fix drops the `!TY_ARRAY`
 * exclusion symmetrically (arrays zero-fill like every other
 * composite, Go-zero per user ruling); the zero-fill extent is the
 * array's chased ABI size (lu->size / chased tinfo.size, NOT the
 * slot-padded size), so a non-8-multiple array zeroes its exact byte
 * count.
 *
 * GATE-BLIND → the load-bearing net is a RUNTIME zero-read, NOT asm
 * presence: a clean (fresh) stack frame is already 0, masking the bug.
 * So every row DIRTIES the stack first (a filler fn writes 165 across
 * a 512B frame), then declares the uninit array in a sibling frame
 * that reuses that region, and asserts the read is 0. byte-id won't
 * catch a regression here — only run-and-check-value will.
 *
 *   row              | shape (after a 165-dirtied stack)        | want
 *   -----------------+------------------------------------------+-----
 *   array_elem_0     | let a: [3]int;  sum a[0..2]               | 0
 *   narrow_array_0   | let a: [4]u32;  sum a[0..3]  (esz 4)      | 0
 *   nonmult8_array_0 | let b: [20]u8;  sum b[0..19] (ABI 20 !=   |
 *                    | slot 24 — extent-source guard)           | 0
 *   array_2d_0       | let m: [2][2]int; sum all 4              | 0
 *   control_initd    | let c: [3]int = [7,8,9]; sum (no-regress)| 24
 *
 * Each row also asserts cstage/wwstage .s byte-id (rule 10 — the fix
 * adds the SAME insns to both). NNN<950, self-contained (/tmp, no
 * imports) — rule-14's selfhost-sibling race does not apply (941/944
 * precedent). #84 array-only; the tagged/plain-*T reject-set is #113.
 */
#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;
}

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), cb = fgetc(fb);
		if (ca != cb) { rc = -1; break; }
		if (ca == EOF) break;
	}
	fclose(fa); fclose(fb);
	return rc;
}

struct row { const char *label; const char *src; int want; };

/* Every src dirties the stack via dirty() (a 512B [64]int filled with
 * 165) before the reader's uninit array lands on that region. */
#define DIRTY \
	"fn dirty() int = {\n" \
	"	let j: [64]int;\n" \
	"	for (let i: int = 0; i < 64; i += 1) { j[i] = 165; };\n" \
	"	return j[0];\n" \
	"};\n"

static const struct row rows[] = {
	{ "array_elem_0",
	  "package main;\n" DIRTY
	  "fn rd() i32 = { let a: [3]int; return (a[0]+a[1]+a[2]): i32; };\n"
	  "export fn main() i32 = { dirty(); return rd(); };\n", 0 },
	{ "narrow_array_0",
	  "package main;\n" DIRTY
	  "fn rd() i32 = { let a: [4]u32;\n"
	  "	return (a[0]+a[1]+a[2]+a[3]): i32; };\n"
	  "export fn main() i32 = { dirty(); return rd(); };\n", 0 },
	{ "nonmult8_array_0",
	  "package main;\n" DIRTY
	  "fn rd() i32 = { let b: [20]u8; let s: i32 = 0;\n"
	  "	for (let i: int = 0; i < 20; i += 1) { s += b[i]: i32; };\n"
	  "	return s; };\n"
	  "export fn main() i32 = { dirty(); return rd(); };\n", 0 },
	{ "array_2d_0",
	  "package main;\n" DIRTY
	  "fn rd() i32 = { let m: [2][2]int;\n"
	  "	return (m[0][0]+m[0][1]+m[1][0]+m[1][1]): i32; };\n"
	  "export fn main() i32 = { dirty(); return rd(); };\n", 0 },
	/* no-regress control: an INITIALIZED array keeps its values. */
	{ "control_initd",
	  "package main;\n" DIRTY
	  "fn rd() i32 = { let c: [3]int = [7, 8, 9];\n"
	  "	return (c[0]+c[1]+c[2]): i32; };\n"
	  "export fn main() i32 = { dirty(); return rd(); };\n", 24 },
};

