ww/test/wcc/758_cgalloc_str_field.c

/*
 * 758_cgalloc_str_field — cgalloc N_STRUCTLIT str-field store (task #22).
 *
 * Pre-fix: wwstage cgalloc's per-field walk routed str-typed fields
 * through the generic `MOVQ (SP), BX ; MOVQ AX, foff(BX)` path, which
 * landed only AX (str.ptr) and clobbered BX (str.len) with the heap
 * base. str.len silently stayed zero (rt_alloc is MAP_ANON-backed, so
 * the slot was zero-init rather than garbage — but still wrong). 990
 * and 995 byte-identity didn't catch this because nothing in the
 * bootstrapped selfhost source uses `alloc(T { strfield = "..." })!`.
 *
 * Fix: a str-field-typed branch mirrors cmd/w6c/cgen.c:4184-4190 —
 * route the heap base through CX so BX=len survives both stores
 * (ptr at foff+0, len at foff+8). Task #23 (slice/tagged/fn-pair
 * multi-word fields) is the broader follow-up; this row pins str.
 *
 * Each row runs the generated binary under cstage and (when present)
 * wwstage; the exit code is the regression-catching gate. The cstage
 * row is the cross-check oracle.
 *
 * Byte-identity is intentionally NOT checked here. cgalloc N_STRUCTLIT
 * already diverges on two pre-existing axes that 995_self_rebuild
 * doesn't exercise because selfhost source uses amalloc, never
 * `alloc(T{...})!`:
 *   - `CALL alloc(SB)` (cstage, via ffi_resolve) vs `CALL rt_alloc(SB)`
 *     (wwstage, hardcoded symbol).
 *   - `(BX)` (cstage txt.c omits zero displacement) vs `0(BX)`
 *     (wwstage emitint(0) is unconditional). The new str branch
 *     follows the existing float / int branch shape and inherits the
 *     same formatting; aligning all three with cstage is a separate
 *     follow-up.
 */
#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[] = {
	/* Singleton str field. Pre-fix p.s.len stayed 0; post-fix 5. */
	{ "alloc_str_singleton",
	  "package main;\n"
	  "import os;\n"
	  "type holder = struct { s: str };\n"
	  "fn main() i32 = {\n"
	  "    let p: *holder = alloc(holder { s = \"hello\" })!;\n"
	  "    return p.s.len;\n"
	  "};\n",
	  5 },
	/* i32 field before str. Verifies field iteration restarts cleanly
	 * after the str-field branch and that the i32 store path is
	 * unaffected. Pre-fix: 100 + 0 = 100; post-fix: 100 + 2 = 102. */
	{ "alloc_i32_then_str",
	  "package main;\n"
	  "import os;\n"
	  "type holder = struct { n: i32, s: str };\n"
	  "fn main() i32 = {\n"
	  "    let p: *holder = alloc(holder { n = 100, s = \"hi\" })!;\n"
	  "    return p.n + p.s.len;\n"
	  "};\n",
	  102 },
	/* str field before i32. Verifies foff>0 routing for the trailing
	 * i32 store after the str-field branch. Pre-fix: 0 + 7 = 7;
	 * post-fix: 5 + 7 = 12. */
	{ "alloc_str_then_i32",
	  "package main;\n"
	  "import os;\n"
	  "type holder = struct { s: str, n: i32 };\n"
	  "fn main() i32 = {\n"
	  "    let p: *holder = alloc(holder { s = \"world\", n = 7 })!;\n"
	  "    return p.s.len + p.n;\n"
	  "};\n",
	  12 },
	/* Two str fields. Pre-fix both lens stayed 0; post-fix 3 + 6 = 9.
	 * Pins that `fi = nil` advances correctly between str fields. */
	{ "alloc_two_str",
	  "package main;\n"
	  "import os;\n"
	  "type holder = struct { a: str, b: str };\n"
	  "fn main() i32 = {\n"
	  "    let p: *holder = alloc(holder { a = \"foo\", b = \"barbaz\" })!;\n"
	  "    return p.a.len + p.b.len;\n"
	  "};\n",
	  9 },
	/* Float-then-str-then-int. Pre-fix str.len=0 so result is
	 * 0 + 10 = 10; post-fix 3 + 10 = 13. Confirms the str-field
	 * branch slots between the existing float and integer branches
	 * without disrupting either. */
	{ "alloc_f64_str_i32",
	  "package main;\n"
	  "import os;\n"
	  "type holder = struct { f: f64, s: str, n: i32 };\n"
	  "fn main() i32 = {\n"
	  "    let p: *holder = alloc(holder { f = 1.5f64, s = \"abc\", n = 10 })!;\n"
	  "    return p.s.len + p.n;\n"
	  "};\n",
	  13 },
	/* Read-back via p.s[i]: confirms str.ptr survived the store
	 * (foff=0 case) while still pinning str.len. Pre-fix len=0 so
	 * the loop body never executes; post-fix sum is 'h'+'i' = 209.
	 * Indexes the string by hand to avoid pulling in stdlib. */
	{ "alloc_str_readback",
	  "package main;\n"
	  "import os;\n"
	  "type holder = struct { s: str };\n"
	  "fn main() i32 = {\n"
	  "    let p: *holder = alloc(holder { s = \"hi\" })!;\n"
	  "    let sum: i32 = 0;\n"
	  "    let i: i32 = 0;\n"
	  "    for (i < p.s.len) {\n"
	  "        sum += p.s[i]: i32;\n"
	  "        i += 1;\n"
	  "    };\n"
	  "    return sum;\n"
	  "};\n",
	  209 },
};

/* run_driver — compile r->src via the given driver and exec; return
 * the process exit code. Mirror of 703/704. */
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/wcas_%d_%d.ww", getpid(), i);
	snprintf(tmpdir, sizeof tmpdir, "/tmp/wcas_%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;
}

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, "cgalloc_str_field: 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,
				    "cgalloc_str_field[%s][%s]: exit=%d want=%d\n",
				    drivers[d].name, rows[i].label,
				    got, rows[i].want);
				fail++;
			}
		}
	}

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