/*
 * 947_deref_narrow_run — runtime + byte-id net for #116: an integer
 * pointer deref must read its pointee's actual width, not a fixed 8B
 * MOVQ. Before #116 the TK_STAR integer arm in cgen.c:2318 / cgenexpr
 * .ww:2834 emitted a raw `MOVQ (AX), AX` regardless of pointee size,
 * so `*p` over a packed `*i32` / `*u32` / `*iN` slot pulled the next
 * 4–7 bytes into the high half of RAX. Truncating sinks (i32 store,
 * i32 return) dropped the garbage; width-preserving sinks (CMPQ vs
 * an i32 literal, 64-bit arith) saw it. The fix routes the load
 * through localloadop(n->type), the same MOVSXD/MOVSWQ/MOVSBQ +
 * MOVL/MOVZWQ/MOVZBQ dispatch already shared by IDENT / DOT / index
 * loads (cgen.c:264 fldloadop, :372 localloadop; cgenutil.ww:884
 * loadopsz, :904 localloadop). Load-twin of the landed signed-narrow
 * scalar-reads sweep (selfhost/CLAUDE.md "Signed-narrow scalar reads
 * sign-extend honestly") — TK_STAR was the omitted site.
 *
 * Each row carries (a) a cstage `ww build` + run asserting the exit
 * code (the i32_cmpq row would return 2 pre-fix), and (b) a w6c vs
 * w6c_ww `.s` cmp (rule-10 byte-id) — the gate-blind family discipline
 * the rest of the suite enforces. The aliased-narrow row exercises the
 * TY_NAMED / TBANG peel in localloadop's tinfo lookup.
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/wait.h>

#define RUN_SKIP (-1)

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_exit; };