/* build+run via a driver (ww / ww_ww); returns 0 pass, nonzero fail. */
static int
run_driver(const char *driver, const struct row *r, int i)
{
	char src[96], tmpdir[96], errf[96], cmd[1024];
	snprintf(src, sizeof src, "/tmp/azi_%d_%d.ww", getpid(), i);
	snprintf(tmpdir, sizeof tmpdir, "/tmp/azi_%d_d_%d", getpid(), i);
	snprintf(errf, sizeof errf, "/tmp/azi_%d_e_%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 && timeout 20 %s build %s >/dev/null 2>%s",
	    tmpdir, driver, src, errf);
	int brc = runwait(cmd);
	if (brc != 0) {
		fprintf(stderr, "row[%s]: build via %s failed\n",
		    r->label, driver);
		unlink(src); unlink(errf); rmdir(tmpdir);
		return -1;
	}

	const char *base = strrchr(src, '/');
	base = base ? base + 1 : src;
	char outbin[256];
	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); unlink(errf); rmdir(tmpdir);
	if (got != r->want) {
		fprintf(stderr, "row[%s]: %s exit %d, want %d\n",
		    r->label, driver, got, r->want);
		return 1;
	}
	return 0;
}

/* cs==ww .s byte-id (rule 10). */
static int
asm_byte_identical(const char *bin, const struct row *r, int i)
{
	char src[96], cs[96], ws[96], cmd[1024];
	snprintf(src, sizeof src, "/tmp/azi_asm_%d_%d.ww", getpid(), i);
	snprintf(cs,  sizeof cs,  "/tmp/azi_asm_%d_%d_c.s", getpid(), i);
	snprintf(ws,  sizeof ws,  "/tmp/azi_asm_%d_%d_w.s", getpid(), i);

	FILE *f = fopen(src, "wb");
	if (!f) return -1;
	fputs(r->src, f);
	fclose(f);

	snprintf(cmd, sizeof cmd, "%s/w6c -o %s %s 2>/dev/null", bin, cs, src);
	if (runwait(cmd) != 0) {
		fprintf(stderr, "row[%s]: w6c errored\n", r->label);
		unlink(src);
		return -1;
	}
	snprintf(cmd, sizeof cmd, "%s/w6c_ww -o %s %s 2>/dev/null",
	    bin, ws, src);
	if (runwait(cmd) != 0) {
		fprintf(stderr, "row[%s]: w6c_ww errored\n", r->label);
		unlink(src); unlink(cs);
		return -1;
	}
	int rc = slurp_eq(cs, ws);
	if (rc != 0)
		fprintf(stderr, "row[%s]: cstage vs wwstage asm differs\n",
		    r->label);
	unlink(src); unlink(cs); unlink(ws);
	return rc;
}

int
main(void)
{
	const char *bin = getenv("BIN");
	if (!bin) bin = "out/bin";
	char absbin[2080];
	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[2120], wdrv[2120];
	snprintf(cdrv, sizeof cdrv, "%s/ww", bin);
	snprintf(wdrv, sizeof wdrv, "%s/ww_ww", bin);

	int n = (int)(sizeof rows / sizeof rows[0]);
	int total = 0, fail = 0;

	for (int i = 0; i < n; i++) {
		total++;
		if (run_driver(cdrv, &rows[i], i) != 0) fail++;
	}
	if (access(wdrv, X_OK) == 0) {
		for (int i = 0; i < n; i++) {
			total++;
			if (run_driver(wdrv, &rows[i], i) != 0) fail++;
		}
		for (int i = 0; i < n; i++) {
			total++;
			if (asm_byte_identical(bin, &rows[i], i) != 0) fail++;
		}
	}

	if (fail) {
		fprintf(stderr, "array_zeroinit: %d/%d checks failed\n",
		    fail, total);
		return 1;
	}
	printf("array_zeroinit: %d/%d ok\n", total, total);
	return 0;
}