ww/test/wcc/962_opaque_assign_cast_run.c

/*
 * 962_opaque_assign_cast_run — runtime + byte-id proof of #108 sub-fold
 * (c): opaque as a type-erasure sink. Two assignability rules + the
 * reinterpret casts sort's implementation relies on.
 *
 *   rule 1  `*T -> *opaque`  IMPLICIT (no cast). Any pointer is the
 *           universal void-pointer. harec type_is_assignable, pointer
 *           arm: ref/harec/src/types.c:1053 (`case STORAGE_OPAQUE:
 *           break;` — the referent need not match).
 *   rule 2  `[]T -> []opaque` IMPLICIT (no cast). Any slice is the
 *           type-erased slice; the {ptr,len,cap} header is normal,
 *           the byte stride is supplied at runtime (itemsz). harec
 *           slice arm: types.c:1094 (`if (to_secondary->storage ==
 *           STORAGE_OPAQUE) return true;`).
 *   casts   `[]opaque -> *u8` (slice -> byte ptr; cgexpr leaves the
 *           ptr in AX, so the cast naturally takes .ptr) and
 *           `*opaque -> *u8` / `*opaque -> *i32` (ptr->ptr reinterpret,
 *           a no-op). drew described the Hare idiom as `*[*]u8`; ww has
 *           no unbounded-array `[*]`, so the ww-faithful reinterpret
 *           target is `*u8` + uintptr stride arithmetic.
 *
 * Rule-10 placement (per-rule, empirical):
 *   rules 1 & 2 are CSTAGE-ONLY. cstage type_assignable (cmd/wcc/
 *   type.c) gained the opaque sink; the wwstage check.ww isassignable
 *   is a resolve-only AST approximation that returns "can't tell, stay
 *   quiet" (confident=false) for a ptr/slice whose element it cannot
 *   match, so it already ACCEPTS every form here (let-init AND call-
 *   arg). Verified empirically: w6c_ww compiles each row's source with
 *   exit 0, byte-identically to w6c (the cs==ww gate below). cstage
 *   rejected these before the type.c change. No ww twin is needed
 *   (same align-down precedent as 960/961's cstage-only arms).
 *   The casts are validation-free in BOTH stages (N_CAST never checks
 *   legality) and the reinterpret cgen needed no change — proven by
 *   the cs==ww byte-id gate.
 *
 * Array->[]opaque (harec's array->slice decay, types.c:1080-1099) is
 * deliberately EXCLUDED: ww has no implicit array->slice conversion for
 * any element type (`let s: []i32 = a` is rejected too — a slice is
 * built only via an explicit `a[0:n]`), so there is no array->slice-
 * header cgen. Accepting array->[]opaque alone would assign a fat
 * array local into a 24-byte slot with no decay: a silent miscompile
 * (rule 7). sort's caller passes a slice, so slice->[]opaque suffices.
 *
 * opaque is unused by the bootstrap, so the new rules fire only on
 * opaque-typed operands — INERT on the selfhost corpus, 990-997 stay
 * byte-identical. But that same inertness means the 990-997 gates
 * never exercise opaque cs==ww; this test carries its own w6c-vs-w6c_ww
 * byte-id gate (dimension (b)) to cover the rule-10 symmetry directly.
 *
 * Each row carries BOTH dimensions, like 953_f64crossmod_run:
 *   (a) cstage `ww build` + run, asserting the exit code — pins that
 *       the converged asm is runtime-correct (the type erasure round-
 *       trips: a value written/read through the opaque path reads back
 *       intact).
 *   (b) w6c vs w6c_ww `.s` cmp — FAILS if the stages diverge.
 *
 * NOTE — call results are bound to locals before any comparison, never
 * compared inline (`if (f(x) != k)`). That inline-call-result-in-
 * comparison shape is mis-compiled by a PRE-EXISTING cgen bug (#116
 * family: reproduced with zero opaque — a fn-call result compared
 * inline when its pointer arg was produced by a prior call doing
 * uintptr arithmetic). Binding first is the same dodge 960 uses; it is
 * NOT a workaround for the opaque feature, which is exercised in full.
 */
#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;
}