static const struct row rows[] = {
	/* The #116 repro: packed *i32 deref with a CMPQ-width sink (the
	 * `if (*p != 20i32)` comparator widens the i32 literal to 8B and
	 * compares with CMPQ). Pre-fix MOVQ pulled buf[1] | (buf[2]<<32)
	 * into AX, the compare failed, exit=2. */
	{ "i32_cmpq",
	  "package main;\n"
	  "export fn main() i32 = {\n"
	  "	let buf: [4]i32 = [10, 20, 30, 40];\n"
	  "	let p: *i32 = &buf[1];\n"
	  "	if (*p != 20) { return 2; };\n"
	  "	return 0;\n"
	  "};\n", 0 },
	/* *u32 — zero-extend (MOVL r/m32,r32 zeroes upper 32). 0xFFFFFFFF
	 * round-trips intact only if the read is u32-wide and zero-
	 * extended. Pre-fix MOVQ overlapped the next slot — and even with
	 * a tail-element so there's no spill, the value compared against
	 * 0xFFFFFFFFu32 (widened to 64B) would carry whatever
	 * uninitialised stack lives at buf+12. */
	{ "u32_zeroext",
	  "package main;\n"
	  "export fn main() i32 = {\n"
	  "	let buf: [3]u32 = [10u32, 20u32, 0xFFFFFFFFu32];\n"
	  "	let p: *u32 = &buf[2];\n"
	  "	if (*p != 0xFFFFFFFFu32) { return 2; };\n"
	  "	return 0;\n"
	  "};\n", 0 },
	/* *u8 — narrowest unsigned, MOVZBQ. */
	{ "u8_zeroext",
	  "package main;\n"
	  "export fn main() i32 = {\n"
	  "	let buf: [3]u8 = [10u8, 20u8, 0xFFu8];\n"
	  "	let p: *u8 = &buf[2];\n"
	  "	if (*p != 0xFFu8) { return 2; };\n"
	  "	return 0;\n"
	  "};\n", 0 },
	/* *i8 — signed-narrow, MOVSBQ. -2i8 must sign-extend to -2i32
	 * through the explicit cast; a raw MOVQ would leave the upper
	 * bytes as the next two array slots and a subsequent `: i32`
	 * cast would still read the low byte correctly — so the cast
	 * acts as the truncating sink. The compare against -2i32 widens
	 * to 64B (CMPQ) so the sign-extension must happen on the load. */
	{ "i8_signext",
	  "package main;\n"
	  "export fn main() i32 = {\n"
	  "	let buf: [3]i8 = [-1i8, -2i8, -3i8];\n"
	  "	let p: *i8 = &buf[1];\n"
	  "	let v: i32 = (*p): i32;\n"
	  "	if (v != -2i32) { return 2; };\n"
	  "	return 0;\n"
	  "};\n", 0 },
	/* Aliased signed-narrow: `type err = !i32; *err`. The TY_NAMED /
	 * TBANG peel in localloadop's tinfofornode chain must reach the
	 * underlying i32 width for the MOVSXD opcode to fire. Base is a
	 * struct field (not an array literal) to dodge a pre-existing
	 * cs/ww divergence in [N]alias array-init store width — out of
	 * scope for #116. */
	{ "alias_signext",
	  "package main;\n"
	  "type err = !i32;\n"
	  "type box = struct { v: err };\n"
	  "export fn main() i32 = {\n"
	  "	let b: box = box { v = -7i32: err };\n"
	  "	let p: *err = &b.v;\n"
	  "	let r: i32 = (*p): i32;\n"
	  "	if (r != -7i32) { return 2; };\n"
	  "	return 0;\n"
	  "};\n", 0 },
	/* *bool — also 1B (MOVZBQ); same dispatch shape but worth a
	 * control since the bool branch in fld_issigned returns 0
	 * explicitly. */
	{ "bool_ctrl",
	  "package main;\n"
	  "export fn main() i32 = {\n"
	  "	let buf: [3]bool = [true, false, true];\n"
	  "	let p: *bool = &buf[1];\n"
	  "	if (*p) { return 2; };\n"
	  "	return 0;\n"
	  "};\n", 0 },
	/* *i16 — MOVSWQ. Struct-field base (with a NEXT byte set so the
	 * pre-fix MOVQ pulls non-zero high bytes and the 64B CMPQ fails),
	 * sidestepping the same `[N]i16` array-init store-width concern as
	 * the alias_signext row. */
	{ "i16_signext",
	  "package main;\n"
	  "type box = struct { v: i16, m: u16 };\n"
	  "export fn main() i32 = {\n"
	  "	let b: box = box { v = -200i16, m = 0xABCDu16 };\n"
	  "	let p: *i16 = &b.v;\n"
	  "	let r: i32 = (*p): i32;\n"
	  "	if (r != -200i32) { return 2; };\n"
	  "	return 0;\n"
	  "};\n", 0 },
	/* *u16 — MOVZWQ. Same struct-field shape; #128 ([N]u16 array-init
	 * cs/ww store-width divergence) is unrelated to this fold. */
	{ "u16_zeroext",
	  "package main;\n"
	  "type box = struct { v: u16, m: u16 };\n"
	  "export fn main() i32 = {\n"
	  "	let b: box = box { v = 0xFFFFu16, m = 0xABCDu16 };\n"
	  "	let p: *u16 = &b.v;\n"
	  "	if (*p != 0xFFFFu16) { return 2; };\n"
	  "	return 0;\n"
	  "};\n", 0 },
	/* Enum-aliased narrow: `type flag = enum i8 { ... }`. The TY_NAMED
	 * /TY_ENUM peel in typeissigned (lib/ww/typ.ww:390 → typeisunsigned
	 * → TY_ENUM recurse on sub) + tinfo.size on the NAMED wrapper must
	 * land on MOVSBQ. Distinct from the TBANG row above — same recursion
	 * shape but a different tykind branch. Struct-field base dodges the
	 * sibling-of-#128 [N]alias array-init concern. */
	{ "enum_signext",
	  "package main;\n"
	  "type flag = enum i8 { A = -2i8, B = 1i8 };\n"
	  "type box = struct { v: flag, m: u8 };\n"
	  "export fn main() i32 = {\n"
	  "	let b: box = box { v = flag.A, m = 0xABu8 };\n"
	  "	let p: *flag = &b.v;\n"
	  "	let r: i32 = ((*p): i8): i32;\n"
	  "	if (r != -2i32) { return 2; };\n"
	  "	return 0;\n"
	  "};\n", 0 },
	/* *i64 control — MUST still emit MOVQ (no shift). Regression
	 * guard: a width-correct case shouldn't be perturbed. */
	{ "i64_ctrl",
	  "package main;\n"
	  "export fn main() i32 = {\n"
	  "	let buf: [3]i64 = [100i64, 200i64, 300i64];\n"
	  "	let p: *i64 = &buf[1];\n"
	  "	if (*p != 200i64) { return 2; };\n"
	  "	return 0;\n"
	  "};\n", 0 },
	{ NULL, NULL, 0 }
};

