ww/test/wcc/760_def_widen_const.c

/*
 * 760_def_widen_const — const-scoped cross-prim-width integer widening
 * in a `def` initializer (PROJECT #113).
 *
 * The gap: a def-reference types as the referent's DECLARED type, so
 * `def INT_MIN: int = I32_MIN;` saw the rhs as i32 and the def-init
 * assignability check (cmd/wcc/check.c, type_assignable) rejected i32 →
 * int. The fix: in a def initializer the rhs is a flexible constant, so
 * a const integer that folds to a concrete primitive width widens to
 * the declared integer type exactly as an UNTYPED_INT literal would,
 * when the value fits the target (def_cast_fits). This is the
 * const-scoped subset of Hare's general integer-widening; non-const
 * widening stays stricter in ww (PROJECT #115). It rides the #88
 * eval_def_const fold + stamp, so cgen's literal-only emit lays the
 * 8-byte DATA row with no codegen change.
 *
 * The fix is cstage-only: the wwstage checker (selfhost/cmd/wcc/check.ww,
 * "let init / return assignability") intentionally never checks def-init
 * assignability (it stays quiet, leaving full inference to the C side),
 * so it never rejected the widening — the #88 stamp already laid the
 * correct row. Relaxing the cstage aligns the richer side DOWN to the
 * leaner side (CLAUDE.md rule 10), and both stages stamp the identical
 * folded value, so the emitted asm is byte-identical.
 *
 * Coverage:
 *   1. EXEC (cstage `ww`, + wwstage `ww_ww` if built): i32 → int (a
 *      negative value, to pin sign-extension across the widen) and
 *      u64 → size (a value above the u32 range, to pin the full 8-byte
 *      slot) — each read back at a use site to prove the DATA row links
 *      and carries the right value.
 *   2. BYTE-ID: cstage w6c vs wwstage w6c_ww `.s` for every exec row
 *      (proves the const-fold stamp is bit-identical across stages).
 *   3. FAIL-LOUD (rule 7), cstage only: an out-of-range narrowing
 *      def-ref (`def S: i16 = BIG;` where BIG overflows i16) must still
 *      fail the cstage build — def_cast_fits keeps the widening from
 *      becoming a silent truncation. Asserted on the cstage alone
 *      because the wwstage has no def-init assignability check at all
 *      (pre-existing leanness, unchanged by #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;
}

/* ---- 1. EXEC rows (compile+link+run) -------------------------------- */

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

static const struct row exec_rows[] = {
	/* i32 → int widening of a negative value: `def INT_MIN`-shaped.
	 * I32_MIN = -2147483648; read back as int it must sign-extend to
	 * the full 8-byte slot. main returns 42 iff the value round-trips. */
	{ "i32-to-int-neg",
	  "def A_I32: i32 = -2147483648;\n"
	  "def A_INT: int = A_I32;\n"
	  "fn main() i32 = {\n"
	  "\tlet x: int = A_INT;\n"
	  "\tif (x == -2147483648) { return 42; };\n"
	  "\treturn 1;\n"
	  "};\n",
	  42 },

	/* small negative i32 → int, to pin -7 specifically (the task's
	 * worked example). */
	{ "i32-to-int-small",
	  "def A_I32: i32 = -7;\n"
	  "def A_INT: int = A_I32;\n"
	  "fn main() i32 = {\n"
	  "\tlet x: int = A_INT;\n"
	  "\tif (x == -7) { return 42; };\n"
	  "\treturn 1;\n"
	  "};\n",
	  42 },

	/* u64 → size widening of a value above the u32 range: pins the
	 * full 8-byte slot survives the widen (0x1_0000_0003 = 4294967299). */
	{ "u64-to-size",
	  "def BIG_U64: u64 = 4294967299;\n"
	  "def S_SIZE: size = BIG_U64;\n"
	  "fn main() i32 = {\n"
	  "\tlet x: size = S_SIZE;\n"
	  "\tif (x == 4294967299) { return 42; };\n"
	  "\treturn 1;\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/dwc_%d_%d.ww", getpid(), i);
	snprintf(tmpdir, sizeof tmpdir, "/tmp/dwc_%d_d_%d", getpid(), i);

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

	mkdir(tmpdir, 0755);
	/* timeout 180 per repo convention; test/run does not bound
	 * individual binaries, so an unguarded hang would stall make test. */
	snprintf(cmd, sizeof cmd, "cd %s && timeout 180 %s build %s 2>/dev/null",
	    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;
}

/* ---- shared .s emit -------------------------------------------------- */

static int
emit_s(const char *w6c, const char *src, char *out_s, size_t cap)
{
	char cmd[1024];
	snprintf(cmd, sizeof cmd, "timeout 180 %s -o %s %s 2>/dev/null",
	    w6c, out_s, src);
	(void)cap;
	return runwait(cmd);
}