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;
}

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

static const struct row rows[] = {
	/* rule 1: `*T -> *opaque` IMPLICIT (no cast) at a let-init AND a
	 * call-arg. Round-trip a real *i32 through *opaque and back, deref. */
	{ "rule1_implicit_ptr",
	  "package main;\n"
	  "fn readi32(p: *opaque) i32 = { let pi: *i32 = p: *i32; return *pi; };\n"
	  "export fn main() i32 = {\n"
	  "	let n: i32 = 42;\n"
	  "	let po: *opaque = &n;\n"		/* let-init  *i32 -> *opaque */
	  "	let v: i32 = readi32(po);\n"
	  "	let v2: i32 = readi32(&n);\n"		/* call-arg  *i32 -> *opaque */
	  "	if (v != 42) { return 1; };\n"
	  "	if (v2 != 42) { return 2; };\n"
	  "	return v;\n"
	  "};\n", 42 },
	/* rule 2: `[]T -> []opaque` IMPLICIT (no cast) at a let-init AND a
	 * call-arg. Read .len, round-trip .ptr (a *opaque) back to *i32. */
	{ "rule2_implicit_slice",
	  "package main;\n"
	  "fn slen(o: []opaque) i32 = { return o.len: i32; };\n"
	  "fn first(o: []opaque) i32 = { let p: *opaque = o.ptr; let pi: *i32 = p: *i32; return *pi; };\n"
	  "export fn main() i32 = {\n"
	  "	let a: [4]i32 = [11, 22, 33, 44];\n"
	  "	let s: []i32 = a[0:4];\n"
	  "	let o: []opaque = s;\n"			/* let-init  []i32 -> []opaque */
	  "	let n: i32 = slen(o);\n"
	  "	let n2: i32 = slen(s);\n"		/* call-arg  []i32 -> []opaque */
	  "	if (n != 4) { return 1; };\n"
	  "	if (n2 != 4) { return 2; };\n"
	  "	let f: i32 = first(s);\n"
	  "	if (f != 11) { return 3; };\n"
	  "	return n;\n"
	  "};\n", 4 },
	/* sort's actual usage end-to-end: a `fn(items: []opaque, itemsz:
	 * size)` called with a []i32; inside, reinterpret the slice as a
	 * byte base (`items: *u8`), uintptr-arith two element addresses,
	 * byte-swap them by itemsz. Then read back through the *opaque
	 * element path and through the original []i32 view — the type
	 * erasure round-trips iff both agree. Also a *opaque arg straight
	 * from a *i32 (rule 1). exit 0 == every assertion held. */
	{ "sort_pattern",
	  "package main;\n"
	  "fn elemptr(items: []opaque, i: size, itemsz: size) *opaque = {\n"
	  "	let base: *u8 = items: *u8;\n"		/* []opaque -> *u8 (takes .ptr) */
	  "	let off: uintptr = (i * itemsz): uintptr;\n"
	  "	return ((base: uintptr) + off): *opaque;\n"
	  "};\n"
	  "fn swap(items: []opaque, x: size, y: size, itemsz: size) void = {\n"
	  "	let pa: *u8 = elemptr(items, x, itemsz): *u8;\n"
	  "	let pb: *u8 = elemptr(items, y, itemsz): *u8;\n"
	  "	let k: size = 0;\n"
	  "	for (k < itemsz) {\n"
	  "		let qa: *u8 = ((pa: uintptr) + k: uintptr): *u8;\n"
	  "		let qb: *u8 = ((pb: uintptr) + k: uintptr): *u8;\n"
	  "		let t: u8 = *qa;\n"
	  "		*qa = *qb;\n"
	  "		*qb = t;\n"
	  "		k = k + 1;\n"
	  "	};\n"
	  "};\n"
	  "fn readi32(p: *opaque) i32 = { let pi: *i32 = p: *i32; return *pi; };\n"
	  "export fn main() i32 = {\n"
	  "	let a: [4]i32 = [10, 20, 30, 40];\n"
	  "	let s: []i32 = a[0:4];\n"
	  "	swap(s, 0: size, 3: size, size(i32));\n"  /* []i32 -> []opaque call-arg */
	  "	if (a[0] != 40) { return 1; };\n"	/* erased swap round-trips */
	  "	if (a[3] != 10) { return 2; };\n"
	  "	let p0: *opaque = elemptr(s, 0: size, size(i32));\n"
	  "	let v0: i32 = readi32(p0);\n"
	  "	if (v0 != 40) { return 3; };\n"
	  "	let nn: i32 = 77;\n"
	  "	let pn: *opaque = &nn;\n"		/* *i32 -> *opaque let-init */
	  "	let vn: i32 = readi32(pn);\n"
	  "	if (vn != 77) { return 4; };\n"
	  "	let o: []opaque = s;\n"
	  "	let ol: i32 = o.len: i32;\n"
	  "	if (ol != 4) { return 5; };\n"
	  "	return 0;\n"
	  "};\n", 0 },
	{ NULL, NULL, 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 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, "opaque_assign_cast: w6c_ww missing — cannot "
		    "run the cs==ww byte-id gate (the rule-10 proof)\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/wwopqc_%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 in a scratch dir. */
		char tmpdir[64];
		snprintf(tmpdir, sizeof tmpdir, "/tmp/wwopqc_%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: emit .s from both stages, cmp. */
		char cs_s[64], ws_s[64];
		snprintf(cs_s, sizeof cs_s, "/tmp/wwopqc_%d_%d_cs.s",
		    getpid(), i);
		snprintf(ws_s, sizeof ws_s, "/tmp/wwopqc_%d_%d_ww.s",
		    getpid(), i);

		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 opaque assign/cast tests failed\n",
		    fail, n);
		return 1;
	}
	printf("opaque_assign_cast: %d/%d ok (cstage run + cs==ww byte-id)\n",
	    n, n);
	return 0;
}