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);
		int cb = fgetc(fb);
		if (ca != cb) { rc = -1; break; }
		if (ca == EOF) break;
	}
	fclose(fa); fclose(fb);
	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 w6c[1100], w6c_ww[1100];
	snprintf(w6c, sizeof w6c, "%s/w6c", bin);
	snprintf(w6c_ww, sizeof w6c_ww, "%s/w6c_ww", bin);
	if (access(w6c_ww, X_OK) != 0) {
		fprintf(stderr, "derefnarrow: w6c_ww missing — cannot run the "
		    "cs==ww byte-id gate (the whole point of this test)\n");
		return 1;
	}

	int n = 0, fail = 0;
	for (int i = 0; rows[i].src; i++, n++) {
		char src[64];
		snprintf(src, sizeof src, "/tmp/wwdrn_%d_%d.ww", getpid(), i);
		FILE *f = fopen(src, "wb");
		if (f == NULL) { fail++; continue; }
		fputs(rows[i].src, f);
		fclose(f);

		/* (a) cstage build + run. */
		if (rows[i].want_exit != RUN_SKIP) {
			char tmpdir[64];
			snprintf(tmpdir, sizeof tmpdir, "/tmp/wwdrn_%d_d_%d",
			    getpid(), i);
			mkdir(tmpdir, 0755);

			char cmd[2048];
			snprintf(cmd, sizeof cmd, "cd %s && %s/ww build %s",
			    tmpdir, bin, src);
			if (runwait(cmd) != 0) {
				fprintf(stderr, "row[%s]: cstage build failed\n",
				    rows[i].label);
				fail++;
				unlink(src); rmdir(tmpdir);
				continue;
			}

			char outbin[128];
			const char *base = strrchr(src, '/');
			base = base ? base + 1 : src;
			snprintf(outbin, sizeof outbin, "%s/%s", tmpdir, base);
			char *dot = strrchr(outbin, '.');
			if (dot && strcmp(dot, ".ww") == 0) *dot = '\0';

			int got = runwait(outbin);
			if (got != rows[i].want_exit) {
				fprintf(stderr, "row[%s]: cstage exit %d, want %d\n",
				    rows[i].label, got, rows[i].want_exit);
				fail++;
			}
			unlink(outbin); rmdir(tmpdir);
		}

		/* (b) cs==ww byte-id gate. */
		char cs_s[64], ws_s[64];
		snprintf(cs_s, sizeof cs_s, "/tmp/wwdrn_%d_%d_cs.s",
		    getpid(), i);
		snprintf(ws_s, sizeof ws_s, "/tmp/wwdrn_%d_%d_ww.s",
		    getpid(), i);

		char cmd[2048];
		snprintf(cmd, sizeof cmd, "%s -o %s %s 2>/dev/null",
		    w6c, cs_s, src);
		if (runwait(cmd) != 0) {
			fprintf(stderr, "row[%s]: w6c failed\n", rows[i].label);
			fail++; unlink(src); continue;
		}
		snprintf(cmd, sizeof cmd, "%s -o %s %s 2>/dev/null",
		    w6c_ww, ws_s, src);
		if (runwait(cmd) != 0) {
			fprintf(stderr, "row[%s]: w6c_ww failed\n",
			    rows[i].label);
			fail++; unlink(src); unlink(cs_s); continue;
		}
		if (slurp_eq(cs_s, ws_s) != 0) {
			fprintf(stderr,
			    "row[%s]: cstage/wwstage .s DIFFER (rule-10 "
			    "byte-id violation)\n", rows[i].label);
			fail++;
		}
		unlink(src); unlink(cs_s); unlink(ws_s);
	}

	if (fail) {
		fprintf(stderr, "%d/%d narrow-deref tests failed\n",
		    fail, n);
		return 1;
	}
	printf("derefnarrow: %d/%d ok (cstage run + cs==ww byte-id)\n",
	    n, n);
	return 0;
}