/* ---- 2. byte-identity of cstage vs wwstage .s ----------------------- */

static int
asm_byte_identical(const char *bin, const char *src, const char *label, int i)
{
	char wwsrc[64], cs[64], ws[64];
	snprintf(wwsrc, sizeof wwsrc, "/tmp/dwc_bi_%d_%d.ww", getpid(), i);
	snprintf(cs, sizeof cs, "/tmp/dwc_bi_%d_%d_c.s", getpid(), i);
	snprintf(ws, sizeof ws, "/tmp/dwc_bi_%d_%d_w.s", getpid(), i);

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

	char w6c[640], w6c_ww[640];
	snprintf(w6c, sizeof w6c, "%s/w6c", bin);
	snprintf(w6c_ww, sizeof w6c_ww, "%s/w6c_ww", bin);

	if (emit_s(w6c, wwsrc, cs, sizeof cs) != 0) {
		fprintf(stderr, "row[%s]: w6c errored\n", label);
		unlink(wwsrc);
		return -1;
	}
	if (emit_s(w6c_ww, wwsrc, ws, sizeof ws) != 0) {
		fprintf(stderr, "row[%s]: w6c_ww errored\n", label);
		unlink(wwsrc); unlink(cs);
		return -1;
	}

	FILE *fc = fopen(cs, "rb");
	FILE *fw = fopen(ws, "rb");
	int rc = 0;
	if (!fc || !fw) {
		rc = -1;
	} else {
		for (;;) {
			int a = fgetc(fc);
			int b = fgetc(fw);
			if (a != b) { rc = -1; break; }
			if (a == EOF) break;
		}
	}
	if (fc) fclose(fc);
	if (fw) fclose(fw);
	if (rc != 0)
		fprintf(stderr, "row[%s]: cstage vs wwstage asm differs\n",
		    label);
	unlink(wwsrc); unlink(cs); unlink(ws);
	return rc;
}

/* ---- 3. fail-loud (cstage only): out-of-range narrowing def-ref ----- */

/* `def BIG: i32 = 70000; def S: i16 = BIG;` — 70000 overflows i16, so
 * def_cast_fits says the value does not fit and the const-scoped widen
 * does NOT fire; the def-init assignability check then rejects i32 →
 * i16. Compile via w6c only; success means the build FAILED as required
 * (nonzero w6c exit), never a silent truncation. */
static const char narrow_src[] =
	"def BIG_I32: i32 = 70000;\n"
	"def S_I16: i16 = BIG_I32;\n"
	"export fn main() i32 = { let s: i16 = S_I16; return s: i32; };\n";

static int
cstage_narrow_fails(const char *w6c)
{
	char src[64], s[64], cmd[1024];
	snprintf(src, sizeof src, "/tmp/dwc_nl_%d.ww", getpid());
	snprintf(s, sizeof s, "/tmp/dwc_nl_%d.s", getpid());

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

	snprintf(cmd, sizeof cmd, "timeout 180 %s -o %s %s 2>/dev/null",
	    w6c, s, src);
	int rc = runwait(cmd);
	unlink(src); unlink(s);
	if (rc == 0) {
		fprintf(stderr,
		    "narrow[cstage]: w6c exited 0 (expected loud failure, "
		    "no silent truncation)\n");
		return -1;
	}
	if (rc == 124) {
		fprintf(stderr, "narrow[cstage]: w6c timed out\n");
		return -1;
	}
	return 0;
}

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], w6c[1024], w6c_ww[1024];
	snprintf(cdrv, sizeof cdrv, "%s/ww", bin);
	snprintf(wdrv, sizeof wdrv, "%s/ww_ww", bin);
	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 total = 0, fail = 0;

	/* 1. exec via cstage `ww` (+ wwstage `ww_ww` if built) */
	struct { const char *name; const char *path; int gated; }
	drivers[] = {
		{ "cstage",  cdrv, 0 },
		{ "wwstage", wdrv, 1 },
		{ NULL, NULL, 0 },
	};
	int nexec = (int)(sizeof exec_rows / sizeof exec_rows[0]);
	for (int d = 0; drivers[d].name; d++) {
		if (drivers[d].gated && access(drivers[d].path, X_OK) != 0) {
			fprintf(stderr, "def_widen_const: skip %s (no %s)\n",
			    drivers[d].name, drivers[d].path);
			continue;
		}
		for (int i = 0; i < nexec; i++) {
			int got = run_driver(drivers[d].path, &exec_rows[i], i);
			total++;
			if (got != exec_rows[i].want) {
				fprintf(stderr,
				    "def_widen_const[%s][%s]: exit=%d want=%d\n",
				    drivers[d].name, exec_rows[i].label,
				    got, exec_rows[i].want);
				fail++;
			}
		}
	}

	/* 2. byte-id on every exec row (only when wwstage is built) */
	if (have_ww) {
		for (int i = 0; i < nexec; i++) {
			total++;
			if (asm_byte_identical(bin, exec_rows[i].src,
			    exec_rows[i].label, i) != 0)
				fail++;
		}
	}

	/* 3. fail-loud (cstage only) */
	total++;
	if (cstage_narrow_fails(w6c) != 0) fail++;

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