test: port 989_ffivariadic_run to ww; retire the C carrier
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@@ -1,256 +0,0 @@
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/*
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* 989_ffivariadic_run — C1 (catB-54): a ww caller of a C variadic function
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* (`@symbol("f") fn f(a: i64, ...) f64;`) must set the SysV AL register to
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* the number of XMM regs used to pass the variadic FLOAT args. The C callee
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* gates its xmm-save-area stores on `test %al,%al`, so a wrong AL makes
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* va_arg(double) read garbage.
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*
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* THE BUG (cat-A silent miscompile, byte-id-blind): cgen.c hardcoded AL=0
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* (`XORQ AX,AX`) at the variadic-call site — correct only for a zero-float
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* variadic call. THE FIX: emit AL = the XMM cursor `fi` (the count of float
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* args placed in XMM regs). Ref SysV §3.5.7, ref/qbe/amd64/sysv.c:384.
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*
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* RUNTIME gate (byte-id can never see AL correctness): each row builds a ww
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* caller that calls the C fixture `double fixture(long n, ...)` (a
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* va_arg(double) summer, test/wcc/data/ffivariadic/fixture.c, linked from
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* libffifix.a) and asserts the returned sum. Runs on BOTH the cstage `ww`
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* and wwstage `ww_ww` drivers (C2): AL is byte-id-blind, so a wwstage fi /
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* f32-promotion divergence is caught only by a wrong runtime sum here.
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*
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* NON-VACUITY DEVIATION (reported to lead): the spec's `fixture(2,1.0,2.0)`
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* is VACUOUS on this box — with AL=0 the two skipped xmm slots happen to
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* alias stale stack that already holds 1.0/2.0, so the 2-float call returns
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* the correct 3.0 even unfixed. At 3+ floats the coincidence breaks: AL=0
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* deterministically returns the wrong sum. Every row below uses >=3 floats,
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* so reverting the fix to `XORQ AX,AX` FAILS this test (proven). A 2-float
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* row would pass both ways and prove nothing.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <errno.h>
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#include <unistd.h>
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#include <sys/stat.h>
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#include <sys/wait.h>
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static int
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runwait(const char *cmd)
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{
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int rc = system(cmd);
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if (rc == -1) return -1;
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if (WIFEXITED(rc)) return WEXITSTATUS(rc);
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return -1;
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}
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struct row {
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const char *label;
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const char *src;
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int want_exit; /* 0 == sum matched */
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};
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static const struct row rows[] = {
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/* 3 floats: 1+2+3 == 6. The smallest non-vacuous count (see header). */
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{ "three",
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"package main;\n"
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"@symbol(\"fixture\") fn fixture(n: i64, ...) f64;\n"
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"export fn main() int = {\n"
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" let r: f64 = fixture(3, 1.0, 2.0, 3.0);\n"
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" if (r == 6.0) { return 0; };\n"
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" return 1;\n"
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"};\n",
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0 },
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/* 5 floats, fewer than the 8 XMM arg regs: 1+2+3+4+5 == 15. */
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{ "five",
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"package main;\n"
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"@symbol(\"fixture\") fn fixture(n: i64, ...) f64;\n"
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"export fn main() int = {\n"
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" let r: f64 = fixture(5, 1.0, 2.0, 3.0, 4.0, 5.0);\n"
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" if (r == 15.0) { return 0; };\n"
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" return 1;\n"
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"};\n",
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0 },
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/* 8 floats == all XMM arg regs (AL caps at 8): 1+..+8 == 36. */
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{ "eight",
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"package main;\n"
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"@symbol(\"fixture\") fn fixture(n: i64, ...) f64;\n"
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"export fn main() int = {\n"
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" let r: f64 = fixture(8, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0);\n"
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" if (r == 36.0) { return 0; };\n"
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" return 1;\n"
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"};\n",
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0 },
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/* 3 f32 args (#14): C default arg promotion widens each to f64, so
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* the callee's va_arg(double) reads 1.5+2.5+3.0 == 7.0. Values are
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* exact in f32, so the f64 compare is exact. Unpromoted (MOVSS, 4B)
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* the high 4B of each 8B slot is stale stack, so va_arg(double)
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* pulls garbage and the sum misses 7.0 — this row FAILS pre-fix. */
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{ "f32three",
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"package main;\n"
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"@symbol(\"fixture\") fn fixture(n: i64, ...) f64;\n"
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"export fn main() int = {\n"
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" let r: f64 = fixture(3, 1.5: f32, 2.5: f32, 3.0: f32);\n"
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" if (r == 7.0) { return 0; };\n"
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" return 1;\n"
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"};\n",
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0 },
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/* Sharper than f32three: 0.1 is INEXACT in f32, so the f32-rounded
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* value differs from the f64 literal 0.1. The expected side `(x: f64)`
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* is the SAME f32 var widened at runtime (CVTSS2SD), so equality holds
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* iff the variadic arg carried the f32-rounded value promoted to f64 —
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* NOT the original f64 literal and NOT stale-high-bit garbage. Both a
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* no-promote (MOVSS) and a hypothetical direct-f64 pass would miss it.
