ww/test/wcc/816_def_arr_len.c

/*
 * 816_def_arr_len — cstage and wwstage agree, byte-for-byte and at runtime,
 * that `.len` on a module-level `def NAME: [N]T = [...]` array is the static
 * element count (an immediate `MOVQ $alen, AX`).
 *
 * The bug (GAP-A.len, WWSTAGE-ONLY): the #7 let-global `.len` cgdot arm in
 * selfhost/cmd/wcc/cgenexpr.ww gated on letvartnode (c.lets only). A `def`
 * lives in c.defs, missed that arm, and fell through to the module-qualified
 * SB fallback that mis-emitted `MOVQ len(SB)` → w6l: undefined reference to
 * 'len' (a build/link failure, not silent). cstage cgen.c already emitted the
 * immediate, so the two stages also DIVERGED. The fix adds a def-twin `.len`
 * arm using defvartnode (the def-side mirror of letvartnode) — `.len` ONLY.
 *
 * SCOPE: `.len` only. `.ptr` (cstage itself emits LEAQ (BP), task GAP-A.ptr)
 * and `.cap` (arrays have no cap; cstage rejects, wwstage silently emits
 * garbage, task GAP-A.cap) are SEPARATE bugs, not mirrored here.
 *
 * Covers BOTH the explicit-length `def [3]int` and the inferred `def [_]int`
 * (#11-stamped) so the deftnode/.rhs immediate path is exercised for the
 * inference case too.
 *
 *   row            | shape                                       | want
 *   ---------------+---------------------------------------------+-----
 *   explicit_len   | def A: [3]int=[10,20,30], A.len             | 3
 *   infer_len      | def B: [_]int=[1,2,3,4], B.len              | 4
 *   sum            | A.len + B.len  (ken oracle)                 | 7
 *   one_elem       | def C: [_]int=[9], C.len                    | 1
 *   u8_len         | def D: [_]u8=[1u8..5u8], D.len              | 5
 */
#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; };

static const struct row rows[] = {
	{ "explicit_len",
	  "package main;\n"
	  "def A: [3]int = [10, 20, 30];\n"
	  "export fn main() i32 = {\n"
	  "\treturn A.len: i32;\n"
	  "};\n",
	  3 },

	{ "infer_len",
	  "package main;\n"
	  "def B: [_]int = [1, 2, 3, 4];\n"
	  "export fn main() i32 = {\n"
	  "\treturn B.len: i32;\n"
	  "};\n",
	  4 },

	/* ken oracle: explicit + inferred together = 7. */
	{ "sum",
	  "package main;\n"
	  "def A: [3]int = [10, 20, 30];\n"
	  "def B: [_]int = [1, 2, 3, 4];\n"
	  "export fn main() i32 = {\n"
	  "\treturn (A.len: i32) + (B.len: i32);\n"
	  "};\n",
	  7 },

	{ "one_elem",
	  "package main;\n"
	  "def C: [_]int = [9];\n"
	  "export fn main() i32 = {\n"
	  "\treturn C.len: i32;\n"
	  "};\n",
	  1 },

	/* narrow stride — `.len` is a count, independent of element width. */
	{ "u8_len",
	  "package main;\n"
	  "def D: [_]u8 = [1u8, 2u8, 3u8, 4u8, 5u8];\n"
	  "export fn main() i32 = {\n"
	  "\treturn D.len: i32;\n"
	  "};\n",
	  5 },
};

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/dal_%d_%d.ww", getpid(), i);
	snprintf(tmpdir, sizeof tmpdir, "/tmp/dal_%d_d_%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 && %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;
}

/* asm_byte_identical — w6c vs w6c_ww .s for the same source must match.
 * Post-fix both stages emit `MOVQ $alen, AX`; the rule-10 convergence
 * invariant. */
static int
asm_byte_identical(const char *bin, const struct row *r, int i)
{
	char src[64], cs[64], ws[64], cmd[1024];
	snprintf(src, sizeof src, "/tmp/dal_asm_%d_%d.ww", getpid(), i);
	snprintf(cs,  sizeof cs,  "/tmp/dal_asm_%d_%d_c.s", getpid(), i);
	snprintf(ws,  sizeof ws,  "/tmp/dal_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;
	}

	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",
		    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[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];
	snprintf(cdrv, sizeof cdrv, "%s/ww", bin);
	char wdrv[1024];
	snprintf(wdrv, sizeof wdrv, "%s/ww_ww", bin);

	struct { const char *name; const char *path; int gated_on_existence; }
	drivers[] = {
		{ "cstage",  cdrv, 0 },
		{ "wwstage", wdrv, 1 },
		{ NULL, NULL, 0 },
	};

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

	for (int d = 0; drivers[d].name; d++) {
		if (drivers[d].gated_on_existence
		    && access(drivers[d].path, X_OK) != 0) {
			fprintf(stderr, "def_arr_len: skip %s (no %s)\n",
			    drivers[d].name, drivers[d].path);
			continue;
		}
		for (int i = 0; i < n; i++) {
			int got = run_driver(drivers[d].path, &rows[i], i);
			total++;
			if (got != rows[i].want) {
				fprintf(stderr,
				    "def_arr_len[%s][%s]: exit=%d want=%d\n",
				    drivers[d].name, rows[i].label,
				    got, rows[i].want);
				fail++;
			}
		}
	}

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

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