ww/test/wcc/907_f32arg_run.c

/*
 * 907_f32arg_run — runtime + byte-id regression net for #143: passing an
 * f32 as a function argument must spill through the stack at the f32 class
 * width (MOVSS, 4-byte), not MOVSD (8-byte). cstage lowered the arg-push
 * (cgen.c N_CALL push) and arg-pop (the pop-into-XMM loop) with a hardcoded
 * MOVSD; wwstage already split f32/f64 via exprfloatkind (MOVSS for f32).
 * The result was a cs!=ww byte-id break on EVERY f32 argument — a pure
 * divergence, not a runtime miscompile (the callee reads its f32 param as
 * the low 32 bits via MOVSS regardless of how the caller spilled it), but
 * it blocked the cs==ww gate and therefore fold-5b (strconv f32tos, whose
 * core calls math.f32bits(n) — an f32 arg).
 *
 * ABI-correct form is MOVSS for single precision per SysV: ref/qbe
 * amd64/emit.c:524 — the slot->slot copy-through-XMM path (exactly ww's
 * X0 -> 8B stack slot -> XMMn arg-spill shape) narrows the class to Ks for
 * non-wide floats and emits movss (clstoa[Ks] == "ss"); movsd is the
 * double (Kd) form. The fix aligns cstage UP to MOVSS via the existing
 * op_for(node_isf32) helper at both the push and pop sites. wwstage is
 * unchanged. This is the f32-arg-push half of the float-register family
 * (#119 f32-arr-load, #122 f32-arr-store, #125 float-arr-index, #157
 * tagged-float-return) — "f32 must route through the right XMM width."
 *
 * Each row carries BOTH dimensions (like 955 / 964 / 965):
 *   (a) cstage `ww build` + run, asserting the exit code (end-to-end ABI:
 *       the callee must read the correct f32 value out of the XMM reg).
 *   (b) w6c vs w6c_ww `.s` cmp — FAILS if the stages diverge (rule-10).
 *
 * The 990-997 byte-id gates are BLIND to a reintroduction here only if the
 * gated selfhost tools never pass an f32 arg (they don't — bootstrap-
 * NEUTRAL), so this executed-and-byte-id-checked probe is the live net.
 */
#include <stdio.h>
#include <stdlib.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_exit; };

static const struct row rows[] = {
	/* single f32 var arg — the minimal repro. takef32(2.5) -> 2.5,
	 * truncated to i32 == 2. On the bug the byte-id breaks (MOVSD push)
	 * but the value still rounds (MOVSD carries the low 4 bytes too). */
	{ "single_var",
	  "package main;\n"
	  "fn takef32(x: f32) f32 = { return x; };\n"
	  "export fn main() i32 = {\n"
	  "	let a: f32 = 2.5f32;\n"
	  "	let r: f32 = takef32(a);\n"
	  "	return r: i32;\n"
	  "};\n", 2 },
	/* f32 LITERAL directly as the arg (ken's original getj(1.0f32)
	 * shape that surfaced #143). id(3.0f32) -> 3.0 -> 3. */
	{ "literal_arg",
	  "package main;\n"
	  "fn id(x: f32) f32 = { return x; };\n"
	  "export fn main() i32 = {\n"
	  "	let r: f32 = id(3.0f32);\n"
	  "	return r: i32;\n"
	  "};\n", 3 },
	/* multiple f32 args — each pushed/popped independently; all must
	 * use MOVSS on both stages. 1.5 + 2.5 + 4.0 == 8.0 (exact in f32). */
	{ "multi_f32",
	  "package main;\n"
	  "fn add3(a: f32, b: f32, c: f32) f32 = { return a + b + c; };\n"
	  "export fn main() i32 = {\n"
	  "	let x: f32 = 1.5f32;\n"
	  "	let y: f32 = 2.5f32;\n"
	  "	let z: f32 = 4.0f32;\n"
	  "	let r: f32 = add3(x, y, z);\n"
	  "	return r: i32;\n"
	  "};\n", 8 },
	/* f32 + f64 MIX — the f64 arg must stay MOVSD (8-byte), the f32 args
	 * MOVSS (4-byte), and BOTH stages must agree per-arg. 1.5 + 10.0 +
	 * 0.5 == 12.0 (exact). Guards against the fix over-reaching to f64. */
	{ "mixed_f32_f64",
	  "package main;\n"
	  "fn mix(a: f32, b: f64, c: f32) f64 = "
	  "{ return a: f64 + b + c: f64; };\n"
	  "export fn main() i32 = {\n"
	  "	let p: f32 = 1.5f32;\n"
	  "	let q: f64 = 10.0;\n"
	  "	let s: f32 = 0.5f32;\n"
	  "	let r: f64 = mix(p, q, s);\n"
	  "	return r: i32;\n"
	  "};\n", 12 },
	/* STACK-passed f32: 10 float args — 8 ride X0..X7, args 9+10 stay on
	 * the stack (fpidx >= 8). The push-spill still diverged on the bug;
	 * this exercises the fpidx>=8 leave-on-stack arm. 1.0 * 10 == 10.0. */
	{ "stack_passed",
	  "package main;\n"
	  "fn ten(a: f32, b: f32, c: f32, d: f32, e: f32, f: f32, "
	  "g: f32, h: f32, i: f32, j: f32) f32 = {\n"
	  "	return a + b + c + d + e + f + g + h + i + j;\n"
	  "};\n"
	  "export fn main() i32 = {\n"
	  "	let v: f32 = 1.0f32;\n"
	  "	let r: f32 = ten(v, v, v, v, v, v, v, v, v, v);\n"
	  "	return r: i32;\n"
	  "};\n", 10 },
	{ 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, "f32arg: 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 tmpdir[64];
		snprintf(tmpdir, sizeof tmpdir, "/tmp/wwf32a_%d_d_%d",
		    getpid(), i);
		mkdir(tmpdir, 0755);

		char src[128], outbin[128], rmcmd[160];
		snprintf(src, sizeof src, "%s/wwf32a_%d_%d.ww",
		    tmpdir, getpid(), i);
		snprintf(outbin, sizeof outbin, "%s/wwf32a_%d_%d",
		    tmpdir, getpid(), i);
		snprintf(rmcmd, sizeof rmcmd, "rm -rf %s", tmpdir);

		FILE *f = fopen(src, "wb");
		if (f == NULL) { fail++; runwait(rmcmd); continue; }
		fputs(rows[i].src, f);
		fclose(f);

		/* (a) cstage build + run. */
		char cmd[2048];
		snprintf(cmd, sizeof cmd, "%s/ww build -o %s %s",
		    bin, outbin, src);
		if (runwait(cmd) != 0) {
			fprintf(stderr, "row[%s]: cstage build failed\n",
			    rows[i].label);
			fail++;
			runwait(rmcmd);
			continue;
		}

		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++;
		}

		/* (b) cs==ww byte-id gate: emit .s from both stages, cmp. */
		char cs_s[128], ws_s[128];
		snprintf(cs_s, sizeof cs_s, "%s/wwf32a_%d_%d_cs.s",
		    tmpdir, getpid(), i);
		snprintf(ws_s, sizeof ws_s, "%s/wwf32a_%d_%d_ww.s",
		    tmpdir, 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++; runwait(rmcmd); 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++; runwait(rmcmd); 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++;
		}
		runwait(rmcmd);
	}

	if (fail) {
		fprintf(stderr, "%d/%d f32-arg-push tests failed\n", fail, n);
		return 1;
	}
	printf("f32arg: %d/%d ok (cstage run + cs==ww byte-id)\n", n, n);
	return 0;
}