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* Single f32 arg also exercises the fi==1 boundary. */
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{ "f32inexact",
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"package main;\n"
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"@symbol(\"fixture\") fn fixture(n: i64, ...) f64;\n"
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"export fn main() int = {\n"
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" let x: f32 = 0.1: f32;\n"
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" let r: f64 = fixture(1, x);\n"
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" if (r == (x: f64)) { return 0; };\n"
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" return 1;\n"
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"};\n",
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0 },
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/* Mixed f32 + f64 in one variadic call: only the f32 args (1.5, 3.5)
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* promote; the f64 arg (2.0) passes at its native width and must NOT be
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* double-promoted or skewed. 1.5+2.0+3.5 == 7.0, exact in both widths. */
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{ "f32mixed",
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"package main;\n"
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"@symbol(\"fixture\") fn fixture(n: i64, ...) f64;\n"
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"export fn main() int = {\n"
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" let r: f64 = fixture(3, 1.5: f32, 2.0, 3.5: f32);\n"
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" if (r == 7.0) { return 0; };\n"
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" return 1;\n"
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"};\n",
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0 },
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};
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/* run_build — build+run `src` via cstage `driver`, linking libffifix.a from
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* `libdir`. Returns the binary's exit code, or -1 on a build failure. */
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static int
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run_build(const char *driver, const char *libdir, const struct row *r, int i)
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{
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char src[128], tmpdir[64], outbin[128], work[160], cmd[1024];
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snprintf(tmpdir, sizeof tmpdir, "/tmp/ffivar_%d_%d", getpid(), i);
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if (mkdir(tmpdir, 0755) != 0) {
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perror(tmpdir);
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return -2;
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}
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snprintf(src, sizeof src, "%s/ffivar_%d_%d.ww", tmpdir, getpid(), i);
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snprintf(outbin, sizeof outbin, "%s/out", tmpdir);
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int result = -2, cleanfail = 0;
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FILE *f = fopen(src, "wb");
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if (!f) {
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perror(src);
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goto cleanup;
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}
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int werr = fputs(r->src, f) == EOF;
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if (fclose(f) != 0) werr = 1;
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if (werr) {
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perror(src);
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goto cleanup;
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}
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/* explicit -o so both the binary and out.sepwork land INSIDE tmpdir */
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snprintf(cmd, sizeof cmd,
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"%s build -L%s -lffifix -o %s %s 2>/dev/null",
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driver, libdir, outbin, src);
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int brc = runwait(cmd);
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int got = -1;
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if (brc == 0) got = runwait(outbin);
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result = brc == 0 ? got : -1;
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cleanup:
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if (unlink(src) != 0 && errno != ENOENT) {
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perror(src);
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cleanfail = 1;
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}
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if (unlink(outbin) != 0 && errno != ENOENT) {
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perror(outbin);
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cleanfail = 1;
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}
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snprintf(work, sizeof work, "%s.sepwork", outbin);
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snprintf(cmd, sizeof cmd, "rm -rf %s", work);
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if (runwait(cmd) != 0) {
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fprintf(stderr, "ffivariadic[%s]: cleanup failed: %s\n", r->label, work);
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cleanfail = 1;
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}
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if (rmdir(tmpdir) != 0) {
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perror(tmpdir);
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cleanfail = 1;
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}
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if (cleanfail) {
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fprintf(stderr, "ffivariadic[%s]: temporary cleanup failed\n", r->label);
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if (result == r->want_exit) result = -2;
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}
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return result;
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}
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int
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main(void)
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{
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const char *bin = getenv("BIN");
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if (!bin) bin = "out/bin";
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char absbin[1024];
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if (bin[0] != '/') {
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char cwd[1024];
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if (getcwd(cwd, sizeof cwd) == NULL) return 1;
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snprintf(absbin, sizeof absbin, "%s/%s", cwd, bin);
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bin = absbin;
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}
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char cdrv[1024], wdrv[1024], libdir[1024];
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snprintf(cdrv, sizeof cdrv, "%s/ww", bin);
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snprintf(wdrv, sizeof wdrv, "%s/ww_ww", bin);
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/* libffifix.a lives beside $(BIN) under $(OUT)/ffivariadic — the
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* Makefile builds it there as a prereq of this test binary. */
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snprintf(libdir, sizeof libdir, "%s/../ffivariadic", bin);
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/* C2: run each row on BOTH the cstage `ww` and the wwstage `ww_ww`
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* driver. AL correctness is byte-id-blind, so a wwstage fi/promotion
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* divergence is invisible to the 990-997 gates but caught here as a
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* wrong sum (nonzero exit). wwstage is access-gated like the other
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* dual-stage runtime tests (989_chainidx_run) so a cstage-only tree
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* still runs the cstage rows. */
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struct { const char *name; const char *drv; int gated; }
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drivers[] = {
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{ "cstage", cdrv, 0 },
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{ "wwstage", wdrv, 1 },
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{ NULL, NULL, 0 },
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};
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int n = (int)(sizeof rows / sizeof rows[0]);
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int total = 0, fail = 0;
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for (int d = 0; drivers[d].name; d++) {
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if (drivers[d].gated && access(drivers[d].drv, X_OK) != 0) {
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fprintf(stderr, "ffivariadic: skip %s (no %s)\n",
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drivers[d].name, drivers[d].drv);
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continue;
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}
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for (int i = 0; i < n; i++) {
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total++;
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int got = run_build(drivers[d].drv, libdir, &rows[i], i);
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if (got != rows[i].want_exit) {
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fprintf(stderr,
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"ffivariadic[%s][%s]: exit=%d want=%d\n",
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drivers[d].name, rows[i].label, got,
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rows[i].want_exit);
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fail++;
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}
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}
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}
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if (fail) {
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fprintf(stderr, "ffivariadic: %d/%d fixtures failed\n",
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fail, total);
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return 1;
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}
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printf("ffivariadic: %d/%d ok\n", total, total);
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return 0;
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}
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