ww/test/wcc/703_nested_structlit.c

/*
 * 703_nested_structlit — silent zero of nested STRUCTLIT fields
 * (task #17).
 *
 * Pre-existing landmine surfaced by worker-cgnassign during #5.
 * For a struct literal whose field value is itself an N_STRUCTLIT
 * of a struct-typed field, the outer field-walk did
 * `cgexpr(field_value); store-AX-sized` — cgexpr has no whole-
 * struct-in-register convention, so for a nested literal it lands
 * AX = first qword and the trailing bytes silently stay zero (or
 * stack garbage in the hostile case). The same shape applies at
 * three sites in each stage:
 *   - N_LET N_STRUCTLIT — `let o: outer = outer { i = inner{...} }`
 *   - N_ASSIGN N_IDENT-lhs N_STRUCTLIT — `o = outer { i = inner{...} }`
 *   - N_RETURN N_STRUCTLIT — `return outer { i = inner{...} }`
 *
 * Workaround used in 701_cgassign_struct rows that need nested
 * shape: `let o: outer; o.f = ...` (write-by-field). Avoids the
 * bug; doesn't fix it.
 *
 * Fix: a shared helper `cg_structlit_fill_bp` (cstage) /
 * `cgstructlitfillbp` (wwstage) factors the field-walk, recursing
 * when a field's value is itself an N_STRUCTLIT for a struct-typed
 * field. Bp-relative addressing only; the N_ASSIGN N_DOT-lhs
 * structlit walks (via_ptr / global) keep their inline field-walk
 * and still drop nested-STRUCTLIT silently — separate follow-up
 * task ("cgen: nested STRUCTLIT in N_ASSIGN N_DOT structlit").
 *
 * Each row pins:
 *   - cstage value correctness (process exit code).
 *   - wwstage value correctness (when ww_ww exists).
 *   - cstage vs wwstage byte-identical .s output (catches drift).
 */
#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[] = {
	/* N_LET nested structlit, all i64 fields. Pre-fix: only o.i.a
	 * (first qword) was stored; o.i.b silently stayed 0. Want:
	 * 7 + 8 + 12 = 27. */
	{ "let_nested_i64",
	  "type inner = struct { a: i64, b: i64 };\n"
	  "type outer = struct { i: inner, t: i64 };\n"
	  "fn main() i32 = {\n"
	  "    let o: outer = outer { i = inner { a = 7i64, b = 8i64 }, t = 12i64 };\n"
	  "    return (o.i.a + o.i.b + o.t): i32;\n"
	  "};\n",
	  27 },
	/* N_LET nested structlit, multi-level (3-deep). Pre-fix:
	 * only o.m.in.a was stored; b and t and outer.x silently 0.
	 * Want: 1+2+3+4 = 10. */
	{ "let_nested_3deep",
	  "type leaf = struct { a: i64, b: i64 };\n"
	  "type middle = struct { in: leaf, t: i64 };\n"
	  "type outer = struct { m: middle, x: i64 };\n"
	  "fn main() i32 = {\n"
	  "    let o: outer = outer {\n"
	  "        m = middle {\n"
	  "            in = leaf { a = 1i64, b = 2i64 },\n"
	  "            t = 3i64\n"
	  "        },\n"
	  "        x = 4i64\n"
	  "    };\n"
	  "    return (o.m.in.a + o.m.in.b + o.m.t + o.x): i32;\n"
	  "};\n",
	  10 },
	/* N_LET nested structlit, narrow i32 fields. Pins sized-store
	 * dispatch in the helper — MOVL not MOVQ. Want: 4+5+6+7 = 22. */
	{ "let_nested_i32",
	  "type inner = struct { a: i32, b: i32 };\n"
	  "type outer = struct { i: inner, x: i32, y: i32 };\n"
	  "fn main() i32 = {\n"
	  "    let o: outer = outer { i = inner { a = 4, b = 5 }, x = 6, y = 7 };\n"
	  "    return o.i.a + o.i.b + o.x + o.y;\n"
	  "};\n",
	  22 },
	/* N_ASSIGN N_IDENT-lhs nested structlit. Pre-fix: o.i.b
	 * stayed 0 after the reassign (only first qword stored).
	 * Want: 9+11+30 = 50. */
	{ "assign_ident_nested",
	  "type inner = struct { a: i64, b: i64 };\n"
	  "type outer = struct { i: inner, t: i64 };\n"
	  "fn main() i32 = {\n"
	  "    let o: outer;\n"
	  "    o = outer { i = inner { a = 9i64, b = 11i64 }, t = 30i64 };\n"
	  "    return (o.i.a + o.i.b + o.t): i32;\n"
	  "};\n",
	  50 },
	/* N_RETURN nested structlit. Pre-fix: only b's first qword
	 * (its .a) landed in the receive slot; b's .b silently 0.
	 * Want: 13+17+25 = 55. */
	{ "return_nested",
	  "type inner = struct { a: i64, b: i64 };\n"
	  "type outer = struct { i: inner, t: i64 };\n"
	  "fn mko() outer = {\n"
	  "    return outer { i = inner { a = 13i64, b = 17i64 }, t = 25i64 };\n"
	  "};\n"
	  "fn main() i32 = {\n"
	  "    let r: outer = mko();\n"
	  "    return (r.i.a + r.i.b + r.t): i32;\n"
	  "};\n",
	  55 },
	/* Mixed: inner struct surrounded by other scalar fields, with
	 * the inner appearing in the MIDDLE of the outer (non-zero
	 * outer foff for the recursion target). Pins that the helper
	 * threads `bpoff + outer_foff` correctly. All fields are i64 so
	 * the wwstage/cstage struct-layout alignment divergence (task
	 * #15, mixed i32/struct fields) doesn't bite — switch to i32
	 * once #15 lands. Sum: 100+1+2+50 = 153. */
	{ "let_nested_middle",
	  "type inner = struct { a: i64, b: i64 };\n"
	  "type outer = struct { pre: i64, i: inner, post: i64 };\n"
	  "fn main() i32 = {\n"
	  "    let o: outer = outer {\n"
	  "        pre = 100i64,\n"
	  "        i = inner { a = 1i64, b = 2i64 },\n"
	  "        post = 50i64\n"
	  "    };\n"
	  "    return (o.pre + o.i.a + o.i.b + o.post): i32;\n"
	  "};\n",
	  153 },
};

/* run_driver — compile r->src via the given driver and exec; return
 * the process exit code. Mirror of 701/702. */
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/wcns_%d_%d.ww", getpid(), i);
	snprintf(tmpdir, sizeof tmpdir, "/tmp/wcns_%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",
	    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 — generate .s via cstage's w6c and wwstage's
 * w6c_ww and diff. Mirror of 701/702. */
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/wcns_asm_%d_%d.ww", getpid(), i);
	snprintf(cs,  sizeof cs,  "/tmp/wcns_asm_%d_%d_c.s", getpid(), i);
	snprintf(ws,  sizeof ws,  "/tmp/wcns_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, "nested_structlit: 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,
				    "nested_structlit[%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,
		    "nested_structlit: %d/%d fixtures failed\n",
		    fail, total);
		return 1;
	}
	printf("nested_structlit: %d/%d ok\n", total, total);
	return 0;
}